RCA Tubes

[RossH]

I am looking for some comparative experience in tubes. I hear that for EL-84's people really like JJ's. I've yet to try them but I will. I've been using groove tubes and old NOS Westinghouse brands.

I have a friend who owns a engineering testing laboratory who does a lot of military testing. When he found out I was building tube amps he said he had some leftover mil-spec tubes from the 60's he would give me. But he said that he did sell a large lot of Tung-sol's. He gave me two boxes of mostly brand new assorted tubes and out of over 100 tubes I found about 15 that I could utilize. The rest I've never heard of and will need to research some.

But, the ones I am using in the 18 are a RCA 5AR4 (I built the Lite II and used this rectifier). It has a Great Britian stamp on it. The others are RCA 12AX7A's. Then there are a a couple GE 12AX7's and a bunch of National Electronic 12AX7's in which the box says Illinois on it. I was using Sovteks for both rectifier and 12ax7 positions and just changed the tubes mid-jam on Monday to the RCA's. I was blown away at the difference! I tried the National's as well and they were awesome as well. In the short run they put my Sovtek's to bed. So I was wondering, does anyone have any experience with this RCA tubes and how they compare to anything in modern production? And does anyone know anything about these National tubes?

TIA,
~ Ross

[EBE]

RCAs are great tubes but they won't drive the trem.

Norm

[HeeBGB]

I put RCA 6BQ5's in my 18 when I first built it. They sounded killer but after about two months one blew. So I put in a couple of GE's which also sound killer. The GE's have a little more gain than the RCA's but otherewise sound the same. I have a Univiox that runs two 6BQ5's and it has mesa power tubes in it and I put those in the 18 for about two seconds. They sounded very brittle and not musical at all. But I won't put any of my NOS stuff in the univox. It sounds OK the way it is. I'm going to pick up a set of JJ's and try them though. I run Electro Harmonix 12AX7EH's in the preamp and I like them very much but haven't compared them to any NOS stuff yet.

Greg

[nigelb]

Ross, If you have used the Groove Tubes EL84-S then they are JJs, just matched and gain graded. The GT EL84-R are Sovtek and the EL84-Y are EI. I have compared normal JJs amd GT EL84-S tubes and can't hear a huge difference though the GTs have an edge on smoothness.

I use EH or JJ 12AX7s and I like both very much but neither will work in the trem position - unless you like motorboating - I have an old EI there which works fine.

The only NOS EL84s I'd like to try are Mullards but my mortgage is high enough as it is. Just waiting to come across someone who has on old stash and doesn't know what they are worth.

[RossH]

Ross, If you have used the Groove Tubes EL84-S then they are JJs, just matched and gain graded.

Well, that is interesting. I am using the 'S'. I think they are 7's.

So Mr. Trem is the fussy guy. In my case he is non-existent but that is good to know.

~ Ross