Big Muff Volume Control

[shiner_man]

I absolutely love my Russian Big Muff but it has two problems:

1.  The enclosure is HUGE!
2.  The volume control goes from quiet to crazy loud very easily. 

Alas, I'm planning on building my own Big Muff using the following vero:



I was wondering how I could make the volume knob more usable.  If I use, say a 500k audio pot instead of the
suggested 100k audio pot for the volume control, will this make the volume more usable?  Will it adversely affect
the sound of the pedal in any way?

[jefe]

I would try the 100k first. Have you ever opened up your factory Russian Muff to see what pot they used? I'm thinking it's possible that they didn't use a 100k, which is causing the volume to act wierd.

[shiner_man]

I would try the 100k first. Have you ever opened up your factory Russian Muff to see what pot they used? I'm thinking it's possible that they didn't use a 100k, which is causing the volume to act wierd.

No I haven't.  I'll have to check that out.

It's really unbearable.  It goes from barely audible to loud as hell in about 3mm of turning.

[jefe]

No I haven't.  I'll have to check that out.

It's really unbearable.  It goes from barely audible to loud as hell in about 3mm of turning.

Interesting! Now I'm really curious about which value pot they used.

Wait, is this muff from the 70's, or some kind of re-issue? I'm not sure about the Russian ones in particular, but generally speaking, I've read that the 70's big muffs were notorious for using whatever parts they could get their hands on. So, maybe there was a month where they couldn't get 100k pots, so they just used 10k or something.

Another possibility is that your muff just has a faulty pot, but I don't know.

[Paul Marossy]

I would try the 100k first. Have you ever opened up your factory Russian Muff to see what pot they used? I'm thinking it's possible that they didn't use a 100k, which is causing the volume to act wierd.

No I haven't.  I'll have to check that out.

It's really unbearable.  It goes from barely audible to loud as hell in about 3mm of turning.

Could be due to a linear pot instead of an audio pot.

[jefe]

Could be due to a linear pot instead of an audio pot.

Yeah, that's quite possible.

[shiner_man]

No I haven't.  I'll have to check that out.

It's really unbearable.  It goes from barely audible to loud as hell in about 3mm of turning.

Interesting! Now I'm really curious about which value pot they used.

Wait, is this muff from the 70's, or some kind of re-issue? I'm not sure about the Russian ones in particular, but generally speaking, I've read that the 70's big muffs were notorious for using whatever parts they could get their hands on. So, maybe there was a month where they couldn't get 100k pots, so they just used 10k or something.

Another possibility is that your muff just has a faulty pot, but I don't know.

It's a re-issue Russian Big Muff.

http://www.ehx.com/products/big-muff-pi-russian

In the video demo, you can see that he has the volume a little past 12 o'clock in the beginning.  That's pretty much unity gain.  If you  go slightly below 12 o'clock you can barely hear it. 
If you go slightly above a little past 12 o'clock, it's ear piercingly loud.

I'm not sure if this is just the nature of the beast or what but it sucks.  I'm going to sell it on ebay and build another one. 

[jefe]

Oh, if this is a re-issue, then something does seem wrong.

[DiscoVlad]

The pots in the black russian reissues aren't the best quality, and will go bad sooner rather than later. A huge jump in volume from a small turn is a good sign that either there is a bad solder joint/broken wire to the pot, or that the pot has worn out. Replace both and the problem should be fixed.

Volume is 100k Audio, Tone and Sustain are 100k Linear.

[bobcunningham]

check that schematic/vero. i think it's been corrected/verified.

[shiner_man]

The pots in the black russian reissues aren't the best quality, and will go bad sooner rather than later. A huge jump in volume from a small turn is a good sign that either there is a bad solder joint/broken wire to the pot, or that the pot has worn out. Replace both and the problem should be fixed.

Volume is 100k Audio, Tone and Sustain are 100k Linear.

Yeah, I just opened mine up and that's what they all are.  100k.

I guess it's just the design then.  I don't think there is anything wrong with the pots.

[jefe]

The pots in the black russian reissues aren't the best quality, and will go bad sooner rather than later. A huge jump in volume from a small turn is a good sign that either there is a bad solder joint/broken wire to the pot, or that the pot has worn out. Replace both and the problem should be fixed.

Volume is 100k Audio, Tone and Sustain are 100k Linear.

Yeah, I just opened mine up and that's what they all are.  100k.

I guess it's just the design then.  I don't think there is anything wrong with the pots.

But are they 100k A (Audio) or 100k B (Linear)? The volume pot should say 100k A, and the other two should say 100k B.

The volume pot shouldn't act that way, it's not part of the design. Your volume pot is either the wrong one, or it's broken.

[shiner_man]

The pots in the black russian reissues aren't the best quality, and will go bad sooner rather than later. A huge jump in volume from a small turn is a good sign that either there is a bad solder joint/broken wire to the pot, or that the pot has worn out. Replace both and the problem should be fixed.

Volume is 100k Audio, Tone and Sustain are 100k Linear.

Yeah, I just opened mine up and that's what they all are.  100k.

I guess it's just the design then.  I don't think there is anything wrong with the pots.

But are they 100k A (Audio) or 100k B (Linear)? The volume pot should say 100k A, and the other two should say 100k B.

The volume pot shouldn't act that way, it's not part of the design. Your volume pot is either the wrong one, or it's broken.

They are all 100KA and they all appear to be the original pots (they have russian markings on them).

[DiscoVlad]

But are they 100k A (Audio) or 100k B (Linear)? The volume pot should say 100k A, and the other two should say 100k B.

The volume pot shouldn't act that way, it's not part of the design. Your volume pot is either the wrong one, or it's broken.

Irrespective of if it's in the one true design or not, my russian muff (one of this model: http://www.kitrae.net/music/big_muff_history2B.html#SmallBlackRussian) has linear pots for sustain and tone, and a log pot for volume.

While many manufacturers use the same standard markings for component characteristics, it's not _all_ of them... especially when they're old mil-surp russian components

The values on these particular russian pots all say "100kA" and they all measure within 20% of 100k, it's the other markings (in Cyrillic) which signify the taper.

From 0 -> 50 -> 100% rotation, volume measures 0, 11k, 104k (i.e. Audio taper or close enough to it), the other two measure 0, 40k, 92k (i.e. linear) at the same positions.

edit: looking at that again... I appear to have interpreted that as you saying the volume pot isn't supposed to be Log taper, my apologies if that is the case!

[Hides-His-Eyes]

If they ALL say 100kA, and the tone control works as expected, it's possible they're using out-of-date markings from when A used to mean linear.

[shiner_man]

I was mistaken.  They all say 100KM:

[jefe]

edit: looking at that again... I appear to have interpreted that as you saying the volume pot isn't supposed to be Log taper, my apologies if that is the case!

Yeah, I have no idea what the markings should be on these russion-made pots.. I was only saying that the taper should be log/audio for the volume pot.