Big Muff v4: bypassed signal is boosted? How?

[Skreddy]

I'd re-flow a couple of those solder joints, FYI.

[Angle Loss]

I popped mine open. The pots date to February 1980 and it uses a UA741 and a JRC4560 not a 4558.

[lux_interior]

Originally Posted by Angle Loss

Interesting...mine is both wired and labeled as a Tone Bypass, which is what yours should be also. Someone may have switched the top case or they might have used up an old case or as you said just plain wired it up wrong. Check the pot codes. It should start 137yyww (year=yy ie 80 is 1980, 33 is the 33rd week of production that year). That will help you date it. The pedal will be made on that year or later.

I can't remember...but I think these were made around 1980. Yours has the 1980's style knobs. Take a look at yours and I'll take a look at mine and get back to probably tomorrow morning. I'd be curious to find out more.

The pots on mine say "1378004" and "1378005", so I guess that according to your instructions they were made in the end of January and the beginning of February of 1980.

One of the opamps that I managed to take a look at says LM741CN, so it's not a 4558! Surprise, surprise... wasn't that the one that was used in the MXR Distortion? What tonal difference would it have in a Muff? Would it be common, or was it another "frankestein" idea that the EH guy had on that morning 30 years ago?

@Skreddy: excellent advice, thanks a lot. Another thing that I have to do is start Googling to see what changes need to be done to convert the on-off switch into a tone bypass one. Any opinions?

[Skreddy]

Originally Posted by lux_interior

The pots on mine say "1378004" and "1378005", so I guess that according to your instructions they were made in the end of January and the beginning of February of 1980.

One of the opamps that I managed to take a look at says LM741CN, so it's not a 4558! Surprise, surprise... wasn't that the one that was used in the MXR Distortion? What tonal difference would it have in a Muff? Would it be common, or was it another "frankestein" idea that the EH guy had on that morning 30 years ago?

@Skreddy: excellent advice, thanks a lot. Another thing that I have to do is start Googling to see what changes need to be done to convert the on-off switch into a tone bypass one. Any opinions?

Opinion (mine): I'm not a fan of Big Muff tone bypass, personally. I'd keep the on/off switch.

[Angle Loss]

Originally Posted by lux_interior

The pots on mine say "1378004" and "1378005", so I guess that according to your instructions they were made in the end of January and the beginning of February of 1980.

One of the opamps that I managed to take a look at says LM741CN, so it's not a 4558! Surprise, surprise... wasn't that the one that was used in the MXR Distortion? What tonal difference would it have in a Muff? Would it be common, or was it another "frankestein" idea that the EH guy had on that morning 30 years ago?

The 741 is a classic single opamp (the JRC4558 being a dual opamp--like two 741's in one package). You should have a 4558 or a 4560 in their as well. Different manufactured opamps were probably subbed depending on what they could find cheap. We both have "741" opamps but slightly different variations--shouldn't make to much difference in sound. You are right, the MXR Distortion+ does use a 741.

[lux_interior]

Originally Posted by Skreddy

Opinion (mine): I'm not a fan of Big Muff tone bypass, personally. I'd keep the on/off switch.

I understand, but it can give an additional flavour... and if I don't like it, no harm done - I could still set the switch for the tone stage to be on... As far as the tone bypass function in Muffs goes, I've only had experience with my Tone Wicker Muff, and although I haven't used it yet for any songs, I like the raw tone - it's a bit of extra mayhem that can work very nicely in spite of the high gain levels.

[lux_interior]

Originally Posted by Angle Loss

The 741 is a classic single opamp (the JRC4558 being a dual opamp--like two 741's in one package). You should have a 4558 or a 4560 in their as well. Different manufactured opamps were probably subbed depending on what they could find cheap. We both have "741" opamps but slightly different variations--shouldn't make to much difference in sound. You are right, the MXR Distortion+ does use a 741.

Thanks for your answer!



P.S. It seems it's not an 8db boost on the clean bypassed tone but considerably larger... I didn't do any proper measurements, but to my ears it sounds something like double that. For the record my main amp (and only these days) is a Boogie MKII combo with an Eminence Tonker (swapped the original EVL but kept it, of course), a Tung Sol 12AX7 in V1, and TAD 6L6WGB as power tubes (amazing tubes, and I've tried a lot). I use the clean channel, and every guitar sounds gorgeous (Classic Player 50s Strat and an Eastwood Ultra GP with Bare Knuckle Mules without covers, and various other upgrades). Plus, those rich Pumpkins tones are ridiculously easy to get - no need for JCM800s with 4x12s and KT88s.

That active bypass doesn't make anything sound muffled, far from a tone suck or anything. I have a ZVex SHO coming in a few days, and I can't wait to see how it compares to the boosted bypass from my Muff. Can it be that special? I haven't heard anyone raving about such a thing.