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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Those are super low Rbb transistors for low Z input stages. 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 datashwet. The 2SA Hitachi that I pointed out earlier is a popular replacement used in quite a few preamp stages that previously had the 2SB April 01, You can buy small quantities on the web I still have some back in my lab.
If you sprinkle when you tinkle, please be neat and wipe the seat. Hi all, looks like two of the channels of my mixing console were fried when a phantom power 2sb7337 capacitor blew up.
Dxtasheet there any equivalent for this?
Perhaps they are protecting against some latch up condition. 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 dattasheet.
A am wondering what Midas is using or their XL42 preamp now. March 29, You are about to become the voice of Interplanetary Parliament. There are some newer substitutes that aren’t as low R’bb but are acceptable in general microphone preamps. If you sub a newer part, you may want to back off on the current density datasueet optimal noise performance or not.
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. Started by jrmintz The Lab. The 85 looks identical except for higher breakdown voltage than 84 so no problem with either.
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. Thank you very much That design looks like around 1 mA nominal set by ohm and Vbe of 2sc Looking forward to some results!
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 They were using truck loads of the 2sd NPN version. But that will not last for ever. February 18, Very nice that Mr.
2SB Datasheet, Equivalent, Cross Reference Search. Transistor Catalog
Transistor substitution in GAR Other observations about the schematic, the diode across the uF looks a little odd. I don’t remember what transistor Peavey switched to. Hi Have these transistors in bad Delta channel. Low noise devices are generally graded for beta, as in the more beta the better for low noise applications.
2SB737 Datasheet, Equivalent, Cross Reference Search
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. The -E parts are higher beta than the -D. I’ve used the npn counterpart 2SC with good results.
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.
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