Bassifying a Muff

[jrhevron]

Anyone else give this a shot? I have a new muff and replaced C3, C4, C7, C12 (I only had 4 caps) with 220n. It is much bassier, and the clipping goes down into the bassier end of the spectrum. I have done it on a previous muff and liked it, but I'm a little more attuned with this one.

I'd like to get a little more clarity to the tone... any ideas on what to do?

Are there specific coupling caps to NOT replace (like C3 mentioned above)? or should I try to use something inbetween 100-220?

Again, the tone was great for bass with 100n caps, but now I feel like there is just slightly too much bass and I want to dial it back a little bit.

 

[cdwillis]

I'd leave the 100nf coupling caps alone, but I think if you increase C3 to something like 10uf you'll have fuller bass signal getting through at lower sustain pot levels. You'll have less distortion/fuzz so more clarity while retaining the low end.

Remove the first two clipping diodes (d3 and d4 on the pcb I think). This will increase the overall level, create a little less compression, and increase bass response. This is a jumbo tone bender type of mod. You can also put red LEDs here for a similar effect.

If you replace the 470pf caps with something smaller like 220pf or 100pf you might get some more high end presence in there. With less bass reponse it might sound fizzier, but it'll probably sound good with the bass guitar signal.

 

[jrhevron]

I'd leave the 100nf coupling caps alone, but I think if you increase C3 to something like 10uf you'll have fuller bass signal getting through at lower sustain pot levels. You'll have less distortion/fuzz so more clarity while retaining the low end.

Remove the first two clipping diodes (d3 and d4 on the pcb I think). This will increase the overall level, create a little less compression, and increase bass response. This is a jumbo tone bender type of mod. You can also put red LEDs here for a similar effect.

If you replace the 470pf caps with something smaller like 220pf or 100pf you might get some more high end presence in there. With less bass reponse it might sound fizzier, but it'll probably sound good with the bass guitar signal.

Maybe I'll try the C3 mod. I've done a lot of diode experimenting... into that. I actually did go down to 430pf with those caps (civil war values) and didn't like it. Made the bass a little too tight and refined.

 

[jrhevron]

Just played it with a band: had a russian with the coupling cap switch and a ram's head with the 100n coupling caps, so I could compare and contrast pretty easily (despite the different versions). I def need to get somewhere inbetween. So, maybe 160 caps?

 

[Silver Blues]

150 and 180nF are standard values, you could try those!

 

[cdwillis]

C5 and C8 make a huge difference in bass response. A Rams Head is going to have 100nf caps there and a Russian will have 47nf. This makes a bigger difference than the coupling caps imo. A 100nf cap should already be letting the entire bass signal through.

 

[jrhevron]

C5 and C8 make a huge difference in bass response. A Rams Head is going to have 100nf caps there and a Russian will have 47nf. This makes a bigger difference than the clipping caps imo. A 100nf cap should already be letting the entire bass signal through.

I have heard that 100nf caps should be letting everything through as well... but when I increased some of the caps to 220nf, the bass (at least seemed to) increase. It was like it took up more of the signal. Is that just perception? Or really happening?

 

[Feral Feline]

I have heard that 100nf caps should be letting everything through as well... but when I increased some of the caps to 220nf, the bass (at least seemed to) increase. It was like it took up more of the signal. Is that just perception? Or really happening?

An aside regarding perceived bass response:

Jack Orman swears his MOSFET Boost is good for guitar or bass. He's done the math, so it must be good on bass I'm sure ... BUT!
The input-cap is 1n and the output-cap is 100n.

Now, take a look at Catalinbread's Sogrado Poblano Picoso, it was marketed as a bass pedal — it's the same circuit, ORMAN's, BUT!...
The input-cap is 10n and the output-cap 220n.


Trust your ears.


Maybe try this on the breadboard: keep the early stages 100n and then for the last stage let a LOT of bass through — try 220n, 470n, even 1µ.


