has anyone ACTUALLY measured the tranny's on a Big Muff Triangle?

[svirfnebli]

Hey all,

I was educating myself on the Big Muff Triangle 1st generation over the weekend and was reading about those FS36999 tranny's made by Fairchild Semi Conductor. I gave fairchild a call and they said they wouldnt be able to locate any records on the old transistors. There is alot of speculation out there about what is ACTUALLY the correct replacement tranny for that unit. Some say it's one type, others say its another.

Has anyone ACTUALLY measured the transistors on a vintage unit? If so would you share the info?

matt

[R.G.]

Has anyone ACTUALLY measured the transistors on a vintage unit? If so would you share the info?

I have not ACTUALLY measured the transistors on a vintage Big Muff. But I can promise you that if you had a barn full of them and measured every single transistor you'd find that - they vary. There is and can be no 'the gain' of a bipolar transistor, especially one that is inexpensive. Worse yet, the actual gain of a *single* transistor varies with temperature and collector current.

Beyond that, all of the transistors in a Big Muff are used in feedback situations where the feedback will cover up the actual transistor differences to a greater or lesser extent.

Measuring the transistors on a single vintage Big Muff will produce some numbers. You will not know whether those numbers are the best, worst, highest, lowest, representative, or atypical for other Big Muffs. Viewed that way, the exact numbers almost don't matter, nor do the exact type numbers. Transistor makers back in the day used to cook up a bunch of transistor dies in the diffusion ovens and then test them, sorting into buckets. The ones with gains below X were tossed as too low; between X and Y were labeled with one type number, between Y and Z another type number, and so on. The bucket size was typically between 3:1 and 10:1 for gain measurements. Users who needed a specific gain were expected to order a bunch and test them themselves.

Finally, EH is notorious for making pedals out of whatever parts they could buy on the surplus markets. Part values varied a lot in real, true, vintage Big Muffs.

I hope that relieves some of the urgency about the quest.

[oliphaunt]

In my (very limited) experience I have to say that transistor types certainly matter a good bit in the Big Muff.  I recently built a couple of Ram's Heads and tried 5088, 5089 and (my favourite) 2N5133.  The gains of the 2N5133s measured from around 70 to 250, well below value of the other transistor types, but the various gains didn't seem to make a lot of difference as I tried higher and lower values in the various locations. 

I agree with RG that it doesn't really matter that much, as we seem to know that the FS36999 was basically a 5088, and we know the values varied considerably from unit to init.  Still, I would love for someone to answer the question and give us some "real" values!

[Greg_G]

Beyond that, all of the transistors in a Big Muff are used in feedback situations where the feedback will cover up the actual transistor differences to a greater or lesser extent.

Wise words.. people obsess too much about the gain numbers in the Muff when the circuit controls the effective gain anyway.

[petemoore]

  I started tryin' 'em all, measuring each one.
  Soon I figured out I have choices:
  Low gain [under say 450-500hfe], reduces circuit gain, not-preferred by user.
  High gain/low noise 2n5088 or higher [2n5089, MPSA18], very little difference in gain, or anything else.
  The 'low noise' blurb is nice to have on a transistor for BMP data sheet header, 2n3904 made quite a noise-floor racket, four transistors do a lot of work together, but noise can get out of hand in there.
  BCxxx, to my ears sound like BC's, a bit of a resonant-rattle-tone, can be cool, 2n5088's or 2n5089's made me happy.

[Greg_G]

 
  Low gain [under say 450-500hfe], reduces circuit gain, not-preferred by user.
 

Internet myth I think.
The gain of each stage is only around 20.
I've read that some of the early versions had transistors in the 100 to 200 range and sounded great.

[petemoore]

  2n3904's are around 350+, sticking those in there reduced the gain-tone in my bmp.

[oliphaunt]

The low gain 2N5133s  (HFE 70-250) I put in my Muff definitely reduced the "gain" (meaning apparent amount of distortion) compared to 5088s and 5089s.  They darkend the tone as well.  Those are both good things to my ear, but others would disagree, I am sure.

[ode2no1]

in my recent two big muff builds (civil war and triangle knob) i went thru quiet a few transistors trying to get a certain tone from them and from my experience in doing this i really didn't notice a big difference in gain...even when using 2n5133's with hfe's of 60-70. there is however a noticeable difference in high end, which was what i was chasing when building the civil war for a buddy of mine who wanted me to clone his production model. i ended up sticking a super high hfe transistor up front and then using 2 2n3904's in the middle section and a bc109 as the last transistor. it was kind of a balancing act as far as the character of the pedal went in terms of brightness or how tight the low end was, but honestly the amount of gain never did change much at all.

[yeeshkul]

I have an original Ram's at home right now. I am trying to get as close as possible to the sound with my clone. Not much luck.
Transistor gain type doess have influence on the "power" of the sustain, no myth, i can hear it clearly - whatever the stage gains are.
The original unit uses 5088 (with two painted strips on the back) and the overall gain/distortion seems to be higher and mushier than my clone so far.
The original unit has more mids and sounds warmer.

[Dan N]

Not much help. I tested some once when my triangle didn't work after fixing some traces. Didn't take notes, but they all tested fine .



After giving that non-functioning POS away I realized that I hadn't taken the fact that it was pos ground into account when I reattached the battery leads. Now it works fine.

For the guy I gave it to.