Transistors and Diodes in the Rams head Big Muff?

S. Thompson · Post by **S. Thompson** » Tue Oct 12, 2010 2:58 am

Anyone have a definitive answer on what types of transistors and diodes are used in the Rams head big muff (v2)?

It seems like the most common answer I've found is 2N5087 PNP transistors and 1N914 diodes. I know in the early years of EHX a lot of parts weren't standard too.

Either way, I'm thinking about swapping the transistors and diodes in my NYC reissue big muff. I altered the tone stack to match the rams head version and I already notice a difference from the reissue.

- Steve

timhulio · Post by **timhulio** » Tue Oct 12, 2010 8:05 am

The Ram's Head (I know, it's not really a ram) version is positive ground, so it won't be a matter of just switching the transistors on the (negative ground) NYC reissue.

Post by **Mike** » Tue Oct 12, 2010 8:13 am

The Ram's head main difference is in the tone stack, but there's some others in the clipping stages too. I plan to start making an npn negative ground version at some point but I've been mad busy recently.

S. Thompson · Post by **S. Thompson** » Tue Oct 12, 2010 2:24 pm

Alright then... wasn't aware of the positive ground issue on the rams head.

Can anyone recommend new transistors and diodes to get closer to the rams head using the NYC muff?

I know it won't be exact, but anything closer is better in my opinion.

- Steve

Post by **Mike** » Tue Oct 12, 2010 2:36 pm

Differences:

Input cap in Ram's head - 10uF vs 1uF = more bass into the pedal
Intermediate stage coupling caps in Ram's head - 100nF vs 1uF = less bass transitioned through the pedal
Feedback Cap/Resistors on first stage in Ram's head 560p/470K vs 470p/510K - this has an effect on the tonal response of the peda;
Feedback caps are 560pF in Ram's head vs 470pF on the Clipping stages, the Diode couples are also 100nF and 1uF vs 1uF and 1uF - again clipping characteristic differs.
There are some biasing differences also which probably don't effect the sound much.
The Tone stack is more scooped in the Ram's head.

It's sort of not really that type of thing, I'm afraid. If you want a Ram's head, just build or buy one. There are a multitude of differences and to be honest the Diodes and Transistors probably have the least effect.

S. Thompson · Post by **S. Thompson** » Tue Oct 12, 2010 2:50 pm

I was under the impression that using different transistors could affect the noise and gain of the pedal.

Right now, the NYC muff gives me tons of noise anytime the effect is even on.

- Steve

Post by **Mike** » Tue Oct 12, 2010 2:59 pm

I would really sell it and buy a better pedal. The NYC ones are really, really shite in my opinion.

Muffs are noisy but these are pretty ridiculously so and the one I owned back in the day was barely unity volume with the volume and sustain maxed out. If you really, really want to play with it, pull the transistors, socket them and try some low noise Bipolar NPNs like some 2n5089s

Earth · Post by **Earth** » Thu Oct 14, 2010 8:49 pm

For all your big muff needs visit my friend Kit's site: Here.Kit mentions transistors on his site.

And my site here: Here. My site has all the mods missing, I need to fix that part of the site but there's still a fair bit of info there.

Bill Oakley · Post by **Bill Oakley** » Thu Oct 14, 2010 11:46 pm

Technically, you could flip the battery connections and any polarized caps around and use PNP transistors. Probably couldn't use the DC jack anymore unless you used it's own power supply.

Edit: A little off topic but still in the BMP realm: I just finished building this 1977 Op-Amp BMP for someone and it sounds killer. It has crazy loud volume but is super quiet.

S. Thompson · Post by **S. Thompson** » Fri Oct 15, 2010 12:18 am

Bill Oakley wrote:Technically, you could flip the battery connections and any polarized caps around and use PNP transistors. Probably couldn't use the DC jack anymore unless you used it's own power supply.

Edit: A little off topic but still in the BMP realm: I just finished building this 1977 Op-Amp BMP for someone and it sounds killer. It has crazy loud volume but is super quiet.

Smashing Pumpkins reference?

- Steve

S. Thompson · Post by **S. Thompson** » Fri Oct 15, 2010 12:28 am

Earth wrote:For all your big muff needs visit my friend Kit's site: Here.Kit mentions transistors on his site.

And my site here: Here. My site has all the mods missing, I need to fix that part of the site but there's still a fair bit of info there.

Great sites! I've used Kit's site before too! Really nice info!

- Steve

Bill Oakley · Post by **Bill Oakley** » Fri Oct 15, 2010 12:31 am

S. Thompson wrote:
Bill Oakley wrote:Technically, you could flip the battery connections and any polarized caps around and use PNP transistors. Probably couldn't use the DC jack anymore unless you used it's own power supply.

Edit: A little off topic but still in the BMP realm: I just finished building this 1977 Op-Amp BMP for someone and it sounds killer. It has crazy loud volume but is super quiet.

Smashing Pumpkins reference?

- Steve

Yes, the guy I made it for is a huge Pumpkins fan.

Post by **Mike** » Fri Oct 15, 2010 9:19 am

Yup, I make IC Muffs, they're brilliant.

S. Thompson · Post by **S. Thompson** » Thu Oct 21, 2010 10:55 pm

I swapped out the stock trannies (BC550) for 2N5089s. Thus far, I like the sound less than before. I replaced the 22k resistor in the tone stack with a 33k to mimic the scoop of the rams head and I felt like that was an improvement on the pedal. The transistor swap seems to have affected chord definition (although the NYC never sounded great to me with chords), but boosted the sustain.

I have to play with it more, but thus far I'm not as much of a fan.

- Steve