I often see circuits with "choke-points", the circuit's coupling caps throughout are large for lots of bass, then there'll be a choke-point with a much smaller-value cap. For example this Kit Rae traced circuit has HUGE in/out and couplers then choked after the first stage and is often the case for Muffs with big couplers, choked after the tone-stack:





So why aren't all the bass players raving about this Ram's head? It's got huge caps, even with the choke-points it should deliver the bass freqs.
Look at the diode caps in the clipping section (C6 and C7), they're huge compared to a Russian's 0.047µ, so more of the bass freqs are getting clipped here and mushing out the overall sound. The Russian clips more upper-range freqs with the 47n, leaving more clean bass in the overall signal and I suspect that is why many bass players prefer the Russian version of the circuit.


I'd like to go with 47n caps for the C6 & C7, and see how this Ram's Head would then sound on bass. I'd also like to experiment more with coupling caps in general and by controlling the bass passing through the circuit, not overloading it for the clipping, then let as much bass out as possible AFTER clipping... hmmm basically what HamishR said in post #19.


Maybe it'd sound better overloading the circuit with bass and getting lots of distortion from that bass overload, then dial it back for the final output so it doesn't overload whatever's next in the chain (another pedal, amp, whatever).

 

[jrhevron]

An aside regarding perceived bass response:

Jack Orman swears his MOSFET Boost is good for guitar or bass. He's done the math, so it must be good on bass I'm sure ... BUT!
The input-cap is 1n and the output-cap is 100n.

Now, take a look at Catalinbread's Sogrado Poblano Picoso, it was marketed as a bass pedal — it's the same circuit, ORMAN's, BUT!...
The input-cap is 10n and the output-cap 220n.


Trust your ears.


Maybe try this on the breadboard: keep the early stages 100n and then for the last stage let a LOT of bass through — try 220n, 470n, even 1µ.


I often see circuits with "choke-points", the circuit's coupling caps throughout are large for lots of bass, then there'll be a choke-point with a much smaller-value cap. For example this Kit Rae traced circuit has HUGE in/out and couplers then choked after the first stage and is often the case for Muffs with big couplers, choked after the tone-stack:

View attachment 59440



So why aren't all the bass players raving about this Ram's head? It's got huge caps, even with the choke-points it should deliver the bass freqs.
Look at the diode caps in the clipping section (C6 and C7), they're huge compared to a Russian's 0.047µ, so more of the bass freqs are getting clipped here and mushing out the overall sound. The Russian clips more upper-range freqs with the 47n, leaving more clean bass in the overall signal and I suspect that is why many bass players prefer the Russian version of the circuit.


I'd like to go with 47n caps for the C6 & C7, and see how this Ram's Head would then sound on bass. I'd also like to experiment more with coupling caps in general and by controlling the bass passing through the circuit, not overloading it for the clipping, then let as much bass out as possible AFTER clipping... hmmm basically what HamishR said in post #19.


Maybe it'd sound better overloading the circuit with bass and getting lots of distortion from that bass overload, then dial it back for the final output so it doesn't overload whatever's next in the chain (another pedal, amp, whatever).

Interesting that you would bring up how the ram's head would sound with 47n caps in C6 and C7... right now I have a violet ram's head and the green russian on my board. I switched out the C6 and C7 from 100n to 47n and it sounds a lot better on bass. Does what it should: moves the clipping up to the mid/treble and leaves more of the bass untouched, which is more ideal in this application. The fact that it leaves more clean bass in the signal is exactly why it sounds better for bass. The Pharaoh actually uses this value as well, which explains why it is also popular with bass players.

Now, the Pharaoh is a good one to bring up because all of the coupling caps in it are 470n (it's wrong on the kitrae site). This is interesting because it's way above the normal muff coupling cap value of 100n. It's actually an interesting one to look at because a lot of the early builder schematics said that the caps were 47n and then people switched them to 470n and made some comparisons:

"I replaced all the 47n caps with 470nf and for my taste at least it has made a noticeable improvement. I've yet to try it through my proper rig but it seems to have changed the responsiveness of the tone controls dramatically, perhaps the combination of more lows being allowed through in some sections (C4, C7 & C12) but being also cut in others (C6 & C9) as a result of the bigger caps has given the overall tone a bit of extra oomph but also some highs in there too which make it seem more aggressive." https://www.madbeanpedals.com/forum/index.php?topic=18122.30

So, while some are suggesting to just try to switch out one cap at a time, this report seems to say that the cumulative effective of making all the caps bigger gives you more highs and lows-- more balanced. I don't know, just what I'm seeing here.

