i made a pedal with a couple of s9015 transistors, 1n4007s and LEDs for clipping. when i run the circuit on a breadboard, it either gives a 1.tiny bass fuzz, 2. no sound , or 3. very nice overdrive-y distortion. problem is, i need to somtimes repeatedly hit the wiring to get the distrtion sound. since i thought that the problem was with the wires, i put it on pcb. when i tested it, it just gave the tiny bass fuzz instead of the overdrive!!! pls help i really want a overdrive unit...
Welcome to the forum.
You haven't given us anything to work on here. We will need circuit diagram, BB layout and pictures to stand a chance but here are a couple of things to consider when using breadboards
Breadboards are not all made equal. Cheap ones can lead to poor connections. Likewise with patch wires
If you alter the effect of the circuit by moving the wires, you have connected, disconnected or shorted something. Trouble is, you don't know which one of the 3 has happened so you don't actually know the state of the circuit so sort that issue before continuing.
It's likely that the 'tiny bass fuzz' was the correctly working effect as you had it on the BB. Time to break out the breadboard again
>
anything to work on here. We will need circuit diagram.... to stand a chanceQuote"We may have had our break! This record is a manual of sorts. It provides some wiring blueprints Renfry has been able to identify with that cat's cradle of cords up there."
"Some wiring." Renfry's enthusiasm did not match Ashe's at that moment. "About one line in ten! This is like trying to put together a missile head when all your working instructions are written in code! Yeah—the red cord hits the plate there—but does it say anything about these white loop-de-loops to the left?"
Ashe squinted at the loops in question and consulted the record reader again. "Yes!"
Renfry was down on his knees in an instant to see for himself the diagram on the picture screen.
"Well—that's more like it!" Ross climbed the rest of the way into the cabin and stooped to look over Ashe's shoulder at the miniature screen.
"I'd say it's closer to the plans for a demon-inspired highway system," he commented judiciously.
― Andre Norton, Galactic Derelict
Quote from: stallik on May 19, 2020, 10:50:25 AM
Welcome to the forum.
You haven't given us anything to work on here. We will need circuit diagram, BB layout and pictures to stand a chance but here are a couple of things to consider when using breadboards
well, here are the images of the circuit and such...
(https://i.postimg.cc/QV0zBTh8/98607453-249771082768577-2428350526061019136-n.jpg) (https://postimg.cc/QV0zBTh8)
(https://i.postimg.cc/F76npXYw/98067646-596914654265945-132910657782677504-n.jpg) (https://postimg.cc/F76npXYw)
(https://i.postimg.cc/sBdHFP9c/99277324-764682940602807-1533740874465280000-n.jpg) (https://postimg.cc/sBdHFP9c)
Quote from: stallik on May 19, 2020, 10:50:25 AM
It's likely that the 'tiny bass fuzz' was the correctly working effect as you had it on the BB. Time to break out the breadboard again
if this is the case, why would there sometimes be a overdriven sound?
Lotsa things going on here. Biggest probably is that you need coupling caps after each transistor. The soldering ain't so great, no offense. It's not a good practice to solder to the eyelets on the pots.
Quote from: willienillie on May 20, 2020, 03:10:58 AM
The soldering ain't so great, no offense. It's not a good practice to solder to the eyelets on the pots.
yeah i suck at soldering. thanks for the tip :icon_biggrin:
Am I the only guy who thinks Q1 is not quiescent biased..??
(as it is, it only works during heavy negative signal waneform..)
P.S.
Is (+) on 9V a typo, or are we talking about reverse-active region..??
MPS9015, I presume. I can't find any info whether PNP or NPN.
S9015 (as clearly stated on schematic) is definately p-n-p .. :icon_wink:
Quote from: antonis on May 20, 2020, 08:05:21 AM
S9015 (as clearly stated on schematic) is definately p-n-p .. :icon_wink:
well, for some reason, when i use my multimeter to test my transistors, the s9015s reacted like npns and my s9014(npn equivalent of s9015) reacts like pnps. i know for sure that my multimeter isnt broken of anything... and also my s9015s dont work if i make the circuit specifically for pnps...
Quote from: antonis on May 20, 2020, 06:07:18 AM
P.S.
