Throbak Overdrive Boost Schematic  [traced]

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mxrmxr
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skywise
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Post by skywise »

Kinda seems like a waste of a germanium transistor just to use it as a diode. :scratch:

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Post by Bernardduur »

It sells :)

Hmmmm, were 2N2222A's ever used in the Colorsound Overdriver???/ That as they state on their website that the use the EXACT same transistors as the original.........

Commercial talk I guess :)
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Post by beedotman »

skywise wrote:Kinda seems like a waste of a germanium transistor just to use it as a diode. :scratch:
Those could be very low or very high gainers and/or leaky ones, useless for other functions...

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Post by Ben N »

Thanks, I've been looking forward to seeing this one. I admit I'm a bit disappointed that the Ge is just a clipper, and "Pre-Gain" is just a switchable input attenuator (at the cost of the original circuit's volume control), but what works works, I guess. The schem doesn't say, but I'm assuming 9v?

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Post by silverface »

Are you sure the resistor on the Bass pot is 3k9 ? On most other schematics of the original overdriver/powerboost it's 39k.

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Post by mxrmxr »

silverface wrote:Are you sure the resistor on the Bass pot is 3k9 ? On most other schematics of the original overdriver/powerboost it's 39k.
See for yourself....

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Post by bgobeske »

Nicely DONE!!! Quick question the board shows 4 trimpots. is one of these the 500k pot showed in the schematic. if so dose the 3rd pin of this pot go to ground or is it use like the three other trimmers?

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Post by mictester »

skywise wrote:Kinda seems like a waste of a germanium transistor just to use it as a diode. :scratch:
I do it all the time - it's a great way to use up leaky transistors!
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Post by Nocentelli »

gigelmargel wrote:Hello,

Maybe I am stupid, maybe I am blind, but I can't see any schematic here :)

Can anyone help me?

Thank you very much!
Seems to have been pulled by the original poster: Thankfully Mirosol did a vero layout -

http://tagboardeffects.blogspot.co.uk/2 ... boost.html

...so it shouldn't be difficult to re-draw.
vanessa wrote: 20 Aug 2007, 17:51 You can't arrest someone for reverse engineering something.

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Post by Nocentelli »

Maybe, the last post from mxrmxr was two months ago, so while waiting for it to show up again you could compare mirosol's layout to the stock colorsound overdriver schem and note the few differences.
vanessa wrote: 20 Aug 2007, 17:51 You can't arrest someone for reverse engineering something.

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Post by bajaman »

Throbak Overdrive Boost Schematic.jpg
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Post by Ripdivot »

Thanks Baja

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Post by snofla1900 »

Oh I see you already have it. I just sent you a copy.
What it reminds me of is the Coloursound overdriver, just compare.

Alf

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Post by tube-exorcist »

If the schematic is correct and the pedal really wired this way then it is a piece of junk. Think of the pre-gain-poti fully down but bypassed..... But what does one expect from a solder-jockey clone.
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Post by roseblood11 »

...and in both positions of the switch the 2M2 at the input would be useless.
I can't believe that this schematic is correct.

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Post by V1nce69 »

I successfully built this pedal using the layout from tagboardeffects. I can confirm that this layout works and that the pedal sounds really fine.

As for me less wiring from the board, the better, I made some slight changes to the layout:

- I didn't use the dummy connection to the board (PGSW1/Pregain 3), thus 1 cut less. I wired the Pregain switch 1 directly to Pregain pot 3.
- there's only 1 ground wire going out of the board; Pregain1, Gain 1&2 and Volume 1 are daisy chained to ground on the DC jack.
- I used a 3PDT for the Boost switch as I didn't have a DPDT.


The wiring itself is kinda tricky and it took me quite a while to figure it out. I made 3 or 4 different versions before getting it working the way it should.
Actually it was my first attempt to build on veroboard…

So I thought I would post the layout I used and a few pics of the build itself.


Layout:
layout
layout
Outside:
outside
outside
Inside:
inside
inside
Board
board
board

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rocket8810
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Post by rocket8810 »

I've built this using the same layout on tagboardeffects and it fired out right away and sounds great. A there is one anomaly that bothers me. Whether the boost is engaged or not the pregain pot will effect the signal. Now, it's not a big change when the boost is off, it's much more drastic when the boost is engaged. I would have thought that when the boost is off the pregain pot is out of the circuit.

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Post by Nick123 »

Using DPDT instead of a SPDT switch would decouple the pregain pot from the rest of the circuit.

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Post by rocket8810 »

hmmm, i wired it with a 3pdt switch since i didn't have any dpdt switches laying around, cause i wanted to have an led indicator too. i wonder if that's the issue. i may have to go back and take a look at it, but for now it sounds good to me.

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