A batter replacement for the 6GH8A - Videokarma.org TV - Video

mpatoray · #1 10-09-2012, 09:16 AM

Hi all,

I need to replace some tubes in my B&K 1077B and I need some 6GH8A's. I have heard there is a better more reliable/stable replacement tube for the 6GH8A. I was wondering what that tube may be, as i know this is not the best tube in the world...

Thanks,

Matt

N2IXK · #2 10-09-2012, 10:15 AM

Quote:

Originally Posted by mpatoray

Hi all,

I need to replace some tubes in my B&K 1077B and I need some 6GH8A's. I have heard there is a better more reliable/stable replacement tube for the 6GH8A. I was wondering what that tube may be, as i know this is not the best tube in the world...

Thanks,

Matt

6EA8 and 6U8 are similar tubes with the same pinout. Both will cost you more than 6GH8s will.

dieseljeep · #3 10-09-2012, 10:23 AM

Quote:

Originally Posted by N2IXK

6EA8, 6AN8 and 6U8 are similar tubes with the same pinout. All will cost you more than 6GH8s will.

6EA8 is the only one that comes close. That instrument can't be that hard on 6GH8's. Plus it isn't used as much, as a color set, that uses them.

Einar72 · #4 10-09-2012, 11:54 AM

My vote is for the 6EA8. Heathkit adored this tube; my HR-10 had one or two, as did many of their products. The 6CH8 was some forced-loyalty attempt that is dissimilarly-based.

I have a retired TV repairman freind who replaced 6GH8's by the handful. I believe the 6GH8 was designed to save money, but tried to fill too many shoes at once. I have a late-era 19" RCA color portable that's full of 5GH8A's.

Oh, look what I found:

http://www.videokarma.org/showthread.php?t=250003

miniman82 · #5 10-09-2012, 07:32 PM

I replace them with 6U8's every chance I get, because the 6U8 never has failed on me.

ctc17 · #6 10-09-2012, 08:59 PM

6KE8,so long as its not series string. You saw it in one of my videos. 6U8 is good to but more expensive and harder to find.

The audiofreakals havnt discovered the KE as a suitable phase inverter yet.

Einar72 · #7 10-10-2012, 11:19 AM

I was surprised to hear Dynaco switched to the 6GH8 from the forced-loyalty-pinned 7199. There are even Hong Kong adapters on ePay to sub them instead! Let the oxygen-free copper wire wrap'n'fill-cap-lovin' audioboobs suckle at the golden 'GH8 teat, we'll use the others.

N2IXK · #8 10-10-2012, 11:40 AM

Nobody makes 7199s anymore AFAIK, and the price on NOS ones is through the roof, assuming you can find one that isn't noisy and/or microphonic. The remaining ones out there have been pretty well picked over.

I think the choice to respin the Dynaco design around the easily available 6GH8 was the only way to go at the time. After they made the change, Sovtek made a "7199" for a while, though it has been discontinued. No idea if it was actually a low noise, coiled heater premium audio tube like the original RCA design, or just a repinned 6GH8 sold at a premium price.

TerrySmith · #9 10-12-2012, 08:42 AM

I'm into Hi-Fi, not an "audiophool", and the only stock build I ever did with a 6GH8 type was a Dynaco ST70. I repinned the 7199 sockets and rolled different types and settled on a Sylvania JAN 6U8/6678. Nowadays I duild my own driver circuit with a 6SL7 / 6SN7 combo. The 6AN8 is a different pinout!

One 6GH8 type is most likely as good or as bad as the others, use a top tier brand if possible. Stay away from the cheap ITT, Lindal, ElMenco, etc.

Sorry, had to throw it in!

holmesuser01 · #10 10-12-2012, 09:05 AM

Quote:

Originally Posted by TerrySmith

I'm into Hi-Fi, not an "audiophool", and the only stock build I ever did with a 6GH8 type was a Dynaco ST70. I repinned the 7199 sockets and rolled different types and settled on a Sylvania JAN 6U8/6678. Nowadays I duild my own driver circuit with a 6SL7 / 6SN7 combo. The 6AN8 is a different pinout!

One 6GH8 type is most likely as good or as bad as the others, use a top tier brand if possible. Stay away from the cheap ITT, Lindal, ElMenco, etc.

Sorry, had to throw it in!

I second the Lindal avoidance! I bought a case of 6GH8's from them for testing, and nearly all of them would short internally after an hour or so of use! I never had issues with the RCA built ones.

I just aquired a pair of Sarkes-Tarzian branded 7199's They are in my Dynaco ST-70. So far, so good.

init4fun · #11 10-12-2012, 09:08 AM

Edit l

mpatoray · #12 10-12-2012, 01:38 PM

Maybe he is listening to C-Quam AM Stereo with it!

DavGoodlin · #13 10-12-2012, 03:32 PM

C-quam LOL, I remember a local AM station selling AM stereo radios promoting the format.

Thanks for the Tip Terry on ITT Lindal and others. I got lots of those lurking all over my boxes and caddies.

ChrisW6ATV · #14 10-12-2012, 06:18 PM

The comments about "re-pinning" tubes gave me a question. I have a Tube Substitution Guide as was commonly published in the past, but have any of you known of a published or online guide/list of some of those "equivalent but with a different pinout"-type replacements? My CT-100 had a 6JE6 that had been modified and soldered into an octal base to replace the original (I think) 6CD6 horizontal output.

Mal Fuller · #15 10-12-2012, 09:44 PM

I always felt that Sylvania & GE manufactured 6GH8s were superior to RCA and Japanese manufactured versions.
EIA code 188-5 (GE - Owensboro KY) and EIA code 312 (Sylvania). Even RCA chose Sylvania made tubes for the critical color oscillator circuit. RCA branded tubes that were made by Sylvania use green ink for their envelope branding, instead of orange.