I'm looking for some modern or still produced replacements for a couple of transistors after finding out the hard way a lot of fakes are for sale even from reputable (at least I was told so) distributors.
I have a Denon PMA-1560, one channel was completely dead, most of the transistors have been replaced with original parts I had but I'm still looking for replacements for a pair of 2SB1328/2SD2004. Also is it safe to by a TLP521-1 photocoupler on ebay ?
Next a Marantz PM-5 had blown one channel, was previously repaired and then got to me with a faulty voltage amp stage. Turns out on one channel Q717/Q720 were shorted. Those are 2SA1124/2SC2632. I ordered a pair from dalbani UK and received two 2SA1124 marked Japan that seem ok but the 2SC2632 had no brand name and one actually turned out to be a PNP 😕. I asked for a refund but so far nothing. Anyway I prefer to go for some modern replacements. Also the drivers seem to have been under a lot of stress and I would like to replace them as well, those are 2sa1111/2sc2591, any ideas ?
Just to recap, I'm looking for replacements for :
-2SB1328/2SD2004
-2SA1124/2SC2632
-2SA1111/2SC2591
🙂
I have a Denon PMA-1560, one channel was completely dead, most of the transistors have been replaced with original parts I had but I'm still looking for replacements for a pair of 2SB1328/2SD2004. Also is it safe to by a TLP521-1 photocoupler on ebay ?
Next a Marantz PM-5 had blown one channel, was previously repaired and then got to me with a faulty voltage amp stage. Turns out on one channel Q717/Q720 were shorted. Those are 2SA1124/2SC2632. I ordered a pair from dalbani UK and received two 2SA1124 marked Japan that seem ok but the 2SC2632 had no brand name and one actually turned out to be a PNP 😕. I asked for a refund but so far nothing. Anyway I prefer to go for some modern replacements. Also the drivers seem to have been under a lot of stress and I would like to replace them as well, those are 2sa1111/2sc2591, any ideas ?
Just to recap, I'm looking for replacements for :
-2SB1328/2SD2004
-2SA1124/2SC2632
-2SA1111/2SC2591
🙂
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You should be able to find subs at Mouser or Digi-Key. If you do not trust eBay for the bjts, can you trust eBay for a TLP521-1 photo-coupler
-2SA1111/2SC2591, MJE15030/MJE15031 or 2SC4883A/2SA1859A or FJP5200/FJP1943
-2SA1124/2SC2632, KSC2316/KSA916
-2SB1328/2SD2004, KSC2690A/KSA1220A
-TLP521-1 TLP521X-ND?
You are going to have to verify these and the pinouts, I just did a quick search.
-2SA1111/2SC2591, MJE15030/MJE15031 or 2SC4883A/2SA1859A or FJP5200/FJP1943
-2SA1124/2SC2632, KSC2316/KSA916
-2SB1328/2SD2004, KSC2690A/KSA1220A
-TLP521-1 TLP521X-ND?
You are going to have to verify these and the pinouts, I just did a quick search.
That's kind of what I though concerning the photo-coupler but it went out of production a little later than those transistors so maybe there still are some originals out there.
For the MJE15030/15031 the dc current gain as well as the transition frequency seem very low compared to the originals, is that going to be a problem here ? The 2sA1859A/2SC4883A are closer but not available at mouser which would mean more shipping costs...
For the KSA916 its more the output capacitance that troubles me 5pf for the originals against 40pf for the replacement, same question as above.
Otherwise, thanks for the great suggestions, pin outs are the same as well.
For the MJE15030/15031 the dc current gain as well as the transition frequency seem very low compared to the originals, is that going to be a problem here ? The 2sA1859A/2SC4883A are closer but not available at mouser which would mean more shipping costs...
For the KSA916 its more the output capacitance that troubles me 5pf for the originals against 40pf for the replacement, same question as above.
Otherwise, thanks for the great suggestions, pin outs are the same as well.
I really do not know 100% if these subs will work correctly, I listed what I thought off the top of my head, with little research. Sounds like you know better than I if you are doing in depth comparisons of Cob. Buy everything from Digi-key if you choose to use the Sanken devices.
Simulate the design(s) if you need to know more like phase margins,oscillations etc..
