FS: 5x GEC KT88 valves, vintage, test as NOS!

[Lawrence001]

Ah, OK... well, it had nothing to do with the valves, if that's what you mean, but if it helps I'll tell the story...

I used to own a lovely John Wood KT88 amp. It came fitted with Sovtek KT88s, and when I asked John about upgrading, he recommended vintage GEC KT88s as the 'best', so I started looking for/collecting them over the course of a year.

Unfortunately for me, I did not realize at that time that John's amps (or at least this particular one) are not self-biasing, and not only that but JW wouldn't let anyone else re-bias it apart from himself, even other qualified engineers. That meant I had to deliver the amp back to him in Nottingham if I ever wanted to change the valves. And since I'm in London, and also busy, I never got round to doing that. I have since recently sold that amp (on here) and am now left with these rare and expensive valves, and no use for them.

I appreciate its an pricey investment for anyone, as it was for me. Not only that but along the way of my search I probably got ripped off for £500+ worth of dodgy old valves on ebay while trying to find decent GEC KT88s. All those valves had to be binned, and these are the 5 I found that I would have used myself had I kept that John Wood amp.

So in that sense I stand by my claim that they are as good as they test. I only included the disclaimer at the end in the interest of complete honesty, as it's true I never got to test them in an amp. I've no reason to believe that there would be any problem with them however.

SO... since it is a big investment for someone, I'm willing to change the condition and say that if any/all of the valves prove to be unusable in practice, say within a standard 14 days return period, I will refund part/all of your money. Can't say fairer than that.

That makes sense and it's good of you to stand by the valves. I think it's in the spirit of the forum too. I wouldn't worry about testing them in an amp, if you offer the 14 day return, the buyer will know where they stand.

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[karma67]

nick for my own clarification,these are for the 4 large valves on my amp with 1 spare?

[nickbaba]

Hi Jamie - yes, exactly right.

As mentioned before JW recommended these to me when I wanted to upgrade from the Sovteks to the 'best' available. They are pretty much the 'holy grail' of KT88s, and a decent matched Quad set will go for £1200+ on ebay. They will beat any currently manufactured valves including Gold Lions and all that stuff.

But as I say, I'm not sure about selling these now, until I have had the chance to try them in practice and can vouch for them 100%

[Edward]

Nick if it helps you and you are near by you are welcome to try out your KT88s in my amp which is currently sporting some nice McIntosh KT88s. Fully able to bias etc. I'm in London N2.

[Jazid]

When I tested them these valves worked as you would expect, no h/c leakage, no cold shorts, no gas, no irregularities in the testing, nothing to suggest they aren't rock solid. And yes, there was a bunch of crap Nick bought as well but had to discard, I don't think it was a 'jackpot' purchase for him.

As with all old valves, if you wish to use them it makes no sense to put them in an extreme environment by which I mean running them at their design limit. This applies to new valves as well but they cost less and are easy to replace ...

Of course anyone interested can PM me and I'll tell them what I know which is that these are honestly represented by a decent chap. I didn't charge for measuring them and have nothing to gain, no relationship with the seller, etc. In my opinion these are as good a punt as old valves ever can be.

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[nickbaba]

Thanks for your post, James. Very kind of you.

[mac72]

If James (Jazid) tested these buy with confidence ,
best KT88 out there and extremely rare

[steveharman]

Before selling my vintage GEC KT66s and others (GZ32s, EF86s) I sent the lot to http://www.timetravelaudio.co.uk/ser...ing-servicing/

Edinburgh, Scotland iirc).

I think it cost £70 all-in for around 12 valves to be tested and shipped back to me? Something like that. In any case I was able to sell each with an individual reading of all the various plate voltages and currents etc.

It seemed to be a transparent way for the buyer to know what they were getting and protection for me to know there shouldn't be any returns.

Very friendly and efficient service. There are plenty of other mail-order testing services but this guy (Stewart iirc) is to be recommended.

Steve

[Lawrence001]

I don't think there was any question over Jazid's testing.

[Jazid]

Power to this chaps elbow, he's seventy quid richer than me. Other than that it's the same service.

Having read the blurb on his website - for a commercial service - I would feel inclined to note that no one tester, and certainly not the 163 can test every valve, at least not at close to working voltages and currents, and for some valves with little accuracy. Best to ask the limitations first, especially if using old or power triodes, regulator or rectifier tubes, and transmission valves.

KT series and all those mentioned in Steve's post are fine however.

Another thorny issue is 'calibration' . I am not aware of any true calibration service for valve testers. This is because of the difficulty and time/cost of working on the machines which do not reach original spec (read 99+%) in order to bring them up to it - which is the whole point of calibration: It should be independent and certified. I think most people mean that their valve tester agrees within say 5% of readings obtained for a particular valve on a 'known good' other tester eg Amplitrex, or a well fettled Neuberger or pi-tracer. There will be some who may have checked HT and bias voltages, and maybe current readings, that's about it. It is not very honest to claim ones tester is calibrated if it isn't: being me I'd ask to see a copy of the calibration certificate and date.

Hence my earlier caveats about buying used valves, and one reason for the ubiquitous disclaimer on eBay from sellers showing test results that the figures given are correct from their machine, not from yours!

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