WAD KEL84 upgrade suggestions

[buddam]

Hi all
I recently bought a KEL84 integrated, which Bob Orbell once owned. It looks great and sounds ok, but is a long way short of the richness I had with a previous KEL84 wired as a power amp, using a WAD Phono II and Pre II (as cathode follower). The sound is clean but thin, albeit that I did not run it in for very long (I just wanted to check all was ok after purchase, and have not used it since).

I am now about to start on the upgrade path. I will keep it as an integrated for now. I plan to change the PS caps from 100uF to much higher, but how high is advisable. In my old KEL84 power amp I belive the 3 caps were all rated at 470uF after upgrading the 100uFs but I may be wrong. I don't need boutique caps here, just low ripple low ESR caps of a decent quality. Any suggestions?

I will then do the pseudo shunt mod on the volue pot using, probably, a 47K carbon film (Kiwame I expect as I always liked them when tweaking in the past).

Orange drop caps to follow (2 x 0.22uF and 1 x 0.47uF per channel). From various cap reviews/shoot-outs I expect to go for Jantzen Superiors as a cost effective upgrade, but will start with by-passing the orange drops with Cornell 0.01uF.

This is a long-winded intro to a question: which resistors and caps are most critical to upgrade? The cct diag is (I hope) attached to this message.

Any views gratefully received. I appreciate that I have been here before with a KEL84 and that some here will have answered similar questions in the pst, so apologies for putting people to any trouble. I have searched the WD forum and found some answers, but not to the Qs above

ANY INFO at all gratefully received (on brands, vaues, etc).

Best wishes

Adrian

[bob orbell]

Hi Adrian, here is my take on the subject, the power supply, yes, upgrading this will give the best performance, so I would suggest Evox Rifa low ESR power supply capacitors, may be up to 220uF but no bigger, I don't remember what HT diodes I used but, Schottky would do a better job. The shunt pot mod is to me a big no as it makes the HF to much, some like it, coupling capacitors, the Orange drops ( Vishay BC to be precise ) are good, my personal preference is Wima MKP4 or 10, the 10 is quite big but both give a very natural sound as do C. D. Carbon resistors generally make the sound dull but can help in bright systems, the best, but expensive resistors are charcroft Z-Foil, I have 10 of these in my Phono III and are amazing, but so they should be at just over £160.00. I hope this helps you. Bob

[Richard]

Hi Adrian, It may be just the bass rolling off a bit early. I'd change C6/7 to 2200uF (or tag another 1000uF in parallel) for a quick listen. There is some related info on the WD CD Kel80 article if you remember the humerous comments about curry!

[buddam]

Hi Bob and Richard, that's very helpful - many thanks. Perhaps the shunt mod is why, Bob, I always felt my old KEL84 was a bit energetic in the top end, despite the overall richness. I fiddled with that for years and maybe the shunt was the problem all along.

One query Bob, you mention that the Wima are good and then say "as are C. D." Not sure what you meant there.

Richard, will look at the thread you mentioned.

Thanks again

Adrian

[bob orbell]

Sorry Adrian, its Cornell Dubilier, . Bob

[buddam]

Ah yes. Thanks.
Richard, can’t find that thread. Could you post any other details please?

Thanks
Adrian

[Richard]

Hi Adrian, it was in the article Double Vision KEL80 Nov 1999 on the WD Gold CD about the KEL80 C14, but would also apply to KEL84; try increasing the cap C6/7 for a lower f response