Big Muff Transistor HFE difference??

Started by illuminatiNPS, August 21, 2015, 12:52:24 PM

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illuminatiNPS

I currently have a custom Big muff build that called for 2n706A transistors. At this moment, due to what was available we used other metal can style  transistors. 2n222s in the first and last stage and bc108 in the clipping stages. If I switch them all to the 2n706a's, should i expect a big difference. Just wanted to feel this out on this forum. I know there is a lot of literature about transistor type not making a big deal when it comes to BMP. Seems like the rsistors and caps in the stages play more of a roll in tone. What you guys think??

Mark Hammer

If you look over the many issues of the BMP, you'll see that the emitter and collector resistance values often changed along with the transistor itself.  Don't think of the transistor hfe as some sort of fixed gain.  It is a range of possibilities, the specific one of which is dictated by the surrounding resistor values.

illuminatiNPS

Ok. So what i read on Kit rae is accurate. The reason i ask is because the 2n706a's that are called for average around 20 or 30 hfe ands the 2n2222's are over 100, same for the bc108. Most tone changes that i read about seem to be subtle.

theehman

It can make a world of difference.   I tried some transistors in my Big Muff clone that had a number similar to what I normally used and they sounded much different, in my words and a friend's, they sounded "blocky".
I tried some NOS 2N5133 and I wasn't impressed.   What I was using before sounded much better.
Changing caps and resistor values could make them sound better but I stuck with what I already trusted.
Ron Neely II
Electro-Harmonix info: http://electroharmonix.vintageusaguitars.com
Home of RonSound effects: http://www.ronsound.com
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Gus

something I posted before note the collector voltage change from 2N2222 to higher beta 2N5089

plexi12000

ii'd try a LOT of transistors until you find "the sound".  they definately sound different.

LightSoundGeometry

get a tester circuit up on a breadboard so you can swap parts in and out before permanent home :)

very awesome to post voltages ..now that I am advancing somewhat I am always curious as to what voltages are supposed to be where, and why !