Some recent threads rekindled my interest in Joe Davisson's circuits, the first thing I threw on the board was his original Vulcan and it sounded great.
Lots of range from sparkly to saturated, tons of extra volume available. I decided the first thing to add was a simple Rat Filter, then some extra clipping diodes on a switch.
I also added a resistor (5K6 R20) to keep the distortion control from going all the way off.
Finally some tone changing filter caps to block some unwanted noise and radio stations and these are the caps in question.
:icon_question: C11 (2n2) helped block unwanted extra noise coming in and changed the tone in a nice way but is there another way to do the same thing here? What have I done here? It sounds good, so is it good?
:icon_question: C7 (47p) blocks out the radio station and doesn't seem to have any affect on the overall tone, but it works anywhere between C2 and C4. Is there any "best" place to put it?
All diodes are 1N914 and transistors are 2N5088
(https://s17.postimg.org/g5saghcin/Vulcan_Rat_Scheme.png)
Looks great Ben.
Can't wait to hear it.
Is it still at the breadboard stage?
There's a few tricks you could try maybe.
Lookie here
https://dl.dropboxusercontent.com/u/7464107/Bogner%20Ecstasy%20schematic.pdf
A jfet xtc emulation schematic.
From this post
http://www.diystompboxes.com/smfforum/index.php?topic=86151.0
Look at the values C1
C3 is a neat trick too
Just throwing it out there.
Cool, thanks Rich. I liked this one so much that it went from BB to completed pedal in 2 days. I still have a BB layout going to tinker with as well.
This circuit has a great range of tones and it's very sensitive/dynamic/whatever.. sounds like a tube amp is what I'm saying I guess.
I thought about the SWTC for this but it has so much expendable volume that the RAT Filter is just fine and it fits the layout easier.
I will try to make a vid when I get a chance
Cool man.
I used a variation of this in my B52 emu
http://www.muzique.com/lab/tone3.htm
There's a demo here
http://www.diystompboxes.com/smfforum/index.php?topic=111869.msg1030599#msg1030599
> C11 (2n2) ...What have I done here?
Loaded-down the guitar. The effect will be *different* for every guitar setting, every guitar, or any non-guitar sources.
I suggest a smaller value Q1 C to ground, where it is isolated from the input.
> C7 (47p) blocks out the radio station and doesn't seem to have any affect on the overall tone, but it works anywhere between C2 and C4.
The whole C2-C4 network should be small and tight. No long wires! If unavoidable, shield them. If you use a small "C11" where I suggested, you may not need a little cap here. If you feel you do, R6 wiper may be the best place, and nothing wrong with ~~50pFd. However if you get radio on breadboard, you really should not get it when properly boxed.
Thanks Paul
"I suggest a smaller value Q1 C to ground"
Sorry, I'm not sure I follow. Is it:
remove C11, put small cap where I show it here as C15
(https://s18.postimg.org/niltoqpft/PRR_Mod.png)
Quote from: Ben Lyman on November 24, 2016, 12:31:25 AM
Thanks Paul
"I suggest a smaller value Q1 C to ground"
Sorry, I'm not sure I follow. Is it:
remove C11, put small cap where I show it here as C15
(https://s18.postimg.org/niltoqpft/PRR_Mod.png)
I interpreted it as replacing the C3.
Ah yes, of course. thanks stonerbox, that makes sense.
In the meantime, I simply removed my C11 "Loading Cap" and called it a day.
Here's a long boring demo. First part is Strat into pedal into 1w TDA2822 amp with 2x12" cab; Second part is with my PT2399 delay, SD-1 clone, Really Cheap Compressor and Wah Wah. And Green Ringer.
I was experimenting on the breadboard with this and tried a bipolar buffer in front, it's the 5th one down this AMZ page: http://www.muzique.com/lab/buffers.htm
I didn't notice any change in the pedal, can anyone tell me if there is any advantage to adding it? It says the input impedance is low but I also moved my 2M2 pull down resistor onto the buffer input, does that help?
It's like this right now:
(https://s12.postimg.org/v3py36ui5/Vulcan_Rat_w_buffer_Scheme.png)
Quote from: Ben Lyman on November 24, 2016, 09:04:18 PM
I was experimenting on the breadboard with this and tried a bipolar buffer in front, it's the 5th one down this AMZ page: http://www.muzique.com/lab/buffers.htm
It says the input impedance is low but I also moved my 2M2 pull down resistor onto the buffer input, does that help?
It actually says that
the Input impedance is lower compared to Fets..!!
Imput impedance for BJT is the parallel combination of biasing resistor(s) and Emitter resistor times beta..
(about 100k in your buffer..)
For Fets it's just the biasing resistor(s) which is (are) much bigger than the respective BJT because of practically "current independence"..
Quote from: Ben Lyman on November 24, 2016, 09:04:18 PM
I didn't notice any change in the pedal
Just calculate the In-Out impedances before and after buffer placement.. :icon_wink:
Thanks Antonis! So probably around 390K(ish) input impedance, maybe acceptable or a little low. I can raise it to about 1M easily then, just change the emitter R to 10k, right?
So my 2M2 doesn't really have any bearing on the input impedance, I guess?
Input impedance of the original design without buffer looks more appealing, does it not?
I'm still learning this stuff, so I could be way wrong, but I think your input impedance will always be lower than R22 (220k) in your last schematic. I don't think the pulldown has much effect in that setup, because it's so much higher. You could raise R21 and R22 to 2M2 if you wanted to approach a 1M input impedance. I think.
You are probably right, but..
for BJT is the parallel combination of biasing resistor(s) and Emitter resistor times beta..
Hmm.. so I always just look at the lowest R in the equation and figure. "about that but a bit less" so.. I currently have 3K9 emitter R.. times that by 100= (app)390K
This all brings me back to wondering: Is it even worth adding a buffer to this particular circuit? I think the original input impedance it probably fine but I also wonder if a buffer does more than I know of, like help with adding another pedal in front.. a wah wah.. or using different guitars.. or.. ?
<So my 2M2 doesn't really have any bearing on the input impedance, I guess?>
Right.. :icon_wink:
<Input impedance of the original design without buffer looks more appealing, does it not?>
It does.. :icon_wink:
Quote from: Ben Lyman on November 25, 2016, 01:14:40 PM
You are probably right, but..
for BJT is the parallel combination of biasing resistor(s) and Emitter resistor times beta..
Hmm.. so I always just look at the lowest R in the equation and figure. "about that but a bit less" so..
Actually, lower than the lowest one...!! :icon_wink:
And in your circuit the 3k9 x 100 is the biggest one..
<Is it even worth adding a buffer to this particular circuit?>
Maths can answer your query but I think your ears already verified it... :icon_wink:
Quote from: thermionix on November 25, 2016, 12:05:32 PM
but I think your input impedance will always be lower than R22 (220k) in your last schematic.
It actually will be lower than the half of R22 or R21..
(220k)//(220K)//(3k9x100+25R*)
*B-E junction resistance for 1mA Emitter current - which is negligible here.. :icon_wink:
P.S.
Many people tend to only count on the resistor(s) leading to circuit's GND and forget than DC supply must also considered GND for AC signals..
Yes, I guess my ears have verified it but since i'm on a mini learning streak..
umm, why is my 3K9 the biggest? not the 2x 220k ?
