Of Cabbages and Kings...

[synsei]

As I've been browsing ebay looking for spare valves for my amp I've ascertained that test measurements of valves are extremely important for a buyer to ascertain the health or otherwise of the valves they are buying. I have worked out that the higher the value the better the health of the valve, for example I'm currently watching a pair of Mullard ECC83's which measure 73/72 & 73/73 respectively, and according to the seller that is about as good as it gets for a used valve (is it?). I understand the concept (higher is better) but in practice what is being measured here and how? Do I need to source a valve tester, and if so, which is best and where do I get one? Is there such a thing as a valve testing service?

And another thing: When is a 6L6 not a 6L6? I'm on the hunt for a spare quad of power valves and what do you know? It's not as simple as all that. It would appear that some versions of this valve type may not necessarily be compatible. Why? How will this affect my amp if I happen to purchase the wrong ones? Does my amp have biasing adjusters? I'm in another world, I now know how Alice felt when she stepped through the Looking Glass... :eyebrows:

[Dingdong]

But you already have Mullards and they will last a very long time.

The amp did have Chinese 6P3P'S in it. Not it has Svet 6l6gc's. You could also put 5881's in it I believe.

[Marco]

Do I need to source a valve tester, and if so, which is best and where do I get one? Is there such a thing as a valve testing service?


Yes, he's called Anthony TD! ;)

Seriously, send any valves you've got to Anthony, and he'll test them and give you the measurements, for a small fee. It's well worth it :)

Marco.

[synsei]

I'm not having a whinge by the way, I am just overawed by the scope of what I need to learn. Mark, I've read that in general valves are pretty reliable and when treated correctly they will last a very long time. I have also read however that like filament lightbulbs they can sometimes just blow for no apparent reason and that it always pays to keep some spare valves knocking around for such eventualities, hence why I'm on a bit of a learning binge ;)

Thanks for the advice Marco, I will send them off to Anthony once I acquire a spare set. What is being measured in the example I posted BTW, volts, amps, resistance? I am keen to hear how other makes of ECC83 change the character of the sound so I am also watching some GEC's and Philips versions.

[Mr Kipling]

Noel Keywood once did an article on the most popular valves used in audio. The 6L6 and its variants was included. The 5881 can be used as can the EL34, I think. The World 5881 amp used Sovtek ones.

Ta-Raaaa. . .

[Mr Kipling]

Thinking about it, I have a Leak TL 25+ and the chassis itentifies the valves and shows alternatives. The 6L6 and the 5881 are shown as alternatives to the EL 34 which was normally used.

Mention of the EL 34 has me thinking back to Peter Whotshisname of Audio Note. In one of his articles in The Audiophile he indicated he wasn't a fan of the device saying that it wasn't very good for audio use and as such it was never used in any of their designs. I don't know if that view changed in later years. The Leak TL 25+ isn't regarded in the same way as the Stereo 20. Perhaps this is down to the EL 34s. I haven't read of anyone trying it with 6L6s or 5881s. Then again, there's a multitude of designs out there using the EL 34. Are they all duffers, Matey?

Hooo Hooo. Ta-Raaaa. . .

[Barry]

Thinking about it, I have a Leak TL 25+ and the chassis itentifies the valves and shows alternatives. The 6L6 and the 5881 are shown as alternatives to the EL 34 which was normally used.

Mention of the EL 34 has me thinking back to Peter Whotshisname of Audio Note. In one of his articles in The Audiophile he indicated he wasn't a fan of the device saying that it wasn't very good for audio use and as such it was never used in any of their designs. I don't know if that view changed in later years. The Leak TL 25+ isn't regarded in the same way as the Stereo 20. Perhaps this is down to the EL 34s. I haven't read of anyone trying it with 6L6s or 5881s. Then again, there's a multitude of designs out there using the EL 34. Are they all duffers?



No, the Radford Series III amplifiers (both the 15wpc and 25wpc designs) use EL34s and are very well regarded - so much so that used samples change hands for £1000.