As you're in Canada, have you considered the huge stocks often held by Rochester Electronics? A quick search of the high gain version BC550CG, brings up some quite affordable prices, assuming they are current and reliable figures:
BC560 Price & Stock | DigiPart
BC560 Price & Stock | DigiPart
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This is a rare case of building, not designing.
Here's the amp I'm building. It's the QSXM2, by Per-Anders Sjostrom.
Attachments
Today I ordered 1000 x BC550C at RS and 1000 x BC560C at Distrelec. In total less than 50 euro, to arrive in some days. Are you interested suzyj?
RS appear to have BC560 on back order. Maybe they have an order placed with ON Semi for the last purchases as they are obsoleting them. As Ian mentioned TO-92 are going. Seems industrially only SMD's are going to be used in future. Pity, because many of us started out with thru-hole devices as they (still are) were easy to build with. SMD's not so much fun. but you can make much smaller circuits with them (if you are prepared to use tweezers and fine solder tips).
Origin PRC, I'll ask them tomorrow to name the manf as round is the oem name used by Distr. If no good I send them back.
Rochester acts like a distributor, not a retailer. They won't sell you a few dollars of goods. The minimum order is IIRC about $250. Yes, on 8-cent parts this is a LOT of pieces.
I will be trying out some ZTX 450/550s shortly on an amp I'm rebuilding. They are pin compatible with the 550/560s but appear to be equivalents to the MPS8099/8599. Not certain of their noise figures. Quite a few RIAAs that I've seen use the ZTX devices.
P.S. Just checked the ZTX458 & 758 seem to be the equivalent and they're still available from RS; they're 400 V devices!
P.S. Just checked the ZTX458 & 758 seem to be the equivalent and they're still available from RS; they're 400 V devices!
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Where did you get that info from? The ONSemi BC327 datasheet doesn't even show noise characteristics, and I really doubt on that!
Best regards!
If you can get by with the "C" variant on tape reels, Mouser has 2,000 BC550s in stock and 40,000 on order for February delivery.
560s? That's a different story altogether. DigiKey will source them for you but there are only 39,000 available.
560s? That's a different story altogether. DigiKey will source them for you but there are only 39,000 available.
That has been mentioned before on this site somewhere. It is possible, as the 337 and 327 are higher current devices and may have a better physical layout (e.g. interdigitated) than the old ring-rot structure that at least the early BC107 types were. I've not investigated any physical structures on recent devices, so don't know, but suspect the BD5xx are very similar.
If the 3x7 have a lower base resistance (as a result of a better layout to enable higher currents) the noise could be lower. It's something I've been meaning to investigate.
The junction capacitances might be larger though.
Here, with some technical background: diyaudio.com/forums/solid-state/243432-low-noise-transistors-gone-2.html
Here is a nice read with some real-world measurements, and if you believe him you won't be sad when the BC550C goes away😱:
Here for NPN: www.dicks-website.eu/low_noise_amp_part3/part3.html.
And here for PNP: www.dicks-website.eu/low_noise_amp_part5/part5.html
(Unfortunately no BC560C tested).
I would more worry about the loss of good brand rather than good types.
Hi the fact that BC327/337 (Philips) are less noisy and can handle higher current than BC550/560 (Philips) I know since my childhood when I started with electronics and read Elektor magazine 🙂
I bought both by the bag in the past. BC550/560 are nothing special since one can find lower noise parts easily.
I bought both by the bag in the past. BC550/560 are nothing special since one can find lower noise parts easily.
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