Hello all. I hope I'm posting this in the appropriate place, and I apologize for making my first post a request for assistance (I hope to be able to actually contribute something in the future). I have a fondness for vintage Dynaco equipment - hence the screen name Dynasor :=)
I recently acquired a Pioneer SA-9500 II (80 Watts/8 Ohm, 100 Watts/4 Ohm) integrated amplifier in nice condition but with only one working channel. A previous owner had removed the four output transistors from the non-working side, together with a heatsink-mounted varistor diode which I imagine is for temperature compensation.
The output stage for each channel consists of two 2SD588A (NPN) and two 2SB618A (PNP) power transistors in parallel (I don't know whether these are specified as matched pairs or not - the parts list doesn't indicate). These devices have been discontinued, together with their ECG380 and ECG381 replacement counterparts, probably because their unusual "TB-33" case style is long-obsolete. The specs for these identical complementary transistors are:
Vcb-150V, Veb-5V, Ic-7A, Pd-80W, Tj-150*C, hfe-80 @ Vce-5V and Ic-1A, Ft-14MHz
(The drivers for these output devices are a 2SD381 and a 2SB536.)
I've been unable to find full datasheets for the D588A and B618A and am thus unable to make meaningful comparisons with current devices. Nonetheless, I thought that something like ON Semi's MJW-21191/92 might work OK. I'm prepared to deal with the slightly different mounting, so long as the electronic interchange is good and doesn't require re-engineering of the circuit as a whole. Any thoughts - or recommendations for better substitutes for improved performance? I'd like to stay with flat packages such as TO-220, TO-247, etc. if possible, but will go for a TO-3 package if absolutely necessary or greatly advantageous (more difficult heatsink modifications required in this case).
The missing temperature compensating varistor diode has me stumped. Mounted on the same heatsink as the outputs, this part is identified on the schematic as "STV4H" ("STV-4H" in the Parts List) and is a flat rectangular package about 1/4" x 3/8" with two 1 1/4" wire leads and a slot for the heatsink mounting screw. It's schematic symbol resembles four diodes in series ( -|>|>|>|>|- ). Can't even find the STV-4H listed anywhere, much less identify a replacement. Any ideas?
The 9500 II isn't a bad amplifier for home use, having decent specs and some nice features as well as impressive build quality. If the power amplifier problem can be solved, I'll probably do some re-capping etc. to bring it up to par.
Thanks in advance - I really appreciate any help anyone can provide.
I recently acquired a Pioneer SA-9500 II (80 Watts/8 Ohm, 100 Watts/4 Ohm) integrated amplifier in nice condition but with only one working channel. A previous owner had removed the four output transistors from the non-working side, together with a heatsink-mounted varistor diode which I imagine is for temperature compensation.
The output stage for each channel consists of two 2SD588A (NPN) and two 2SB618A (PNP) power transistors in parallel (I don't know whether these are specified as matched pairs or not - the parts list doesn't indicate). These devices have been discontinued, together with their ECG380 and ECG381 replacement counterparts, probably because their unusual "TB-33" case style is long-obsolete. The specs for these identical complementary transistors are:
Vcb-150V, Veb-5V, Ic-7A, Pd-80W, Tj-150*C, hfe-80 @ Vce-5V and Ic-1A, Ft-14MHz
(The drivers for these output devices are a 2SD381 and a 2SB536.)
I've been unable to find full datasheets for the D588A and B618A and am thus unable to make meaningful comparisons with current devices. Nonetheless, I thought that something like ON Semi's MJW-21191/92 might work OK. I'm prepared to deal with the slightly different mounting, so long as the electronic interchange is good and doesn't require re-engineering of the circuit as a whole. Any thoughts - or recommendations for better substitutes for improved performance? I'd like to stay with flat packages such as TO-220, TO-247, etc. if possible, but will go for a TO-3 package if absolutely necessary or greatly advantageous (more difficult heatsink modifications required in this case).
The missing temperature compensating varistor diode has me stumped. Mounted on the same heatsink as the outputs, this part is identified on the schematic as "STV4H" ("STV-4H" in the Parts List) and is a flat rectangular package about 1/4" x 3/8" with two 1 1/4" wire leads and a slot for the heatsink mounting screw. It's schematic symbol resembles four diodes in series ( -|>|>|>|>|- ). Can't even find the STV-4H listed anywhere, much less identify a replacement. Any ideas?
