Deluxe Big Muff

[Rodgre]

I'm looking for a schematic for the Deluxe Big Muff. If anyone has a working one, I have a couple of questions.

I just picked up an ailing one. It works, but the compression seems to be tremoloing.... like it's feeding back into itself or something. The distortion sounds too squished, even with the compression off. Maybe a power supply thing?

I don't know. I'd like a schematic.

There is one 4558 on the board facing a different direction than all the rest. I wanted to make sure that was correct, as it had been worked on before I got it.

Roger

[Ed G.]

I think the dlx. big muff is a blackfinger compressor with the big muff, so if you can find a schem for that compressor it might help.

[sir_modulus]

no black fingers in there. The pedal is only like 100 canadian while the black finger is over 300. fuzzcentral has a schematic of a deluxe big muff. From what i know, the sustain is a small version of a soul preacher compressor.[/url]

[Mark Hammer]

Unfortunately, no DBM there, just the BMP.  If you check the back issues of DEVICE at my site (http://hammer.ampage.org) there is an article on modding the DBM.  It is a combo BMP and Soul Preacher.  The Soul Preacher schem is posted around, and a close inspection reveals it to be not categorically different than an Orange Squeezer.  Both of these compressors have a single op-amp gain stage which provides both the output and also feed an envelope follower which controls a FET to attenuate the input signal on peaks.  Where the SP and OS differ is that the SP uses a full-wave rectifier (to produce less envelope ripple), and also has a transistor input stage to provide some boosting ahead of the FET.  The SP also has a switchable bypass cap on the output level control to compensate for the normally occurring loss of treble in compressors.

Not sure what is causing the sound you describe, but normally when things oscillate at a perceptible rate, the source is connected to a medium-to-large capacitor.  As well, with FETs, they need to be biased right to work as intended.

The SP has a historical/reputation as noisy, but quite frankly, I can't see anything in the schematic/design that would suggest it to be any noisier than any other compressor.  To paraphrase Neil Young, "That's their sound, man".  I suspect it is a reputation that is largely undeserved, or at least not deserved any more than other pedals of a similar type and age/era.