Advice on my KT66 Monoblocs

[Lawrence001]

I've had these quite a few years now and they have probably been used less than 10 times in all that time because of young children and the hassle of putting a system together and away again for the sake of a few hours' listening.

I was wondering what any of the more savvy valve experts on here could tell me about the build as I know so little about them. I do know they have 2x KT66 1x ECC83 and 1x EF86 each.

The guy I bought them off said they were made by an ex BBC engineer who made 2 pairs, one for himself and one for him. While I've heard stories about ex BBC engineers before, this guy was very honest about the stuff I bought off him and I have every reason to believe he was telling the truth. I recall something about being an improvement on the Quad II circuit but I could be wrong. These are not valve rectified like the Quads anyway, whether that's a good or a bad thing I'm not sure. In particular I was wondering if it's a known circuit and what all those numbered metal boxes inside them are. I haven't been able to find anything on the internet with this particular combination of valves which is what intrigued me.

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[Firebottle]

They look very well made Laurence and I don't doubt they were made by an ex BBC engineer, I believe that occurred often.

The valve line up almost certainly equates to EF86 input stage, ECC83 phase splitter driving the KT66 output valves.
Has a smoothing choke in the power supply, auto bias, negative feedback, I imagine they sound rather good.

The numbered blocks are film capacitors I guess.

[AD Audio]

Alan's said it all. I'd hazard a guess the green caps are the metallised film coupling caps and the large numbered aliens are big film caps for the power supply. Lovely amp!

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[Lawrence001]

Thanks for the information guys, good to know they're good'uns. Of course having heard them, I had thought they must be!

So would the Quad II have had an EF86 as input stage like this but the second EF86 as the phase splitter then? I'm assuming it's a double triode like the ECC83.

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