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).

Author: Douhn Mikat
Country: Peru
Language: English (Spanish)
Genre: Education
Published (Last): 24 December 2015
Pages: 446
PDF File Size: 14.81 Mb
ePub File Size: 11.78 Mb
ISBN: 179-6-44709-945-2
Downloads: 65481
Price: Free* [*Free Regsitration Required]
Uploader: Mubar

But look at the data sheets for NF vs impedance curves, for something that doesn’t suck into ohms. Those are super low Rbb transistors for low Z input stages. I looked around briefly this afternoon and didn’t see anything obvious The 2SA Hitachi that I pointed out earlier datawheet a popular replacement used in quite a few preamp stages that previously had the 2SB If you sub a newer datasheer, you may want to back off on the current density for optimal noise performance or not.

If you sprinkle when you tinkle, please be neat and wipe the seat. Rossi probably knows more than I do about what folks are using these days. 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 My stash of s are from my design work back in the ’70s, before I worked at Peavey.

Other observations about the schematic, the diode across the uF looks a little odd.


Substitution for a transistor 2SB

Yup, they have been obsolete for years. They were using truck loads of the 2sd NPN version. Is there any equivalent for this? There are some newer substitutes that aren’t as low R’bb but are acceptable in general microphone preamps.

2SB737 Datasheet

Just to get the channel working you could datawheet parallel up a few 2n per, but longer term you want to use a proper low catasheet part. I’ve used the npn counterpart 2SC with good results. 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. Low noise devices are generally graded for beta, as in the more beta the better for low noise applications.

The -E parts are higher beta than the 2sb7737. Transistor substitution in GAR datawheet The 85 looks identical except for higher breakdown voltage than 84 so no problem with either. You tell me whar a man gits his corn pone, en I’ll tell you what his ‘pinions is. The number sounds familiar First increasing current there, will decrease input signal swing before saturation, unless you change other values, but more importantly, I suspect the newer replacement devices are higher Rbb and happier at lower current density.

(PDF) 2SB737 Datasheet download

I typically would have run the 2sb at a little higher current density. So I’d drop them in and see how it works. I also want to know if there is a good modern replacement for the 2sb out there. Hi all, looks like two of the channels of my mixing console were fried when a phantom power coupling capacitor blew up.


Perhaps they are protecting against some latch up condition. Thank you very much I don’t remember what transistor Peavey switched to.

Hi Have these transistors in bad Delta channel. You can buy small quantities on the web I still have some back in my lab.

2SB Datasheet – Transistors, Bipolar, Si PNP Low-Power from ROHM Co.

April 01, 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. But that will not last for ever. That design looks like around 1 mA nominal set by ohm and Vbe of 2sc Started by jrmintz The Lab. Also on this forum are some threads about this part, but no conclusion what to use instead.

One weak link sonically for that design is the uF cap in the gain leg Very nice that Mr. You probably have two of those datasheey mic input.

February 26, No simple fix to avoid the scratchy noise with gain changes due to small DC offsets, but you might want to experiment with cap quality there. June 06, Roberts joins the thread!