12AX7A preamp tubes - ribbed vs smooth plate

It was only a matter of time. Surprised it took this long. 

As I understand it, women seem to have a preference for the ribbed tubes. 😁

I too am shocked at the differences between rectifiers, including differences between direct-heated and indirect heated rectifiers. Fun to roll in my Woo headphone amplifier.

BTW, this is the first I am hearing of Bill Thalmann’s death. I met him in 1974 when he sold me my second pair of Advents while he was a salesman at the old Atlantis Sound in Falls Church, VA. The next year he very kindly helped me build an Ampzilla amplifier kit. I last spoke with him last fall as he was closing his shop. What a wonderful guy…it’s very sad news.

That is very sad new indeed I knew Bill had been ill what an audio legend may he RIP.

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.