Javi mentioned on the original IC BMP post that the original 2 ICs instead of the quad used in that layout make the circuit sound a lot better. So i thought i'd draw up a layout for '78 tone bypass switch version with two opamps. This way one can build a clone that's closer to the original and/or try out different opamps for it. It is per Analogguru's schematic which has couple of notes on it. First of all, the sustain connections are tweaked to function better. Both can be easily be modified per original on this board. And then there's a note for 820K resistor from supply to IC2 pin 3. That resistor needs to be 1M if you want to use TL071 or similar FET opamps for IC2.
Excellent layout matey. I'm glad you did this, I really don't like my earlier layouts at all and wanted to redo them anyway.
ReplyDeleteThanks. It turned out a bit big, but otherwise ok. Let's just hope that it works :)
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hello. ty. it works. but - very sputter and intermittent "broken" sound at the ends of the notes, very short sustain. where can be a problem?
DeleteI've built a few of these myself and the layout works. You should probably use a probe to see where your signal goes bad. Also, usual debugging methods may be handy. Measure voltages on I pins to see if there's anything off with those.
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hmm.. and Sustain works like Volume. pedal works only when Sustain pot on max
DeleteGREAT!
ReplyDeleteBut are there no cuts underneath D2 and D5?
Thanks for noticing. There should be. I'll fix it once i'm back home.
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Updated.
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What do the blue dots mean?
ReplyDeleteDouble link...
DeleteThe blue dots indicate double links. So for example, rows 2,7,9 and 15 are all linked. Hope that makes sense
DeleteCheers
Dave
Depending on the wire that you use, you may have to enlarge the hole. I have to take the tiniest drill bit that I own, that is only slightly larger than the diameter of the hole, and drill out the opening just a tad. Be careful not to drill away the copper trace completely though.
DeleteUse resistor cut offs. You can easily get 3 in if you're using the common blue 1/4 watt MF25 metal film.
DeleteThanks, that was what I thought. I think I never made something that uses them, so I wanted to be sure!
DeleteBuilt it. Rocks.
ReplyDeleteIn fact, this became instantly my favourite BMP, trumping even the Triangle, which i earlier though was the greatest of the versions. It surely sounds like a Bigg Muff, but there's something it its character that separates it from the rest. Recommended build. Definitely.
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Miro, what do you think of the tone bypass mode? Is it a useful sound, or would you pretty much stick to the standard mode with the tone control?
DeleteExtremely useful. It gives you 6-9dB boost and the mids come out a lot better while still keeping the fat muffesque buzz in tact. Very good option and adds a lot of versatility.
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please could somebody send me a picture of the circuit in how it is made n what parts r required a total newbee on the circuit building
ReplyDeleteYou should probably try out something a bit smaller and simpler to begin with. Check the build guide http://tagboardeffects.blogspot.fi/2012/04/vero-build-guide.html
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ReplyDeleteThanks for all your job...
ReplyDeleteIs it possible to replace the u741 uc with a LM1458??
Thank you very much¡¡
No. 1458 is a dual opamp with completely different pinout than UA741, which is single opamp.
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Forgive my ignorance, but can I use two of the u741s instead if two different op amps?
ReplyDeleteInstead of*
DeleteNo you can't. 741 is a single opamp and 4558 is a dual opamp. The pinouts do not match.
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Thanks!
DeleteThis is probably the best muff version I've played so far. Still loving modded stuff more than original muffs :)
ReplyDeleteFiga :)
ReplyDeleteHi,
ReplyDeleteHaving some trouble - can you please share what the volt readings should be at the pinouts of both ICs? Would really appreciate it. Thanks!
Hi -sorted. Amazing sound. Love it. Thanks man!
ReplyDeleteHello Miro, which one could be a good Fet opamp for IC2?
ReplyDeleteI think i would go with TL071 or TL081.
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Thank you very much Miro.
DeleteI've just built it and it sounds great, BUT, the tone control doesn't work and when I change the spdt switch position, the sound almost disappear. When changing the switch back to the original position, the problem persists, you can hardly hear it. Any ideas what may be causing this?
ReplyDeleteHas anybody built this with IC2 being something other than the UA7421?
ReplyDeleteI have done this one with a RC4558NB and a TL071 on IC2. Sounds great! A Little bit sag sound. I put a buffer in front of him and works great too.
