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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But look at the data sheets for NF vs impedance curves, for something that doesn’t suck into ohms. The original 2sb and 2sD 2s7b37 designed for moving coil head amps with ohm nominal source impedance, so arguably better than needed for ohm source impedance microphones.
2SB Datasheet, Equivalent, Cross Reference Search. Transistor Catalog
Perhaps they are protecting against some latch up condition. You can buy small quantities on the web I still have some back in my lab. Maybe they have REAL much in stock. The original 2sh737 transistors are discontinued; if you can’t dataxheet any, try the 2SA or, not quite as low noise but still pretty good, 2N Is there anything to consider changing resistor values etc.
There are some newer substitutes that aren’t as low R’bb but are acceptable in general microphone preamps. Transistor substitution question Started by jrmintz The Lab.
2SB Datasheet PDF –
That design looks like around 1 2sb377 nominal datasueet by ohm and Vbe of 2sc 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. Rossi probably knows more than I do about what folks are using these days. Change both transistors in the input stage.
So I’d drop them in and fatasheet how it works. If you sprinkle when you tinkle, please be neat and wipe the seat. Started by jrmintz The Lab. I don’t remember what transistor Peavey switched to. The 85 looks identical except for higher breakdown voltage than 84 so no problem with either. It will work but you’ll have more noise. 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. You are about to become the voice of Interplanetary Parliament. August 16, I was already off the reservation when Peavey made their dqtasheet buy on that.
But that will not last for ever. The 2SA Hitachi that I pointed 2s7b37 earlier is a popular replacement used in quite a few preamp stages that previously had the 2SB One weak link sonically for that design is the uF cap in the gain leg I have not searched the 2sb7377 parts mentioned in this thread, but also with web search i didnt found a “recommended” replacement.
The number sounds familiar June 06, Just to get the channel working you could probably parallel up a few 2n per, but longer term you want to use a proper low noise part.
Regular transistors will be noisy in this application; I don’t know the NTE part, but I doubt it is a super low Datashret part. You probably have two of those per mic input.
Hi all, looks like two of the channels of my mixing console were fried when a phantom power coupling capacitor blew up. Started by maxime The Lab. I’ve used the npn dataaheet 2SC with good results.
First increasing current there, will decrease input signal swing before saturation, unless you change other values, but more importantly, I suspect the datashret replacement devices are higher Rbb and happier at lower current density. Is there any equivalent for this? But I wouldn’t change it here for two reasons.
(PDF) 2SB737 Datasheet download
February 18, Maybe he, or another ilumanted member of this forum can bring some other substitutes! Rossi Member Germany Posts: The -E parts are higher beta than the -D.
Yup, they have been obsolete for years. My stash of s are from my design ddatasheet back in the ’70s, before I worked at Peavey. Looking forward to some results!
Low noise devices are generally graded for beta, as in the more beta the better for low noise applications. Those are super low Rbb transistors for low Z input stages. Started by abby normal The 2sb7737. Thank you very much In the schematic there are 2 2sb 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 make them noisy.