View Full Version : sovtek kt88 valves
im thinking of trying something different in my john wood amp,has anyone gone from sovteks and bought better? what did you try?
I was in the same quandry a few weeks ago, my suggestion would be to phone John and ask him what he would recommend. I suspect he will suggest a quad of NOS GEC 6550 he can lay his hands on, the best amps deserve the best valves, trouble is you probably wont see much change out of £1k but John did seem to think they wouldnt need replacing in the foreseable future as his amps present a very easy life for the valves
He didnt appear at all keen on JJ or EH.
Sovteks (orginal fitment) are difficult to source are these days and looked the same as EH to me - at the "cheaper" end of the market John appeared to me to be favouring Shuguang kt88.
I ended up with Gold Lion reissue myself, they certainly look and feel to me to be better quality than the JJ, EH and Sovtek. I have never noticed that much difference sound wise between different makes of output tubes myself so leave that for those with better ears.
hi ian,
thanks for the info,i think it might be wise to take a drive up to johns,(long trip) to give the amp a look over.
the new old stock valves are a bit too much for me at the moment and to be honest i dont know which of the valves are off,it may only be one of the smaller valves.
im thinking of trying something different in my john wood amp,has anyone gone from sovteks and bought better? what did you try?
Mine are 6550s
I went from Russian sovtek style to Tung Sol reissues, lots more detail. Not too expensive.
Wakefield Turntables
03-12-2018, 09:08
Tried sovtek, they were OK. Tried JJ a little better. I'm replacing the JJS with gold lion reissues. It's my little Xmas pressie.
That was my choice if I have to buy a set of 4.:cool:
John has never charged me for revalving and servicing, his after sales service is exemplary but if you are planning to visit him talk to him about valves to get before you visit. Heads up he doesn't carry stock, he is very passionate about what goes into his amps, he tends to work late and sleep in so best to call after 14:00 hours and lastly I find a phone call works better than email but you might need to leave a message first.
Swapping out the input and phase splitter tubes is a straightforward swap over and not that expensive. JJ ECC81 and latest I had from John a pair of russian 6H8C (instead of the 6SN7 that were orginally fitted)
for 6H8C look for the blue and yellow boxes mid 70s vintage - example listing from a supplier I have used before
https://www.ebay.com/itm/2x-6N8S-NEVZ-Novosibirsk-Soviet-Russian-Military-TUBES-MATCHED-PAIR-6SN7-6-8/253982265868?hash=item3b2285d20c:g:yVMAAOxyyghQ7k3 4:rk:2:pf:0
Thanks ian, so it’s only the power valves that need re biasing.
I will call him later
That is correct, the KT88 output valves need the bias level checked and set when the valves are replaced, the other valves do not. It takes a couple of hours because in very simple terms its sort of adjust, wait for the amp to stabalise, readjust, stablise, adjust etc etc.
In theory there is no reason why a local specialist couldnt do this for you but John does like to look after his amps and you can be pretty confident that he wont be ripping you off or making up unnecessary repairs
im off to john woods on saturday,top guy,no charge and if i bring my multimeter he will teach me how to bias it.
how bloody good is that!
Wakefield Turntables
03-12-2018, 18:08
I'm getting a Quad of gold lion, and I think I'll probably need to re-bias my amp just like yourself.
im off to john woods on saturday,top guy,no charge and if i bring my multimeter he will teach me how to bias it.
how bloody good is that!
which valves did JW reccommend
he wasn't specific ian,he just mentioned he had loads with him,ive only ever heard sovteks in this amp so anything that betters them is a bonus, i may be tempted once im there though :stalks:
he wasn't specific ian,he just mentioned he had loads with him,ive only ever heard sovteks in this amp so anything that betters them is a bonus, i may be tempted once im there though :stalks:
tread carefully - you might want to check out how to find Hotrox in Nottingham before you go and check they are open and have stock, its a long journey if you dont like the options John has available. He likes GEC and a used quad could be pricey.
I have never known him to carry stock in the way of new output valves, (sellers give very short warranty on them). I am sure he has part used if you are thinking about that route. if he has much else but I guess its possible that he might have a one off quad that was bought in for a new build or something.
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