KAT 6550 C5 values and mods

[LSfarzo]

Hi all,

I have a question regarding the C5 values of my KAT6550.
After a few time I built the kit I decided to use BG caps for the power supply part and applied the heater supply mod (a great mod, indeed!!).

Now I have to place an order for some resistors on my phono II and so I would try to put out of the box an old upgrade for the Kat6550 that I have yet not tried:swapping the C5 cap in the power supply part of the amplifier with a better one.

I ask you all if somebody can tell me something about this cap. It is really worth the effort swapping it to a better performance one?
In my schematics the C5 is a 82uF, 500V I guess if I could use a 100uF, 500V without problems; 82uF is a not so easy to find value.
There's to say that I've already applied a lot of mods like tants resistors on the signal path and pio caps for the coupling one and so on.. so I guess if this last is useful or not as the cap is not so much "cheap"

Bye
Luca

[Tony Moore]

Hi Luca,

I found that changing C5 for a low ESR cap made quite a large improvement. Initially I used a Rifa 150uF (the standard cap at the time I bought my Kit6550 was 120uF 500v) and then more recently I have fitted a Black Gate WKz at 100uF 500v.

I'd say that in my opinion it was a very worthwhile upgrade. The main problem is the extra dimensions of the cap in close proximity to the heat of the choke.

Best wishes,
Tony
ps. Have you already changed the other psu caps to low ESR types?

[david counter]

Hi
it is a good upgrade because it is the last cap in the ps and can have an effect on the signal circuit,

as Tony says a lot have people have used B'gate 100 mfd wkz to great effect,

[NickG]

I found it also worth adding 1u and 10n poly bipass caps (unless you use a BG).