|
Tubes Asylum Questions about tubes and gear that glows. FAQ |
|
|
|
Tubes Asylum Questions about tubes and gear that glows. FAQ |
|
In Reply to: Amperex tubes with no etched codes??? posted by vrogers3 on November 12, 2006 at 19:45:36:
vrogers,It happens I recently bought 6GH8A's a possible substitute for the 6U8A in a McIntosh MR67 tuner. Modaferri, who had a hand in McIntosh tube designs, recommends that substitution. The higher gain of the 6GH8A apparently helps things along.
I also bought Amperex 6GH8A's. These are orange globe, but marked "Made in France" and these do have Philips France 1970 etched codes. All 5 read: "AAC2 +-0K5". "AAC" is one of only 7 three-digit Philips type codes and interestingly stands for "ECF80A"- which is the 6BL8. The "+-" sign stands for La Radiotechnique, Clichy (Neotron), France. The surprise for these 6GH8As is that they are as visually identical to the 2-6BL8 "Audio Amplifiers" in the MR67. Those are labelled "McIntosh by Amperex" as well as "Made in France"- also "+-" codes. They both have that same double triangular getter support- looks very sturdy!
Another time, we might consider what seems to be the possible interchangeability of 6U8, 6GH8, and 6BL8.
You might find that the codes on your Amperex are just very faint- and esp. if they are are the dual tringular support ones, I wouldn't be surprised if they are Philips, France. Also, the seams on the top can be deceptive as there is usually one strong seam and the other can be fainter to the point of invisibility- which is the case for my French Amperex- only the faintest ripple in the other direction.
As for your other 6GH8As- the "Realistics", if these have: a wider, thickened base to the getter support with little vertical ribs, and a stamped number like "53"- possibly upside down, and the point at which the pins pass through the glass shows more red than usual, then I believe you have acquired Tungsrams- Hungarian. I haven't tried these, but Tungsrams are among the best of East European tubes.
I didn't do nearly as well as you on the price as the 6GH8A's I bought cost $3 average each.
I think there were not too many makers of the 6GH8A, and possibly these European ones are interchanged with the 6U8 and 6BL8 (ECF80). By the way, I don't know your use for the 6GH8A, but if you can substitute the 6BL8 in those spots-and the Philips 6GH8s are the same as their 6BL8s- you might consider the premium version. I'm starting to really like that type. Because it's a communications tube, there is a premium, military version called the "E80CF" and/or "7643" which are gold-pinned and mil-spec, low noise rated and rugged- 10,000 hour tubes. They are, like other of the tuner tubes- pleasantly inexpensive for the best- I bought Valvo, Hamburg 1964 red label, military label, pinched waist, gold pin E80CF for $15 each. The structure of those appears identical to the Amperex 6GH8As. Siemens E80CF/7643, you will find, are Telefunken (diamond mark) and these can be $5-6 tubes.
Cheers,
Bambi B
This post is made possible by the generous support of people like you and our sponsors:
Follow Ups
- Amperex and Realistic 6GH8A - Bambi B 06:33:17 11/13/06 (0)
Top of Page ]
[ Contact Us ]
[ Support/Wish List ]
[ Copyright © 2024, Audio Asylum, all rights reserved ]
