Can someone ID this 12ax7a? thx.

[JeffreyC]

http://petecornish.co.uk/wood12.html

http://petecornish.co.uk/Woodwork-12.jpg

[Swarty]

Not from that pic. How about a detailed close-up?

[epluribus]

OT-ish--what's the "A" on the end mean? I have two of these, '66 RCA OEMs.

[JeffreyC]

These are pics of Peter Cornish working on Gilmours pedalboard before he toured this year. These tubes are in new Tube Drivers built by BK Butler. I have one of these new pedals and so I'm curious about the tubes. They don't look like the stock one BK put's in them, but maybe he put something different in there - my guess is that Pete Cornish installed the tubes. Anyway, there are more pics on the site, but you can see the drawing of a tube in yellow on this one...

http://petecornish.co.uk/Woodwork-14.jpg

[Blue Strat]

Isn't that tube outline shaped logo the TAD logo?

[JeffreyC]

Isn't that tube outline shaped logo the TAD logo?

Could be - I looked around at some of the TAD tubes and it doesn't quite look the same.

[JeffreyC]

another pic...

http://petecornish.co.uk/Control-Panels-1.jpg

[uberpict]

The plates look really similar to 60's Sylvania tubes, the plates are gray, long and wide and the rib is narrow. Never seen them with that logo, it's not TAD or Amperex with the tube logo, maybe a Phillips import.

[rockon1]

No,I dont think its sylvania.Pic looked better before I resized it but I think its a shorter plate and not the thin sylvania LP style....just guessing though as I cant get a good look...


http://tinypic.com/42nvamb.jpg

[JohnnyL]

Not a Sylvania. I own a good deal of Sylvanias and have never seen those types of 'seams' at the top of a single one.

What tubes have that thick a seam in the glass? I can't venture a guess right now...

Peace,

JL

[rockon1]

Not a Sylvania. I own a good deal of Sylvanias and have never seen those types of 'seams' at the top of a single one.

What tubes have that thick a seam in the glass? I can't venture a guess right now...

Peace,

JL

Good eyes! Philips have 2 or 4 seams. (Amperex,Mullard,Valvo etc...)

[JohnnyL]

Good eyes! Philips have 2 or 4 seams. (Amperex,Mullard,Valvo etc...)

The only European tubes in my collection with seams that prominent are from the Siemens Halske factory. All the Euros have seams but not as raised or 'pinched' like the ones pictured here.

JohnnyL

[JeffreyC]

Thom?? Any ideas?

[jack anderson]

I *think* this is the same tube. It's an EI, with the Real Tube logo. Click on the thumbnail.


http://img178.imageshack.us/img178/1528/12ax7a001mp9.th.jpg (http://img178.imageshack.us/my.php?image=12ax7a001mp9.jpg)


http://img83.imageshack.us/img83/7883/12ax7a002fe1.th.jpg (http://img83.imageshack.us/my.php?image=12ax7a002fe1.jpg)

[rockon1]

Yep,Ei.... Forgot about that "choice" so early in the morning when I posted. They have 4 seams prominent like that too. The one in the last picture is Ei for sure. I suspect the others are too.

[Timbre Wolf]

Thom?? Any ideas?
You guys are doing fine without me!

I'm floating in the eternal twilight of electric babyland now, and probably don't have a grounded point of view anyway :angel

- Thom

[JeffreyC]

So are these older Ei's that you can't buy anymore? I've looked around a little and can't seem to fine ones with this logo.

[jack anderson]

RealTube used selected ones in their effects in the , probably, 1990's. Pesocaster, a forum member, worked for RealTube, and gave me the one pictured.

They're not being made anymore, but there should still be some available ; the trick is finding a well-screened one you can depend on.

[Sparky6string]

So are these older Ei's that you can't buy anymore? I've looked around a little and can't seem to fine ones with this logo.

They can still be found as NOS. The logo isn't important, as long as the tube is a geunuine Yugo Ei.

