KT66 in ST70 is 'da bomb' !

[mugsy]

Hi folks!

Just wanted to say how amazed I am at the performance of the stock (well NEW circuitboard and hand-matched components, original design!) ST70 with KT66 tubes. Everything I want from an amp is here. Lovely magical midrange, soundstaging to die for, a shimmering top end, and bass you can feel as well as hear! To those who claim that valve amps cannot do bass.... well I blow raspberries in their general direction!!!

I've been alternating between JJ KT77s, EH EL34s, and Watford Valves Harma KT66s (re-branded Russian repros of the original GEC). The EL34s offer a VERY romantic and typically 'tubey' sound, which I could live with gladly at a pinch. The KT77s initially impressed me, but they sound a bit too hard... too solid-state to really draw me into the music like a good valve amp should. Perhaps I need more run-in time with these, or need to experiment with bias a little more. Definately a top-class valve though, until you've heard the KT66...

I'm just in awe of the ST70 with the KT66. From now on this is my valve of choice, and it seems to work well with all types of music as well. I have some GEC KT66s here which I'd love to try, but two of them have dodgy filaments, and another one started it's own firework show when I turned on power so I need to get a pro to have a look at these, and test/grade them etc. However I can't imagine they could sound THAT much better than these Harmas. BTW the Golden Dragon KT66 retros sounded almost as good as the Harmas. (oddly enough when used in my Quad II the situation is reversed - the GD sound better than the Harma - go figure!).

I have a VTA board waiting to be assembled and installed... all I can say is it will have its work cut out to beat the new stock circuit as it sounds at present. I'm almost reticent to install it now, but if I don't like it the original is pretty easy to put back in again I guess.

Have been using these Harma's for approx. 7 years now (originally in Quad IIs) and they're still going strong, so reliability would seem to be on par with the GECs which makes them great value for money.

Hope this is of help to the ST70 tweakers out there :)

- John

[mugsy]

UPDATE: Just been burning in a new quad of Golden Dragon KT66s and must report that they do sound as good as the Harma's in my ST70, they just needed a few extra days of burning in (compared to my Harma's 7 years!!!). They are not quite as 'bottom heavy' sounding as the Harma's, and have a more delicate top end, and an overall brighter tonal balance. I couldn't really choose between either of them - the ideal choice lie's between them - Lol!

You cannot go wrong with either in the ST70.

- John

[kt88pppamp]

Did you have to change the PSU voltage at all to operate the KT66 Tubes? You probably just had to change the bias.

[burnedfingers]

Try 6BG6GA's in you amp Yellow_Light_Colorz_PDT_08