12AX7A preamp tubes - ribbed vs smooth plate

Sorry to be the bearer of bad news re Bill Thalmann. We took the equipment he was going to restore for me down to Virginia on our way out of NY when we moved to Texas in January, 2017. Met Bill, got a tour of the shop, he touched base while he was doing the work- restoring my old Technics SP 10 mk I (which I bought new in 1973), a pair of Quad II amps (I found the glass, including real GEC KT 66’s!) and a McI MX110z which I bought from a vendor online and had shipped directly to Bill for restoration. Sounds wonderful with my old Quad 57s which were also restored (by Kent McCollum). This is my "vintage" system in the front parlor. (Main system is in a dedicated room upstairs)

This system is a close approximation of what I ran in 1975, except I used all ARC stuff then (SP3-a-1 and Dual 75a). I still have the amp and a fresh complement of tubes that I bought from ARC back in the aughts. At some point, I’ll bring the Dual 75a back to life--it would probably play if I fired it up, but should be recapped and checked.

I didn’t know Bill well, but I really appreciated the care he put into his work and he was a gentleman in every sense of the word.

On rolling rectifiers, the Allnic H-3000 and its bigger brothers (phono stage) is very susceptible to sonic changes owing to the rectifier. I’ve tried a bunch and have several more that I’m sitting on. I did secure a NIB old metal base Mullard (really a Philips-Miniwatt from Holland)--a grail tube. It has profound bass, but at least in the circuit and system, lacked the air of my preferred GEC u-52.

That GEC tube is not a direct equivalent to a 5AR4, but works in the Allnic. It has a "cup" base- I have a couple of them, a brown base and a black base-which I understand may be earlier-or intended for industrial use. Not an easy to find tube in unused condition.

@whart Mullard's have no top end!

lacked the air of my preferred GEC u-52.

The Mono amplifier uses 4 12AT7 tubes and while four seems a bit much for rectifying (ie converting AC to DC) maybe two are devoted to this worthy cause and then it leads to the question what are the other tubes used for . I thought preempt tubes were a way to describe use of this tube within an amplifier (ie taking the week analogue level signal from the pre-amplifier and turning it into a stronger line Signal) and is this also considered to be a signal tube?

I thought preempt tubes were a way to describe use of this tube within an amplifier (ie taking the week analogue level signal from the pre-amplifier and turning it into a stronger line Signal) and is this also considered to be a signal tube?

I’ve never made any claim whatsoever to be an audio/electrica/tube guru, so maybe I’ve been wrong all these years, but I always thought of the tubes in a preamp (or the preamp section of an integrated) as being the "preamp tubes", and then all of the tubes in an amplifier, including the smaller input or driver tubes, as amplifier tubes. For example: In my amp, I have always considered the pair of 6922s and pair of EL84s that are in front of the dozen EL34 output tubes as all being amplifier tubes. And I have then also considered the six 6SN7s in my preamp as the "preamp tubes." But like I said, maybe I have been wrong about that.

As far as "signal tubes", technically, I guess they would be any tube in the signal path? Although I guess that when someone says "signal tube" maybe we usually think of the smaller tubes in the front of an amp or the tubes in a preamp?

I don’t know for sure, and here’s to hoping someone will educate me, and as I typed previously--I guess it doesn’t really matter what you call them (although it may be confusing if we all call them by different nomenclatures).

I grey up in the 70s and early 60s type smooth plate was more preferred.

siemens isat least on paras Tele  . 50-60s preferred for both,  early 70s, no 80s.

check Andy at vintage tube services. The most knowledge on tubes period !

Brent Jesse audio has been around also ,as well as vacuum tubes  dot net