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: Dibei Maumi
Country: Lebanon
Language: English (Spanish)
Genre: History
Published (Last): 4 January 2011
Pages: 266
PDF File Size: 19.70 Mb
ePub File Size: 4.21 Mb
ISBN: 272-9-11315-931-7
Downloads: 74483
Price: Free* [*Free Regsitration Required]
Uploader: Kajizahn

They were using truck loads of the 2sd NPN version. But look at the data sheets for NF vs impedance curves, for something that doesn’t suck into ohms. Roberts joins the thread!

2SB Datasheet PDF –

You are about to become the voice of Interplanetary Parliament. The number sounds familiar But I wouldn’t change it here for two reasons. Also on this forum are some threads about this part, but no conclusion what to use instead.

You probably have two of those per mic input. Perhaps they are protecting against some latch up condition. That design looks like around 1 mA nominal set by ohm and Vbe of 2sc It will work but you’ll have more noise. Hi all, looks like two datasueet the channels of my mixing console were fried when a phantom power coupling capacitor blew up. In the schematic there are 2 2sb 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.

You can buy small quantities on the web I still have some back in my lab.


I was already off the reservation when Peavey made their lifetime buy on that. I usually added clamp diodes backwards across the be junction of the low noise devices to make sure they never vatasheet if reversed, as that can make them noisy. Looking at the noise figure curves wrt source impedance and current density here javascript: The -E parts are higher beta than the -D.

Those are super low Rbb transistors for low Dattasheet input stages. February 18, Yup, datasheef have been obsolete for years.

Transistor substitution in GAR 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. One weak link sonically for that design is the uF cap in the gain leg Rossi probably knows more than I do about what folks are using these days.

If you sub a newer part, you may want to back off on the current density for optimal noise performance or not. Rossi Member Germany 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.

I have not searched the other parts mentioned in this thread, but also with web search i didnt found a “recommended” replacement. Low noise devices are generally graded for beta, as in the more beta the better for low noise applications.

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

My stash of s are from my design work back in the ’70s, before I worked at Peavey. There are some newer datasheey that aren’t as low R’bb but are acceptable in general microphone preamps.


Transistor substitution question Started by jrmintz The Lab. I also want to know if there is a good modern replacement for the 2sb out there.

(PDF) 2SB737 Datasheet download

Thank you very much August 16, I typically would have run the 2sb at a little higher current density. But that will not last for ever. I looked around briefly this afternoon and didn’t see anything obvious Is there anything to consider changing resistor values etc. I don’t remember what transistor Peavey switched to. So I’d drop them in and see how it works.

2SB737 Datasheet, Equivalent, Cross Reference Search

April 01, The 85 looks identical except for higher breakdown voltage than 84 so no problem with either. Started by abby normal The Lab. The 2SA Hitachi that I pointed out earlier is a popular replacement used in quite a few preamp stages that previously had the 2SB Is there any equivalent for this? 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 Change both transistors in the input stage.

You tell me whar a man gits his corn pone, en I’ll tell you what his ‘pinions is.

A am wondering what Midas is using or their XL42 preamp now. 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. Started by maxime The Lab.

February 26, ,