ReplyDeletephotos: https://www.flickr.com/photos/77206179@N02/sets/72157648864378317/
Anyone else have this sag-velcro sound? My settings are sustain all the way up, tone one o'clock and volumen 2-3 o'clock.
I ordered some op amps from Mouser to try and build this. I have an RC4558IP and UA741CP. I'm not sure if the prefixes and suffixes matter or not. Will these op amps work? Fingers crossed. Navigating Mouser's catalog is a bit daunting for neophytes like myself! The 1/4w resistors I ordered are all pretty huge too, so in some places I'm gonna have to mount them upright.
ReplyDeleteI'm also wondering how I'd build this without the tone bypass switch. I assume just a jumper in place of the switch, but would it be between rows 3 and 9 or rows 9 and 11? Or is there a simpler way still if I'm omitting the tone bypass? I'd like to incorporate it, but with the graphic layout I have planned the only way I could see it fitting would be possibly on the side of the enclosure. Hmmm.
One more question. Which way would the op amps orient? Should I be able to read the text on the op amp upright as viewed from the left side of the board or from the right side?
DeleteFirst, just leave the switch wires out and connect tone 2 straight to volume 3. That would be the simplest way to go.
DeleteThose ICs will work fine. The prefix usually indicates the manufacturer (the same chips have been produced by a number of different brands) and the suffiz usually indicated the packaging the chips were shipped out in. So basically those don't matter at all.
If you look at the layout, there is a lighter grey recessed marking on the top side of each opamp. You should have similar recessed dent on your opamps.
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According to images over at kitrae of actual units, the 330p capacitor is usually 160J or 150J which is 16p 5% or 15p 5% ... one of those pepetuated bad schema deals.
ReplyDeletefrom the schematics i looked at you are correct. one thing to keep in mind though that this is a feedback resistor. the larger that cap is it will smooth out the clipping, and rolls off some of the highs, and get some more bottom end. if you lower it you'll get more "crunch", and less low end. you can play with different values and see what you want to do. i personally built mine as the layout is and it's perfect. it's a little smoother, and bassier then some of the videos i've heard of the 77 op amp. i think it's much, much better.
DeleteHow would be able to add a mid control on this? I know on the Russian you replace the C1 with a 22nf and change the R2 with a 22k and resistor in series. But I can't find a stock IC schematic to compare.
ReplyDeleteIs it normal that the high notes sound a little bit 'gated' and less clear/more silent? I had it first build with the tone switch, but no sound came trough with the tone bypassed.
ReplyDeleteWith a boost in front (SD1) the higher notes are a lot clearer, so maybe a gain stage problem?
I also have this issue.
ReplyDeleteTry a buffer before the muff.
ReplyDeleteI don't know if this gets read, but.. What is the function of the 120nf cap between the tone and volume? I don't have one right now and am not sure if the 100n or 150n would be a better substitute.. I changed the ceramic to a 15pf and the volume to a 100k but was wondering what a better sub would be in this case.. Or order one
ReplyDeleteThat cat is from tone 1 to ground and it's a part of the tone stack. With cap subs, i'd say it's always better to go up rather than down - unless you want the circuit to sound thinner. 150n will be just fine.
DeleteFor Svein and zosotone - haven't seen this behaviour with mine.. Are your diodes ok? Are you using 741 for the IC2?
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Yes, my 4148's are ok and I used a UA741 for the IC2.
ReplyDeleteThat seems rather strange to me as i've built a few of these and the behaviour is new to me. And i can't explain it straight away...
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Ive built 3 of these and the last one seems to have the same issue, very gated, have to hit the strings hard to get any volume. the first 2 worked fine. I have ordered more diodes and chips to try them out but mine sounds like a wet fart, did you manage to find what was wrong?
DeleteWell I still have the gated sound, I thing because this model has a lot of gain so I turn down de gain knob about 1 o'clock with my amp a little bit crunchy. Usually people use the gain knob at max.
ReplyDeleteI also put a trimmer from 9v to the circuit and I have a more compressed sound.
With the amp clean the fuzz sounds more open of course.
ReplyDeleteIs it possible to sub a 1N5818 at D7 for the 1N5817 without issue?
