Author Topic: issues with modified ts808 pedal  (Read 1308 times)

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Belanger

issues with modified ts808 pedal
« on: August 31, 2016, 01:54:06 PM »
ok, so this is a slightly modified ts808 that I made off of the regular ts808 layout at tagboard. it sorta works but only when the gain is turned down really low and same with the volume. I'm going to try using the stock 500k for gain now instead of the 1m and let you know if that helps, other two pots are 5kb and 100kb. other subs are mostly just a few resistor values being dropped the same as the dead horse od as well as a few caps being increased
input cap 27nf, and the 47 nf is bumped up to a 220nf   all resistors match the dead horse exactly   ill post some pictures in a minute

my voltages are

IC
1-2.40
2-4.25
3-4.23
4-0
5-2
6-2.78
7-2.82
8-9.74

Q1
E-3.3
B-3.45
C-9.73

Q2
E-3.45
B-3.50
C-9.72
Music is moral law

Belanger

Re: issues with modified ts808 pedal
« Reply #1 on: August 31, 2016, 02:04:55 PM »




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Kipper4

Re: issues with modified ts808 pedal
« Reply #2 on: August 31, 2016, 02:05:10 PM »
Are the B E pins shorted? Surely there should be a diode drop from B to E?
A schematic wouldnt hurt. Belanger. Dead Horse you say......I've flogged a few of those.....
« Last Edit: August 31, 2016, 02:10:08 PM by Kipper4 »
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Belanger

Re: issues with modified ts808 pedal
« Reply #3 on: August 31, 2016, 02:06:22 PM »
also i know the diodes are facing the same way, i meant to do that
Music is moral law

Belanger

Re: issues with modified ts808 pedal
« Reply #4 on: August 31, 2016, 02:10:13 PM »
Also, I wrote the diode thing before reading anything you said lol just so you don't think I was saying that in reference to your comment.  This one I built here there isn't an exact schematic of It just traced the pedal and its another one of their OD pedals which like I said is very lightly modified . It's a very lightly modified dead horse OD

« Last Edit: August 31, 2016, 02:15:59 PM by Belanger »
Music is moral law

Groovenut

Re: issues with modified ts808 pedal
« Reply #5 on: August 31, 2016, 02:43:55 PM »
Just so you are aware, this schematic has an error. In the feedback loop of the first opamp, there is a resistor of 51R that should be a cap of 51p. If you did indeed put a resistor there, you wont get any gain at all.
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Belanger

Re: issues with modified ts808 pedal
« Reply #6 on: August 31, 2016, 02:53:03 PM »
yeah I knew that thanks, though, it's the silver mica cap on my board. like I said the only thing I used from this schematic is the resistor values and that because there the exact same as the pedal I traced which is a signature OD by them.  the rest is really similar but I didn't build from this schematic this is just a reference for you guys because someone asked me for a schematic

he uses gauss markovs tube screamer etch layout to build all of his OD pedals so it was really easy to figure everything out.  I own the merrow, Loomis and Misha signature OD pedals and the only differences are a few cap values and one resistor value on one of them
« Last Edit: August 31, 2016, 02:58:42 PM by Belanger »
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intripped

Re: issues with modified ts808 pedal
« Reply #7 on: August 31, 2016, 03:25:35 PM »
what transistors have you used? have you checked the pinout?

also check that 10K resistor close to the opamp: looks like 100K

Kipper4

Re: issues with modified ts808 pedal
« Reply #8 on: August 31, 2016, 03:40:07 PM »
The copper doesn't look very shines on the vero.
Did I say vero and I don't get along too well.
Jellybean dodging since 2012.
Smoke me a Kipper. I'll be back for breakfast.

pappasmurfsharem

Re: issues with modified ts808 pedal
« Reply #9 on: August 31, 2016, 03:56:11 PM »
also i know the diodes are facing the same way, i meant to do that

WHy?
"I want to build a delay, but I don't have the time."

slacker

Re: issues with modified ts808 pedal
« Reply #10 on: August 31, 2016, 04:19:56 PM »
It looks like you've got a blob of solder shorting the "tone 2" row to the one above it, that would cause weirdness. Your pin 1 voltage is way off, it should be about 4.5 volts as should 5, 6 and 7. I would try unsoldering one end of the 1k that connects pins 1 and 5, to break the connection between them and then measure the voltages again. If pin 1 reads 4.5 volts the problem is probably somewhere round pin 5 if pins 5,6 and 7 read about 4.5 volts the problem is around pin 1.

Belanger

Re: issues with modified ts808 pedal
« Reply #11 on: September 01, 2016, 04:52:51 PM »
what transistors have you used? have you checked the pinout?

also check that 10K resistor close to the opamp: looks like 100K

2n5088
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Belanger

Re: issues with modified ts808 pedal
« Reply #12 on: September 01, 2016, 04:55:48 PM »
also i know the diodes are facing the same way, i meant to do that

Why?

because that's how it is in the pedal i'm cloning
Music is moral law

Belanger

Re: issues with modified ts808 pedal
« Reply #13 on: September 01, 2016, 05:00:49 PM »
It looks like you've got a blob of solder shorting the "tone 2" row to the one above it, that would cause weirdness. Your pin 1 voltage is way off, it should be about 4.5 volts as should 5, 6 and 7. I would try unsoldering one end of the 1k that connects pins 1 and 5, to break the connection between them and then measure the voltages again. If pin 1 reads 4.5 volts the problem is probably somewhere round pin 5 if pins 5,6 and 7 read about 4.5 volts the problem is around pin 1.



i just checked the entire board for shorts with the continuity setting and i can't find any   i did what you suggested anyway but still the same voltages
« Last Edit: September 01, 2016, 05:14:25 PM by Belanger »
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robthequiet

Re: issues with modified ts808 pedal
« Reply #14 on: September 01, 2016, 05:07:32 PM »
[edit: never mind, re-read mica cap part]


[edit: closeness of the E to B pins looks weird, but I would ascribe that to some miniscule solder or bent trace bridge somewhere. Pot values would change the feel, but not the basic functionality, imo]
« Last Edit: September 01, 2016, 05:24:58 PM by robthequiet »
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pappasmurfsharem

Re: issues with modified ts808 pedal
« Reply #15 on: September 01, 2016, 06:39:44 PM »
also i know the diodes are facing the same way, i meant to do that

Why?

because that's how it is in the pedal i'm cloning

From what I've read on the dead horse, it has your typical diodes in parallel and reversed as you would expect. With exception that the larger one has a switch to add an extra DIODE in series with one for asymetrical clipping.

As it is you wont be clipping one half of your input signal (unless you clip the OPAMP)
"I want to build a delay, but I don't have the time."

Gus

Re: issues with modified ts808 pedal
« Reply #16 on: September 01, 2016, 07:25:06 PM »
Some of your IC voltages are wrong
Pin 8 should be the +9
Pin 4 ground
pins 2, 3, 1 and 5, 6, 7 should all be about 1/2 the supply voltage
The transistor base voltage are a little low
I would first check around pin1

Check all the nodes with the incorrect voltages for connection issues.
« Last Edit: September 01, 2016, 07:27:22 PM by Gus »

J0K3RX

Re: issues with modified ts808 pedal
« Reply #17 on: September 01, 2016, 10:15:34 PM »
In regards to the diodes, the gaussmarkov layout vs. the tagboard vero layout, when they are both pointed in the same direction they are not quite the same..

D1 and D2 are pointing in the same direction but, the way the traces are running makes it different from the vero.


See D1 and D2 in the schematic.
Doesn't matter what you did to get it... If it sounds good, then it is good!