Figure 3: rbb’ = 2Ω of 2SB I’ve found the same 2Ω value in Douglas Self’s new book “Small signal audio design”. Although the. 2SB Rohm data sheet. 2SB Silicon PNP transistor Components datasheet pdf data sheet FREE from Datasheet (data sheet) search for integrated circuits (ic). 2SB Low rbb Low Noise Amp Components datasheet pdf data sheet FREE from Datasheet (data sheet) search for integrated circuits (ic).

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Is there any equivalent for this?

2SB737 Datasheet, Equivalent, Cross Reference Search

That design looks like around 1 mA nominal set by ohm and Vbe of 2sc One weak link sonically for that design is the uF cap in the gain leg Maybe he, or another ilumanted member of this forum can bring some other substitutes! So I’d drop them in and see how it works.

You are about to become the voice of Interplanetary Parliament. August 16, Bookkeeper Member Czech Republic Posts: The original 2sb and 2sD were designed for moving coil head amps with ohm nominal source impedance, so arguably better than needed for ohm source impedance microphones. The 2SA Hitachi that I pointed out earlier is a popular replacement used in quite a few preamp stages that previously had the 2SB But look at the data sheets for NF vs impedance curves, for something that doesn’t suck into ohms.


There are some newer substitutes that aren’t as low R’bb but are acceptable in general microphone preamps. Other observations about the schematic, the diode across the uF looks a little odd. I looked around briefly this afternoon and didn’t see anything obvious Regular transistors will be noisy in this application; I don’t know the NTE part, but I doubt it is a super low Rbb part.

Transistor substitution question Started by jrmintz The Lab. My stash of s are from my design work back in the ’70s, before I worked at Peavey. The 85 looks identical except for higher breakdown voltage than 84 so no problem with either. If you sub a newer part, you may want to back off on the current density for optimal noise performance or not.

Very nice that Mr.

Started by abby normal The Lab. You probably have two of those per mic input.

2SB Datasheet PDF –

Those are super low Rbb transistors for low Z input stages. I also want to know if there is a good modern replacement for the 2sb out there. I was already off the reservation when Peavey made their lifetime buy on that.


Also on this s2b737 are some threads about this part, but no conclusion what to use instead. Looking forward to some results! I usually added clamp diodes backwards across the be junction of the low noise devices to make sure they never zener if reversed, as that can 2sb773 them noisy. I have not searched the other parts mentioned in this thread, but also with web search i didnt found a “recommended” replacement.

But that will not last for ever. Low noise devices are generally graded for beta, as in the more beta the better for low noise applications.

(PDF) 2SB737 Datasheet download

But I wouldn’t change it here for two reasons. Started by jrmintz The Lab. The original Rohm transistors are discontinued; if you can’t source any, try the 2SA or, not quite as low noise but still pretty good, 2N June 06, As we all know the 2SB has practically become extinct so I thought I’d follow Rossi’s recommendation and have them replaced by 2SA actually 2SA which I can get at my local dealer.