But to go back to your point about pinched areas in the circuit-- also an interesting thing to bring up because when I was first listening to the muff I'm trying to tune, that was my impression "the sound was pinched" at least compared to an old muff build with 220 coupling caps. And that's what led me on this journey. And yes, I agree what what you are saying... I don't want to overload the clipping... I just want more of a wide, full-spectrum sound without sounding pinched. The pinched sound has its place, but it's not what I'm going for her.

 

[Feral Feline]

Excellent @jrhevron, I look forward to hearing what you eventually settle on.

I, too, had noticed Kit Rae's 47n discrepency (and I've wondered why he never fixed it after the correct Pharaoh coupler sizes have become more common knowledge and verified at that.) There are a few other anomalies I've found, but KR's Muff Pages are such a wonderful resource I shouldn't bitch about so few minor bits at all.

I've given a lot of mental energy to various aspects of the Muff circuit, but need to give some physical energies to breadboarding/building a bunch.

 

[eh là bas ma]

I was going to try to put C6 and C7 caps on a toggle to see the difference between 47n and stock value.

My build is from uk-electronic.de and here are the schematics :

So both 120n caps near the diodes are after the diodes instead of before them, as shown in all Ram's Head schematics i could find. Never noticed it before...

Is it bad ? Can they still do their job ? Should i do something about it ?

 

[Feral Feline]

... Should i do something about it ?

YES!

Put an order switcher in there for the:
caps and diodes,

*flip sw*​

diodes and caps.

Then let us know what you think, or post a demo even.


I'd do it myself, but am not equipped for such demo-ing.

 

[eh là bas ma]

Like this at both locations ? Would this wiring work ?


There's a connection between the 680p cap and the diodes that i erased on this picture : On the usual schematics (reply #28), this side of C12 (680p) isn't connected to D3 and D4. I'm not sure how i can connect the 120n cap between them without unsoldering the 680p's leg, but in the other position, with an unsoldered leg, the 680p/diodes connection will be lost ?

Maybe i shouldn't have erased this connection ? No need to unsolder the 680p leg ? Would it work if i keep the 680p/diodes connection as it is ?

 

[jrhevron]

I don't know.... I'd just make those caps the 47n of the russian... I just did that on my ram's head and it sounds better on bass. I wouldn't worry about a switch. Just try both and see what you like. You aren't going to want to go back and forth once you find what you like. Make a switch for the diodes, though. LED/SI

 

[jrhevron]

Excellent @jrhevron, I look forward to hearing what you eventually settle on.

I, too, had noticed Kit Rae's 47n discrepency (and I've wondered why he never fixed it after the correct Pharaoh coupler sizes have become more common knowledge and verified at that.) There are a few other anomalies I've found, but KR's Muff Pages are such a wonderful resource I shouldn't bitch about so few minor bits at all.

I've given a lot of mental energy to various aspects of the Muff circuit, but need to give some physical energies to breadboarding/building a bunch.

It's a great resource... and I'm not sure if he even updates it, does he? I can see going so deep on one topic and then not really wanting to go back to it. I couldn't blame him if he didn't.

 

[eh là bas ma]

Make a switch for the diodes, though. LED/SI

I already put a Roto Tone pcb in there, with 4 clipping settings on a rotary switch.

I just did that on my ram's head and it sounds better on bass

That's better indeed !

Thank you so much for this good idea.

How would you call this variant ? The Big Muff Ram's Green ? The Big Muff Rumssian's Head ?

 

[cdwillis]

The Mosfet booster has a 10m input impedance if I remember correctly. If you use the AMZ filter calculator (https://www.muzique.com/schem/filter.htm) with the 10m resistor and the small 1nf input cap you get a 15.9hz frequency knee on the high pass filter it creates.

