Hi all,
I have just been given an Aiwa P80 amp that has been through the wars and is missing the output devices in both chanels. I don't suppose anybody out there would happen to have a schematic for this particular amp so that I have some idea of what might have been there when it was alive and well.
Thanks in anticipation.
I have just been given an Aiwa P80 amp that has been through the wars and is missing the output devices in both chanels. I don't suppose anybody out there would happen to have a schematic for this particular amp so that I have some idea of what might have been there when it was alive and well.
Thanks in anticipation.
DocP said:Thanks Hugo,
You're going to lots of trouble over this but it is appreciated.
Despite some trouble, no results. If only some people would do some effort, this world would be a nicer place. Unfortunately, even climbing stairs costs money...
/Hugo - has to give up on this, but only on this…
I know this is a very stale thread, but if you still have the amplifier.... the output modules are STK8250.
A mediocre pdf file is available by googling for STK8250. You can make out the internal circuitry at least
I don't know the VA rating, but the transformer voltage (before the bridge) is 32.5-0-32.5 on my workbench with 120VAC input.
HTH
Chris
A mediocre pdf file is available by googling for STK8250. You can make out the internal circuitry at least
I don't know the VA rating, but the transformer voltage (before the bridge) is 32.5-0-32.5 on my workbench with 120VAC input.
HTH
Chris
Thanks Chris,
It is a very old thread and I had given up hope a long time ago on this. It's nice to see something come out of the blue.
I found the pdf data sheet you metioned. My japanese isn't the best but the cct diagrams are certainly useful.
I take it from your mail that you have one of these amps. What is your opinion of it? Does it sound anyway decent? I had though of bridging it and using it to drive a sub. I live with adjoined neighbours so the sub will never get pushed too hard and I thought it might do a decent job. It probably would have been canabalised for parts by now only I have of late but wherefore I know not lost all my free time. My audio excursions are limited to fixing my kids diskmans after they bounce them off the floor again..... <sigh>
Thanks again
DocP
It is a very old thread and I had given up hope a long time ago on this. It's nice to see something come out of the blue.
I found the pdf data sheet you metioned. My japanese isn't the best but the cct diagrams are certainly useful.
I take it from your mail that you have one of these amps. What is your opinion of it? Does it sound anyway decent? I had though of bridging it and using it to drive a sub. I live with adjoined neighbours so the sub will never get pushed too hard and I thought it might do a decent job. It probably would have been canabalised for parts by now only I have of late but wherefore I know not lost all my free time. My audio excursions are limited to fixing my kids diskmans after they bounce them off the floor again..... <sigh>
Thanks again
DocP
Hi DocP,
I do have the amp in question, I won it on eBay a few weeks ago. I only received it the day I posted the message. (I was looking for opinions myself!)
To be honest I have not had much chance to evaluate the unit, but it it relatively well built. Quite a clever packaging job, making it so compact. Sound wise it is too early to say, but it didn't blow me away by any stretch. I think it would be a very good unit for the test bench or garage. I believe it would be great for a kids room too, it is probably much better than a Best Buy boombox.
I suspect it would be a decent unit for small scale sub duty. The heatsinking is certainly adequate for it. Mine never got much past room temperature. I don't know how the STK chips handle low impedances though..
If I ever get a chance to sit and listen, I'll post back.
Chris
I do have the amp in question, I won it on eBay a few weeks ago. I only received it the day I posted the message. (I was looking for opinions myself!)
To be honest I have not had much chance to evaluate the unit, but it it relatively well built. Quite a clever packaging job, making it so compact. Sound wise it is too early to say, but it didn't blow me away by any stretch. I think it would be a very good unit for the test bench or garage. I believe it would be great for a kids room too, it is probably much better than a Best Buy boombox.
I suspect it would be a decent unit for small scale sub duty. The heatsinking is certainly adequate for it. Mine never got much past room temperature. I don't know how the STK chips handle low impedances though..
If I ever get a chance to sit and listen, I'll post back.
Chris
Well,
I used this amplifier at my workbench for a few months. A nice little amplifier, unexciting, but more than adequate for its intended role. Unfortunately one of the STK8250's blew while testing a Chrysler/infinity car speaker. It didn't like the 3.2 ohm load much.
I opened the STK module and can see that the PNP output transistor is burned.
The module is very simple, with just over a dozen components inside. I'm thinking of trying to resurrect it by disconnecting the two output transistors and patching in a 2sa3281 and 2sc1302. I know that the 2sc is counterfeit, so I figure I have nothing to lose but possibly a little smoke. If it works I could use a better pair of transistors.
Am I foolish to attempt this?
Would I be better off using the PS, case and heatsinks to serve as a home for a pair of LM3875 GC amplifiers? (The components are appropriate, if a 30000uF capacitor bank is okay for a GC).
I used this amplifier at my workbench for a few months. A nice little amplifier, unexciting, but more than adequate for its intended role. Unfortunately one of the STK8250's blew while testing a Chrysler/infinity car speaker. It didn't like the 3.2 ohm load much.
I opened the STK module and can see that the PNP output transistor is burned.
The module is very simple, with just over a dozen components inside. I'm thinking of trying to resurrect it by disconnecting the two output transistors and patching in a 2sa3281 and 2sc1302. I know that the 2sc is counterfeit, so I figure I have nothing to lose but possibly a little smoke. If it works I could use a better pair of transistors.
Am I foolish to attempt this?
Would I be better off using the PS, case and heatsinks to serve as a home for a pair of LM3875 GC amplifiers? (The components are appropriate, if a 30000uF capacitor bank is okay for a GC).
Well done It's probably a bit late in the day as I guess you have it all back together again but a photo of the inside of the module with your grafted transistors would be interesting.
I still haven't had time to resurrect my P80. I found a source for the SKT module and it was extortionately expensive so I decided to gut it and go down the GC route. All I need is another 48 hours in every day and I'll be fine.......
It's probably a bit late in the day as I guess you have it all back together again but a photo of the inside of the module with your grafted transistors would be interesting. I still haven't had time to resurrect my P80. I found a source for the SKT module and it was extortionately expensive so I decided to gut it and go down the GC route. All I need is another 48 hours in every day and I'll be fine.......
PICTURES!
Well, it only took me a month to get around to it, but here are some pics of the frankenamp, as it should be called. My sincere apologies to anyone who may have a TM on that name.
The resurrected channel:
The 'normal' channel
close up 1
close up 2
Well, it only took me a month to get around to it, but here are some pics of the frankenamp, as it should be called. My sincere apologies to anyone who may have a TM on that name.
The resurrected channel:
An externally hosted image should be here but it was not working when we last tested it.
The 'normal' channel
An externally hosted image should be here but it was not working when we last tested it.
close up 1
An externally hosted image should be here but it was not working when we last tested it.
close up 2
An externally hosted image should be here but it was not working when we last tested it.
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