The Amp Garage

[overtone]

Hi Paul,
NOS RFT EL34s popped up today. I bagged them.
PM sent.
Best, tony

[Paul-in-KC]

[Paul-in-KC]

Hey Guys,

Found some interesting (at least to me) info posted on another forum (Rig Talk). This was responding to use of RFT EL34 tubes in amps with high (500+) plate voltages.

Anyway - thought some of you might find it interesting also...

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Unfortunately (or fortunately) it's not that simple, to judge about RFT's

First you have to differ between 60's production, 70's production and 80's production (production has ended in spring 1989)!
Second you must know, that 60's production is superior to 70's production, but 70's production is superior to 80's production!

But how to differ?

50's and 60's RFT's do have a pretty flat tube's base.

70's RFT's have printed additional to the 6-digit production code "TGL9649" and most of them additional do have a triangle printed on, where inside is either a "S" or a "1" or a "2" or it's empty.
- S is the best choice and means "Sonderklasse" - translated ~about~ best selection
- 1 means, that the tube was tested and is of an excellent quality, most of them went into export
- 2 means, that the tube was tested, but parameters weren't absolutely convincingly. These tubes went uinto the national supply.
- empty means, this tube wasn't tested for purpose, but has easily withstand a quick test.

I've attached a sheet, but describtion is in German

80's RFT's only wear the RFT logo and a 6-didgit production code - nothing else.

But keep in mind, that many of the 'Siemens' or some misspell it 'Seimens' labelled RFT tubes went over the pond in the early 90's and are from late 80's production. Often you can't verify this, because the tubes became relabelled 'Ultron' or 'RCA' or 'Mesa/Boogie' or, or, or.....

... but then watch the tube's top! Is there a smooth dimple, then it's presumably from the 70's or from the very early 80's
is there a not so nice spot, what rather looks like a welding spot from automotive production, then it's presumably mid to late 80's

Ok, this was the lesson of today
But now to my (over 20 years) experience with RFT's:

I've never had failing a 60's RFT in any amp. They all were strong, constant and have had a remarkable life span.
With only a hand ful exceptions the same is valid for all the 70's RFT's, which already went through my hands.
I've built 70's RFT's into earl 70's Marshall Super Lead's with a B+ of 530V (!) w/o any problems!
I've built in 70's RFT's in Marshalls of customers with 150+ gigs every year - and after 3 years the tubes still were working well.
But I've had troubles and headache with 80's RFT's, especially with mid to late 80's and especially in amps with a B+ close to 500V or beyond.

But in amps with a B+ up to 470V they're nonetheless working fine.

And there's only one EL34 type, what IMO nails the RFT soundwise, in reliability and longevity - it's the 'real' Mullard, NOT made in Russia!

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Posted by screen name "novosibir" in 2009.

-Paul

[paulster]

Larry (novosibir) is also a member here. And he knows pretty much all you need to know about Siemens/RFT EL34s!

[Paul-in-KC]

[Paul-in-KC]

Okay,

Finally here is an audio clip. The clip isn't that good - but it's the first one that I have that gives some sense of the amps sound.

BUT I am a long way off of getting a good recording here.

My office has hard wood floors and in this particular clip I have a "room" mic on the left channel. If you pan to full right - you'll hear the close-in SM57 that was right on the grill.

The power tubes are NOS RFT's (relabeled by Mesa).
V1 = NOS JAN Sylvania 5751
V2 = NOS JAN Phillips 12AX7WA
PI = NOS Tungsram ECC83

The guitar is an early-mid 90's Strat Plus Deluxe (Lace Sensor Pickups). The speaker is a Celestion Vintage 30 (in my Mesa DC3 combo)
The player is an early 60's no-talent model

The format is MP3 - just to stay under the 5MB limit.

Any pointers for future amp recording posts would be much appreciated.

I'm sure I can get a much better sound with a little experimentation.

-Paul

[Paul-in-KC]

Also - all the knobs were at 12:00-ish. Bright switch (down or middle).

Completely dry recording.

-Paul

[Reeltarded]

hahaha that is hilarious and impossible. Silly. Rediculous.

Amps aren't supposed to do that. Stop it.

[Paul-in-KC]

[Reeltarded]

No, I meant the crazy nature of turning the knob and what that does with everything @ noon.

Yikes! Insane! Impossible clean from all that.

[Paul-in-KC]

[Paul-in-KC]

...the other thing I guess i should mention is that I am palying through a Dr.Z Airbrake.

It was set either on 4, or all the way to Bedroom (at about 12:00 - between min and max).

-Paul

[Reeltarded]

Your amp snarls, big time. I like that lil sucker!

When micing pretty much anything, I put my head down with my right ear pointing at the source. I move my head around until I find a line toward the source that I like, and I put the mic on that axis aiming at that spot, with guitar I prefer about 1/4 inch off the cone, but it always depends on what mic, what amp, how loud. After 3 years of doing this, I can still hear! (anything below 800Hz)

I like space. I probably like that mic twice as far away, or even farther like down the hall.

I like using cabinets without cloth or a grille of any kind.

Aside: That center thing in the speaker.. don't mic that. It's a dust cover. It doesn't sound like anything, and by nature just aiming at it creates all kinds of phase garbage and smear. If you are on axis with the dust cover, you are off axis from where the noise is coming from.

[Paul-in-KC]

[Reeltarded]

In the open then to clarify for anyone using search.

A direct box properly looped in before the amp as the recording. You need to fiddle around depending on what your setup is with the goal being what you hear from the amp is what you get on the recording when played back through the amp. I don't know what your inputs are to your recorder. Levels matter!

Oh, those DIs I use that someone asked about days ago before the onset of Flupocalypse 2012 are Radial JDIs.