The 9500 II isn't a bad amplifier for home use, having decent specs and some nice features as well as impressive build quality. If the power amplifier problem can be solved, I'll probably do some re-capping etc. to bring it up to par.
Thanks in advance - I really appreciate any help anyone can provide.
Prefix Part # Qty Target Price Mfg Date Code Company Availability
STV 3HY n/a n/a Summit Electronics AVAILABLE
STV 3HY SANYO n/a Summit Electronics AVAILABLE
STV 3HY SANK n/a Summit Electronics AVAILABLE
STV 3HY SANK n/a Summit Electronics AVAILABLE
STV 3HY SANK n/a Summit Electronics AVAILABLE
STV 3HY SANK n/a Summit Electronics AVAILABLE
STV 3HY N/A n/a Summit Electronics AVAILABLE
STV 3HY SANK n/a Summit Electronics AVAILABLE
A 3H MOT n/a Summit Electronics AVAILABLE
A 3H MOT n/a Summit Electronics AVAILABLE
--------------------------------------------------------------------------------
Search Result
If you can't find your part number, please call us at 800.226.6960 or 561.226.8500.
To send a Request For Quote, place a check mark in the check box under Create RFQ at left and hit "Create RFQ".
Prefix Part # Qty Target Price Mfg Date Code Company Availability
4H n/a n/a Summit Electronics AVAILABLE
4H IC n/a Summit Electronics AVAILABLE
ATS 4H RUSSELL n/a Summit Electronics AVAILABLE
C 4H n/a n/a Summit Electronics AVAILABLE
CE 4H n/a n/a Summit Electronics AVAILABLE
DAS 4H n/a N/A Summit Electronics AVAILABLE
DIO 4H APEM n/a Summit Electronics AVAILABLE
DX 4H NSC 1998 Summit Electronics AVAILABLE
EPA 4H ECT n/a Summit Electronics AVAILABLE
F 4H RUSSELL n/a Summit Electronics AVAILABLE
--------------------------------------------------------------------------------
I buy STV3H from Summit, the outputs you have selected should work fine.
If they don't have the four diode stacks you can always make one.
2SD588 n/a n/a Summit Electronics AVAILABLE
2SD588 MAT n/a Summit Electronics AVAILABLE
2SD588 SVNTC n/a Summit Electronics AVAILABLE
2SD588 NEC n/a Summit Electronics AVAILABLE
2SD588 n/a N/A Summit Electronics AVAILABLE
2SD588 N/A N/A Summit Electronics AVAILABLE
2SD588 NEC n/a Summit Electronics AVAILABLE
2SD588 SVNTC n/a Summit Electronics AVAILABLE
2SD588 SVNTC n/a Summit Electronics AVAILABLE
2SD588 n/a n/a Summit Electronics AVAILABLE
--------------------------------------------------------------------------------
Search Result
If you can't find your part number, please call us at 800.226.6960 or 561.226.8500.
To send a Request For Quote, place a check mark in the check box under Create RFQ at left and hit "Create RFQ".
Prefix Part # Qty Target Price Mfg Date Code Company Availability
2SB618 NEC n/a Summit Electronics AVAILABLE
2SB618 n/a n/a Summit Electronics AVAILABLE
2SB618 NEC 1997 Summit Electronics AVAILABLE
2SB618 n/a N/A Summit Electronics AVAILABLE
2SB618 NEC n/a Summit Electronics AVAILABLE
2SB618 NEC n/a Summit Electronics AVAILABLE
2SB618 n/a n/a Summit Electronics AVAILABLE
2SB618 N/A N/A Summit Electronics AVAILABLE
2SB618 NEC n/a Summit Electronics AVAILABLE
2SB618 NEC 1988 Summit Electronics AVAILABLE
--------------------------------------------------------------------------------
Looks like Summit has lots of NEC outputs available too.
They had 500,000 from SVNTC available (used in cheap car stereo).
