Four Boosts in One Box

soulsonic · Post by **soulsonic** » 21 Aug 2008, 03:15

The trimmer looks fine.
Make sure the transistors for the MiniBooster are JFETs and not MOSFETs. I used 2SK117 in mine.

About the Opamp boost; it's just a standard noninverting opamp stage. I used an LF411 for the opamp. The input impedance is ~1M. The gain control is a 50K linear pot. It's very full bandwidth.
The MAX1044 circuit is just the generic app note circuit for generating a negative supply. It's essential for giving the opamp boost a bipolar supply and for being able to easily use a PNP Ge transistor for the Rangemaster.

asfastasdark · Post by **asfastasdark** » 25 Aug 2008, 21:50

Could we get sound clips of all four (three?) together, I might be interested in building one of these. I've always really liked the idea of combining a couple of pedals in one box and using the combination of their sounds as an advantage, and with four boosts it's gotta be a pretty huge boost!

soulsonic · Post by **soulsonic** » 06 Sep 2008, 09:30

asfastasdark wrote:Could we get sound clips of all four (three?) together, I might be interested in building one of these. I've always really liked the idea of combining a couple of pedals in one box and using the combination of their sounds as an advantage, and with four boosts it's gotta be a pretty huge boost!

A recent purchaser said he would record some clips. There's hundres of tones available when stacking the boosts: everything from overdrives to fuzzes!

Solidhex · Post by **Solidhex** » 06 Sep 2008, 18:47

Damn

I gotta do that. Having a bunch of different boosters laying around is annoying. If one circuit doesn't float your boat at least you didn't waste the time dedicating a single enclosure/wiring job on it... Those all sound like good times though.

--Brad

LMJS · Post by **LMJS** » 07 Sep 2008, 14:59

SoulSonic: "a super-clean opamp boost of my own design,"

Is there any chance you can share that one with us????

soulsonic · Post by **soulsonic** » 08 Sep 2008, 05:19

LMJS wrote:SoulSonic: "a super-clean opamp boost of my own design,"

Is there any chance you can share that one with us????

Okay. It's very simple. It must have a bipolar power supply (either from two batteries or a charge pump circuit) for it to function correctly. It's basic textbook stuff.

Silent Fly · Post by **Silent Fly** » 08 Sep 2008, 08:20

soulsonic wrote:Okay. It's very simple. It must have a bipolar power supply (either from two batteries or a charge pump circuit) for it to function correctly. It's basic textbook stuff.

It may sound a silly question but... what is C9 for?

If DC and lower freq are filtered by C7, why do you need C8?

Last question: why R12?

soulsonic · Post by **soulsonic** » 08 Sep 2008, 08:46

Silent Fly wrote:
soulsonic wrote:Okay. It's very simple. It must have a bipolar power supply (either from two batteries or a charge pump circuit) for it to function correctly. It's basic textbook stuff.
It may sound a silly question but... what is C9 for?

If DC and lower freq are filtered by C7, why do you need C8?

Last question: why R12?

There is likely some (tiny) DC offset caused by the large resistor R9, so I have C9 to make sure that any DC offset isn't amplified. I suppose that if an offset null circuit was included, then C9 wouldn't be needed, but there isn't very much space left on the board as it is... maybe in a standalone version there can be offset null. With the offset null, I may be able to not use any caps at all.

R12 is added protection from short circuits on the output. A short circuit shouldn't damage most normal ICs, but R12 protects against excessive current draw if there is ever a case of a continuous fault.

I made these choices based on advice I've gotten at various times from Analogguru and R.G. Keen.

LMJS · Post by **LMJS** » 08 Sep 2008, 10:04

Thanks for sharing that.

Post by **modman** » 10 Sep 2008, 19:16

I think this is a great thread, the idea is so stupid and simple but it's an easy way for beginning builders to start experimenting with distortion beyond building carbon copies. For me it also shows how thin the line between originality & imitation go hand in hand

...