If you use that same calculator on a Big Muff's typical 100nf 100k high pass filter you get that same 15.9hz frequency knee, but I think the lowered input impedance may mess with the actual frequency. I'm just not learned enough to figure out how.

 

[jrhevron]

I already put a Roto Tone pcb in there, with 4 clipping settings on a rotary switch.


That's better indeed !

Thank you so much for this good idea.

How would you call this variant ? The Big Muff Ram's Green ? The Big Muff Rumssian's Head ?

Ultra Violet Muff

• Add LED clipping options (less compressed/more open)
• Up the value of the coupling caps (more bass)
• Make the clipping caps the same value as Russian (just clips the upper end but lets more clean bass pass)

 

[jrhevron]

I think if you are going this route, there are a few things that matter to bass and that you can socket:

1: Clipping caps: seems like 47n is ideal, but worth experimenting
2: Coupling caps: standard is 100n. I thought that 220n might be a little high. I have read that it may not matter if you change all of them.
3: C2, C5, C8 (at least on the Mudbunny schematic): Russian/Ram's are 470 and the Civil War is 430. Civil War has a tighter bottom end with a little more grit on top. Russian/Ram's have a looser bottom end with a smoother top.
4: Clipping diodes: all kinds of things possible. Leave first ones out for more low end. Standard seems SI first pari and then a switch on the second pair. I like LED in the 2nd set.

Resistors: Of course, these matter, esp in making in higher or lower gain and the overall sound that makes the version—gives it the fuzziness of a ram's head. In terms of the bass response, though, the resistors seem to matter less. If you aren't using a mids switch/pot, then there are some things that do matter: R18/R19 (on madbean) 22/20 for Russian/Civil War and 33/33 for Ram's Head. Higher values roughly equal more mids. They work in tandem with C10/C11, so if you are thinking mids, think about how those two caps/resistors work together.

Transistors: Lots of people say they don't really matter as long as you get the HFE that you want. I've experimented a bunch and in the mix of things, it's hard to say what really matters. I will say that the W&C TFR uses 5088's for the first three and then a mystery transistor in the last/volume position (Q4 on madbean). The last transistor determines output. So, if you want to mess around with transistors, just make the first three 5088's and experiment with the last one.

And, of course, everything is interactive. You can get lost in the weeds with the intricacies of the muff. I think that the W&C TFR is the best one that I've tried. It has a very mellow, laid back tone that you can have on all the time. They have figured out a really sweet deep dive combo of parts. That said, side jack only without clipping options and only a flat mids option... so the form factor isn't ideal for modern pedalboards. So, it's still worth rolling your own AND I think that if you experiment with the caps, you will get pretty close to the bass tone/response that works for you.

When experimenting and listening to the results, ask yourself:

• How tight is the bass? Does it matter if it's tight or loose? Does that matter to how it sits in the mix?
• Is the bass heavy but the rest of the signal kind of weak/ill defined? Does that matter?
• Where is the signal being clipped? Top end, or all through?
• Is there enough clean bass coming through?
• Is the lower end clipped in a way that works or makes the signal ultimately less distinct?
• If I put a boost/drive in front of the muff, does it resolve some of the eq issues?
• Is the overall sound strong/intense, or looser and less intense? What works better?
• Are there dynamics to the tone? Or is it one intense pulse?

Pitfalls: See what sits in the mix best and not what is the loudest/gnarliest/fuzziest. A little subtlety can be good.

• Adding too much bass
• Overpowering with the mids
• Clipping the whole signal so that it gets mushy
• Making it too high gain

 

[jrhevron]

Findings (or what I like) so far... 180n caps for the coupling caps. 430p for more Civil War.

Tried a few other things and the jury is out.

Has anyone messed with the limiting resistors? Standard on russian/civil war is 10K. Ram's head is 8.5k. The lower you go, the more input into the clipping channels, so the fuzzier you get. I'm wondering if I should even try a 12K just to see if it's more overdrivey.

This is R7 and R12 on the original posted diagram.