Is (+) on 9V a typo, or are we talking about reverse-active region..??
i just added +9v just to signify positive 9 volts.. sorry for confusion... :icon_frown:
No need for apologies & no confusion alsor..
I mentioned (+) sign before 9V 'cause, in accordance with your drawing, Q1&2 are P-N-Ps so they should be fed from -9V..
(positive ground circuitry..)
ahh ok.. is it a good idea to desolder everything and go back to breadboard? also, the only time this thing overdrives is when the red led lights up according to the guitar signal. thats how i knew when it was working(back in the breadboard). i thought that it was just bcos the wiring was bad so i transferred everything to pcb. when i tried it, the led doest light up already. it isnt broken though.according to this, what do u guys think i shoud do now...?
Quote from: antonis on May 20, 2020, 08:05:21 AM
S9015 (as clearly stated on schematic) is definately p-n-p .. :icon_wink:
Yes, you are right. I just assumed "MP" was left off the marking, you know how they do that sometimes. But searching "s9015" brings back plenty of info. PNP it is.
Quote from: 11-90-an on May 20, 2020, 10:44:34 AM
is it a good idea to desolder everything and go back to breadboard?
Going back to the breadboard is a good plan for sure. Desoldering everything might be more trouble than it's worth, unless those are the only parts you have.
Quote from: willienillie on May 20, 2020, 03:53:53 PM
Going back to the breadboard is a good plan for sure. Desoldering everything might be more trouble than it's worth, unless those are the only parts you have.
well, I have really few parts, which is why I'm using less common s9015s instead of more common ones like 2n3904. I tried to buy some j201s before quarantine but my local electronics shop does not sell it. do you guys think any of these transistors could be of any use?
-s9014
-9018f
-s8550
-mpsa13
Where did that schematic come from? At first I thought you had channeled the "Hilo, Hawaii" fix, which is to whack any piece of electronics to produce an immediate fix on the gig! :-)
Quote from: 11-90-an on May 20, 2020, 11:38:47 PM
do you guys think any of these transistors could be of any use?
All working transistors can be useful somewhere. The MPSA13 is a very high gain NPN darlington type, fairly common, great for buffer stages. The rest in your list are unfamiliar to me, as the S9015 was, but you can google up the datasheets. J201 is (was) a common n-channel JFET, maybe you know already. Those are getting harder to find.
Quote from: aron on May 21, 2020, 12:49:33 AM
Where did that schematic come from?
Probably from : www.youcanthrowanythingyoulikeintoverifiednonworkingcircuits.com
@ 11-90-an: Are we now talking for suitability of whatever is inside your transistor drawer (from pnp BJTs up to npn Darlingtons, involving also some Fets..) to be placed into the very particular and "universal" bias circuit posted above..??
Quote from: aron on May 21, 2020, 12:49:33 AM
Where did that schematic come from? At first I thought you had channeled the "Hilo, Hawaii" fix, which is to whack any piece of electronics to produce an immediate fix on the gig! :-)
Well, i just made the schematic by myself after some research about diode distortion and stuff like that. Whacking the breadboard works but whacking pcbs dont :'(
Quote from: antonis on May 21, 2020, 06:52:20 AM
@ 11-90-an: Are we now talking for suitability of whatever is inside your transistor drawer (from pnp BJTs up to npn Darlingtons, involving also some Fets..) to be placed into the very particular and "universal" bias circuit posted above..??
Well, I just want to know if there are any type of pedals that i can make during this quarantine so that i may be satisfied that i might have achieved something. It would really be good though if one of theese transistors could really be an effective replacement for the s9015 transistors.
Quote from: 11-90-an on May 21, 2020, 09:56:34 AM
Well, i just made the schematic by myself after some research about diode distortion and stuff like that. Whacking the breadboard works but whacking pcbs dont :'(
So you made a Mojo-Whack.. :icon_lol:
Don't get me wrong but try to make a more "sensible" schematic/circuit.. :icon_wink:
(e.g. decide of transistor type and try to make them working at forward-active region.. And a bias configuration should also be useful..)
Quote from: antonis on May 21, 2020, 03:19:25 PM
Don't get me wrong but try to make a more "sensible" schematic/circuit.. :icon_wink:
(e.g. decide of transistor type and try to make them working at forward-active region.. And a bias configuration should also be useful..)