Maybe I misunderstood your equation. Is it parallel value of all 3 R's times 100?
Or is it emitter R(100) in parallel with base R's?
i.e. 1/220k + 1/220k + 1/3K9(100) divided by 1 = 85K8
oops, never mind. You answered as I was asking :) Thanks!
I've just answered to thermionix on that.. :icon_biggrin:
edit: You've read it.. :icon_biggrin:
@ Ben: Imagine the base of the transistor as a node with all the resistors incoming there and outcoming to the same point (which is GND)..
Cool, thanks again antonis, I can imagine that :)
Quote from: antonis on November 25, 2016, 01:29:54 PM
Quote from: thermionix on November 25, 2016, 12:05:32 PM
but I think your input impedance will always be lower than R22 (220k) in your last schematic.
It actually will be lower than the half of R22 or R21..
(220k)//(220K)//(3k9x100+25R*)
*B-E junction resistance for 1mA Emitter current - which is negligible here.. :icon_wink:
P.S.
Many people tend to only count on the resistor(s) leading to circuit's GND and forget than DC supply must also considered GND for AC signals..
Yes, thanks for clarifying. I was thinking it was R21 in parallel also but I wasn't sure. Was hoping somebody would comfirm that.
Hey, Ben, I liked what I heard on the demo, and I am considering building one of these myself. Couple of quick questions, though:
- I have 2N2222, 2N7000 and 78L05 transistors (and ONE 7805!) on hand. Will any of these work as a replacement for the 2N5088's or is this a no go? I am a complete newb here, so please bear with me... I have only built 2 pedals so far (well, 3, but the 3rd one is not yet working, so I am not counting that one!).
- Similarly in the diode department; I don't have 1N914's, but I have 1N4148's, 1N4007 and some other one that, to be frank, I don't even remember what it is (looks like 4148's, but with a green painted top
- Last but not least, is this that latest schematic?
(https://s12.postimg.org/v3py36ui5/Vulcan_Rat_w_buffer_Scheme.png)
Thanks in advanced!
Felipe
PS: Many components are kind of hard to find in Costa Rica, where I live!
> 2N2222, 2N7000 and 78L05 transistors
78L05 is not a transistor, it is a Regulator.
2N7000 is "a transistor" but a MOSFET not a BJT. The circuit would be very different.
In a conservatively designed BJT circuit, try 2N5088. If you are out of '5088s, try 2N2222. It will probably work.
THIS circuit is not "conservatively designed". It depends on the transistor gain (Beta) being in a certain range. A high-gain '2222 has the same gain as a low-gain '5088, so odds are it will "work", at least pass loud signals. At that point, get collector voltage measurements from a working sample. Diddle the 4.7Meg resistors up or down (probably down) to get similar collector voltage. An assortment of 1Meg 2.2Meg 3.3Meg and maybe a couple 470K (half Meg) will be handy. You can series several to add-up to 2.8meg or 4.1meg, whatever makes the circuit happy with the different transistor.
Diodes is diodes. 1N4007 used to cost a lot more than 1N914, because it handles a hundred times the power, but today the prices are all the same near-enough. But FWIW, 1N4148 "is" 1N914 with "better" specs. Anything sold today under the 1N914 number will BE from the 1N4148 production line, just re-marked to make buyers happy.
Quote from: PRR on November 27, 2016, 12:17:35 AM
78L05 is not a transistor, it is a Regulator.
You are right; my bad! So is 7805...
Quote from: PRR on November 27, 2016, 12:17:35 AM
In a conservatively designed BJT circuit, try 2N5088. If you are out of '5088s, try 2N2222. It will probably work.
THIS circuit is not "conservatively designed". It depends on the transistor gain (Beta) being in a certain range. A high-gain '2222 has the same gain as a low-gain '5088, so odds are it will "work", at least pass loud signals.
I will give the 2N2222's a try. Is there any difference between the 2 types? I have both of them on hand (well, 2 of the can type, so I will have to use the others for this project), just wondering if one is better...
(http://i.ebayimg.com/images/g/sCQAAOxyjNlRzKOm/s-l300.jpg)
This is what I call the can type; not sure what they are really called!(http://i1050.photobucket.com/albums/s411/ic-touch/transistor/2N2222_zpse5de9709.jpg)
Quote from: PRR on November 27, 2016, 12:17:35 AM
At that point, get collector voltage measurements from a working sample. Diddle the 4.7Meg resistors up or down (probably down) to get similar collector voltage. An assortment of 1Meg 2.2Meg 3.3Meg and maybe a couple 470K (half Meg) will be handy. You can series several to add-up to 2.8meg or 4.1meg, whatever makes the circuit happy with the different transistor.
You lost me there... Let me explain it to see if I am getting the concept. Breadboard the circuit using the 2N2222, and measure collector voltage. Based on your the voltage of your prototype, adjust the resistors to get a similar collector voltage to what you are getting (using either larger resistor [or using parallel resistors to increase resistance] or smaller resistors [more likely]). Is that correct?
Quote from: PRR on November 27, 2016, 12:17:35 AM
Diodes is diodes. 1N4007 used to cost a lot more than 1N914, because it handles a hundred times the power, but today the prices are all the same near-enough. But FWIW, 1N4148 "is" 1N914 with "better" specs. Anything sold today under the 1N914 number will BE from the 1N4148 production line, just re-marked to make buyers happy.
OK, will try to 4007. Quick question; do you know what these are:
(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20161126_212537.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20161126_212537.jpg.html)
Sorry about the crappy resolution. There are no letters or numbers, just the band and color... I have about 10 of them.
Last question,
Is the diagram the latest one?
Greetings from rainy California Filipe! I would try what PRR says with the 2N2222, I've had plenty of 2N2222 from Radio Shack in the 500-600 HFE range so maybe you'll get lucky.
That schemo you posted was a failed experiment, here's the final, as heard in the video:
(https://s22.postimg.org/obs1s6z2p/Vulcan_Rat_Scheme.png)
Here's a layout that fits a 125B, extra distortion diodes mounted right on a SPST
(https://s14.postimg.org/hfpsyq0hd/BJT_Vulcan_Final_Layout.png)
The 47pF (upper left corner) can be moved around, possibly left out completely
Thanks Ben! I will use that one then.
cool, let me know how it goes. If it's on the breadboard, you might try experimenting with different tone stacks.
It has a ton of volume boost available so any kind of tone stack should probably work. I just went with the simple low pass filter because i'm a minimalist and it's an easy one to fit into a layout.
The SWTC II is a good read: http://www.muzique.com/lab/swtc.htm
A Big Muff Pi tone stack might be cool.
Or the tone knob plus presence knob found in the Crunch Box
Actually, having volume, gain, tone and presence (4 knobs) would work just fine, because I only got big boxes left, so aethetically, it would make more sense to have a big box for 4 knobs and a switch. Just help me with my lack of knowledge (I just got started a month ago with building pedals; unfortunately, I am now hooked!):
In the diagram above, the tone stack is the filter, right? (C10, R17 & R18, right?)
R17 R18 C13
> the can type; not sure what they are really called!
"Metal can".
The other is "plastic".
