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Author Topic: Vulcan Rat Creation  (Read 40327 times)

robthequiet

Re: Vulcan Rat Creation
« Reply #100 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?

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jfrabat

Re: Vulcan Rat Creation
« Reply #101 on: December 15, 2016, 11:56:47 PM »
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?


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?
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I build.  I fix.  I fix again.  And again.  And yet again.  (sometimes again once more).  Then I have something that works! (Most of the time!).

robthequiet

Re: Vulcan Rat Creation
« Reply #102 on: December 16, 2016, 12:29:53 AM »
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.
« Last Edit: December 16, 2016, 12:51:58 AM by robthequiet »
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Ben Lyman

Re: Vulcan Rat Creation
« Reply #103 on: December 16, 2016, 01:27:08 AM »
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

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"I like distortion and I like delay. There... I said it!"
                                                                          -S. Vai

duck_arse

Re: Vulcan Rat Creation
« Reply #104 on: December 16, 2016, 08:40:55 AM »
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?
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Ben Lyman

Re: Vulcan Rat Creation
« Reply #105 on: December 16, 2016, 09:42:54 AM »
good call Duck, it's there but it looks like a 5.6k!
 
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"I like distortion and I like delay. There... I said it!"
                                                                          -S. Vai

duck_arse

Re: Vulcan Rat Creation
« Reply #106 on: December 16, 2016, 10:17:05 AM »
bingo! guess what's fitted where the 5k6 should be ......
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jfrabat

Re: Vulcan Rat Creation
« Reply #107 on: December 16, 2016, 11:06:17 PM »
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? 




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...
« Last Edit: December 16, 2016, 11:09:52 PM by jfrabat »
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I build.  I fix.  I fix again.  And again.  And yet again.  (sometimes again once more).  Then I have something that works! (Most of the time!).

Ben Lyman

Re: Vulcan Rat Creation
« Reply #108 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?
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"I like distortion and I like delay. There... I said it!"
                                                                          -S. Vai

jfrabat

Re: Vulcan Rat Creation
« Reply #109 on: December 16, 2016, 11:34:15 PM »
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
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I build.  I fix.  I fix again.  And again.  And yet again.  (sometimes again once more).  Then I have something that works! (Most of the time!).

Ben Lyman

Re: Vulcan Rat Creation
« Reply #110 on: December 17, 2016, 12:12:23 AM »
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
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"I like distortion and I like delay. There... I said it!"
                                                                          -S. Vai

duck_arse

Re: Vulcan Rat Creation
« Reply #111 on: December 17, 2016, 08:45:59 AM »
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?
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jfrabat

Re: Vulcan Rat Creation
« Reply #112 on: December 17, 2016, 09:16:41 AM »


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.

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I build.  I fix.  I fix again.  And again.  And yet again.  (sometimes again once more).  Then I have something that works! (Most of the time!).

robthequiet

Re: Vulcan Rat Creation
« Reply #113 on: December 17, 2016, 01:53:30 PM »
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.
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Ben Lyman

Re: Vulcan Rat Creation
« Reply #114 on: December 17, 2016, 01:57:32 PM »
A victory video would be cool...

mandatory!  ;)
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"I like distortion and I like delay. There... I said it!"
                                                                          -S. Vai

jfrabat

Re: Vulcan Rat Creation
« Reply #115 on: December 17, 2016, 05:47:57 PM »
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!




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I build.  I fix.  I fix again.  And again.  And yet again.  (sometimes again once more).  Then I have something that works! (Most of the time!).

jfrabat

Re: Vulcan Rat Creation
« Reply #116 on: December 17, 2016, 07:37:39 PM »
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:



And this is the artwork for the waterslide sticker (in JPG form; the original is AI):



You have to imagine it with a yellow background!

Video coming soon...

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I build.  I fix.  I fix again.  And again.  And yet again.  (sometimes again once more).  Then I have something that works! (Most of the time!).

jfrabat

Re: Vulcan Rat Creation
« Reply #117 on: December 17, 2016, 08:35:07 PM »
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I build.  I fix.  I fix again.  And again.  And yet again.  (sometimes again once more).  Then I have something that works! (Most of the time!).

jfrabat

Re: Vulcan Rat Creation
« Reply #118 on: December 17, 2016, 08:52:50 PM »
By the way, the video is with no diodes and all the pots maxed out, which is not my favorite setting, but it works!
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I build.  I fix.  I fix again.  And again.  And yet again.  (sometimes again once more).  Then I have something that works! (Most of the time!).

Ben Lyman

Re: Vulcan Rat Creation
« Reply #119 on: December 18, 2016, 02:27:41 AM »
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.
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"I like distortion and I like delay. There... I said it!"
                                                                          -S. Vai
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