[mmorse]

Well, if they are circa 90s EIs they aren't anything special. They are overly bright and thin sounding. Now the older EIs, (early 80s and before) are great sounding tubes. But that might not be much of an issue in this application.

For the person who asked in a previous post, a 12ax7A can be used in both series and parallel filament circuits. A standard ax7 can only be used in parallel filament circuits.

I would think a mill spec tube like a 12ax7wa or a 5751 might be better suited as both are more rugged than your standard ax7 and could withstand more abuse sitting in a pedal board.

[epluribus]

a 12ax7A can be used in both series and parallel filament circuits. A standard ax7 can only be used in parallel filament circuits.

Thanks MM. Been curious about that. I'll have to check and see if this circuit uses a serial filament circuit.

--Ray

[rockon1]

For the person who asked in a previous post, a 12ax7A can be used in both series and parallel filament circuits. A standard ax7 can only be used in parallel filament circuits.

Intersting Ive never seen this to be an issue.Is there an amp you can tell me about that wont accept a 12AX7? Just curious.:)

[jack anderson]

Just for the record, my 1955 Sylvania tube manual lists 12AX7's as having filaments that work in series and in parallel. My 1957 manual shows 12AX7's, plus 12Ax7A's ; the A's have improved noise and hum reduction.

[Timbre Wolf]

Just for the record, my 1955 Sylvania tube manual lists 12AX7's as having filaments that work in series and in parallel. My 1957 manual shows 12AX7's, plus 12Ax7A's ; the A's have improved noise and hum reduction.
Sylvania went from its long black-plate 12AX7 to the short black-plate 12AX7 in late 1955. In late 1956 they began using the short gray-plates in their new 12AX7A. A couple of years later, they went to long gray plates in their 12AX7As (late '50s through early '60s). That transition, from long black-plate to short black-plate, and short gray-plate to long gray-plate, was atypical of the progressions of other tube companies.

- T

[Sparky6string]

Intersting Ive never seen this to be an issue.Is there an amp you can tell me about that wont accept a 12AX7? Just curious.:)

I doubt that modern amplifiers have that design. I've read that it was mainly something found in older equipment that ran on tubes.

[uberpict]

The only European tubes in my collection with seams that prominant are from the Siemens Halske factory. All the Euros have seams but not as raised or 'pinched' like the ones pictured here.

JohnnyL

I've got a GE with a very prominent seam and 4 Sylvania's with similar seams around the stem. I wouldn't rule out Sylvania based on that. When they attach the envelope to the stem they give it a little push to fuse it properly creating the seams, most tubes should have some seam in that area.

Another reason I think they're Sylvania is there appears to be a smaller rib on each side of the plates near the edge where the crimp should be on most other tube styles. It's really hard to tell from the pictures though. Somebody call Dave and see if he'll pull one out and take a better picture, LOL.

The Sylvania's also have a very high Rp when new, 1500-1600 microhmos, which would work well in a tube driver being a "hotter" tube.

[rockon1]

I've got a GE with a very prominent seam and 4 Sylvania's with similar seams around the stem. I wouldn't rule out Sylvania based on that. When they attach the envelope to the stem they give it a little push to fuse it properly creating the seams, most tubes should have some seam in that area.

Another reason I think they're Sylvania is there appears to be a smaller rib on each side of the plates near the edge where the crimp should be on most other tube styles. It's really hard to tell from the pictures though. Somebody call Dave and see if he'll pull one out and take a better picture, LOL.

The Sylvania's also have a very high Rp when new, 1500-1600 microhmos, which would work well in a tube driver being a "hotter" tube.

Both are probably relabeled. I have a couple GE that are actually Mullards with two seams. I havent run across any relabeled Sylvanias but I have a LOT of them and none have seams.

[uberpict]

Both are probably relabeled. I have a couple GE that are actually Mullards with two seams. I havent run across any relabeled Sylvanias but I have a LOT of them and none have seams.

Mea Culpa, I'm looking at the radial seam at the base that every tube has, didn't see the vertical one at the tip. :jo

Okay, I got nothing. :D