Back around 1970, we thought the metal was a better seal against moisture. But not perfect. Meanwhile the plastic (epoxy) technique got very much better. Today the epoxy is widely preferred even in very tough environments. Metal can is nearly obsolete. (That particular "metal can" may be epoxy in a metal shell. True METAL has a metal base plate and glass seals.)
(http://www.interfacebus.com/TO-39-BC141-NPN-Medium-Power-Transistor.jpg)
If you have to play on Mars, get expert advice. For any likely place you would play, any case type is totally fine.
True metal case is likely to be "vintage". But 2N2222 kinda marks the point in history when transistor technology "matured". The '2222 and all later types work very predictably and all about the same, unlike older types which could be a bit squirrelly.
By the way, I didn't include my power filter/protection in the schematic..
You can see all the parts in the layout but here's what it looks like.
(https://s11.postimg.org/ee38nedlf/Power_Source.png)
@Ben: Better raise C1 to 100nF (preferably ceramic disc..) 'cause a 333kHz LPF is quite useless.. :icon_wink:
You could also halve C2 to 47μF for a hum-free supply..
(IMHO, ripple filtering should be still adequate..)
Ben! Nice demo!
Thanks Larry!
Antonis, thanks, that is a typo, it's s'posed to be this:
(https://s15.postimg.org/8sy3df2bv/Power_Source.png)
But now you got me curious about using a 47uF for C2.. why is 47u better than 100u?
How about I also raise R2 to 100r?
(https://s16.postimg.org/mh8ftzpqd/Power_Source_II.png)
So, combining the tone stack of the Crunch Box with the pedal would look something more or less like this?
(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/Vulcan%20Crunchy%20Rat.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/Vulcan%20Crunchy%20Rat.jpg.html)
Please give it a once over and see if you spot any obvious errors. Also, please check if the pots values make sense (I used what I found for the Crunch Box). Keep in mind I dont fully understand this yet... Yet being the key word here!
I still need to define which values I need to on the power filter/protection...
This...
(https://s15.postimg.org/8sy3df2bv/Power_Source.png)
or...
(https://s16.postimg.org/mh8ftzpqd/Power_Source_II.png)
I got some time, though, as I will not start work on this pedal this week anyway.
Felipe
Quote from: Ben Lyman on November 28, 2016, 10:12:54 AM
But now you got me curious about using a 47uF for C2.. why is 47u better than 100u?
How about I also raise R2 to 100r?
Also raising R2 to 100R (from 47) shouldn't have any effect on LP filter 'cause you've lower C2 to 47μF (from 100) - so you've kept the same RC product.. :icon_wink:
Additionally, raising R2 should result in higher voltage drop from PS to +9V point (added to Schotky's Fvd..) - which is negligible in this case but it's a theoretical discussion.. :icon_redface:
The propose of using a 47μF cap with the 47R resistor is to form a more effective HP filter (at about 72Hz instead of 35Hz) for "hum" rejection (50-60 Hz).
The higher the cut-off frequency the better the filter effectiveness (6db/octave) but you also need a relatively big capacitor for power supply ripple smoothing so, as almost everywhere, it's a matter of compromise.. :icon_wink:My bad... :icon_redface:
We deal with LP filter so disregard the above absurdity..
P.S.
You probably experience a significant Volume drop between S1 open & closed mode - if so, a better arrangement with a series resistor at S1-Off mode should result in no need for Volume pot adjustment...
..We deal with LP filter so disregard the above...
Ahh yes, I thought maybe such ;)
Filipe: either of those power filters work and do the same thing, I always go with the top one.
As antonis said, there is less voltage drop going through the 47 ohm resistor as opposed to using the larger 100r.
If you don't have a 1N5817 schottky diode, there are other diodes/methods but I was taught to do it this way and it hasn't failed me yet.
For the tone stack, I don't know what that will sound like as you've pictured it. Probably breadboard it first.
Look into the way the crunch box tone pot is set up, it's different than the Rat filter which we have here.
One final thing, try leaving out the extra diodes+2.2nF until you listen to the pedal and then decide if you really want more distortion.
I only added them because it's so easy but probably not really important in a pedal like this. you can always build a tubescreamer to go in front of it anyway :)
I think I'll start breadboarding yours and then play with it a bit and see if I can blend a bit of the Crunchbox into it. I am not confident enough in my skills to try to do it from scratch. I have barely started making pedals, and of the 2 I have finished, one works wonderfully, but the other, not so much... And the one I got in progress I will most likely have to restart!
Started breadboarding... missing one cap, which I have to get (100p), but something is obviusly not connected right, as I am getting no sound yet.
(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20161205_212024.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20161205_212024.jpg.html)
I don't think there is a 100p in this... do you mean the 47p? That one is not important.
Check the transistor pin outs. Maybe they're backwards?
Quote from: Ben Lyman on December 06, 2016, 10:40:59 AM
I don't think there is a 100p in this... do you mean the 47p? That one is not important.
Check the transistor pin outs. Maybe they're backwards?
Yeah, I am missing the 47 pF cap (sorry)... I have to check the whole layout; I also need to check it against the right diagram. I just noticed I used the failed experiment as a base. I just finished building it last night, but was too tired to check it. I will get to it tonight. It is not that complicated of a design, so I just have to go over it. I am sure I will get it working without many issues.
Check the breadboard voltages.
My breadboard for example needs a jumper from one half of the power rails to the other.
Well IT could be??????? :P
See here
Breadboard power rail jumper https://imgur.com/a/iSk0w
I do have the Jumpers... on the left side of the pic you can see them (red and black).
even the experimental one will work, I just didn't like it much.
check that each power rails are connected horizontally as well. Some boards have a break in the center
Quote from: Kipper4 on December 06, 2016, 12:43:20 PM
See here
Breadboard power rail jumper https://imgur.com/a/iSk0w
kipper - see that nest of transistors top right corner of yer BB? get in the habit of sticking them in so the pins are all shorting, so 90
o turned from shown. when/if you happen to stick a mosfet in, it will then be protected from static damage.
Well, I got home last night and decided to start from scratch. So I pulled everything off the breadboard, put the schematics back on the screen, and realized MAYBE it was not working because I connected the guitar to the output and the amp to the input... Of course I realized this AFTER I took everything off the breadboard! Anyway, I started putting it in the breadboard again, but I did not finish (took the wife to the movies instead; that's a kind of important project as well! ;D ). I can't work on it tonight, but I'll finish it tomorrow and take it for a spin. Well see how it goes...
...connected the guitar to the output and the amp to the input... Of course I realized this AFTER I took everything off the breadboard...
Good! This is the kind of stuff that speeds up the learning process!
It didn't kill you so obviously, it just made you stronger ;)
Something like that... Now I am debating if I BB this one or the Deep Blue Delay... I want to do both, but dont have enough breadboard space! LOL!
definitely do both but remember:
You can live without delay but you can't live without distortion! :icon_mrgreen:
That delay is a bit more complex than the Vulcan but all things considered, they are both pretty simple
I am getting frustrated, to be honest... I got home late, and decided to take a crack at the Deep Blue Delay. Got it on the breadboard, but could not get it to work. That means my last 3 tries have been fails! I got a little angel all boxed up, but no chorus effect. I built the vulcan rat, but could not get it to work (out of stupidity, yes, but still!), and now the delay! I do have my own overdrive (I call it the Screechy Cat), and it sounds pretty good, but I wanted something more aggressive (which is why I wanted to do the vulcan rat, and still will). I am just PO's that all the latest tries have been for naught!