What do you mean by the bias configuration? I always see this in transistor tutorials but i dont really understand it that much. Does it relate to the Ic=hfe * Ib? Im sorry i dont really understand these things... :(
My nails are very short so let's take a deep breath and try to lightly scratch the surface of "bias".. :icon_redface:
A BJT can be set to work on 4 regions:
1. Cut-off (no current through it, dead..)
2. Saturation (full current, alive till its death comes very quickly ..)
3. Reverse-active (like in your schematic, zobie of good intentions..)
4. Forward-active mode (alive and well, you can call it "amplifier" ..)
All 4 above regions can be obtained via proper bias configuration..
(we order transistor to do a job, hopping it will obey us..)
That order is, in his vast majority, implemented by adding a DC voltage on transistor's Base..
This voltage "activates" a Collector current (of hFE times Base current) so we can set any of the above 4 regions (working conditions)..
(well, almost 'cause region 3 needs more than this..)
Now, we have to deal with transistor type (n-p-n or p-n-p)
Conventional current flow is considered from Collector to Emitter for n-p-ns and from Emitter to Collector for p-n-ps..
The above said, we also have to take into account power supply polarity in conjunction with BJT type..
(even if we DO wish region 3 operation..)
For an effective bias orded implementation, there are various resistive configurations (read attachments below), all of them having to do with famous/notorious Quiescent point..(the "idle" working state..)
This DC Q point is set according to the intented use and Collector voltage (for CE amp) can vary above & below of it..
(more of DC & AC line in attachments below)
https://www.electronics-tutorials.ws/amplifier/transistor-biasing.html (https://www.electronics-tutorials.ws/amplifier/transistor-biasing.html)
https://www.electronics-tutorials.ws/amplifier/transistor-biasing.html (https://www.electronics-tutorials.ws/amplifier/transistor-biasing.html)
https://en.wikipedia.org/wiki/Bipolar_transistor_biasing (https://en.wikipedia.org/wiki/Bipolar_transistor_biasing)
https://www.allaboutcircuits.com/textbook/semiconductors/chpt-4/biasing-techniques-bjt/ (https://www.allaboutcircuits.com/textbook/semiconductors/chpt-4/biasing-techniques-bjt/)
All in all, we can't just kick, in cold blood, the Base of a BJT without, at least, some explanation for our impolite action..
(in case of our explanations are fairly good, we might get forgiven - we even might meet our task with success, who knows..) :icon_wink:
Thanks @antonis !! ;D ;D
To stay close to your original design.. :icon_wink:
(https://i.imgur.com/lGvTVnW.jpg)
P.S.
Define the role of all resistors (R5, R6 excluded..)
(weekend homework..) :icon_wink:
^
(https://i.pinimg.com/originals/4c/ae/d1/4caed1ac5a702dfdebc4cc3ec5f0d69e.png)
And maybe move C7.
Quote from: antonis on May 22, 2020, 10:52:20 AM
To stay close to your original design.. :icon_wink:
(https://i.imgur.com/lGvTVnW.jpg)
P.S.
Define the role of all resistors (R5, R6 excluded..)
(weekend homework..) :icon_wink:
THANKS !!!! :icon_wink: :icon_lol:But there's a problem though, i happen to not have a 100k pot, can i use a 10k pot instead? also, can the 470k resistor be replaced with a 560k ? otherwise, I already have everything else.
and for the resistor uses,
1, 2, 7, 8 - voltage divider bias circuit
4, 9 - collector feedback bias circuit
Quote from: willienillie on May 22, 2020, 07:19:25 PM
And maybe move C7.
Do you mean move it before diode pair of delete it..??Thank's for the coffee - Q2 Collector should feel grateful also.. :icon_wink:
You shouldn't ask about 470k/560k replacement in case you've indeed read about feedback bias configuration.. :icon_wink:
(its value is depended on particular BJT current gain and is set by [(Vcc/2 - 0.7) X hFE]/ICollector..)
So, 470k is a safe "estimation" for hFE of about 200 - 560k should also do the job fine..
