Prescription Electronics - Depth Charge  [traced]

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destro
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Post by destro »

soulsonic wrote:
Sound pretty nice too; though I might want to increase the value of R9 because the clean blend seems to overpower the fuzz too easily.
Agreed. Built it from the schem and pictures and it works! The clean is too overpowering, though. You have to run it all the way to wet for it to seem blended.

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Post by soulsonic »

destro wrote:
soulsonic wrote:
Sound pretty nice too; though I might want to increase the value of R9 because the clean blend seems to overpower the fuzz too easily.
Agreed. Built it from the schem and pictures and it works! The clean is too overpowering, though. You have to run it all the way to wet for it to seem blended.
Yep, that's how it is, so you must have gotten it all correct! :lol:
Increasing R9 to something like 470k helps a bit. Maybe the best thing to do would be to try a different blend circuit entirely. The kind that has the blend control's wiper going to ground would probably work better, but you'd need to add some additional mixing resistors to the circuit and move some stuff around.
"Analog electronics in music is dead. Analog effects pedal design is a dead art." - Fran

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Post by soulsonic »

This is what I'm talking about for a better blend circuit. This arrangement allows for full clean or full fuzz at its extremes.
Values would need to be determined to see what works best.
Also, in the case of the Depth Charge, it might be better to have a large bipolar cap in series with the wiper to ground so that it doesn't upset any DC biasing of the following stage.
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destro
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Post by destro »

Well, I threw a 500k pot in there and ended up going with 390k. Any more and it seemed that there was a noticable volume loss. Mine doesn't get much higher than unity. So I did a little digging and found a common fix by throwing a capacitor in parallel with the recovery stage's emitter resistor. I went with a 100uf. Got less clean to blend and more volume now and a stupid chirping noise when cranked too hot, but overall, worthwhile mods for my taste. I've hand drawn a perf layout if anyone wants to do it up right, let me know and I'll send you a scanned copy.

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Post by GodSaveMetal »

Please:
Can anybody post an schematic with a PCB for etching this fantastic pedal!!!!!!!
Please I beleive that you can!!!!!!!!!!! :applause: :applause: :applause:

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Post by gkoerselman »

I build this one the other day and wanted to share my PCB, but I realised I had forgotten the 22u filter cap on the +9V so I've redone the PCB layout a bit. For my build order I also messed up the 0.22u elec. caps so I've installed 220n non polarity for the time being... Please note that I dropped the protection diode!

Any comments or corrections are as always appreciated. PM me with your e-mail address if you want my Eagle files.

Thanks to soulsonic for the schematic!!! :applause:
Attachments
DepthCharge - PCB02.png
DepthCharge_.png
DepthCharge - Schematic_.png
RIMG1000.JPG

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destro
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Post by destro »

My perf layout based off schematic and pics posted in this thread. Mine works great though I would verify as you build. Sorry it took so long. Put it together tonight. Diylayout creator is awesome. Will use more in the future. Enjoy!

Image

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Post by lohstah »

belated thanks for posting that perf layout, destro ! :thumbsup
what transistors did you use in your build ?

cheers,
lohstah

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destro
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Post by destro »

Thanks man! I figured, what the hell, and went with the 2n3707's from mouser. They were pretty cheap. Can't remember the HFE range but I got enough to where they were all pretty close together. I find myself wanting more of the fuzz in the blend option, but I haven't opened it back up to test a soulsonic blend idea.

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Post by GodSaveMetal »

Excelent Man!!!! can be a replace of 2N3707 perhaps the "BC458 o 459 o 558 o 2N4904 o 2N5088, 5089 o others" it will work with the ever be 2SC828?????, Thanks a lot for the PCB. :applause: :applause:

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Post by shaggy45 »

Hello everyone,

i was wondering if one of fine folks could help me out. I built a vero version of this pedal and it doesn't work right. I've looked over the schematic and the layout
and can't seem to figure out whats wrong. It's from a unverified layout. I've built a good bit of pedals, but i'm just now getting into the mechanics of this stuff and this
would be a great opportunity to learn something about spotting errors. The problem with the pedal is that the blend does something, its not blending though. The tone is acting as a volume knob.



layout is here:

http://guitar-fx-layouts.42897.x6.nabbl ... Charge.png


Q1 and Q2 are the same, but then Q3=Q6, Q4=Q3, Q5=Q4 and Q6=Q5 (layout=schematic).

Any help would be greatly appreciated.

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destro
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Post by destro »

Go through the layout with the schematic posted a few posts above. Double check your wiring. Insure the transistors pinouts are right. Check polarity of caps. Then check vero traces for continuity. If you take your time and go through it methodically you will find the problem. Debugging is tedious, but you will learn from doing it.

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Post by shaggy45 »

I gave up on the vero and etched a board from the image above. Its so close but not there yet. it works but the low end is just not there compared to a real depth charge. the blend didn't work until i connected tone 2 to blend 1. this thing is gonna drive me nuts lol

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Post by shaggy45 »

i opened up my original depth charge today and took a peek. mine doesn't use 1n270's it has what i can make out to be 1n4933 instead. i don't have any of those on hand, but went ahead and ordered some. does anyone think that changing the 1n270 to 1n4933 would make a huge difference on the sound of this thing? maybe my 1n270's are trash? i got them from tayda. any thoughts?

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Post by shaggy45 »

got my 1n4933 diodes today. didn't fix it. seemed to exacerbate the issue. it's just missing something. I'll keep messing with it.

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Post by joeysantoro »

Hi guys, nice to meet all, i'm Giovanni and i'm a new member and a new pedals addicted.
i've repair some vintage tube amp and now i'm starting with pedals. I've here a depth charge with some problems,
the first is a volume loss when fx was engaged and the blend work strange (no full clean signal anyway).
it's a led version with 3PDT. can you help me to identify wich could be the problem?
i suppose it could be a bad (or some) 2n3707, but i'm not sure. pedal it seems to be original with no mod (glue everywhere :D)
thanks

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Post by soulsonic »

joeysantoro wrote:Hi guys, nice to meet all, i'm Giovanni and i'm a new member and a new pedals addicted.
i've repair some vintage tube amp and now i'm starting with pedals. I've here a depth charge with some problems,
the first is a volume loss when fx was engaged and the blend work strange (no full clean signal anyway).
it's a led version with 3PDT. can you help me to identify wich could be the problem?
i suppose it could be a bad (or some) 2n3707, but i'm not sure. pedal it seems to be original with no mod (glue everywhere :D)
thanks
The first thing I would check is if the blend and volume controls are maybe broken or very dirty. Spray them with cleaner and see if the problem changes.
Check the bypass switch. It may be worn out and making poor contact. These mechanical things of pots and switches are usually the first things to die in old pedals.

The next thing would be to check if maybe there is a faulty electrolytic capacitor somewhere in the signal path. Of the components in the circuit, this is the one most likely to expire over time, so if the pedal is very old, one may have gone bad.
"Analog electronics in music is dead. Analog effects pedal design is a dead art." - Fran

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Post by joeysantoro »

Hi guys,
thanks to all for help me and sorry for the big delay. i've fixed It. Checking transistors voltage i found R28 with 466ohm value instead 10k and R4 1.8k instead 1k. Now sound good.

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