big muff pi noise reduction mod

pinkjimiphoton · Post by **pinkjimiphoton** » 10 Sep 2013, 00:53

no idea how this works or why... but if you parallel the bat41 at d4 on the board with a 1n34a oriented the same, it cuts out most of the "ocean" with a big muff pi.
you can still get all the same sounds out of it, but without the noise. seriously. try this and let me know if it works for you!!

did it on a reissue nyc bmp. made an astounding differnce.

karmaniacal · Post by **karmaniacal** » 24 Nov 2013, 03:04

Hi Jimmy,
I had to post to say thanks for this tip.
It works very well.

Regards,

Craig.

pinkjimiphoton · Post by **pinkjimiphoton** » 24 Nov 2013, 06:03

yah, takes out most of the noise, for sure.

any idea why it works??

Cub · Post by **Cub** » 24 Nov 2013, 10:05

I'm going to try this the next time I'm building a Muff. Before the end of the year, I hope, but probably somewhere in January.
Thanks for sharing !

Muffs are noisy beasts by nature, every bit of reduction is welcome.

pinkjimiphoton · Post by **pinkjimiphoton** » 24 Nov 2013, 15:50

it does sacrifice a tiny bit of balls, but unless you run everything dimed hard to notice.

astrobass · Post by **astrobass** » 24 Nov 2013, 16:03

Well, when you run parallel diodes it's only the diode with the lowest voltage drop that's considered, right? And the 1N34A typically falls around 300 mV from what I've seen.

pinkjimiphoton · Post by **pinkjimiphoton** » 24 Nov 2013, 17:18

yah, but why does it work in just that *one* spot? i tried it elsewhere, and no dice. on two bmp's and both the same... weird. that one position makes a big diff.

astrobass · Post by **astrobass** » 24 Nov 2013, 18:13

D4 is on Q3, right? What about running the ge diode parallel to the other diode on Q3 instead? No dice?

If that doesn't work, I'll be puzzled. Right now I'd guess that it works by reducing the signal hitting Q4 by just enough. But it might be something more subtle that I'm not knowledgable enough to guess at.

pinkjimiphoton · Post by **pinkjimiphoton** » 24 Nov 2013, 19:19

if memory serves, it was only that one diode that worked out like that. i don't remember which one without re-reading the thread, but i did try it on the others and it did not have the same effect. did it on a behringer vd1 too, worked there the same. there's just enough room in them to mess with the diodes some and replace 'em with real ones.

roseblood11 · Post by **roseblood11** » 27 Jan 2014, 21:54

We'll have to call in an expert...

ChargerSG · Post by **ChargerSG** » 28 Jan 2014, 06:40

pinkjimiphoton · Post by **pinkjimiphoton** » 30 Jan 2014, 22:21

so...... verdict?

Blend · Post by **Blend** » 01 Feb 2014, 17:29

Wow Jimmy , tried with a AA118 germanium and works great, in my opinion lowers the gain of the ultra big muff and her turbulent noise. it is however necessary to increase the resistance of the sustain minimum that would otherwise be dark in tone. Connected to a momentary switch can generate two different frequencies of feedback Morello style.posting.php?mode=reply&f=28&t=23085#

pinkjimiphoton · Post by **pinkjimiphoton** » 01 Feb 2014, 23:24

cool!! thanks for the verification!
it DOES lower the gain slightly, but i think in a good way... just kinda takes some of the noise out.

only seems to matter on that one diode. what the fuck?!?!?!? lol

Blend · Post by **Blend** » 02 Feb 2014, 21:18

tried 1N34A, perfect, taming the 70% of the magma hum in the background. I use bc239c reputed as the noisiest, shielded cables but with this trick you do not need a noise gate.

ppluis0 · Post by **ppluis0** » 02 Feb 2014, 22:09

Hi folks,

Can anyone tell me where is D4 ? What schematic diagram are you talking about ?

Cheers,
Jose

pinkjimiphoton · Post by **pinkjimiphoton** » 02 Feb 2014, 22:50

you got 4 diodes on any big muff board. try it until ya find the one that works. that's the one ya leave it on.

but it's gotta be germanium. si don't work!

ppluis0 · Post by **ppluis0** » 03 Feb 2014, 00:10

Thank yo Jimi for your answer.

I'll try this trick in my next BMP...

Cheers,
Jose

pinkjimiphoton · Post by **pinkjimiphoton** » 03 Feb 2014, 01:48

cool jose!! just look at a schematic, whatever d4 is is what i found worked in all three muffs i tried including the behringer copy.

AAntonio · Post by **AAntonio** » 16 Feb 2014, 19:22

work, this mod?
to increase the gain?