KAT6550 schematics

[nneilboss]

Hello all,
I have recently bought a second hand KAT6550 of uncertain origin and vintage. I have not yet received the amp, am told it “works“ , but would like to be in a position to service it.
I would be pleased if someone could tell me where to find schematics and layouts from back in the day.
I have had a bit of a look around but although I saw a few old threads on this topic , I cannot seem to find anything.
I was planning to pair this with a set of WD pre-amps.

Many thanks,
Nick

[Greg.]

Welcome to the forum, Nick. If you PM me your email address, I’ll email you PDF’s of the original instructions, diagrams and schematics.

[bob orbell]

Welcome Nick, lots of help and advice on here, I too had a KAT6550, but gave it to a chum after getting a WD WA88, also, if you are considering the Pre and Phono, do consider the Pre III CF, the Pre III will give far too much gain, the former is about perfect, and I would also advise you to reject the series II, any questions, ask. Bob

[pre65]

Bob, you do realise that Pre3 could have it's gain configured in two ways depending on how the transformers were wired up ?

I ask, because my Pre3, which admittedly has the shunt pot mod, does not suffer from the problem you describe.

According to the Pre3 build instructions the standard gain is x6 and x12 is optional for low output sources.

For amps like my MoFo (mosfet follower single ended) x12 may be more appropriate.

So PLEASE, stop putting people off what is a very fine pre amp if configured correctly.

[bob orbell]

Philip, I had one some time back and found it good apart from the very high gain set at x 6, my power amp and all WD amps and a lot of WAD amps require just .5 volts for max output, at x6 with a CD or other sources this Pre is capable of 12 volts output, way too much, why do you think many others have chosen the CF route, as I have said, it is a good pre, but the shunt pot is not for everyone, still far too much gain and spity and if I chose to say so, I will, even our John has looked into the high gain issue and many on this forum have expressed their dislike to too much gain, I have suggested that the poster look at the Cathode Follower pre, so in effect I am trying to put business Matthews way, if you were a moderator, I would respect your comments, but your not, so shut the f**k up. Bob

[pre65]

Originally Posted by bob orbell

if you were a moderator, I would respect your comments, but your not, so shut the f**k up. Bob

That's charming Bob, you could at least try to be civil.

[bob orbell]

Philip, this not the first time you have made comments on my thoughts of the Pre II and III, I respect your thoughts so I expect you to respect mine. Bob

[John Caswell]

Bob if you cannot be civil be prepared to be banned. That sort of language is not called for.

John

[bob orbell]

You are quite right John, and I do apologise to you and Pre65, sorry Philip. Bob

[pre65]

Originally Posted by bob orbell

You are quite right John, and I do apologise to you and Pre65, sorry Philip. Bob

That's OK Bob.

This Covid malarkey is enough to drive anyone to despair.