sansui au-717 transistors

[jblmar]

Hi all,
Anyone know where I can get the following transistors for the AU-717?
No one vendor I've contacted has all the transistors needed. I'm trying to source them from one vendor to save the owner of the amp additional shipping charges.
These transistors are for the amplifier board.
TR01-TR13

2sd382
2sb537
2sc1904
2sc945
2sa899
2sa750
2sc1400

Output transistors:
2sa747
2sc1116

FET01: Anyone know this part #?

Thanks.

[Hyperion]

Well I can get you started...

2sd382 = MJE15030 = Digikey
2sb537 = MJE15031 = Digikey
2sc1904 = KSA2690A = Mouser
2sc945 = 2SC1509S = Digikey
2sa899 = KSA1220A = Mouser
2sa750 = ?
2sc1400 = 2SC1400 or ZTX694B = Digikey

Output transistors:
2sa747 = Very nearly unobtanium - beware of counterfeits - suggest MJ21193 = Digikey
2sc1116 = Very nearly unobtanium - beware of counterfeits - suggest MJ21194 = Digikey

As for the Fet 2SK97 - I would love to know a good replacement for it - a bit paranoid about losing one in my AU-717.

Sorry I can't give you one supplier

[jblmar]

Thanks, John.
This channel has almost all transistors shorted.

[Hyperion]

That is unusual - you are doing the right thing to replace them all, as they must all have been really stressed. The replacements given BTW are all solid gold - as suggested by the experts (e.g EW and others). They have the advantage of being newer equivalents for the older ones which may be suspect old stock - maybe even counterfeits.

There should be an easy equivalent for the 2SA750 - hope someone will chime in with this...

And also the 2SK97 - the best equivalent I have seen discussed was 2 ordinary JFETs (matched) and tightly coupled together with thermal paste +thermal clip. There are other twin JFET's available - but I do not know what circuit changes might be required if one of these were used.

[jblmar]

I'm sure there are suitable replacements.

[EchoWars]

I do not know of a replacement for the Sony input FET (2SK97). Certainly a pair of standard FET's could be matched and used (2SK117's maybe?), but they would have to have about the same transconductance as the originals, and old FET data sheets are even harder to track down than the ones for the old transistors. I'd see if I could get the attention of one of the guys over at DIY Audio who might have more experience with JFET's. But I'd be surprised to see that yours was bad. There aren't many faults that are going to travel all the way back to the input stage.

The outputs can be replaced with standard On-Semi MJ21193/94 or /95/96 units. Since the drivers use the heatsink tab for conduction, the only real choice is the MJE15030 & 15031 (or 15032/33).

For the TO-126 devices, the selection is limited, but Fairchild still has the KSC2690AYS and the KSA1220AYS (TR05, TR07, TR08, & TR11).

There's a couple of 2SC945's (TR06 & TR09), and Fairchild makes this one in a center-base,and a center-collector part. The one to get is the KSC945CLTA, which is a center-collector part just like the original. It comes ammo-style with the leads sandwiched in paper, which is always fun to remove and get the glue cleaned off (if you need the whole lead-length), but it's the only high-gain KSC945 with the center-collector configuration.

For the second differential stage (TR01 & TR02), the KSC1845UBU will do well, and for TR03 & TR04, the KSA992FBU will work.

ZD01 and ZD02 are 22V 1W zeners. I believe the rest of the diodes are simply small signal diodes which can be replaced with 1N4148's.

[jblmar]

Thanks Glenn.
Here's what MCM quoted.
2SA747: $8.53
2SA750: Sub with NTE 254 $1.09
2SA899V: Sub with 2SB649 $1.00
2SB537: Sub with NTE 153 $2.87
2SC945AP: Discontinued IIRC, NTE 85 will do as a last option. Other suggestions?
2SC1116: Sub with 2SD424 $5.92
2SC1400: Sub with 2SC2389 $0.24
2SC1904V: Sub with NTE 373 $1.96
2SD382: Sub with NTE 375 $2.07

MCM has all in stock.
I would rather stay away from NTE semiconductors. At least it's an option if all else fails.

I too doubt that FET 01 is bad. The amp took a big hit, but I doubt that the defect would include the input FET.

Thanks Glenn for the cross reference (ie 2SC945). I'm sure the owner of the amp would rather buy all the parts from the same vendor to save on extra shipping. I'll discuss the issue with him.

[EchoWars]

All the parts I quoted are available at Mouser. You need not substitute for my substitutes.

[jblmar]

Thanks Glenn.
I'll order the parts from Mouser as you suggest.