Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Jennings on October 25, 2011, 08:03:59 am
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I'm sure we've covered this before somewhere but couldn't see quite what I was looking for in a quick search...
...What are the 'best' (or should that be people's subjective choices?!) currently available KT66, and why do you like them over the others?
Also, I've been lead to believe some of the current KT66 (like the Shuguang?) need to be biased hot to get similar results as NOS tubes...is this true, and by 'hot' what value are we talking?
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The actual optimal bias depends on the amp, gear and style.
The various Shuguang KT66s really sing when hot, as do the Saratov (IMO the best recent KT66, but sadly out of production). Tungsolkis and Sovteks are basically repackaged 6L6GCs, so treat them like 6L6GCs. The JJs are real KTs, but closer to KT88s than to KT66s, bias them accordingly.
Oh, and don't forget that if your amp is of the Fender school, with bear claws and/or pin 1 used as a tie point (usually for screen Rs between 1 and 5), using metal-based tubes with an internally connected pin 1 means trouble. Big trouble.
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Cheers FYL...good info there. Makes you wonder how/why some companies brand tubes as something they aren't really. Well I've got a JTM45 clone that I use for a fairly straight up rock n roll rig (Les Pauls and Strats etc). Currently got a set of what I presume to be Shuguangs in it, and I have a couple of pairs of TAD KT66 (also Shuguangs?) in my stock...I just bias them as per the data specs, but wondered what sort of voltages people were using and getting good/better results. I quite fancied experimenting, but wanted to see what experience people had of running them higher...failure rates and tone wise.
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I just won a matched pair of Saratovs for $42 on eBay. Looking forward to seeing how they sound.
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Makes you wonder how/why some companies brand tubes as something they aren't really.
Creative marketing ?
Currently got a set of what I presume to be Shuguangs in it, and I have a couple of pairs of TAD KT66 (also Shuguangs?) in my stock...
Shuguang = Sino = Valve Arts = TAD = Groove Tubes GT KT66-C = many others, give or take a few minor variations. All are manufactured at Shuguang using original GEC blueprints, templates, machines, etc. Materials aren't the same than in the sixties, of course, but they are IMO some of the best KT66s ever. And cheap, too.
I just bias them as per the data specs, but wondered what sort of voltages people were using and getting good/better results. I quite fancied experimenting, but wanted to see what experience people had of running them higher...failure rates and tone wise.
Around 40 mA is OK in a JTM45, hotter means reduced tubes lifetime.
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I'd love to get my hands on some Saratovs or even some NOS to try but I don't think I can justify the expense when I can hunt about and get Shuguangs from about £15 - £28 at the moment. I'd better try to stock up though, I guess, as if they sound great and are about the only true KT66 in production then I can see prices rising due to that alone.
Theundeadelvis - let me know how you rate your Saratovs!
FYL - cheers for the info there...and the bias value. I'll try it out on my amp and see what difference I find to my ear as I go.
I did try some 6L6 in the amp a year or two back. Sounded OK, but to my ear the KT66 sound much more 'massive'. The 6L6s didn't have as much bass to them in my amp either.