Well I simply can't believe this....!

[Yellow]

Hi all,

I reckon my KaT6550 hasn't been switched on for well over six years. It's just been sat there collecting the proverbial dust.
So, the other week, I decided to open it up along with the pre, give it a check over and gentle vacuum-out. To be honest, the insides were sparkling clean which was a surprise.
Anyway, I hooked it all up again, and switched on. CD player first, then the pre and left it for five minutes to settle before the KaT6550. CLICK..... On it came. (I put my cheapest valves in, just in case!!)
I left it as well for a few minutes to stabilise and warm up. At this point, I was expecting something to go pop (or crackle/hiss at best)...but nothing. It was as quiet as a mouse. I couldn't believe it. So on went a CD at low volume and it all worked.

I still can't believe it. It's perfect. Still sounds amazing.

It's years since it had any modifications done, so this winter I'll be looking at a few changes. Those 15+ year old electrolytics must need a change etc....

Brilliant amp!

Neil.

[bob orbell]

Glad you are still here Neil, change the power supply electrolytic's but that is all that I would do and quite possible even that may be a waist of time . Bob

[Yellow]

Hi Bob,

Yes. Still here!!
PSU electrolytic are on the agenda as are the cathode bypass and grid leak resistors. I want to change the internal wiring again too, from the Phono plugs to the ECF80 input valves. Then go from there. Probably look into some new signal caps as well. Really pleased with it.
I'd actually quite like to completely strip it and rebuild with new components throughout, to a really decent level (Takman Carbon film/Audio Note resistors/Elna Cerafine/silver hook-up etc.)
It's had a few tweaks over the years but nothing major, but it is 15 years old now so I'm a little concerned about the caps. Everything else looks good.

Neil.

[Phil Y]

Hello Neil,

I recently changed the PSU electrolytics in my Kat88 (Mundorfs) and found this to be very worthwhile. Mine were about 20 years old.

Phil.

[Yellow]

Originally Posted by Phil Y

Hello Neil,

I recently changed the PSU electrolytics in my Kat88 (Mundorfs) and found this to be very worthwhile. Mine were about 20 years old.

Phil.

Could you give me exact details of what you have fitted please? Been looking at some Mundorf M-Lytics from Hi-Fi Collective. Which version have you got exactly??
Would be nice to know.

Cheers,

Neil.

[Phil Y]

http://www.world-designs.co.uk/forum...ead.php?t=7785

[Yellow]

Hi Phil,
Thanks for the link and associated information.

Looks like the Mlytic HV would be a nice swap for C1 - C4 (100uF/450V) in the KaT6550 PSU circuit, and then either the same again for C5 or a Nichicon KX or Audio Note Electrolytic.

Cheers,

Neil.

[Phil Y]

Hi Neil,

Although I have not used them in the same positions, (so I could be wrong) having fitted a few of both, my impression is that the Mundorfs sound better the the "standard" Audionote ones. I have not tried their more expensive Kaisei ones.

Phil.

[Yellow]

Hi,

For me, I think it would be cost prohibitive to fit five AN Kaisei's in C1-C5 and then another (non-Kaisei as 4700uF isn't available) in C6.
That would come to over £500. I don't think I spent that on the whole kit 15 years ago!!

Neil.