Best tubes for a Brown DeLuxe?

[David Root]

I just hauled my '62 6G3 out of its shipping box from when we moved here two years ago (been bizzy!) along with it's kissin' cousin 6G15 reverb.

For some now unknown reason I had three Telefunken 12AX7s in the 9 pin holes. There's no way to clean up a brown DeLuxe, I musta been nuts!

At least I put a pair of grayplate RCA 6V6GT in the octal holes. I won't tell you what speaker I put in it, but I intend to reload the original (reconed) Oxford.

So what preamp tubes would YOU put in this amp, and why? Oh, it's original except for the PS caps and one dropping resistor.

[Cliff Schecht]

All RCA! Deluxes love american tubes .

[David Root]

Blackplates or grayplates? I like long blackplates in Dumbles but not crazy about short grayplates

[billyz]

Nothing wrong with Telefunkens in a fender. They sound great, lots of detail and even tonal response. Usually very quiet. In fact telefunkens sound good in any amp.

[David Root]

It would completely break up above about 6 with a single P-90. ES-125T. I'll have to do some tube rolling and try other guitars too.

I remember the reconed Oxford sounded very Fendery, quite unlike what I replaced it with. OK, it was a green Tone Tubby ceramic. Maybe that's the wrong speaker.

[billyz]

The Oxfords in the brown deluxe are very much like the Jensens of that period. Try a c12n for that tone. In fact I think those Oxfords are just as good as a jensen. The Later ones gave them a bad rap. I think they opened up the voice coil to keep from blowing them and the tone suffered.

[David Root]

That makes a lot of sense. I had always been told that "Oxfords are inferior to Jensens" but mine, even reconed and not broken in, sounded very nice. Not very efficient maybe, but this is an 18 watt amp, I'm not expecting Madison Square Garden.

IIRC, JBL had the same trouble with the D120 and opened up the voice coil spacing, degrading the tone.

As it happens, I have an Italian C12N, which is what I used in it while I was waiting for the Oxford to come back from Orange County Reconers. The Oxford sounds better.

[Lonely Raven]

Weird. I had Oxfords in my '62 Magnatone 260. I understood why people called them Oxfarts. These were probably a lower end model or something.

[David Root]

Maybe not. That's a much more powerful amp. Here's my Oxford. Nice recone job!.

[David Root]

Tomorrow I'm going to put the Oxford back in it, pull the chassis and put it in my amp cradle, check it over to see what the voltages are compared with the schematic, especially the bias, with this first tube roll:

'66 GE 5AR4

2 x RCA grayplate '50s 6V6GT

'62 GE long grayplate 12AX7 in the PI (took it out of my 6G15 reverb, probably the original tube.) Red lettering. Almost perfect DC balance.

RCA (labeled Tungsol) long grayplate 12AX7 in V1 and V2. Highest gain tube in V1.

Thought I'd try all-American tubes "just becuz!"


Anyone ever tried a pair of 5881s in this amp? With a rebias of course.

[David Root]

Put the Oxford back in this morning, pulled the chassis, just out of interest I checked the resistors to see how much they had drifted in 49 years! Not much, most about 5% only, none more than 10%.

Put in the tubes, turned it on in my amp cradle. High voltages!! Corrected to 120VAC wall, 415v B+1, schematic 375V. Plates & screens also 40V higher than schematic. And so on down V1 B+ 312V vs 270V schematic. V1 plates 35V high. Cathodes all close to schematic. Sounded very clean, good headroom, thru an Altec 417B, and LOUD too! At about 4. I did not crank it as my wife was home.

So I dug out a '61 tan base RCA 5R4GYB and put that in, in place of the GE 5AR4. Dropped B+1 by 20V, on thru to V1 plates, dropped 10V to about 190V. Much sweeter tone!! And a tad more compression I think. I hear no need to roll any more tubes.

Put chassis back in cabinet, tried it out again with the original speaker. I swear that Oxford sounded almost as good as the Altec 417B, just relatively a very little ragged on the high end, not as loud of course but still plenty loud. This is no bedroom amp!

So now I have to order another 5R4GYB for my planned EH-150 build!