Matsushita blue caps from 1991?

[Cap_search]

Hello to all,

I have a question, maybe you can help me.

I have a Harman Kardon amp from 1991 and the input caps are 100uF/10V to the power amp section. I measured both caps (left and right channels), they measured pretty ok on specs (~101uF). But these caps are spread out in the amp, so they look for generic use. I was thinking to replace them with some Silmic or Muse, but maybe there's no need as these blue Matsushtas might be of good quality for audio. What do you advise?

[Agent24]

Re: Matsushita blue caps from 1991?

My understanding is that changing the type of capacitor *might* change the frequency response of the amplifier to some extent, such that there may be a different "colour" to the audio. Such a change may or may not actually be perceptible. Often-times, the apparent 'improvement' is only proportional to the amount of money spent, and is entirely imaginary.

In my opinion, replacing them would be pointless, unless they've actually failed. Even then, the only clearly measurable improvement, and thus compelling argument for expensive capacitors, is a longer service life.

[stj]

Re: Matsushita blue caps from 1991?

if you do need to replace them, just use rubycon YXF.

[Cap_search]

My understanding is that changing the type of capacitor *might* change the frequency response of the amplifier to some extent, such that there may be a different "colour" to the audio. Such a change may or may not actually be perceptible. Often-times, the apparent 'improvement' is only proportional to the amount of money spent, and is entirely imaginary.

In my opinion, replacing them would be pointless, unless they've actually failed. Even then, the only clearly measurable improvement, and thus compelling argument for expensive capacitors, is a longer service life.

Thank you very much, Agent. I kinda agree with you. There are some other caps in the local regulated supply (330uF) that are now lower in value (around 314uF) and I'm going to replace these with newer ones, so I though I could order a couple of Silmics just for the try.

if you do need to replace them, just use rubycon YXF.

Hmmm, that's interesting. Thanks!

[Agent24]

Re: Matsushita blue caps from 1991?

If they are only power supply capacitors, then I think there is even less chance of anything changing.

If the capacitors are in the signal path, then change in properties like ESR, ESL etc may change frequency response slightly, but it all depends on how the actual amplification circuitry works, and how it may or may not be affected by such changes.

You would have to do a frequency sweep before and after, and see if anything is actually different.

If you are serious about getting highest quality audio, then there are other things you can do, such as checking that any film capacitors you install are around the right way: https://youtu.be/BnR_DLd1PDI but even that is probably overkill.

[goontron]

Re: Matsushita blue caps from 1991?

I wouldn't replace if they test good. Matsushita/Panasonic made damn good caps.

[Cap_search]

Thank you very much guys. Yes, the caps in the first pictures (100uF/10V) are in the signal path. But these blue Matsushitas are pretty good indeed. Better than those "lavender" ones found in the vintage Technics gear from the 70's.

The other ones (330uF/25V, rated 85*C) I mentioned are in the regulated PS for the preamp part of this brand TK - similar to the ones in the picture below. I will replace them with 390uF/35V ones rated 105*C, a lot of generated heat in that area also.

[stj]

Re: Matsushita blue caps from 1991?

your lucky it's old, newer harmon junk is full of capxon brand!

[Cap_search]

Re: Matsushita blue caps from 1991?

your lucky it's old, newer harmon junk is full of capxon brand!

Yes, NAD also has Lelon caps in many later models... These earlier HK amps sound pretty good. But so far, all the green TK caps (pictured above) are measuring lower, so I'll replace all of them.

[Cap_search]

Film caps installed the right way

If you are serious about getting highest quality audio, then there are other things you can do, such as checking that any film capacitors you install are around the right way: https://youtu.be/BnR_DLd1PDI but even that is probably overkill.

Wow!

I remember I had a couple of never fixed issues with amplifiers and now I start to think I might have installed some of them backwards!!

I just got a bit confused with the markings: the "band" mark means that that polarity goes to the circuit, right? I don't have the instrument to see if the film cap has the flat line in the Xcope screen, though.

[Andrew F. Ali]

Re: Matsushita blue caps from 1991?

Most times the mark on the PCB is where the -ve capacitor pin goes. However, for Tantalum electrolytic the +ve pin is marked.

[Agent24]

Re: Film caps installed the right way

Wow!

I remember I had a couple of never fixed issues with amplifiers and now I start to think I might have installed some of them backwards!!

I just got a bit confused with the markings: the "band" mark means that that polarity goes to the circuit, right? I don't have the instrument to see if the film cap has the flat line in the Xcope screen, though.

Maybe not. Around the 'wrong' way just means the capacitor may pick up a little more electrical noise and cause the audio signal to lose quality. It's unlikely to cause an actual fault.

There is no band. You test the capacitors with his circuit and then mark the band yourself. The outside foil lead goes to ground etc. Thus it acts as a shield.

I haven't re-watched it recently so might have missed something, though.

[Cap_search]

Ok, thanks.

2 more questions:

- for what is the use low leakage caps?

- and so the polymer hybrid caps?

I see that the latter has much better numbers on endurance, ripple current, very low ESR, etc, over electrolytics...

Example: https://cdn.badcaps-static.com/pdfs/...c8e48b8b6e.pdf