I think on the VR, I will skip the breadboard and design a point to point layout and go straight to the box!
Felipe
Got it back on the breadboard. It's AMAZING how much better it sounds when you connect the amp to the output and the guitar to the input! :P I did have a couple of resistors wrong (I think it was a 2.2K I used instead of a 2.2M) that I corrected. Also had to steal a couple of 223 capacitors from the Deep Blue Delay, but since that one is not yet working, it dont really matter...
I really like the sound, so I'm gonna to a Point to Point layout and put it in a box. Nice compliment for my Screechy Cat!
(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/IMG_20161208_223553.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/IMG_20161208_223553.jpg.html)
Nice way to get my morale back up! I also got a real PCB for my little angel build, so that will also turn out well soon (I HOPE!)!
Felipe
congrats! I'm glad you didn't give up. Did you add the crunch box presence control?
No, right now it is straight out of the schematic. I'll play with it now that I have a working prototype.
Sent from my EVA-L19 using Tapatalk
Quote from: jfrabat on December 08, 2016, 11:45:54 PM
It's AMAZING how much better it sounds when you connect the amp to the output and the guitar to the input! :P
LOL! Been there, done that... :icon_rolleyes:
Glad you're making progress. :)
I am in the process of moving it from the BB to a perforated board and boxing it up... I got everything soldered up (NOT my prettiest job!) on the perforated board, but I am missing 47 ohm resistor for the voltage protection circuit. I also need to make the holes in the box and solder a couple of jumpers to the diodes (which I placed in the board instead of the switch). Tomorrow I'll make the holes in the box, and wire up the stomp switch and jacks. I'll have to go Monday to the store for the resistor. Already checked for continuity, and I did not find any shorts or other issues.
Cool. the 47r is for filtering purposes, it works in conjunction with the 100uF to create a low pass filter... cuts the noise but passes the volts to the effect. If you don't have a 47r you can still get away with anything close, maybe up to 100r at the most? I don't know for sure what is the most you can use, hopefully someone will tell us soon, maybe you can go as big as a 1K?
The 1N5817 diode is the actual protector.
I have 100R if that will work...
ya, 100r is fine, use that
Wired everything up, but screwed up somewhere, cause now it's not working (and it did on the BB). Have to go over it now, but will do it later... I am tired of working on pedals this weekend! Actually working on 2 at the same time!
Started checking with the audio probe. Signal comes in strong to the board. Becomes a bit faint by the time it reaches Q1 base, but it is REALLY faint by the time it comes out of Q1 emitter. I can still track it to Q2, but I cant hear anything by Q3.
Here's the board. Not my best work by far, but I always have a hard time with perf boards!
(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/IMG_20161211_122828.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/IMG_20161211_122828.jpg.html)
The middle pot I had to put off board because it did not fit right. Anyway, I only got big boxes left, so real estate is not an issue....
Oh, and I get no light from the LED... I think I roasted it, cause its getting 9V!
Sent from my EVA-L19 using Tapatalk
For starters, I might suggest desoldering the pots and thoroughly cleaning the perfboard of any remaining solder residue, then try to operate the pedal with the pots off-board. Separate the mechanical issues from the electronical.
Would it be possible to upload a photo of the top of the board? -- then we can magically overlay both with photoshop and see how the layout works.
Here's the top.
(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/IMG_20161211_155947.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/IMG_20161211_155947.jpg.html)
Ignore the positive lead that I just borke off taking the picture...
Basically, it is the same layout that's here:
(https://s14.postimg.org/hfpsyq0hd/BJT_Vulcan_Final_Layout.png)
And here's the schematic:
(https://s22.postimg.org/obs1s6z2p/Vulcan_Rat_Scheme.png)
The voltage protection is not in the schematic, and the diodes are in the bottom square sticking out of the bottom.
The layout works, I have confirmed that but sorry I didn't post my reverse bottom trace layout for you:
(https://s17.postimg.org/5p8ojdisf/BJT_Vulcan_TRA.png)
Hard for me to tell for sure but maybe you don't have the tone pot quite right yet.
Also, notice how I numbered the pot lugs so the middle pot (tone) is actually upside down and goes under the board when installed.
There's a lot of quirky details that I often leave out like my LED is a superbrite clear blue and will shine plenty with a 47K on it.
If you are using a diffused LED, you probably need a much smaller value r on it.
Visual aid:
(http://i.imgur.com/ekYQi2m.jpg)
You said that the signal seemed weak at Q1 emitter -- what about the collector? What are the voltages on the transistors now?
Anyone see any solder ridges I am missing? Or other errors?
I was looking through the solder side and there are some spots I'd like to check out. Ben mentioned the tone pot. Was lug 2 OK? I would like to see the voltages on the transistors too, but there area a few solder joints and lead dress items that caught my eye. I am not sure if I am reading the layout properly, but is R10 in the right place?
if R10 is there, maybe it's hidden by the caps.
can't tell for sure but check where I circled in blue for a solder short.
Also, take your output wire right from the center lug on the volume pot. I've read lots of warnings about trying to solder to those rivets so I've never tried it but maybe won't pass a signal.
(http://a63.tinypic.com/2di3kex.jpg)
This RC filter calculator will allow you to choose components for your desired frequency knee:
http://www.experimentalistsanonymous.com/ve3wwg/doku.php?id=rc_simple_filter (http://www.experimentalistsanonymous.com/ve3wwg/doku.php?id=rc_simple_filter)
Quote from: Ben Lyman on December 11, 2016, 05:42:54 PM
The layout works, I have confirmed that but sorry I didn't post my reverse bottom trace layout for you:
(https://s17.postimg.org/5p8ojdisf/BJT_Vulcan_TRA.png)
Hard for me to tell for sure but maybe you don't have the tone pot quite right yet.
Also, notice how I numbered the pot lugs so the middle pot (tone) is actually upside down and goes under the board when installed.
There's a lot of quirky details that I often leave out like my LED is a superbrite clear blue and will shine plenty with a 47K on it.
If you are using a diffused LED, you probably need a much smaller value r on it.
That diagram looks very different... But you did give me an idea; when I checked this:
(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/IMG_20161211_122828.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/IMG_20161211_122828.jpg.html)
And superimposed the traces:
(http://i46.photobucket.com/albums/f138/jfrabat/Leads%20superimpossed.jpg) (http://s46.photobucket.com/user/jfrabat/media/Leads%20superimpossed.jpg.html)
And compared it to this:
(https://s14.postimg.org/hfpsyq0hd/BJT_Vulcan_Final_Layout.png)
I noticed some differences here:
(http://i46.photobucket.com/albums/f138/jfrabat/Leads%20superimpossed%20errors.jpg) (http://s46.photobucket.com/user/jfrabat/media/Leads%20superimpossed%20errors.jpg.html)
So I at least know where to start looking... I'll report back when I fix those. I doubt the middle pot is the issue, as only pins 1 and 3 are connected (the bridge to pin 2 is in the board), so the effect of wiring them wrong would be the knob turning backwards, but it should still work, right?
That was not it... But something else is loose. I noticed that LED is flashing. I think its somethung in the switch, but I will have to check. But there is still no sound.
