Long Plate verses Short Plate

[Cliff Schecht]

After reading through this thread, I'd agree 100% that long plate tubes are typically more microphonic. I tend to save these for the phase inverter or later positions in my amps as well.

There is another reason to long plate tubes in higher current situations as well though; the larger plates can dissipate more heat. In the phase inverter position you can get a little more drive out of long plate type tubes (because of their overall construction, not just because of the bigger plates) which means more drive before distortion. IME this holds true although the difference isn't huge. Remember that the 12AX7 designation is a specification for performance, not necessarily a hard set construction method that one must follow. The long plate/short plate versions came about in the 50's after the Euro tubes were outperforming the American tubes (thus the 12AX7A was developed in its many flavors). These differences in construction will inevitably change how the tubes sound of course. For more details on this, read page one of this thread .

[renshen1957]

I think slightly Microphonic tubes sound better sometimes if you c an keep them under control

Absolutely. They keep the amp on the egde.

Yugoslavian EI 12ax7 were my must-have, but they ended the production few years ago.

Hi,

I read somewhere that Western Electric purchased the factory in 2006.

Steve

[cbass]

I think slightly Microphonic tubes sound better sometimes if you c an keep them under control

Absolutely. They keep the amp on the egde.

Same with pickups.I like to live on the edge.The edge of wuss cliff

[renshen1957]

Hi

@renshen
Would like to see a pic of that short plate telefunken, unless it is the ecc803s build. I have seen RFT 12ax7's in Telefunken labels, does your short plate tube have the diamond between the pins?

Its the short plate ECC803S, a frame grid tube, some have gold pins.

RE 10m Mullard, not worth the stupid money they go for. Same tones are in a Philips labeled Mullard Blackburn 12ax7a/7025 label with Philips in big white easy to rub off print. Interestingly, both the Philips and the 10m, after repeated on/off cycles, exhibit a purplish colored filament flash deposit on the inside of the bottom of the bottle, a different color than the brownish garden variety (still awesome!) Blackburn stuff. I have both types, not a large sample size of either. That particular Philips has about doubled on ebay in the last three years. My fave 10k hour 12ax7 hands down is the Siemens e83cc.

Hey, great insights, yourself, a good education on the the Phillips tube. I have some Siemens ecc83 tubes NOS from Ebay that I have been itching to try.

best regards,

Steve

[212Mavguy]

if there is a sonic difference between Siemens ecc83 and e83cc my ears fail to detect it...I have a fair amount of both types They sound great clean, but to my ears they come into their own when pushed into the dirt, V2 in most D-clones. Sometimes that e83cc is found in Valvo e83cc as well as Philips 6681 lablels. A couple years ago a seller was selling used medical equipment label Philips 6681 pulls by 12 to 18 unit auctions. Jest kept my mouth shut and kept sniping, average price per tube was around 28 bucks including shipping. Going rate even for used is around 80-c-note apiece on the 'bay for Siemens e83cc regardless of label, that is if the seller knew what he had, of couse.... Ended up with around 35-40 of 'em.

Most had not so high into the good test scores, but the sonics were still excellent even in well used tubes that exhibited silvering between the top mica and what appears to be a third mica above it. They were more compressed than brand new ones, but sonic balance was still good. That uppermost mica did not touch the bottle sides, the part is called a spash guard, it was placed there to keep the getter flashing away from the other tube parts.

Harmonic content is very, rich. Until they are pushed you will notice a strong lower mid and bass content, like a Mullard shortplate They also sound great in PI positions. They scream like a raped ape if you push them into the dirt enough, the upper mid and top end harmonic content then is very musical detailed and complex, and I'd stick one in a Trainwreck build if (I had one) following an RFT in V1.

Interesting detail about the Siemens "not equal" acid etch. At first I mistakenly thought that they were cocky and rightly so about their product qualities, sonically and construction, as in no equal to them. But later on I read that was referring to the Berlin wall dividing eastern and western germany...