Sylvania 7027 datasheet / V4 question

[nsubulysses]

Anyone have one? Is the plate dissipation for this tube 35W ??


People seem to say 7027s are THE tube for this amp, even though many other tubes will work. There is lots of conflicting info out there. Basically just wondering if I could expect anything different sound-wise using old 7027s vs JJ 6L6GCs. I know people say V4s are "happier" with 7027s but I don't understand if they are implying that they handle high plate voltages better and last longer, or that the amp actually sounds different.

[The Dude]

Help, My Amp Has 7027's!

BTW, that's a link to a page about this very situation.

[nsubulysses]

Thank you for your reply. I am familiar with this page and have used V4s with a few different output tubes, just never 7027s. I probably stated my question poorly, and it should read more like this.

I have a quad of Sylvania 7027s I got for free. They are used, but test fine in my tube tester for whatever that's worth. I was considering throwing them in my V4 since I've never used 7027s in a V4. If I haul that beast home from the practice space, retube and rebias, and haul it back, will it just sound the same??

I guess I'm trying to not haul around a V4 if it will be for little or no results. You know what I'm sayin?? I am using JJ 6L6GCs now.

[The Dude]

I don't think there would be any substantial difference; and yeah,...... those things weigh a ton! You might just hang on to the 7027's and wait until next time you re-tube it. There's also the possibility that once you run them at real world parameters, they're not so good. A tube tester won't tell you for certain.

[g1]

Any sound difference will be more an issue of NOS versus modern tubes, rather than tube number. I don't think you will hear a difference between your 7027's and the same vintage sylvania 6L6's.
I know you won't hear a difference between a JJ 6L6 or a JJ 7027, because they are the same tubes, just extra pins connected for the 7027's, same as for Sovtek's and any other maker of new 7027's.
Even if Uncle Ned is wrong, and the vintage 7027's could really handle more voltage, as you can see in his article the plate curves are identical to 6L6's, so they would have sounded the same anyway.

[Audiotexan]

Closest I can offer is the 7027A RCA spec sheet from 59, but given that Syl and RCA often shared specs/tubes and the simple fact that there WERE actual industry standards back then... I'd say yes. There is a difference in the voltages/plate dissipation they'll handle.

7027a (RCA) Aug 1959.pdf

Also, agree with the other comments. Between old-stock tubes there's not going to be a whole lot of difference (again, as the standards were higher), but between then and now, *huge* difference -both in sound quality and operational margins. Not to mention longevity.

If you have to retube once or twice a year with new tubes, versus maybe once every five-ten years (or longer) then the initial outlay usually justifies the expense. Bearing in mind that 7027's in that HV range would have a reduced lifespan vs others operating at lower HV. Even still, it's worth it *to me*. YMMV

[g1]

Just to reiterate if I was not clear, don't waste your money on modern 7027's unless you need the extra pins and 6L6's won't work. The modern versions do not have the higher voltage or power handling and are 6L6's with the extra pins connected. (see max. voltage and wattage for JJ 7027). Most Ampeg's (and many other guitar amps) that call for 7027 have their sockets wired to accept 7027 OR 6L6.
The higher voltage/wattage 7027 is an extinct tube.