Tubes 12AU7 vs. 5814A

[Clay]

I just checked my Mac C20 tubes with my new Heathkit tube tester.

I realized I am running GE 5814A in the 2 x 12AU7 sockets.

All the rest are Dynaco Telefunken 12AX7 and 1 mullard 6x4.

Please advise if I should get some 12AU7 tubes or if the 5814 is the preferred substitute for this amp.

Thanks,

Clay

[Steve Hoffman]

5814 is an industrial equivalent number for 12AU7. In other words, the same tube.

[Clay]

Thank you Steve.
Would you suggest getting Telefunken 12AU7 to improve the sound over the GE 5814?
Thanks, Clay

[Ronflugelguy]

Hi Clay, steve has said before that the Tele 12AU7's are not that good. Bugleboys,Mullards, and RCAs are the main choices for good 12AU7's.I've been comparing Mullards and Bugleboys in my 240 amp. Changes the sound a bit, the Bugleboys have more high end response, Mullards have more midrange.

BTW, did you just get your tube tester?

[Clay]

Hi Ron,
I did find a Heathkit tube tester TC3 for $40. It is easy for a non techie guy to operate. It is great to be able to test the tubes myself. One good looking Mullard EL34 tested 0.

I put togheter a quad of mullards for my ST70. sounds much better than the solveck (sp?) and even the Siemens.

I have some old RCA black plate 5814. I will try them on your suggestion in the Mac.

All the Dynaco Tele's 12ax7 tested over 93%.

[Steve Hoffman]

Telefunkin 12AU7's are sssslow and kind of muddy. Good for "dumbing down" bright tube gear; I used them in my old annoying McIntosh 275 before I sold it.

There are many different kinds of 12AU7's from the Golden Age, British Mullards and Dutch Amperex Bugle Boys being the best (but different from each other) and most reliable. PLEASE NOTE: I've found a bunch of GE 12AX7's and 12AU7's that are really Mullards (with the "Made in Gt. Britain" right on them) but re-branded GE. So, for like $3.00 each I got brand new 1960's $50.00 Mullards. Always look carefully at your tubes!

[Clay]

Great information.

Thank you very much.

I will looking forward to hearing the Mullards and Amperex 12AU7s in the C20.

I still need a few more Grover cables and some DIY speaker cables to get the most out of my electronics.

[MikeP]

Hi Clay,

I use 12AU7's in my preamp and I've done some tube rolling. I liked the Amperex Bugle Boys alot , but the the best tube I found by far was the Amperex 7316 PQ. Just great from top to bottom. Can't say for sure they'll be the best for you, but most people I know who've tried them have stayed with them. They can be a bit hard to find and can also get pricey, but if you're patient you can occaisionaly find a pair for a reasonable price on ebay (or maybe a local tube dealer).

Cheers,
Mike

[Sckott]

I use 6198 JANs for 12AU7's. Usually RCA's. Just my preference :)