RCA 6L6 Blackplates for BC30 - worth it?

[wiggy]

I've been offered a pair of NOS RCA 6L6GC Blackplate valves (fully tested) for silly money and was wondering if they would worth sticking in my BC30. I guess anything is going to be better than the Sovtek 5881s which are i there now but I would really welcome peoples' opinions on these.

[m-theory]

I'd be real suspicious about them being matched (or even that good, for that matter). The NOS tube market is chock full of wild claims by shady dealers. I bought what was supposed to be a "matched pair" on ebay a few years back that supposedly tested "like new," for less than $50. A the time, I think a REAL pair that had been matched and fully tested by a reputable dealer was probably going for $150-$200. I planned to throw them into my BF Pro Reverb, but waited until I had to take it into the shop for something.

 

I brought the tubes along, and my tech tested them. One was "brand new," as he called it, but the other was completely shot. Hardly matched and hardly both "like new." By the time I found this out, the ebay sale was long over, so I just chaulked it up as a learning experience and sold the good one on Ebay for $50, so at least I got my money out of the deal and somebody got a fantastic tube for a great price.

 

I don't know a whole lot about the inner workings of that particular amp of yours, but I'd bet that it doesn't have a bias adjustment pot, which means that if you install tubes that aren't well matched, you're going to get some ugly crossover distortion. If you want to try them in the amp, have them fully tested and matched by a dealer/tech you can trust before plugging them in. I'm sure that, if they test matched and good, they'll sound terrific in any amp. They are the schnizit in 6L6 world. It simply gets no better.

 

That said, solid Sovtek 5881s aren't that bad themselves, although JJ's 6L6 is a better sounding tube, imo. Not so sure about other new production offerings, but there are a couple others that seem interesting on paper, at least.

[wiggy]

Well they arrived a couple of days ago. They're not a matched pair but have been tested on a Hickok 532 tester and came out at full scale for one and 7/8 scale for the other which is plenty close enough for power stage.

 

Only had a chance to have a quick play through them (will be able to really open them up tomorrow) but the difference between them and the Sovteks (6L6WXT's not 5881's as shown on the spec sheet) is incredible. Closest analogy I can come up with is that it's like going from a mid range stereo system to a full blown audiophile setup - music sounds pretty good through the first one but sounds in a whole different league through the second.

 

Cost me less than £25 each incl shipping from the US so well chuffed (I know in reality they're probably REALLY worth about a couple £ each but looking at the sort of prices being charged for them - does anyone really pay $140+ a piece for these things? - I reckon I got a bargain!)