STV 3HY n/a n/a Summit Electronics AVAILABLE
STV 3HY SANYO n/a Summit Electronics AVAILABLE
STV 3HY SANK n/a Summit Electronics AVAILABLE
STV 3HY SANK n/a Summit Electronics AVAILABLE
STV 3HY SANK n/a Summit Electronics AVAILABLE
STV 3HY SANK n/a Summit Electronics AVAILABLE
STV 3HY N/A n/a Summit Electronics AVAILABLE
STV 3HY SANK n/a Summit Electronics AVAILABLE
A 3H MOT n/a Summit Electronics AVAILABLE
A 3H MOT n/a Summit Electronics AVAILABLE
--------------------------------------------------------------------------------
Search Result
If you can't find your part number, please call us at 800.226.6960 or 561.226.8500.
To send a Request For Quote, place a check mark in the check box under Create RFQ at left and hit "Create RFQ".
Prefix Part # Qty Target Price Mfg Date Code Company Availability
4H n/a n/a Summit Electronics AVAILABLE
4H IC n/a Summit Electronics AVAILABLE
ATS 4H RUSSELL n/a Summit Electronics AVAILABLE
C 4H n/a n/a Summit Electronics AVAILABLE
CE 4H n/a n/a Summit Electronics AVAILABLE
DAS 4H n/a N/A Summit Electronics AVAILABLE
DIO 4H APEM n/a Summit Electronics AVAILABLE
DX 4H NSC 1998 Summit Electronics AVAILABLE
EPA 4H ECT n/a Summit Electronics AVAILABLE
F 4H RUSSELL n/a Summit Electronics AVAILABLE
--------------------------------------------------------------------------------
I buy STV3H from Summit, the outputs you have selected should work fine.
If they don't have the four diode stacks you can always make one.
2SD588 n/a n/a Summit Electronics AVAILABLE
2SD588 MAT n/a Summit Electronics AVAILABLE
2SD588 SVNTC n/a Summit Electronics AVAILABLE
2SD588 NEC n/a Summit Electronics AVAILABLE
2SD588 n/a N/A Summit Electronics AVAILABLE
2SD588 N/A N/A Summit Electronics AVAILABLE
2SD588 NEC n/a Summit Electronics AVAILABLE
2SD588 SVNTC n/a Summit Electronics AVAILABLE
2SD588 SVNTC n/a Summit Electronics AVAILABLE
2SD588 n/a n/a Summit Electronics AVAILABLE
--------------------------------------------------------------------------------
Search Result
If you can't find your part number, please call us at 800.226.6960 or 561.226.8500.
To send a Request For Quote, place a check mark in the check box under Create RFQ at left and hit "Create RFQ".
Prefix Part # Qty Target Price Mfg Date Code Company Availability
2SB618 NEC n/a Summit Electronics AVAILABLE
2SB618 n/a n/a Summit Electronics AVAILABLE
2SB618 NEC 1997 Summit Electronics AVAILABLE
2SB618 n/a N/A Summit Electronics AVAILABLE
2SB618 NEC n/a Summit Electronics AVAILABLE
2SB618 NEC n/a Summit Electronics AVAILABLE
2SB618 n/a n/a Summit Electronics AVAILABLE
2SB618 N/A N/A Summit Electronics AVAILABLE
2SB618 NEC n/a Summit Electronics AVAILABLE
2SB618 NEC 1988 Summit Electronics AVAILABLE
--------------------------------------------------------------------------------
Looks like Summit has lots of NEC outputs available too.
They had 500,000 from SVNTC available (used in cheap car stereo).
what are the rail voltages?
dynasor,
can you post the rail voltages, possibly the filter caps (the black thing, ussually 2 or four...)and the blown parts, what packages are they?, my 1990 edition of japanese transistor manual do not even list them, if they are the ones with 2 holes on two ears for mounting, then you can very well replace them with ON Semi MJL3281A/MJL1302A, the drivers you can sub them with MJE15030/31 and you will never run out of spares.... the thing you call varistor is actually a diode string, could be an stv-2 or stv-3 also, japs are fond of this...but you can actually string 4 diodes if you wish....
dynasor,
can you post the rail voltages, possibly the filter caps (the black thing, ussually 2 or four...)and the blown parts, what packages are they?, my 1990 edition of japanese transistor manual do not even list them, if they are the ones with 2 holes on two ears for mounting, then you can very well replace them with ON Semi MJL3281A/MJL1302A, the drivers you can sub them with MJE15030/31 and you will never run out of spares.... the thing you call varistor is actually a diode string, could be an stv-2 or stv-3 also, japs are fond of this...but you can actually string 4 diodes if you wish....
