70's big muff blues :-(

[JasonG]

Hey gang
  I just got a Big muff pi I thought it was a mk 2 but its a mk 3 :-(. Any way my question is, is the mk 3 supposed to sound gated? Or is it having a biasing problem? I have had a MK 2 ( I still miss it ) and it sounds more open and doesnt cut the signal.
                               Thanks !
                                      Jason

[petemoore]

Gated>? BMP is advertised as a sustain enhancer, if it's gating I'd mess with it.
 I'd measure the transistor pin voltages and work from there.
 Sticky: What to do when it doesn't work ... is a good thread to read in any case.

[mrsage]

What's MK2 and MK3?

I only know them based on the common terms, like "triangle muff," "ram's head," etc...

[JasonG]

Well there were three different modals of the BMP the first two were pretty close but the last one was alot different.  It used IC chips insted of just transistors.   I bought it on ebay and thought it was a MK2 because the knobs were 70's style but it must be an early mk3.  Google Big muff there are some good pages out there that explain it all.

[bwanasonic]

There are fans of the IC Big Muff, and I'm pretty certain it's not because it's gatey. I'd check that.

Kerry M

[ErikMiller]

As the person who makes the only currently commercially available op-amp Big Muff, I can tell you that it's NOT supposed to sound gated.

Check your power pin voltages, coupling caps....

[col]

I just built an op amp big muff on stripboard and it isn't gated at all. It has a similar sustain to the other types but has a darker sound, excellent for stoner rock, very similar to the sound Sleep have on 'Jerusalem'. My favourite is still the foxy lady/triangle circuit though which has been in constant use in my band since I built it last year. If anyone can pm me with their e-mail and will put it up I can send a scan of my layout but it might get into next week. I don't have a web page so I can't put pictures up here.
Last night I directly compared a clone of the current build, an op-amp version and the original circuit. They all sound very different but all sound good. The op-amp is probably the most stable version. The current build sounded good with a dynacomp in front too (on and on and on etc.) but it was a bit much for the other two versions.

[JasonG]

[Sir H C]

The op-amp one has a great sound.  If it is gated, then most likely there is a DC biasing problem.  I would guess that the inputs to the op-amp are pulling to the rail (or ground).  

I have an old op-amp BM and have compared it to Erik's, and his is identical in a smaller box.

[jimbob]

As the person who makes the only currently commercially available op-amp Big Muff, I can tell you that it's NOT supposed to sound gated.

I chked out your site= nice..

Anyways- I have been finishing up my take on the 3 different BMP's at the Tonpad site.  All sound Very good.. However, I havnt came across a layout for a op-amp muff. Are there any out there?

[soggybag]

I've never seen a schematic for an op-amp Big Muff? Can anyone point me to one. I'm very curious what's going on with this? I have seen plenty of transitor versions that are all really the same. I have also seen the Swollen Pickle Schematic, which uses a quad transistor array on 14 pin dip.

[AL]

There's an op-amp version here

http://www.j.philpott.com/effectronics/

AL