(it might move Collector quiescent voltage up or down a bit but, afer all, we deal with fuzzy stage..) :icon_wink:
10k pot should be OK after an Emitter folower (buffer) but here it "loads" R4..
(you can considered either in parallel with Q2 Collector resistor or in parallel with next effect imput impedance - in both considerations, its low value dominates Q2 stage Gain..) :icon_wink:
You can try it as it is but, IMHO, you'll not get satisfactory results..
One modification could be the use of much higher gain Q2 (much lower R4 value required..) to be "immune" or R6 low value..
Another (lousy enough) mod could be the addition of a series resistane (47k -56k, say) with R6 upper lug..
It will cut down Volume setting range significantly so proceed under your own risk - do not try it using headphones..) :icon_wink:
P.S.
Pay attention to willienillie's cup of coffee and move C7 before D4/D5 pair..
So.. I finished desoldering everything from the pcb and all the parts still have long legs(i anticipated having to desolder everything from the start) so this pcb was the last one that i have, and also i have near-0 solder left. Would it be better to reuse this pcb, buy another prototype circuit board, or design and print specifically for this application? After breadboarded everything of course...
Here are some pics
(https://i.postimg.cc/FYy8fnY5/1-FC43-DC7-661-E-46-AE-93-FD-BF4-A8-C86888-B.jpg) (https://postimg.cc/FYy8fnY5)
(https://i.postimg.cc/hXWNtqP1/99677822-4-B16-4-F3-C-BC5-C-71-B716663-DD7.jpg) (https://postimg.cc/hXWNtqP1)
I don't presume there is need for printed board for such a simple buid..
I don't suggest also re-usage existing board..
(it needs very scrupulous cleanup both for solder residuals and oxidized/corroded pads..)
Listen, do not fret. I have been exactly where you are at (and not long ago!). Most of what the pro's discuss here is WAAAAY over my head (like trying to understand how transistor works! Sorry, Anotnis, but even your explanation was tough for me to follow!), but every day, I learn something new that is useful, and I keep going.
If you allow me, I would recommend you read and maybe breadboard this:
https://www.premierguitar.com/ext/resources/files/Oct14_PGDistortion_BuildGuide_Final_R2.pdf
I thought it was a great introduction to guitar pedal building, and I even ended making my second pedal from this one (my first pedal "sort of worked" and I still keep it, but in all honesty, it sounds HORRIBLE! This one is still in the pedal board - with many tweaks, of course!!!). It will teach you what each part does, and allows you to play with different choices (like caps, transistors and resistors) to teach you to tailor to your tastes.
And do not feel bad about your soldering; practice makes perfect.
This was me starting to solder:
(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20161122_193134_2.jpg)
This is the same circuit (different board layout, but same circuit) some time later:
(http://i46.photobucket.com/albums/f138/jfrabat/Guitar/Pedals/20170312_102122.jpg)
I still make a mess of things in that type of PCB you are using, though, which is why I taught myself Eagle and now I have my PCB's printed. But that is a different topic! A good soldering iron helps A LOT here too. But you do not need one to start.
The other word of advice I can give you is that if it does not work perfectly on the breadboard, do not even bother with it on a PCB. It will only make chasing the issue more difficult. Other advice include making yourself an audio probe, and getting a multimeter with a continuity sensor. And lastly, only about 10~20% of my PCB's work right out of the gate. Typically I made some stupid mistake with polarity, have a solder bridge or some other issue that I have to troubleshoot. People here have been great at helping me solve these, but they need info, which means voltage readings at different points, which, again, means a multimeter...
Quote from: jfrabat on May 26, 2020, 06:07:11 PM
Listen, do not fret. I have been exactly where you are at (and not long ago!). Most of what the pro's discuss here is WAAAAY over my head (like trying to understand how transistor works! Sorry, Anotnis, but even your explanation was tough for me to follow!), but every day, I learn something new that is useful, and I keep going.
If you allow me, I would recommend you read and maybe breadboard this:
https://www.premierguitar.com/ext/resources/files/Oct14_PGDistortion_BuildGuide_Final_R2.pdf
I thought it was a great introduction to guitar pedal building, and I even ended making my second pedal from this one (my first pedal "sort of worked" and I still keep it, but in all honesty, it sounds HORRIBLE! This one is still in the pedal board - with many tweaks, of course!!!). It will teach you what each part does, and allows you to play with different choices (like caps, transistors and resistors) to teach you to tailor to your tastes.
