Nano Muff mods

[MoltenVoltage]

I inherited a nano muff and it sounds like someone with the dry heaves.

Before I spend a lot of time hacking it, I'm wondering whether anyone has modded one to make it sound better?

Thanks!

[CynicalMan]

I've tried a couple of mods, but I liked the sound anyways, so I wasn't trying to "fix" it. The best mod I've done is adding a switch to add in a 10n or 22n cap in series with the input. It doesn't change the sound much, just adds a mid/treble boost. If you don't like the basic sound, this probably wouldn't help much for you.

[MoltenVoltage]

Thanks for the response.

It also randomly fades up and down in volume while the strings are ringing, so I suspect there is some problem with it.  Maybe that's why it sounds lousy.

Does yours randomly lose about half its volume while the strings are sustaining?

[CynicalMan]

Nope. Yours is probably broken.

By the way, these are commonly broken by people not reading the manual and daisy-chaining them to negative ground pedals. Because they are positive ground, a 10 ohm resistor inside of them connecting the DC input and the pedal's power usually blows and cuts off the power, and the pedal only works on battery until the resistor is replaced. Normally this doesn't have an effect on the sound, but if this happened on yours and someone continued trying to daisy-chain it or replaced the resistor with a jumper, some of the circuit's components could have been damaged.

[MoltenVoltage]

Well I got around to hacking it and, in addition to a new LED and knob, I swapped the transistors for 2N5089 and replaced the 100K base resistor with 500K, which didn't change the sound but seems to have resolved the level fading in and out.

I also got rid of the .063uF cap and put in a switch that chooses between a .02uF and a 1uF tantalum which gives it two very distinct sounds.  I can't say I love the sound, but with a compressor in front of it it sounds decent.

The thing that really got me is that, although EHX advertises it as "True Bypass" and uses a 3PDT switch, there is a .0001uF (101) cap between the two inductors that I accidentally replaced with a .1 uF (104) and it zapped all the high end, even when "bypassed"!  When I switched it back to original, the "bypassed" sound magically re-appeared.

(I don't know how this topic ended up double-posted)

[mountainking]

I've been meaning to make a post about those Nano Muffs for awhile but just haven't had a chance. The reason that they sound like crap is that Q1(the transistor closest to the footswitch if I remember correctly) is upside down. The transistor symbol on the board is wrong so the emitter and collector are reversed. Sounds much better once you flip it around.

Alan

[MoltenVoltage]

I flipped around Q1 and it has more bite, but it's also more nasal.

The mark for Q2 is actually a mirror image as well.  I think they did it to fit the text for both Q1 and Q2 near each other.  Q1 is definitely backwards based on a typical NPN transistor installation - the collector was grounded rather than the emitter.

[bumblebee]

Providing its the transistor version and TH you can mod them into woolly mammoths (with just a vol knob) really easy)I'm just going from schematics). They are 99% identical effects.

If you dontmind can you post a gut shot?

[MoltenVoltage]

Here are the gut shots.

I changed the output cap [C7] from .0001 to .002 uF and it got rid of the harsh high end that shows up if you run it after a compressor



This shows Q1 flipped around:


This shows the [R3] 100K resistor change (looks like I ended up using 330K):


Here you can see Q2 is printed mirror image and Q1 is upside down on the silk screen:
(the red jumper is because I fried a trace)


I ended up having to rewire the switch because the cable shredded after taking it out of the enclosure 3 times:


This shows the two input caps and switch:


In all its glory


It sounds decent now and gets two very distinct sounds with the input cap switch.

[matlevo12]

Hi !

If someone's looking for other mods, here's another topic (with a misleading title !).
My Q1 was upside down too... and I realised that the output cap in this pedal was 1µf and lowered it to the usual fuzz face 100nf, btw.

https://www.diystompboxes.com/smfforum/index.php?topic=111267.0

[nmudra]

tnx matlevo12, that was really useful for me

[Mark Hammer]

Read this:  https://www.diystompboxes.com/smfforum/index.php?topic=77456.0

and this: https://www.diystompboxes.com/smfforum/index.php?topic=121640.0

It's basically a silicon Fuzz Face.  Pretty much anything you can do to a Fuzz Face, you can do to a Neo Muff.