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ReplyDeleteHello, longtime lurker, first time poster,
ReplyDeleteI've built the circuit and I'm having difficulty with intermittent sound. When the effect is engaged, it runs through a variety of noises from it has no fuzz or it sounds faint and distant, or every once in a while, it will roar through as normal or it will sound as if it is in bypass (clean signal going through). I double checked the orientation of my OpAmps (used a JRC 4558D and a UA741CN), my diodes (1N4148 and 1N5817), and Electrolytic caps. I verified my jumpers and cuts were correctly placed and working by a continuity meter. I verified component placement, and only made part swaps where it was within the uncertainty of the resistor (i.e. used a 1K R instead of a 1.2K R). I also used greenie caps as they were what I had on hand. The sound sounds almost like a cap is charging and then letting go. I have used an audio probe to follow the sound, and at pin 5 and 7 of the JRC 4558D I'm not hearing a strong signal. Any tips on what might be going on? I triple checked for shorts across the vero board strips and I do not see any.
Quick update, I found the issue. It was the 10nF cap going to ground. I replaced it and the pedal works great!
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ReplyDeleteHi guys, just finished building this one for a band mate's birthday and I have to say it is one of the coolest muffs ever !
ReplyDeleteI added the EQD Tentacles octa-fuzz stripboard inside the enclosure, it sounds really awesome with the muff, great Fu Manchu riffage there !
It's been 5 years but many thanks for designing this stripboard anyway :)
https://imgur.com/a/HYR85xS
If you are trying to make this from the layout (as at 24/01/2020) you might find you get nothing but a horrible (read pretty cool) squealing sound out of this awesome pedal.
ReplyDeleteRip out the 1M resistor between the input and pin 4 on the 4558 (the one one the left). As far as I can tell it's not supposed to be there. It is not on the schematic. (Everything else is identical)
I've just spend a week testing, replacing parts, checking every solder joint and possible short, pulling my hear out and verifying the layout against the schematics (Second time was the charm), when i finally noticed that one small difference.
At first, with the 1M in, it sorta worked, briefly. Then got worse as I tried to fix it, the symptoms were similar to what others described above, my guess is that their pedals hadn't gotten to the squealing stage and like me had other issues to fix first :)
Any way I hope my tears, sweat and pain helps someone else out (including the the people who posted a long time ago).
But it does leave me with a couple of questions...
How the hell have people managed to make this pedal with the 1M in place?
What is the purpose of this 1M if it is doing something?
Thanks for the layout, I'm off to A/B this sucker with my friend's modern Pumpkin Pi reissue!
The 1M you are referring to connects the input to ground, as pin 4 of the IC is ground.
DeleteI also recently built this and although my issue is not squealing, it's too little gain. Played around with the value of the 8,2K resistor and ended up with around 500R to get "normal" amounts of Big Muff gain levels. Maybe I could also take a look at the 1M at the input.
The 1M resistor is against pop ups sounds when you press the footswitch. I had an osciallating squealing sound too and found out that i miss matched a cap(47nf instead of 4.7nf). After I changed it, everything worked fine.
DeleteHi, does anybody could tell me where to find this schematic? thank you.
ReplyDeleteHi built two but one sounds nicer (well... Dirtier 😂😂)
ReplyDeleteBoth same parts, chips etc. Just seems like the tone part is better than the other (seems to only sweep frequencies nearer the end of the pot compared to the other). I measured resistance on both tones, the good one goes to about 9.2K, the other 8.2K, any suggestions?
Other than that seems fine, and tone bypass sounds pretty identical between them... I think
No matter, tone 2 and 1 were the wrong way. Swapped, sorted
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DeleteIt works. But when sustain knob is on max I hear loud whistle. How to fix it and where is the problem?
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ReplyDeleteHey folks! I love this site, so many great circuits! This was a fun, if a bit unwieldy, build. Unlike others, it worked fine right away. I can’t imagine that using two opamps would sound much different, but that layout is available if you’re interested.
ReplyDeleteI did have a bit of whine at full gain initially, but i moved some wires away from others (lead dress), which provided a quick cure. Boxed it up right away and played some Smashing Pumpkins. The pedal has tons of volume and the tone bypass is handy. Thank you!
Hey. Built this and cat get it working. It'd be great with a schematic for troubleshooting. Could you please link the schematic used?
ReplyDelete