Why do you suspect them to be fakes? If the pinout is correct, and the DC beta is within spec, they're likely to be authentic NXP parts - these devices were never very expensive or worthwhile to counterfeit.
The BC546 fakes I got from CeePee when examined carefully, even look like fakes! The marking is pretty badly done, the leads are extremely thin and flimsy. When I measured the DC gain it was far below specs. Im hoping that poor BEL hasnt sunk so low as to produce such crummy components
. The 639s have poorer specs in terms of fT and dc ct. gain (hFEmin~40). And in any case what if they too are fakes
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The BC546 fakes I got from CeePee when examined carefully, even look like fakes! The marking is pretty badly done, the leads are extremely thin and flimsy. When I measured the DC gain it was far below specs. Im hoping that poor BEL hasnt sunk so low as to produce such crummy components
The 639s have poorer specs in terms of fT and dc ct. gain (hFEmin~40). And in any case what if they too are fakes
BEL does resell a lot of parts that are sourced elsewhere on a contract basis - these include small-signal transistors. In recent years, they probably source it from the lowest-price bidder - which might be CDIL, Crompton-Greaves, or any low-end Chinese manufacturer (the better MNC Chinese fabs like ST, NXP, etc. will be too expensive for BEL). I wouldn't be surprised if the crummy parts are indeed authentic BEL-branded parts.
BC639 can be selected for DC Hfe > 100 (almost all I've seen are at or above that level), if you're OK with lower fT. Alternatively, go with Toshiba BC547B - superbly clean low-noise process, will exceed the linearity and noise specs. of BC549/550 from any other manufacturer. IIRC, DC Beta is in the region of 200-400, which is in the same range as the much-beloved 2sc1815-GR or -BL. In fact, I think it's the same die as the 2sc1815, but just sampled, binned and marked as BC547B if it doesn't meet Vceo specs of the 2sc1815.
The only issue is that I can't seem to find PNP BC557B from Toshiba locally, though I get the original 2sa1015-Y and -GR from time to time.
I checked more on sp road. the cheap ones they are calling as chinese and not as fakes, costs 30-35 bucks, the non chinese are selling for about 95-115/-. I guess I will try both of them and see if there is a difference.
I also need some wire for internal signal wiring in preamp and amps. Any suggestions on what should I get. What about power wiring, will the finolex 1sqmm or 2.5sqmm do this fine. How good or bad are the cabletronix cables (not sure of the name, the cable shop approximately opposite to vishal).
I also need some wire for internal signal wiring in preamp and amps. Any suggestions on what should I get. What about power wiring, will the finolex 1sqmm or 2.5sqmm do this fine. How good or bad are the cabletronix cables (not sure of the name, the cable shop approximately opposite to vishal).
Look at Ian's CCS for the Baby Huey, in the tubes section using back-to-back BJTs.
I use a single BJT upto 10mA, but I've also used 78xx regs which I really like for simple CCS solutions with a resistor that can be changed out as needed above-board. The BJT designs are scaleable quite easily and the 78xx are great for preceding a shunt regulator, or other simple battery charger applications. Noise doesn't matter in either case.
Why don't you want the LM317? It is probably the simplest kind of CCS solution.
I use a single BJT upto 10mA, but I've also used 78xx regs which I really like for simple CCS solutions with a resistor that can be changed out as needed above-board. The BJT designs are scaleable quite easily and the 78xx are great for preceding a shunt regulator, or other simple battery charger applications. Noise doesn't matter in either case.
Why don't you want the LM317? It is probably the simplest kind of CCS solution.
Beware of Rediff Shop.
http://www.diyaudio.com/forums/ever...ng-stories-rediff-shop-india.html#post4239578
If they make a mistake, you will have to pay for it.
Gajanan Phadte
http://www.diyaudio.com/forums/ever...ng-stories-rediff-shop-india.html#post4239578
If they make a mistake, you will have to pay for it.
Gajanan Phadte
A GOOD car amplifier needs a dc-dc converter so that you can use a good discrete power amp. Other 12 volt bridged ICs cannot be classified as good.
After you make the cd-dc converter, any amp of your choice like TDA7294/3 or any of the so many discrete audiophile amps can be constructed.
For laid out circuits, look for posts by Apex.
Gajanan Phadte
After you make the cd-dc converter, any amp of your choice like TDA7294/3 or any of the so many discrete audiophile amps can be constructed.
For laid out circuits, look for posts by Apex.
Gajanan Phadte
It's not possible to say without the pictures, but generally TTC5200 is current production and likely to be genuine, while 2sc5200 is older production and could be counterfeit.
The 2sc5200 is also in production, apparently.
2SC5200 | Bipolar Transistors | TOSHIBA Semiconductor & Storage Products Company | Asia-Pacific
I believe the 'genuine' ones no longer carry the 'Japan' designation on the package. I've a few pairs in action and they seem to test with the correct range of capacitances and weight, but have yet to determine SOA capabilities,, or crack one open to look inside.
In any case the ISC and Fairchild devices are usually 'original' and can be directly swapped in.
2SC5200 | Bipolar Transistors | TOSHIBA Semiconductor & Storage Products Company | Asia-Pacific
I believe the 'genuine' ones no longer carry the 'Japan' designation on the package. I've a few pairs in action and they seem to test with the correct range of capacitances and weight, but have yet to determine SOA capabilities,, or crack one open to look inside.
In any case the ISC and Fairchild devices are usually 'original' and can be directly swapped in.
If you're OK with TO3P plastic packages, On Semi NJW0281G/0302G is an excellent pair with sustained beta and good SOAR, at a very small premium to the price of the Toshiba devices.