If KSA916 does not cut it, then try the lower cap ksa1381.
Simulate the design(s) if you need to know more like phase margins,oscillations etc..
If KSA916 does not cut it, then try the lower cap ksa1381.
Not really actually, I just went through the datasheets and noted the big differences, I know from reading other threads these might be a problem in some cases but not if they will be in mine. I don't really have anything to simulate these circuits.
Just downloaded it and watched some videos about it. Seems like an awful lot of work to put the whole circuit in there, especially because most transistor models aren't imported yet. Am I seeing this wrong ?
yes it is a lot of work, what can I say, no free lunch, to be honest just try the suggested replacements and try them out. if they oscillate investigate further wirh spice.
I bought Bob Cordell;s power amp book as my tutorial, trying to learn spice without the book is a challenge.
I bought Bob Cordell;s power amp book as my tutorial, trying to learn spice without the book is a challenge.
Guess I'll have some studying to do. just to start though, how can I import existing transistor models into the program ?
you can use the .include directive
.INCLUDE -- include another file
.include cordell-models.txt
or add each model to the default libraries located in the install directories.
You can place the model text right in the schematic
There is a ltspice thread in the tools section.
.INCLUDE -- include another file
.include cordell-models.txt
or add each model to the default libraries located in the install directories.
You can place the model text right in the schematic
There is a ltspice thread in the tools section.
thanks, that does help a lot, only problem is from what I have read so far, several of the transistors in the Denon PMA-1560 haven't got their spice models. It seems no one managed to get the complete amp stage simulation done.
Just going to have to use the existing models for now, get the sim running and later if you get experienced, you can make models based on datasheet information.
Most sims use ksc1845/ksa992,bc556/bc560c,ksc3502/ksa1381,MJE15030/31,NJL1302/3281
A good place to start.
Most sims use ksc1845/ksa992,bc556/bc560c,ksc3502/ksa1381,MJE15030/31,NJL1302/3281
A good place to start.
I don't really see how I can make a simulation of this particular amp with different transistors if the whole purpose is to see how it would react with just some transistors changed from the original design.
So it is possible to create the models myself (with the necessary experience/knowledge) ?
So it is possible to create the models myself (with the necessary experience/knowledge) ?
Do you have schematics for these amps? Just curious to have a look.
I take it you have test equipment? Scope, function generator?
Do you have a way to limit current, light bulb or Variac?
I take it you have test equipment? Scope, function generator?
Do you have a way to limit current, light bulb or Variac?
Yes I do, the files are too big to upload but you can find them on hifiengine.
I've got a scope, function generator and a dim bulb yes. I actually got both amps to work with parts I bought on Dalbani UK, problem is I suspect them to be fakes because out of 2 bought of each 1 was bad (I got a 2sc2632 that tested as a PNP and a 2sk215 that tested as an regular npn) so I would like to replace them with modern substitutes to be sure of their build quality. The original sj78/sk215 that were in the amp turned out still good so I'll leave them alone. I'm just looking for the ones I mentioned before.
I've got a scope, function generator and a dim bulb yes. I actually got both amps to work with parts I bought on Dalbani UK, problem is I suspect them to be fakes because out of 2 bought of each 1 was bad (I got a 2sc2632 that tested as a PNP and a 2sk215 that tested as an regular npn) so I would like to replace them with modern substitutes to be sure of their build quality. The original sj78/sk215 that were in the amp turned out still good so I'll leave them alone. I'm just looking for the ones I mentioned before.
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Denon PMA-1560, is available at hifiengine. I took a look at it. It is a challenge to simulate so I suggest to try the replacements that I suggested and see how it goes.
As PB2 suggests make a Dim Bulb tester, details are on audiokarma.
As PB2 suggests make a Dim Bulb tester, details are on audiokarma.
2SB1328/2SD2004 1A 20W 2sa1837/2sc4793
2SB1328/2SD2004, KSC2690A/KSA1220A this is a good previous suggestion
as is:
2SA1124/2SC2632 ksa1381 and comp
2SB1328/2SD2004, KSC2690A/KSA1220A this is a good previous suggestion
as is:
2SA1124/2SC2632 ksa1381 and comp
Some of the cheap testers produce false readouts.
You better off testing devices with a curve tracer.
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