Sent from my EVA-L19 using Tapatalk
I always reverse the trace diagram, that's why it looks different because it's a mirror image. That way I have a picture of the top of the board and all the components and I also have a picture of what it looks like when I turn it over.
It is important to hook up the tone pot wiper but a quick way for you to do this is to attach a short wire right to the pot itself, connecting lugs 1 and 2
EDIT: WHOOPS! you're right, that is way different. Must be one of my rough drafts, I'm afraid I might not have a reverse image of my trace, sorry about that, my bad :P
Great job troubleshooting, I think you nailed it. Check that one spot on the power line that I circled too, fix the others and connect your tone pot lugs 1+2 together and it should be ready to go.
(http://50.6.73.68/picit/1481526848.6399.jpg)
OK, fixed the positive link and added the wiper jumper, on top of the above mentioned fixes. This is the PCB as of tonight:
(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/IMG_20161212_192833.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/IMG_20161212_192833.jpg.html)
I have noticed a significant drop in sound after D1, and even more after Q1. Just a tiny bit of sound is making it to A1M. And almost nothing makes it to D2. I am using 4001 diodes, in case that's an issue... Got tons of others if I need to change this. Look at the video below for the audio probe test. The phone did not capture the tiny amount that made it to A1M, but it is there. including the layout for reference.
(https://s14.postimg.org/hfpsyq0hd/BJT_Vulcan_Final_Layout.png)
Any ideas?
Aha! Is it me, or are all my diodes backwards???
Please confirm, but I think they are...
(http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/IMG_20161211_155947.jpg.html)
Diodes look good to me, but I can't really tell with the red led. Have I missed it or do you have voltage readings for the transistors?
I am wondering if Q1 is amplifying at all, maybe the voltages will help us make sure it is biased correctly.
Ya, the diodes look right. check here next, it looks like it might be bridged where it shouldn't be
(http://a68.tinypic.com/2lvhh51.jpg)
Made progress tonight. I found a short in the input jack (i had all my attention on the board and did not check the jacks! One of those DUH! moments...), and fixed it. It seems that was causing a bad ground, which is why the LED was not lighting up as well. It is lighting up now, though (but I will also re-wire it, because it lights up even when the pedal is bypassed). Now, with the audio probe, the signal makes it all the way across to the circuit output (including the output jack) at about the same volume level as it was coming in. I did not check the output jack to see if it is also shorting with the plug connected, but I will tonight (I just thought about that one, and maybe that's causing no signal to reach the amp). Anyway, I took the Q voltages.
Voltages:
Battery: 8.92
Q1:
E:163mV
B:733mV
C:7.20V
Q2:
E:0V
B:332mV
C:8.71V
Q3:
E:178mV
B:752mV
C:7.13V
For some reason, though, no sou d comes out the amp when I connect the circuit (it does sound when I bypass it). I am truly stumped now!
Sent from my EVA-L19 using Tapatalk
I think the transistor voltages are within range, probably Ben can confirm -- Do the pots do what they are supposed to do?
Just checked my volts, all are 2N5088 so maybe a little different.
Battery 9.4v
Q1
c 4.70
b 1.01
e 0.43
Q2
c 4.60
b 1.02
e 0.44
Q3
c 4.69
b 1.01
e 0.44
jfra - save me going back over the 3 pages - what transistors are you using? because I see you have mirrored Ben's left-to-right components, but also have reversed his transistors. if you are using 2N****, and he used 2N****, yours should still face the same way as his.
unless I've missed a post on back to fronting the layout.
Holy carp, Duck! I think you're right, I just looked back and it does appear that the transistors may be in backwards.
2N2222
I have to check, but now that you mention it, I think you are right. IIRC, I set them looking at the board from the top, but the schematic is looking from the. Uttom
Sent from my SM-G935F using Tapatalk
Felipe, my diylc layout is a veiw from the top looking down on the components, and through them as if you could see the traces underneath. Sorry I thought that was a given but maybe not as clear as I thought.
Anyway, not a big deal, signals is signals and all should flow fine as long as you can unsolder those trannies and flip them around
I would still encourage you to leave out the extra 3 clipping diodes (just for the moment) and see if we can get the main circuit working first. The extra distortion switch is just fluff anyway.
(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/IMG_20161211_155947.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/IMG_20161211_155947.jpg.html)
(https://s14.postimg.org/hfpsyq0hd/BJT_Vulcan_Final_Layout.png)
(https://s22.postimg.org/obs1s6z2p/Vulcan_Rat_Scheme.png)
I think you are correct...
(https://cdn.instructables.com/FKN/04K0/HWTBIEL2/FKN04K0HWTBIEL2.MEDIUM.jpg)
According to this, the Emitter is facing UP and it should be facing DOWN! I think I know what happened now... Because the diagram is in mirror (I built it looking from the BOTTOM of the board, not the top), when I put the transistors in, I put them facing the 100uF cap, but that means it is backwards.
I'll correct them tonight. THANKS FOR THE HELP! This helps A LOT to all that helped (Ben, Duck, Rob, and anyone else I have left out)!!! I hope that's the last of my issues!
Felipe
OK, put in new transistors (could not take old ones out without destroying them!). This is the latest look:
(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/IMG_20161214_195305.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/IMG_20161214_195305.jpg.html)
(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/IMG_20161214_200538.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/IMG_20161214_200538.jpg.html)
Also fixed a broken cable (ground). But there is still something off... I still get no sound. Tried the sound probe, and looks like Q2 is not amplifying.
New voltages:
Battery: 9.1v
Q1:
E: 0.302v
B: 0.880v
C: 6.05v
Q2:
E: 7mv
B: 0.322v
C: 8.79v
Q3:
E: 0.278v
B: 0.848v
C: 6.43v
Well I did fix the Q2 issue now it's amplifying. I got the sound coming all the way out to the output jack on the sound probe but for some reason when I connect the guitar to the circuit and out to the amplifier there's no sound coming out when I activate the circuit ( it works just fine when I bypass the circuit). I have a couple of video is uploading to YouTube so I can show you what I mean.
Sent from my SM-G935F using Tapatalk
<edit, saw the Q2 problem has been solved> Sounds like the bypass switch is our next thing to check. Does the LED still work?
Ya, what Rob said. Also, a long shot but any chance you are accidentally plugging in backwards? That would allow a bypassed signal to work while engaging the effect would not... I know this because... well, umm.. i've done it many times :icon_mrgreen:
it occurs to me now that the pots will probably operate in the opposite direction, are they all set around noon for the test?
No, they are at full volume, but yes, they are backwards. I also checked their operation, and they are working as they should (albeit in the wrong direction). But the signal is at least as loud as the clean guitar; the amp should pick that up, right?
Ya that's weird. Maybe the switch is bad or there is a little short caused by a stray wire trimming or solder blob. But I bet you've examined it closely several times at this point, eh?
what is the little alligator clip for in your video? the one that's clipped to the ground of the output jack? Is that part of the signal generator or test probe or something?
Quote from: Ben Lyman on December 15, 2016, 11:02:17 AM
Ya that's weird. Maybe the switch is bad or there is a little short caused by a stray wire trimming or solder blob. But I bet you've examined it closely several times at this point, eh?
I do have the IN and OUT wires backwards in that traditionally, the IN is at the left and OUT is at the right, and mine are the other way around, but it should not really matter, right? I will replace them anyway to rule it out, but that should not be the issue...