Thanks for the responses - here's what I've got so far:
DJK: Despite the positive search results (thanks for taking the time by the way), Summit is unable to help on the transistors and draws a complete blank on the STV4H diode string. They tell me they'll keep trying, but so far they only have overseas sources with which they can't deal in such small quantities.
Joan2: The rail voltages are + and - 46 volts, and the power supply capacitors are four 12,000 uF/63V, two for each independent power supply (each channel has its own PS). The original outputs are indeed the ones with two mounting holes. I think I've decided to go with the MJL3281A/1302A outputs as you recommend, but did you intend to say that if I substitute these, the drivers must (also) be replaced with the MJE15030/31?
As for making the diode string, what sort of diodes should I use, and how do we know what the original specs were? I located a diode array that consists of four isolated 1N4148s that I figured could easily be series-wired and mounted on the heatsink similar to the original mounting, but so far I've only found it in bare die form (not packaged). Datasheet: http://www.microsemi.com/datasheets/MSC1023.PDF Assuming I can get this as a flatpack or somesuch, will the 1N4148 specs fill the bill? Another possibility is the CMEDA-6i, datasheet: http://www.centralsemi.com/pdf/CMEDA-6i.pdf What do you think?
EchoWars: You really made my day with that! $15.98 plus shipping for a ten cent part! We're all in the wrong business!
DJK: Despite the positive search results (thanks for taking the time by the way), Summit is unable to help on the transistors and draws a complete blank on the STV4H diode string. They tell me they'll keep trying, but so far they only have overseas sources with which they can't deal in such small quantities.
Joan2: The rail voltages are + and - 46 volts, and the power supply capacitors are four 12,000 uF/63V, two for each independent power supply (each channel has its own PS). The original outputs are indeed the ones with two mounting holes. I think I've decided to go with the MJL3281A/1302A outputs as you recommend, but did you intend to say that if I substitute these, the drivers must (also) be replaced with the MJE15030/31?
As for making the diode string, what sort of diodes should I use, and how do we know what the original specs were? I located a diode array that consists of four isolated 1N4148s that I figured could easily be series-wired and mounted on the heatsink similar to the original mounting, but so far I've only found it in bare die form (not packaged). Datasheet: http://www.microsemi.com/datasheets/MSC1023.PDF Assuming I can get this as a flatpack or somesuch, will the 1N4148 specs fill the bill? Another possibility is the CMEDA-6i, datasheet: http://www.centralsemi.com/pdf/CMEDA-6i.pdf What do you think?
EchoWars: You really made my day with that! $15.98 plus shipping for a ten cent part! We're all in the wrong business!
1n4001's will suffice
1n4148 is glass so very brittle, plastic encapsulated ones are easier to handle and cheap too. if you want to replace the outputs to mjl's then you need not replace the drivers is they are still good....i remember, this output transistors, do they have sockets? i remember i must have repaired one of those amps...it's been a long time....
1n4148 is glass so very brittle, plastic encapsulated ones are easier to handle and cheap too. if you want to replace the outputs to mjl's then you need not replace the drivers is they are still good....i remember, this output transistors, do they have sockets? i remember i must have repaired one of those amps...it's been a long time....
Hi:
In case anyone is still searching for these difficult-to-find devices:
I am working on a Kenwood KA-3500 with blown output transistors - they are the same 2SD588/2SB618. I found MAT Electronics to have them in stock (cheapest source so far) at $2.75/$3.23
Good luck
Mayank
In case anyone is still searching for these difficult-to-find devices:
I am working on a Kenwood KA-3500 with blown output transistors - they are the same 2SD588/2SB618. I found MAT Electronics to have them in stock (cheapest source so far) at $2.75/$3.23
Good luck
Mayank
Output transistors for Kenwood KA-3500 int amp
Well, that was back in 2005. Now I could only find those parts for like $20 each (!). [ 2SD588/2SB618 ] Does anyone know if there are substitutes available, or is this KA-3500 with blown outputs destined to become landfill?
Or better yet, anybody have any suggestions for replacing blown outputs on this amp? It was supposed to be a good one...
--
Well, that was back in 2005. Now I could only find those parts for like $20 each (!). [ 2SD588/2SB618 ] Does anyone know if there are substitutes available, or is this KA-3500 with blown outputs destined to become landfill?
Or better yet, anybody have any suggestions for replacing blown outputs on this amp? It was supposed to be a good one...
--
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