Hi,
After a couple of years off I've got the DIY bug again, about to embark on a Modulus 86 build. In the mean time I was thinking about recapping my pair of Sony TA-N55ES, but I do wonder if it's necessary, so I was hoping for a bit of input from you guys.
These amps will be around 20-25 years old, i bought them both separately last year, although they do appear to be the same revision and have fairly close serial numbers (blind luck)
The don't show any issues, no pops on power up or down, I can turn them all the way up with no signal passing and there is barely any hiss through the speakers at 100% (I usually run them at about 20% for listening)
They both seem to out put the same amount of heat after being on for a while, which I would only describe as warm on the vents above the heat sink.
I have been in side them just to check the bias (which was still rock solid and where it should be)
So with all that in mind:
1: am I just looking for faults or an excuse to recap them when they don't need it....
2: ...or is it good practice to recap an amp of this age
3: is there a more rigorous test I can do which may reveal answers.
4:I do produce music and have the ability to test frequency response but not on an amplifier output, is there a way to get that down to line level and analyse it on a PC? Surely that's not as simple as passing the signal though a resistor to drop it, is it? (Edit: Maybe it is, image attached)
Thanks
Tom
After a couple of years off I've got the DIY bug again, about to embark on a Modulus 86 build. In the mean time I was thinking about recapping my pair of Sony TA-N55ES, but I do wonder if it's necessary, so I was hoping for a bit of input from you guys.
These amps will be around 20-25 years old, i bought them both separately last year, although they do appear to be the same revision and have fairly close serial numbers (blind luck)
The don't show any issues, no pops on power up or down, I can turn them all the way up with no signal passing and there is barely any hiss through the speakers at 100% (I usually run them at about 20% for listening)
They both seem to out put the same amount of heat after being on for a while, which I would only describe as warm on the vents above the heat sink.
I have been in side them just to check the bias (which was still rock solid and where it should be)
So with all that in mind:
1: am I just looking for faults or an excuse to recap them when they don't need it....
2: ...or is it good practice to recap an amp of this age
3: is there a more rigorous test I can do which may reveal answers.
4:I do produce music and have the ability to test frequency response but not on an amplifier output, is there a way to get that down to line level and analyse it on a PC? Surely that's not as simple as passing the signal though a resistor to drop it, is it? (Edit: Maybe it is, image attached)
Thanks
Tom
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1 & 2 - If the amps were treated well and saw normal livingroom conditions with a moderate amount of use, chances are that the vast majority of caps would still be good. Sony tended to use good-quality parts in these, and I imagine there would be a bunch of Nichicon and Elna caps in there. These should hold up well, the odd known-bad series aside. Rubycon would be a different story. There really is no general rule - some people have found filter caps in 50-year-old tube radios that measured like new, but in more basic models using cheaper parts they are commonly dead as a doornail.
3 - yes, get an ESR meter and check all the caps. Still wouldn't catch excessively leaky parts, which would require a leakage tester and unsoldering at least one end, but it may still be worth it for some candidates like the big filter caps.
4 - That circuit seems about right, but I would really want a balanced outpu insteadt (even wire terminals would be OK if soldering up a cable is no object), so you can avoid the ground loop issues that will occur otherwise. Finding a pair of suitable balanced inputs should not be a major issue among music-producing folk these days.
3 - yes, get an ESR meter and check all the caps. Still wouldn't catch excessively leaky parts, which would require a leakage tester and unsoldering at least one end, but it may still be worth it for some candidates like the big filter caps.
4 - That circuit seems about right, but I would really want a balanced outpu insteadt (even wire terminals would be OK if soldering up a cable is no object), so you can avoid the ground loop issues that will occur otherwise. Finding a pair of suitable balanced inputs should not be a major issue among music-producing folk these days.
perfect thank you so much for the response.
I think I'll go with option 4, I have plenty of balanced inputs to work with.
This test is more important to me as really all I'm bothered about is the amps accuracy and to how closely aligned they both are, a bunch of tests on a detailed frequency analyser will tell me all i need to know.
I'll get soldering up one of those balanced signal attenuators this week.
I think I'll go with option 4, I have plenty of balanced inputs to work with.
This test is more important to me as really all I'm bothered about is the amps accuracy and to how closely aligned they both are, a bunch of tests on a detailed frequency analyser will tell me all i need to know.
I'll get soldering up one of those balanced signal attenuators this week.
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