Quote from: Ben Lyman on December 15, 2016, 11:02:17 AM
what is the little alligator clip for in your video? the one that's clipped to the ground of the output jack? Is that part of the signal generator or test probe or something?
It's the ground for the voltmeter; I was also checking voltages. I am really stumped as to what could be the cause of the sound not making it to the amp... Especially since I KNOW there is a signal there (checked with the sound probe!).
can you clip jumper wires onto the switch to bypass it? going from in jack straight to board in and another from board out straight to out jack. that might identify the switch problem if it is that
Quote from: Ben Lyman on December 15, 2016, 12:18:43 PM
can you clip jumper wires onto the switch to bypass it? going from in jack straight to board in and another from board out straight to out jack. that might identify the switch problem if it is that
I will try this.
If the signal can be heard on the tip contact on the out jack, if the switch checks out OK I would look into the output jack having a problem when the plug is inserted. You could also alligator clip the output from the center lug of the volume pot to the guitar cable itself. That way we isolate the problem at jack or switch. edit: if you are getting clean signal, it may not be the jack, but a wiring issue that might be revealed by jumpering around as Ben says.
Quote from: robthequiet on December 15, 2016, 12:29:36 PM
If the signal can be heard on the tip contact on the out jack, if the switch checks out OK I would look into the output jack having a problem when the plug is inserted. You could also alligator clip the output from the center lug of the volume pot to the guitar cable itself. That way we isolate the problem at jack or switch.
Good idea...
Tried a new switch, allivators on the jacks, and no change...
Here is the whole circuit:
(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20161215_204829.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20161215_204829.jpg.html)
And the bottom of the board (see any bridges?):
(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20161215_205715.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20161215_205715.jpg.html)
Here are the switch and jacks:
(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20161215_204958.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20161215_204958.jpg.html)
(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20161215_205015.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20161215_205015.jpg.html)
(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20161215_205039.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20161215_205039.jpg.html)
Two more and and some voltages:
(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20161215_210121.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20161215_210121.jpg.html)
(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20161215_210021.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20161215_210021.jpg.html)
Batt: 9.1V
Q1:
C: 6.05V
B: 0.88V
E: 0.302V
Q2:
C: 8.85V
B: 0.331V
E: 0V
Q3:
C: 6.43V
B: 0.848V
E: 0.273
Let me know of any ideas...
Crazy thought: Is is possible that when you insert the input jack the power is not going to the circuit, which is why bypass works OK but with a jack in the plug the effect is being turned off instead of on?
Just to be sure, is this your input jack?
(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20161215_205015.jpg)
Quote from: robthequiet on December 15, 2016, 11:15:57 PM
Crazy thought: Is is possible that when you insert the input jack the power is not going to the circuit, which is why bypass works OK but with a jack in the plug the effect is being turned off instead of on?
Just to be sure, is this your input jack?
(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20161215_205015.jpg)
That's the input. But it is making it to the board (you can hear it in the video I posted earlier), as checked with the audio probe, right?
Right. I was making sure I was not too confused ;D -- So the board is getting power to operate the effect. Q2 values still look a bit off, but if you get the effect at the center lug of the volume pot then it still looks like the switch or the output jack.
Edit: So, signal gets through to the output jack tip lug until you insert the cable? I would be tempted to simply detach the output jack and try with just the wires clipped to the guitar cable. I have some old junk cables that I have cut the jack off for just this purpose. Or you can unscrew the metal case from the jack and alligator clip to the connectors.
I am very curious about this pedal and thinking that the voltage readings at Q2 are not really part of the no-sound problem. The solder side of the board is looking much better now, by the way.
I agree Q2 voltage may not be the problem but it might be a clue.
Take a close look in between the traces and see if you can scrape out any spilled solder
Also, use a continuity tester to see if that whole trace is connected and that it's not touching anything else. I think this is where Q2 emitter connects with the 1K and 22uF. Maybe also check around the 10k from power rail to Q2c, volts seem too high, then go to zero at emitter
(http://a63.tinypic.com/211jrqe.jpg)
me again - I think the Q2 voltages are the problem, because it is not turning on, so is just a load of loading between the good amplifying first Q and the good amping third Q.
there is a 1M on Ben's dia (off the page, grrr, also, now page 6!) that connects the second transistors base diode to ground that I can't locate on the reversed perf build. can you see if it really is missing?
good call Duck, it's there but it looks like a 5.6k!
(http://a63.tinypic.com/16gt2b.jpg)
bingo! guess what's fitted where the 5k6 should be ......
IT'S ALIVE!!!
Thanks all of you for your help!!!
The resistors were most definitely the cause... Well, the latest one anyway! The backwards transistors and shot pots were not helping in any way...
Quick question; how much of a difference in sound should the resistors make? Because I am not hearing it (mind you, I had the volume down 'cause the kids are asleep!)...
Oh, and one last question (opinion anyway): should I go with a 1599Q or 1590B?
(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20161216_215416.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20161216_215416.jpg.html)
(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20161216_215305.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20161216_215305.jpg.html)
imagine all the knobs of the same size in the Q... I only have 2 big ones right now, but can get more locally.
B will be a bit cramped, and I fear no room for battery operation. But Q is a bit too big. Those are the two boxes I have on hand...
how much of a difference in sound should the resistors make?
Do you mean the extra clipping diodes on the switch?
Quote from: Ben Lyman on December 16, 2016, 11:12:48 PM
how much of a difference in sound should the resistors make?
Do you mean the extra clipping diodes on the switch?
Yup
Ya, they add a little extra compression and sustain but in my opinion they really aren't necessary. They were just an experiment, the kind I do a lot just so I can test it with the band.
I would advise you to leave out the switch for now, box it up without connecting the extra diodes and use it for a few days, then open it up and connect the diodes up and use it for a few more days.
Then decide whether or not to leave them in or just clip the connection. I wish I didn't add them to mine, but then if I hadn't I guess I never would've known
I'm glad you got it working and I think the Q box looks super cool
jfrabat - I'd recommend the larger box (or waiting for your next parts order to arrive ...... nah, that's not going to happen, is it?) just because it will be less grief. and in 6 months, when you gut it for a bigger project, less holes to drill!
good work with the debugging, but, we have to ask - do you suffer from any of the various colour blindnesses?
Quote from: duck_arse on December 17, 2016, 08:45:59 AM
do you suffer from any of the various colour blindnesses?
No. Just ADD... Seriously, no joke. I had all my parts ordered, and I guess I simply mislabeled them or something.
Congrats! I always double-check my resistor values with a meter, just in case my eyes fail me, which happens increasingly with age. A victory video would be cool.
A victory video would be cool...
mandatory! ;)
OK, latest news:
1. Box (Q) is in paint. Yellow is not as bright as it should, but it will do...
2. Graphics are in the process of being designed; they will be all black, and I will use waterslide decals to mount. It will be in the same design taste as my Screechy Cat Overdrive and my Little Angel Chorus (which I still have not gotten to work, most likely due to bad PT2399 chips) - SEE BELOW!.