What transistors did you use for this? The 2n3904? I am thinking of ordering that online because it seems like a very useful transitor...
So now im gonna order some parts online...
Any other essential transistors other than 2n3904, 2n3906, bc547, bc557, that i should get?
Get some MOSFETs like 2N7000 and BS170
Quote from: garcho on May 27, 2020, 12:54:03 AM
Get some MOSFETs like 2N7000 and BS170
No MOSFETs only BJTs
Quote from: 11-90-an on May 27, 2020, 02:02:15 AM
No MOSFETs only BJTs..
THAT'S THE SPIRIT..!!! :icon_wink:
P.S.
Waiting for Sir Mike to slap our hands.. :icon_redface:
Quote from: antonis on May 27, 2020, 07:05:04 AM
THAT'S THE SPIRIT..!!! :icon_wink:
hahahaha...
what i mean is that the place that im ordering doen't have any MOSFETs. They only sell BJTs...
(https://i.postimg.cc/tYBW9P3d/Screen-Shot-2020-05-27-at-7-21-30-PM.png) (https://postimg.cc/tYBW9P3d)
(https://i.postimg.cc/PCcDwjFP/Screen-Shot-2020-05-27-at-7-22-02-PM.png) (https://postimg.cc/PCcDwjFP)
anything useful for pedals here?
Almost all of them..!!! :icon_wink:
(although, many of them can be considered of "equivalent" usability - like BC547 to 550, BC556 to 558, etc..)
in some circuits that require a tl072 or a tl074, is it possible to just use 2 or 4 transistors like 2n3904s?
Quote from: 11-90-an on May 27, 2020, 07:22:37 AM
(https://i.postimg.cc/tYBW9P3d/Screen-Shot-2020-05-27-at-7-21-30-PM.png) (https://postimg.cc/tYBW9P3d)
(https://i.postimg.cc/PCcDwjFP/Screen-Shot-2020-05-27-at-7-22-02-PM.png) (https://postimg.cc/PCcDwjFP)
or any others in this list?
Unfortunantely, you'll need much more transistors for TL07X simulation..
( JFETs included..)
In general, you could build basic op-amp stages (differential input, voltage amplifier, emitter follower(s) output but I'm pretty sure you shouldn't wish to mess up with all those nasty blocks for the time being.. :icon_wink:
Quote from: antonis on May 27, 2020, 10:56:55 AM
Unfortunantely, you'll need much more transistors for TL07X simulation..
( JFETs included..)
In general, you could build basic op-amp stages (differential input, voltage amplifier, emitter follower(s) output but I'm pretty sure you shouldn't wish to mess up with all those nasty blocks for the time being.. :icon_wink:
Thanks @antonis! :icon_biggrin:
Right now i will buy:
8 x 2n3904
2 x bc547
2 x bc557
5 x 2n3906
Do you think this is enough? Or more transistors needed? :icon_question:
Before you try doing something silly, could you tell us what is this store that sells various transistors but not op amps?
I bet this circuit is for Germs, leakage bias.
mac
Maybe some high gain BJTs like 2N5089 or MPSA18, also..
On which particular circuit you refer on, Marcelo..??
Quote from: FiveseveN on May 27, 2020, 02:32:48 PM
Before you try doing something silly, could you tell us what is this store that sells various transistors but not op amps?
online store that sells random things... i mean like, at least i have somewhere to buy parts :icon_lol:
BTW, its called Shopee, and ... i can't describe it hehe
https://shopee.ph/SUPER-200pcs10-Values-TO-92-BC327-BC558-Transistor-Assortment-Kit-i.93948225.1718680348
try something like this, wherever you are. there is a good assortment, a darlington, and none of the odd high voltage stuff those others have. AND - they'll have the BCxxx pinout, the one we all want! [the included parts will sub for many of the 2Nxxxx types you will likely find.]
