Clark - Gainster (big box) / Barber

General documentation, gut shot, schematic links, ongoing circuit tracing, deep thoughts ... all about boutique stompboxes.
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call1800ksmyazz
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indyguitarist
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Post by indyguitarist »

call1800ksmyazz wrote:Here ya go.



Kerry
Hi Kerry,
cool, thanks! Always wondered about that one. Crazy that it's just a boss od-1 without buffers and a different nfb network

bw

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analogguru
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Post by analogguru »

Schematic applies only to the unit of Dan N. I have guts from 3 different other units which show 18k/18k for the bias voltage divider.

The right side (added part for the small box) appears a little bit suspicious to me - 1M in parallel to a 100k trim doesn´t make any sense. There exists a different one too, both have to be verified.

analogguru
There´s a sucker born every minute - and too many of them end up in the bootweak pedal biz.

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JHS
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Post by JHS »

The schem is my "custom" version of the Gainster!!!!

Ghandi and me traced it from the pic of Dan's unit. The bias divider of all other Gs is 18k/18k and a 50uF or 200uF C, depending on the version. We choose this unit after prototyping some versions of the G and we had come to the conclusoin this version sounded best (more upfront with better dynamics).

The Bottom control had been designed to suit Ghandi's special needs who wanted to have a possibility for a slightly fatter sound (like on the last Clark Gs). My clone has a switch for selecting the 100n or 1uF, but Ghandi prefered the Bottom control to get some inbetween sounds.

With the 1M the 100k lin Bottom pot acts more even, you can drop it if you like.

I recommend to prototype the circuit and to alter the I/O caps and the 47 and 2,2n and then choose the values those will suit your setup best.

JHS

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bajaman
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Post by bajaman »

A BIG welcome to our friend JHS :D :D :D
Thanks for joining up - looking forward to your posts
Cheers
Steve

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Ghandi
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Post by Ghandi »

hi everyboby,
so I finally found this forum, nice!
I haven't had too much time in the last year to build and modify stompboxes, but playing with all of what I had, me fav is the clark gainster after that exact schematic!

can't praise the old gainster enough,
but if you build one the quality of parts is very very important.
and makes the difference between a "boss od-1 without buffers" and a absolutely great transparent overdrive and beets the hell out of a kot, ocd, eternity and whatever,
at least for me. :)

by the way I switched the ic to a jrc072 which I liked a bit better that the lf353, because it is a bit warmer and fuller.

keep on rockin a free world!
Ghandi

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bajaman
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Post by bajaman »

Hi Ghandi - glad you could make it here :D
enjoy the site :wink:
bajaman

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Post by soulsonic »

Is the Clark name on this pedal the same as the Steve Clark who makes clones of old Fender amps? If it is, we shouldn't feel bad about taking anything from him - he's already a millionaire from other business and he just does this crap for fun. The amps he sells are just stock Weber kits with some nicer parts substituted in. He's probably one of their biggest kit customers.

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JHS
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Post by JHS »

The org. Gainster was built by Mike Clark...

JHS

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call1800ksmyazz
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Post by call1800ksmyazz »

Oh yea, by the way, I was given this schem by JHS so everyone thank him :D

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modman
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Post by modman »

Clark Big Box Gainster Gut Shot

Soon archiving all this completed stuff.
Please, support freestompboxes.org on Patreon for just 1 pcb per year! Or donate directly through PayPal

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JHS
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Post by JHS »

Modman, this gut shot is from a Barber Gainster prototype not from the Clark BB-Gainster.

JHS

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Dan N
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Post by Dan N »


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soulsonic
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Post by soulsonic »

Ha, done like an amp I see - and complete with mojo parts. Nice. I like that kind of style. I can see why its in such a big box!

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JHS
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Post by JHS »

One of the few FX that deservesd the term boutique-pedal.

JHS

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JHS
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Post by JHS »

This G-circuit looks kinda strange, normally there are two 1M Rs in a G., one is the pulldown for the input and the other is the BIAS-R for IC1a/pin 3.

On Dan's pic I can see only one 1M connected to ground, not yet clear if it's a BIAS (pin 3 to ground) or the pulldown R and no BIAS R for pin 3.

Furthermore there are two 10k for the BIAS-divider, all other Gs I saw have two 22k for the divider.

The green PIO-caps should be 100n, the yellow tone cap 47 or 100n.

JHS

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DougH
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Post by DougH »

Resurrecting an old thread here...

I breadboarded this last night to try it out and I confess I don't really get the point. It didn't really develop much internal gain unless the presence was cranked and then it became so trebly it was almost unusable- very icepicky take-your-head-off highs. It sounded like some of the clips I've heard of it in the past.

Can someone describe how they use this thing? Do you use it to boost the front end of your amp? Or do you just use it as an overdrive? What kind of amp do you use it with?

I used it with my Vox AC15 "clone" and it just sounded like a generic run of the mill Fender amp that is cranked up slightly- no big deal. With the presence control in a sane setting, it just added a very slight clip to the clean sound of the amp, barely noticeable.

I'm just trying to figure out what it is used for. If it's used to add a very slight distortion to your 100W Twin at bedroom volume, I guess it makes sense, but it seems like overkill for that.

I'm honestly not trying to be sarcastic. If you like this thing and use it I'd like to hear how it "fits in" to your rig and what you use it for. It's an interesting looking circuit. Nice to see someone doing something with an op amp besides a TS...

EDIT: Okay, I've found some more clips and they sound "fatter" then what I'm hearing on the breadboard. Maybe I have something wired up wrong. Also- are you guys sure the 47n "presence" cap is correct? Seems like that may contributing to some of the "thinness" I'm hearing.

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JHS
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Post by JHS »

With a 1M pulldown R the sound is smoother, furthermore a 250k volume pot kill the icy highs a bit. I recommend to use a N-Semiconductor LF353N or a JRC 072BD, other types I tried sounded bland in this circuit.

I added a 1M pulldown R and raised the 47n to 56n on my clone, IMHO 68n is fine too, 100n was to bassy for my taste.

I use it for pushing Fender tweed and Marshall NM amps (set up clean or at saturation level before the distortion gets in) and the G. is adjusted to produce a treble boost with a bit of grit, soundwise like a Rangemaster, not much gain.

IMHO it's not designed as a stand alone OD, it's more a gritty boost, designed for pushing old tweed amps.

It's a bit harder to get a good sound out of the G. 'cos the Pres. and Gain pots are very interactive and often it takes some time to adjust the 2 pots to archieve the desired sound.

JHS

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Post by polarbearfx »

whats the original op amp in this one?

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Post by DougH »

Thanks JHS, I'm going to play with it some more tonight. One of my issues is my "bench part stock" is dwindling right now for these kinds of experiments. So I'm using an old 50k for the presence pot and it is flaky. I'm going to get that straightened out tonight. There were a couple settings that made my amp "sing" in a real nice way. But dialing up good sounds is difficult with a flaky pot.

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