3. I am installing the switch, but will take out the diodes from the main board. I am making a mini-board (basically an 8 pin socket with the first 3 pins connected, pin 4 and 5 connected, and pins 6-8 connected). this way, I can socket any diodes I want to use (I may just start with BAT41's and those odd ones I do not know about just 'cause), and can change them as I see fit. Pins 4-5 are in case I want to use 2 diodes in series as is the case in the original design (say, pin 1 to pin 4, and pin 5 to pin 8, for example, would have 2 diodes in series).
4. Demo video IS coming! I am still debating if I should wait to finish the box to show it in all its glory, though... Oh, and do not expect a great guitarist, cause I am not one!
(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/IMG_20161106_232754.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/IMG_20161106_232754.jpg.html)
(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20161127_002707.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20161127_002707.jpg.html)
As for the diodes, what do you think I should start with? I have:
BAT41
BAT42
BAT46
1N4007
1N5817
1N34A
1N4148
LED in Blue, Red, Green and Yellow
By the way, this is the new diode board:
(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20161217_182230.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20161217_182230.jpg.html)
And this is the artwork for the waterslide sticker (in JPG form; the original is AI):
(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/Vulcan%20Rat.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/Vulcan%20Rat.jpg.html)
You have to imagine it with a yellow background!
Video coming soon...
Video
https://youtu.be/7CSaIzfIKx0
By the way, the video is with no diodes and all the pots maxed out, which is not my favorite setting, but it works!
Sounds great man, good job!
I like the diode socket. You can also socket that 2n2 and change it out with different diodes and different caps and get all kinds of different tones until you find the perfect combo.
Little late for the 2n2... It is already soldered in. I thought that cap only served for avoiding hiss and noise from reaching the output? Guess I was wrong, though...
Reversed 2 pots that were working backwards (I will later replace the B1M for a C1M when they arrive), and included some diodes:
(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20161218_133643.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20161218_133643.jpg.html)
2 germaniums in series and one BAT46 on the reverse direction.
Put the second coat of paint on the enclosure today. I also need a 2P2T switch to wire the diode LED indicator for the diodes, but that will likely happen in january...
I will post again once the pedal is finished. Tha ks again to all of you for helping me with this project!
Well, I know I said I would not post until it was finished, but what can I say; I am excited it's working! So sue me if you mind me sharing! LOL!
Here's the enclosure so far (knobs and other stuff are only for reference):
(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/3d0c200b-d65c-49a7-bc66-396ca04dd189.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/3d0c200b-d65c-49a7-bc66-396ca04dd189.jpg.html)
I still need to clear coat it and put all the guts in...
Oh, and here is a test without and then with the clipping diodes. I recorded this straight from the DAW, and had to adjust volume so that it was at the same level (Audacity compressor).
https://drive.google.com/open?id=0B88Re3K-59SycVdoSTAzbzVwU1E (https://drive.google.com/open?id=0B88Re3K-59SycVdoSTAzbzVwU1E)
Quote from: jfrabat on December 18, 2016, 08:21:05 PM
... I am excited it's working! ....
I still need to ..... put all the guts in...
this. most important. do not forget.
Quote from: duck_arse on December 19, 2016, 08:30:17 AM
this. most important. do not forget.
Yeah, it is kind of important, isn't it? [emoji1]
I have been using it without the box all weekend, though...
Very cool, love the graphic
Not yet finished, but...
(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20161219_235308.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20161219_235308.jpg.html)
Still have to:
1. Buy the missing knob
2. Cut the pots so that the knobs do not stick upwards
3. Wire the wall dc conector
4. Solder the signal wire on the stump switch I broke installing this
5. Eventuallu change the sitch to a 2P one so that I can wire an LED for it and install that as well.
But so far, so good!
Got the broken cables wired up (one from the diode module had also broken), and put the knobs in place. And like Anakin Skywalker said, "IT'S WORKING!". I have not yet connected the wall plug, as I need to find how to connect it (have not done it in my other pedals either!, but basically that's the only thing missing... Well and changing the switch to a 2P2T so that I can wire an extra LED to indicate the diodes are working... But that I'll do in January after I come back from my trip! Here's a picture next to my other pedals:
(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20161220_205047.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20161220_205047.jpg.html)
From those, the Little Angel is waiting a new PT2399 (it's not yet working), and the Ultimate Overdrive I do not really like all that much (it works, but to be honest, I do not think it is working right, as the sound does not change at all when I switch on and off the different diodes). The Screechy Cat and the Vulcan Rat, on the other hand, are working just fine (actually, without the diodes, the Vulcan Rat sounds similar to the Screechy Cat, but the Cat cleans up faster as you turn the guitar volume down). And a Tremolo just got started...
Thanks to all on here for helping getting this pedal to work! Merry Xmas and Happy New Years to all!
Felipe
Looking good Felipe. You can also run the red clipping LED from its place with some wires and move it right into your LED bezel. Then when you throw the switch to activate the clipping diodes the red LED will glow on and off when you play your guitar. It's a cool visual effect
Well, that's not a bad idea... I'll have to throw a LED into the diode board, though, as I do not have one. Maybe I will take out the Germanium ones and replace them with a red LED. But I will do that in January as well; I got to pack! I am leaving tomorrow!
Don't ask me what I did, because I woke up at 2AM yesterday, took a flight home, and in the afternoon (not wanting to sleep because when I do sleep during the day, I have trouble sleeping at night, and I had to work today!), I decided to add the LED to the pedal. Of course, now it is not working (no sound coming through even when bypassing). My guess is either a wire came loose in one of the jacks or there is a short somewhere (most likely, it's hitting the case). I will have to look into it tonight (or tomorrow night, depending on how tired I get home!). But it is frustrating how delicate this pedal has turned out and I blame the stiff wires, which break rather easily. Luckily, I already have on hand new multistrand 24 gauge wire in different colors that I bought on Mammoth Electronics for my next project, and although I do not like them as much as the ones I got from guitarpedalparts.com (those were a bit stiffer, making them easier to work with), these are much more resistant to both heat and movement than what I was working with.
Found ONE of the culprits... The signal wire broke off the switch. Now bypass is working fine, but I am now getting a lot of noise from the circuit (which I did not have before). There is another loose wire somewhere for sure, as the circuit works sporadically if I move the board around... I just have to sit down and find it.
The wires I used have proven to be a REAL PITA! They are VERY fragile.
So, I have decided to redo the board. I will also print a circuit board for it myself (I have done this twice, but I am happy enough with the results to try it here). I am using the layout of the veroboard for the PCB, but it should look a bit cleaner. I am also using stranded wire I got from Mammoth (I'l be honest, I liked the wire I got from guitarpedalparts.com better, as it was stiffer and thus easier to work with, but I ran out of that one, and I have 4 rolls of the Mammoth ones, so I will use them until the run out!). I have not yet decided if I want to recicle parts or will just use new parts; I am leaning towards new ones just because of the hassle it will be to desolder the old board (unless I have any parts our of stock, of course!). And I will keep the LED in the diode board, as I do want it lighting up when I use the effect.
I'll post some pictures once it is done; it may be a while, though, as I am currently working on 4 pedals! I have my Little Angel that I have yet to get to work (dry signal goes through, but no wet signal), I got an EA Tremolo I started while I waited for the new PT2399 of the Little Angel to arrive (similar error; dry signal works, but no tremolo effect), and I just got a Phaser PCB I bought (I will not start this one until the other 2 are working).
By the way, here's the PCB layout. If anyone wants the PDF, drop me a PM and I will share it.
