Op Amp Big Muff Build - lack of Sustain?

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Op Amp Big Muff Build - lack of Sustain?

Postby kosmonautmayhem » 17 Nov 2011, 23:33

Hi all, This is my first official post in this excellent and incredibly useful forum.
Hoping some of you could lend your experience...

I just built an Op Amp Big Muff (with tone-bypass) using this layout.
http://i102.photobucket.com/albums/m112 ... YPASS2.gif

After a few minor mistakes, I got it working! Its housed in a circa 2000 NYC box. I used the LED hole for my tone bypass switch, so no LED like the originals. I also utilized the power jack so I can use my pedal power or battery.

Overall the pedal sounds nice and like I think it should, with one caveat: I have a lack of sustain. This is especially prevalent on the higher strings. I should easily be able to coax some nice sustain on single note runs, but it disappears pretty quickly. Its pretty underwhelming. I'm also wondering if there should be a touch more gain? I understand the nature of this beast (op amp BM is usually more behaved than the transistor style) and have played a few originals that were definitely more gain-y and sustained with ease.

Any ideas where to start looking. I've double / triple checked my layout and all looks fine. I'm also going to take another look at the solder-side of my board to double check for shorts. All parts are exactly spec to the layout listed above except C10, all i could find was 100nF (vs. 120nF).

Thanks and Cheers,
kM
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Re: Op Amp Big Muff Build - lack of Sustain?

Postby Sonic » 13 Dec 2011, 01:48

It sounds like some sort of amplification problem, can be alot of things that can be wrong. I would start with checking out the components and voltages around the 741, if this one doesn't work, sound will still travel through the diodes producing a small amount of clipping (fuzz/sustain), which you have in your case.
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Re: Op Amp Big Muff Build - lack of Sustain?

Postby kosmonautmayhem » 14 Dec 2011, 19:26

Thanks for the reply!

You know....it may just be that I'm more used to hearing transistor Muff circuits. I've spend a lot of time playing the pedal since my first post and find its not so bad after all. Different guitars / pickups obviously react very different and also the amp and speaker makes a difference too. Another thing that seems like it makes a difference is that it sounds better when running on battery only - could be my head playing tricks though ;). I'll double check my DC jack wiring.

My initial lack of sustain wasn't necessarily gated or un-natural sounding. I'm just used to smoother, more sustaining FF circuits. The biggest difference of all, was cranking this pedal. Tons of sustain! You just have to work for it a little harder than with a fuzz face. Overall output / volume is great. Plenty of volume.

There's a 'sustain mod' I was reading about that I might look into, supposed to coax a bit more sustain and gain out of this circuit...may be a worth while mod.
Of course you can always run an OD/dist box into the muff for more-gain. :)

Cheers,
kM
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Re: Op Amp Big Muff Build - lack of Sustain?

Postby Sonic » 15 Dec 2011, 17:00

Cool :) And yes the opamp Big muff is a little more harsh and a little less sustaining than the transister BM. I also a little interested in the sustain mod, I'll look for it, and maybe my opamp muff can come on my pedal board again, right now I'm using a DIY violet rams head.
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Re: Op Amp Big Muff Build - lack of Sustain?

Postby kosmonautmayhem » 15 Dec 2011, 18:37

Sonic wrote:Cool :) And yes the opamp Big muff is a little more harsh and a little less sustaining than the transister BM. I also a little interested in the sustain mod, I'll look for it, and maybe my opamp muff can come on my pedal board again, right now I'm using a DIY violet rams head.


I'm starting to figure that out! :D
Now I might be inspired to try some other big muff variants. Always wanted to try out a ram's head, civil war, etc.
Have a last run big box Russian thats pretty cool.

Cheers.
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Re: Op Amp Big Muff Build - lack of Sustain?

Postby D-Day » 16 Dec 2011, 19:07

Analogguru has a sustain mod on his schems: viewtopic.php?f=19&t=9481

I liked it better stock though.
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Re: Op Amp Big Muff Build - lack of Sustain?

Postby kosmonautmayhem » 16 Dec 2011, 19:34

What were the differences you noticed about the sustain mod?

Likes / dislike?
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Re: Op Amp Big Muff Build - lack of Sustain?

Postby D-Day » 17 Dec 2011, 19:01

Well I like heavy duty stoner rock and doom type sounds. So I'm not looking for my fuzz to sustain softly and beautifully like a violin or saxophone or something. When I plug in a dirt pedal I want that dirt, ya know? Well AG's sustain 'fix' washes away some of the ICBM's unique dirt nastiness and smooths it out/softens it up a bit. It did not seem to increase the sustain any though it would be hard to tell because my build had plenty of sustain in the first place. YMMV
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