Quote from: duck_arse on May 28, 2020, 11:05:08 AM
https://shopee.ph/SUPER-200pcs10-Values-TO-92-BC327-BC558-Transistor-Assortment-Kit-i.93948225.1718680348
try something like this, wherever you are. there is a good assortment, a darlington, and none of the odd high voltage stuff those others have. AND - they'll have the BCxxx pinout, the one we all want! [the included parts will sub for many of the 2Nxxxx types you will likely find.]
Thanks @duck_arse! This seller sells a lot of kits that i could save money on by just buying all the parts i actually wanted to buy haha (saves me a lot of money since each seller has its own shipping fee...)
Which do you think are better? Carbon film or Metal Film ? i find the carbon films easier to read but the metal films are cheaper...
I don't get it, there's a whole page of search results for TL072 (https://shopee.ph/search?keyword=tl072) and three pages for LM358 (https://shopee.ph/search?keyword=lm358). Was there some other reason besides availability that would drive you to use transistors in place of op amps?
PS: plenty of MOSFETs as well: https://shopee.ph/search?keyword=2n7000
for starting out - spend the extra, take it easy on your eyes, get the carbon. how much cheaper?
Quote from: FiveseveN on May 28, 2020, 11:51:37 AM
I don't get it, there's a whole page of search results for TL072 (https://shopee.ph/search?keyword=tl072) and three pages for LM358 (https://shopee.ph/search?keyword=lm358). Was there some other reason besides availability that would drive you to use transistors in place of op amps?
PS: plenty of MOSFETs as well: https://shopee.ph/search?keyword=2n7000
umm... sorry for the confusion, this website has multiple 'stores'. Each store is has its own shipping fee of like $2-4 (which is expensive-ish for my country). when i say that there are no MOSFETs, i mean in that specific 'store', because sometimes the products are as expensive as the shipping. also, I find that I don't really need op-amps with the pedals that I intend to build...
Quote from: duck_arse on May 28, 2020, 12:04:57 PM
for starting out - spend the extra, take it easy on your eyes, get the carbon. how much cheaper?
the metal film are $4 for 1280pcs (assorted)
the carbon film are $8 for 1000pcs (assorted)
QuoteOn which particular circuit you refer on, Marcelo..??
The first one,
(https://i.postimg.cc/QMV2T0FR/99277324-764682940602807-1533740874465280000-n.jpg)
PNP Germs might work fine, but in&out&interstage caps needed.
mac
Quote from: mac on May 28, 2020, 10:24:38 PM
PNP Germs might work fine, but in&out&interstage caps needed.
Maybe, hitting wiring for circuit working (as OP stated..) was some form of interstage capacitance simulation.. :icon_smile:
is it possible to replace a 2n5088 with a bc549 in a Highway 89? (just so i would know if buying bc549s would be useful or not...)
also, would it be ok to swap the 100k pots for 50k?
(sorry if this is drifting off topic, buying parts can present many options...)
BCs are always useful.. :icon_wink:
Just make clear for its C classification (both 2N5088s & BC549Cs fall into the same hFE & VCEO range..)
Swapping pots values is strongly depended on particular circuit use..
If you refer on 100k Bass & Treble pots of Highway 89, you can swap them for 50k ones but you'll also have to alter side resistors values for Bass pot (the ones connected to its outer lugs) to keep respective capacitors values and Q1 Collector loading the same, in the cost of tighten bandwidth margins..
But, in general, yes.. You can try it..
After all, you will not blow anything.. :icon_wink:
Quotethe metal film are $4 for 1280pcs (assorted)
the carbon film are $8 for 1000pcs (assorted)
hmm, well. are they both types 1/4W? it's up to you - can you read the colour codes without refering to a page/sheet, or do you need practise? I'd suggest practise on carbon till you get the numbers, cause they usually don't make easy sense on the blue metal films, and you'll need to meter measure every time.
QuoteBCs are always useful.. 
Just make clear for its C classification (both 2N5088s & BC549Cs fall into the same hFE & VCEO range..)
more important than the C suffix, the BCxxx pinout is nearly always 180
o rotated to the 2Nxxxx, which is something you have to catch
every single time.
I like the idea of hitting as capacitance simulation, but how do you control the value?
probably worth pointing out that this thread has now degenerated somewhat, as they nearly all do, and as you started it yourself, you can take it any which direction you like.