(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/Vulcan%20Rat%20Creation.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/Vulcan%20Rat%20Creation.jpg.html)
Quote from: jfrabat on January 25, 2017, 04:48:47 PM
By the way, here's the PCB layout. If anyone wants the PDF, drop me a PM and I will share it.
(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/Vulcan%20Rat%20Creation.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/Vulcan%20Rat%20Creation.jpg.html)
After building the pedal, I noticed that there are 2 holes missing. No biggie, and the PDF is updated in case anyone wants it. But just so you know.
Now, back to the pedal construction;
I need help AGAIN! I finished building the pedal for the second time, but it's once again not working (I think I will keep my day job for now!). I basically re-did the whole thing, so anything could be wrong. I also added the wall DC jack, but that's not the issue (voltage is fine). First, here are the pictures:
(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20170129_124931.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20170129_124931.jpg.html)
Here's a shot of most of the pedal (the 2 pots missing are behind the board). Layout is almost exactly the same as before, as I am using the same box, stomp switch, and jacks. Everything else is new (well almost; one pot is not).
(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20170129_124816.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20170129_124816.jpg.html)
Here are the pots. Notice I kept away from the rivets this time around...
(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20170129_124953.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20170129_124953.jpg.html)
Here's a close up of the upper part of the rats nest... Ehrr, the pedal, I mean.
(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20170129_125003.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20170129_125003.jpg.html)
And the stomp switch and diode tray.
(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20170129_124910.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20170129_124910.jpg.html)
(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20170129_124751.jpg) (http://s46.photobucket.com/user/jfrabat/media/Guitar/Pedals/20170129_124751.jpg.html)
Here's the new board. I checked continuity at all suspicious spots, and there is none where there should not be (at least I found none). If you notice the cap and resistor that are slanted next to the LED and IN, it's becuase I drilled the wrong holes larger for the wiring. But as far as circuit, it should not matter. I also noticed while building that I did not use the 47 Ohm resistor as per the instructions; but since the old one had 100 Ohm resistor in place, I went with that.
Now, I checked voltage at the input of the board, and that's working fine. I also used the audio probe, and notice that the signal makes it to the board, but I loose it at Q1. There is no amplification. And I checked Q1, and it seems I soldered it the right way (please double check for me, but it seems that I did). Also checked diode direction, and they seem to be fine (please double check as well). And, as a result of past experiences, I also checked the resistors color codes, and I think they are all correct (please double check!). Any other ideas?
Voltages are as follows:
Battery:
At Socket: 9.23V
At Board: 9.22V
Q1:
E: 2.03V
B: 2.76V
C: 2.04V
Q2:
E: 2.01V
B: 2.74V
C: 2.01V
Q3:
E: 1.99V
B: 2.71V
C: 1.99V
Compared to Ben's, these voltages are WAY off!
Quote from: Ben Lyman on December 13, 2016, 11:22:50 PM
Just checked my volts, all are 2N5088 so maybe a little different.
Battery 9.4v
Q1
c 4.70
b 1.01
e 0.43
Q2
c 4.60
b 1.02
e 0.44
Q3
c 4.69
b 1.01
e 0.44
Any ideas?
Hi, guys; any ideas on what to check? I went through it last night once again, but did not find anything.
jfra - are we still using this circuit? can you give us a parts overlay for your layout? each stage is, for some reason, doing the wrong thing the same way. it almost, almost looks like all your E and C are shorted together, and all your B are shorted, except the B-E voltage looks about right.
(https://s22.postimg.org/obs1s6z2p/Vulcan_Rat_Scheme.png?noredir=1)
Filipe, did you get my PM? I thought it looks like r3 r9 & r12 might accidentally be 4K7 instead of 4M7 in your board
Quote from: duck_arse on February 01, 2017, 08:39:01 AM
jfra - are we still using this circuit? can you give us a parts overlay for your layout? each stage is, for some reason, doing the wrong thing the same way. it almost, almost looks like all your E and C are shorted together, and all your B are shorted, except the B-E voltage looks about right.
(https://s22.postimg.org/obs1s6z2p/Vulcan_Rat_Scheme.png?noredir=1)
Ben, yes, I am using that same layout. But I think Ben hit the nail on the head!
Quote from: Ben Lyman on February 01, 2017, 09:14:33 AM
Filipe, did you get my PM? I thought it looks like r3 r9 & r12 might accidentally be 4K7 instead of 4M7 in your board
Jesus Christ, you are right! It is DEFINITELY a red band instead of a green one!
I can't believe I did not pick this up. I was careful to read every resistor, test it with the MM, and then checked codes TWICE when troubleshooting! And STILL I missed this! I will replace them tonight. Hopefully, that will get it to work!
Thanks a lot, Ben!
PS: No, I did not get the PM!
Quote from: jfrabat on February 01, 2017, 01:50:47 PM
PS: No, I did not get the PM!
Oh wow, sorry you didn't get it a couple days ago. Anyway, I hope that solves it for you, keep us posted. I sent you a test PM just now to see if you get that one.
Good luck!
Quote from: Ben Lyman on February 01, 2017, 02:43:45 PM
Quote from: jfrabat on February 01, 2017, 01:50:47 PM
PS: No, I did not get the PM!
Oh wow, sorry you didn't get it a couple days ago. Anyway, I hope that solves it for you, keep us posted. I sent you a test PM just now to see if you get that one.
Good luck!
No worries. Thanks for taking the time to check my (poor) work! And I did get the second one.
Ben, you are a GENIUS! My pedal is working once again! I just got to check the volume pot, which is not working 100%, but everything else is working just fine!
Quick question, though; I put the LED for the diode, but it does not light up when in use. I read somewhere that it is normal for a clipping LED NOT to light up; is that so?
Mine lights up when I hit the strings and fades out when the notes fade out. Maybe crank the gain knobby up and also the guitar volume just to make sure you get enough signal to light the LED. it also must have some diode(s) going opposite direction, so make sure you got those too
I do; I got 2 diodes oposite plus the LED. Maybe my LED is backwards and thus does not light up? The cathode is connected to the circuit's ground... Or maybe the LED is not bright enough?Gain and guitar were all the way up.
You shouldn't necessarily expect a clipping LED to light up.
Quote from: jfrabat on December 18, 2016, 02:42:54 PM
2 germaniums in series and one BAT46 on the reverse direction.
I don't think those are Germanium diodes, they more look like unbranded Schottky type.
I chenged the diodes; I got one BAT and I dont remwmbwr what the other was.
I once breadboarded a Distortion+ clone with radioshack LEDs for clipping diodes... if I remember correctly, I couldn't see the LEDs light-up unless the room was dark.
Not the same thing, of course, but if an opamp with 10k in series only barely lit the LEDs, a bipolar transistor with a 10k collector resistor certainly can't do any better.
Long story short, don't worry about *that* unless you don't like the way it sounds... or at-least if it still sounds the same with different diodes.
Quote from: antonis on November 29, 2016, 08:29:04 AM
You probably experience a significant Volume drop between S1 open & closed mode - if so, a better arrangement with a series resistor at S1-Off mode should result in no need for Volume pot adjustment...
Antonis, can you expand on this; I am experiencing a significant volume drop with S1, but I want to understand how I would wire that series resistor you mentioned...