Anyway, what I wanted to say: I think this thread should be in the Projects folder and doesn't need explicit schematizing or layouts. Just the idea of a modular boost distortion/fuzz is might inspire some people.

Lemme know if that's ok for you, Soulsonic?

soulsonic · Post by **soulsonic** » 10 Sep 2008, 21:36

Yeah, you can post this in the Projects folder if you like, but I won't put up any layouts or pcb designs. If someone else does, that's fine, I'm just not going to share my commercial PCB artwork.

RnFR · Post by **RnFR** » 11 Sep 2008, 08:14

just a heads up. there are some mistakes in the vero layout i posted. once i get the bugs out and redo it i'll try and make a new one and post it.

i guess it's more fun actually building than sitting in front of a computer

Post by **modman** » 11 Sep 2008, 10:15

Great! Like I said, there is no real need for actual project files here -- there are layout available for the separate circuits at various other places: GGG, Aron's, Tonepad, etc.
If you do want to share your layouts, RnFR, that is great, but make sure that unverified stuff is marked as such and eventually removed. Let me know if you need help.

thanks all!

mike_a · Post by **mike_a** » 18 Nov 2008, 13:54

Great project!

Soulsonic, could you explain (or better yet - draw) the bypass scheme you used?
(I also posted a comment on your site, but that was before I came across this thread...sorry...)

Thanks!

soulsonic · Post by **soulsonic** » 26 Nov 2008, 07:49

mike_a wrote:Great project!

Soulsonic, could you explain (or better yet - draw) the bypass scheme you used?
(I also posted a comment on your site, but that was before I came across this thread...sorry...)

Thanks!

It's the type of bypass that connects the input of the effect to ground when it's bypassed. I'll try to get something drawn up for it. I like to use it because it keeps the effect from making any noise while it's bypassed. Sometimes a circuit can start oscillating or otherwise start acting goofy if it's input is left open when bypassed, so this takes care of that. It also does a good job of being nearly pop-free even without an input pulldown resistor. It's not totally perfect in that respect, but it's close enough for me to be okay with not using an input pulldown. I believe Skreddy and a few other guys out there use this same arrangement.

Sorry I hadn't replied to your comment on my site yet. I'm way behind with keeping up with that stuff.

mike_a · Post by **mike_a** » 26 Nov 2008, 19:36

soulsonic wrote:
mike_a wrote:Great project!

Soulsonic, could you explain (or better yet - draw) the bypass scheme you used?
(I also posted a comment on your site, but that was before I came across this thread...sorry...)

Thanks!
It's the type of bypass that connects the input of the effect to ground when it's bypassed. I'll try to get something drawn up for it. I like to use it because it keeps the effect from making any noise while it's bypassed. Sometimes a circuit can start oscillating or otherwise start acting goofy if it's input is left open when bypassed, so this takes care of that. It also does a good job of being nearly pop-free even without an input pulldown resistor. It's not totally perfect in that respect, but it's close enough for me to be okay with not using an input pulldown. I believe Skreddy and a few other guys out there use this same arrangement.

Sorry I hadn't replied to your comment on my site yet. I'm way behind with keeping up with that stuff.

That drawing would be great!

Thanks again.

remork · Post by **remork** » 06 Dec 2008, 18:06

hey mike
you probly found it by now
but here's my guess

@ soulsonic:
lookin' good..
damn

soulsonic · Post by **soulsonic** » 07 Dec 2008, 22:39

Yes, that's it. Thanks for doing that for me.

evanc521 · Post by **evanc521** » 18 Mar 2009, 06:57

That looks cool as hell.

candletears7 · Post by **candletears7** » 24 Jun 2010, 08:47

RnFR wrote:i think this is how it should look with the trimmer right?

has anyone built and verified the RM > SHO > AMZ Booster from the layout on page 1? If not, I'm keen to give it a crack!