Help needed for transistor cross reference

[maxwall]

Help.......

This is out of a Soundcraft Spirit Studio Console 24x8

transistors I'm having trouble cross referencing to something else.
I have checked the usual online cross reference resources , but there may be others I have not discovered yet

I DONT NEED THE USUAL NTE EQUIVILENT. I'm looking for a fairchild, motorola, STmicro, etc. ( NO CHINESE BLACK MARKET STUFF EITHER)


ORIG # printed on Transistor.................my guess
D786 .............................................................. 2SD786
A970 ............................................................. 2SA970
C2240 ........................................................... 2SC2240

Soundcraft support would not give me a cross reference to another generic part number equivilent. Of course, they wanted me to buy from them at 4 times the cost.

Another funny thing is I have this transistor tester ( BK precision 510 ) that usually tells me that its either a NPN or PNP. for some reason it won't detect these transistors, not sure why.

 

[gyraf]

Yes.

On Jap. transistors, the "2S" is redundant, and rarely written on the transistor..

Third letter:

A= PNP, low power
B=PNP, med-to-high power
C=NPN, low power
D=NPN, med-to-high power
J=FET, P-channel
K=FET, N-channel


Jakob E.

 

[maxwall]

Thanks Jacob,

very helpful info

now I just need to find suitable replacements or substitutions, any chance of choosing a higher performance transistor on these ? I noticed there being used in pairs on the input channels. Not sure if their complimentary pairs.

But the two are probably matched in someway.

 

[Samuel Groner]

Now I just need to find suitable replacements or substitutions, any chance of choosing a higher performance transistor on these?

Why don't you buy the original parts? At least the 2SA970 is still in production. It is very unlikely that you'll find higher performance transistors from the manufacturers you mentioned--in fact you'll have a hard time to find parts that are more or less equivalent.

About the only standard transistor that comes close regarding voltage noise performance is the 2N4403. The lowest voltage-noise transistors currently available are the 2SC3329/2SA1316 pair.

Motorola is now ON Semi, BTW.

But the two are probably matched in someway.

Almost impossible at the price tag of the mentioned manufacturer and pretty unnecessary for the standard mic pre circuitry anyway.

Samuel

 

[bcarso]

[quote author="maxwall"]Help.......

This is out of a Soundcraft Spirit Studio Console 24x8

transistors I'm having trouble cross referencing to something else.
I have checked the usual online cross reference resources , but there may be others I have not discovered yet

I DONT NEED THE USUAL NTE EQUIVILENT. I'm looking for a fairchild, motorola, STmicro, etc. ( NO CHINESE BLACK MARKET STUFF EITHER)


ORIG # printed on Transistor.................my guess
D786 .............................................................. 2SD786
A970 ............................................................. 2SA970
C2240 ........................................................... 2SC2240

Soundcraft support would not give me a cross reference to another generic part number equivilent. Of course, they wanted me to buy from them at 4 times the cost.

Another funny thing is I have this transistor tester ( BK precision 510 ) that usually tells me that its either a NPN or PNP. for some reason it won't detect these transistors, not sure why.[/quote]

The transistor tester probably is set up for a different pinout than the parts.

Chinese black market---hmmm. There really isn't a whole lot of that for semiconductors---and you are not likely to be approached by one of the fences for the stolen IC's that get pinched from time to time anyway. But caveat emptor has always been good advice. There are plenty of Japanese parts made and packaged in other countries though, under their close supervision, and they are generally of excellent quality.

Soundcraft is not being disingenuous when they can't give you those "generic equivalent". The sad fact is that, with the exception of some small firms, there are not that many competitively high quality low-freq discrete semis made by US or European manufacturers anymore. There are plenty made that are good enough for their applications most of the time. But for critical audio apps it's best to go hunt down the original manufacturer's parts. Since the US demand for such is small, many of these mfr's don't officially support the parts in the US, so you have to get them from overseas sources or some of the gray market vendors, some of whom are quite reputable and wholly legal.