Quote from: duck_arse on May 29, 2020, 11:56:53 AM
this thread has now degenerated somewhat..
Like most Emitters of CE amps do.. :icon_wink:
Quote from: antonis on May 29, 2020, 10:22:08 AM
BCs are always useful.. :icon_wink:
Just make clear for its C classification (both 2N5088s & BC549Cs fall into the same hFE & VCEO range..)
Swapping pots values is strongly depended on particular circuit use..
If you refer on 100k Bass & Treble pots of Highway 89, you can swap them for 50k ones but you'll also have to alter side resistors values for Bass pot (the ones connected to its outer lugs) to keep respective capacitors values and Q1 Collector loading the same, in the cost of tighten bandwidth margins..
But, in general, yes.. You can try it..
After all, you will not blow anything.. :icon_wink:
I was able to find some 100k pots ;)
Quote from: duck_arse on May 29, 2020, 11:56:53 AM
Quotethe metal film are $4 for 1280pcs (assorted)
the carbon film are $8 for 1000pcs (assorted)
hmm, well. are they both types 1/4W? it's up to you - can you read the colour codes without refering to a page/sheet, or do you need practise? I'd suggest practise on carbon till you get the numbers, cause they usually don't make easy sense on the blue metal films, and you'll need to meter measure every time.
Yes, both of them are 1/4 W. I continued to search and I found a cheaper carbon film set! It even was cheaper than the first metal film that I saw and had 1500pcs! :) :o
Quote from: duck_arse on May 29, 2020, 11:56:53 AM.
QuoteBCs are always useful.. 
Just make clear for its C classification (both 2N5088s & BC549Cs fall into the same hFE & VCEO range..)
more important than the C suffix, the BCxxx pinout is nearly always 180o rotated to the 2Nxxxx, which is something you have to catch every single time.
Noted! :D
So I was thinking about a spring/plate/idk reverb unit, and i researched and realized that after the signal passes through the spring/plate, it loses about 0.4db. Some people solve this problem by placing a Lm386 as input booster(so the signal will have enough strength to pass through the spring/reverb) and another Lm386 at the other end, to boost the signal again. Would it be practical to just use 1 TL072, since that is basically 2 op-amps in a single package? (Just wanted to know if I should also be buying LM386s hehe :icon_biggrin: )
> after the signal passes through the spring/plate, it loses about 0.4db.
More like 40dB.
Which is why you need gain both before and after.
Quote from: PRR on May 30, 2020, 12:40:31 AM
> after the signal passes through the spring/plate, it loses about 0.4db.
More like 40dB.
Which is why you need gain both before and after.
ok, thanks! ;D
There are 2 types of bc549's right? bc549B and bc549C? Is there basically no such thing as a bc549 (no suffix)?
all [nearly - check your datasheet per type number] of the BCxxx series come in four varieties - let's say the 548 for argument.
you can have BC548, BC548A, BC548B, BC548C. the A, B, C are sorted for hFE, A being lowest, C being highest. no suffix means they are the exact same parts, but unsorted, so you might get 150 hFE, you might get 530 hFE.
and there is the dreaded l suffix [usually also has a no-suffix, standard pinout variant], which means the base pin is on one end, instead of the middle.
another generally rule is - the lower number of a set - ie BC557, BC558, BC559 - will be a higher voltage part, and the higher number in that series will be the lowest noise and slightly lower voltage figures.
AND - don't get caught by the BC639/640 pair, which are meant as drivers for power transistors - they have the end base pinout - no variants. so really, the only general rule that is any good -
ALWAYS check your datasheet.
Quote from: duck_arse on May 30, 2020, 11:00:27 AM
and there is the dreaded l suffix [usually also has a no-suffix, standard pinout variant], which means the base pin is on one end, instead of the middle.
that sounds bad...
thanks for all the help, random pro people! this forum is much more useful than expected haha :icon_biggrin: :icon_redface:
Some times "stomp box" must be taken literally.
From your schematic, I would put the protection diode in the positive supply line rather than the ground line because everything including signal is referenced to ground including any other pedals you have plugged in either ahead of it or downstream of it. Of course, the diode would be facing the other way on the positive rail.