Hi,
The power IC (STK463) for this amp has blown. I removed the 2 filter caps and realized that they are badly leaking. The value of these caps are 6800uf 35V. My local electronic dealer has ran out of stock of these capacitors. They have 8200uf 50V or 4700uf 50V caps only. I would like to ask, which of these 2 type of caps would you recommend and which are more suitable and advisable to use. Please help.
Thanks
Carlosraj
The power IC (STK463) for this amp has blown. I removed the 2 filter caps and realized that they are badly leaking. The value of these caps are 6800uf 35V. My local electronic dealer has ran out of stock of these capacitors. They have 8200uf 50V or 4700uf 50V caps only. I would like to ask, which of these 2 type of caps would you recommend and which are more suitable and advisable to use. Please help.
Thanks
Carlosraj
The 8200 are suitable subject to the physical size and fitment. Use STK465 as a replacement for the output stage. Higher voltage, power output and tolerance.
Definitely get the 8200's. You'll get more bass with them. Also an STK465 will, like JonSnell said, give you more power.
While you're at it, you might want to look into replacing all the electrolytics. If those old filter caps have went belly up, then the rest of them are probably not very healthy either.
I'd replace the small value lytics on the EQ board with film caps.
Also clean switches and pots.
I used to have one of these amplifiers, actually 🙂 I used it with an old Pioneer tuner and a pair of headphones to listen to the radio 😀 Can't really remember how it sounded, it was alright, I guess. It did hum quite a bit. I actually got mine like you got yours - with a blown chip. One channel was dead and it kept blowing a certain cap.
I ended up selling mine. Now that I think of it, I actually want it back 😀 It was a nice little unit with enough room for some cool modifications.
I hope you get yours to work and enjoy it!
While you're at it, you might want to look into replacing all the electrolytics. If those old filter caps have went belly up, then the rest of them are probably not very healthy either.
I'd replace the small value lytics on the EQ board with film caps.
Also clean switches and pots.
I used to have one of these amplifiers, actually 🙂 I used it with an old Pioneer tuner and a pair of headphones to listen to the radio 😀 Can't really remember how it sounded, it was alright, I guess. It did hum quite a bit. I actually got mine like you got yours - with a blown chip. One channel was dead and it kept blowing a certain cap.
I ended up selling mine. Now that I think of it, I actually want it back 😀 It was a nice little unit with enough room for some cool modifications.
I hope you get yours to work and enjoy it!
You will not get "more power" with a higher rated STK. You will simply have a higher SOA, and the ability to output more power. But to do so, you would need to rewind the transformer, or put in another one. Also possibly redesign the entire circuit.
Also, bigger capacitors will not give "more bass" (redesigning the tone control circuit will), and such a small increase will not give any measurable difference in performance.
The problem here is that your new STK will very likely be fake (meaning it will either blow up immediately, or blow up trying to output just a minimal amount of power). Dead amps using STKs like these are usually subject to either the dumpster, or as a DIY project, since the only way to get the proper part is to harvest it from another (functional) amplifier.
Sorry to be the bearer of bad news.
Also, bigger capacitors will not give "more bass" (redesigning the tone control circuit will), and such a small increase will not give any measurable difference in performance.
The problem here is that your new STK will very likely be fake (meaning it will either blow up immediately, or blow up trying to output just a minimal amount of power). Dead amps using STKs like these are usually subject to either the dumpster, or as a DIY project, since the only way to get the proper part is to harvest it from another (functional) amplifier.
Sorry to be the bearer of bad news.
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I bought a new STK from a local small electronics store and it worked just fine, I even gave it a stress test by blasting at full volume for nearly an hour at a party and it was just fine.
I put in the 8200uf caps and replaced with STK465 and it works fine. Thanks to all for the advice.
Carlos
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