Gotta question. Got a Twin Reverb in for checkup/bias. Customer had already bought a new quartet of GT6L6CHP (black plate) aka;5881...all of this printed on
the tube..ha. I have adjusted bias and was double-checking this morn and in the dark test noticed a blue ring(top and bottom) on each of the tubes. Is this
normal for these tubes?....or should I be suspect for something else? Thanks, Rod
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Groove Tube 6L6CHP ?
| Author | Comment | ||
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 retrorod |
Groove Tube 6L6CHP ? |
Lead | |
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Posts: 16 (12/22/08 06:18) |
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EMan |
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Posts: 5198 (12/22/08 09:18) Hell Yes, I'm from Texas |
Any 'blue' glowing of tubes is pretty much normal, and isn't a indicator of something wrong.
It's just stray electrons hitting the envelope, and exciting impurities in the glass.
"I haven't failed, I've just found 10,000 ways that don't work."
- Thomas Edison - |
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 jbltwin1 |
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Posts: 153 (12/22/08 10:30) |
Blue=good,, Red=bad. ALTHOUGH, in my own little world, anything that says GT on it is suspect. NEVER had a set hold up. Yeah, I know, they sell a lot of them.
Just in my own little corner of the planet, they have NO reliability.
You want me to play WHERE?
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EMan |
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Posts: 5200 (12/22/08 17:18) Hell Yes, I'm from Texas |
Makes one wonder why FMIC chose that brand for their amps.
"I haven't failed, I've just found 10,000 ways that don't work."
- Thomas Edison - |
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retrorod |
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Posts: 17 (12/22/08 18:03) |
Thanks guys. The fact that FMIC chooses them is probably just a little 'sweetheart' deal to help GT sell more tubes for quicker replacement !?! |
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SG123 |
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Posts: 8013 (12/22/08 19:53) |
Fender OWNS the GT name now. "Aspen" sold out and retired.
I've also heard that many of the most knowledgeable folks weren't planning to make the move to the Fender stable. Not sure how it all shook out in the end.
So many
frequencies, so little time...
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EMan |
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Posts: 5201 (12/22/08 20:24) Hell Yes, I'm from Texas |
The point was that FMIC did not own them when they started using GTs.
So what was the original imputus.....cheap parts, or becasue they were a good product at a reasonable cost? Would FMIC 'take the hits' on amps for unreliability...or were they feeling good about their product.... ?
"I haven't failed, I've just found 10,000 ways that don't work."
- Thomas Edison - |
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jbltwin1 |
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Posts: 157 (12/23/08 10:34) |
It DOES make you wonder. I'm serious, I've never put a set in ANYTHING GT that they held up. I installed a set in a guys HRDX, biased it up a little on
the cool side and sent him out the door. Mind you, I cooked it for about four hours to let them settle in before I set it up. Called me back THE NEXT DAY-they
went up in smoke. Took a few resistors out and charcoaled up the one socket. THAT'S why I don't sell tubes. I make them bring their own. In this case,
he didn't ask first. Winged C and JJ's are pretty much the thing that works here.
You want me to play WHERE?
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Andy ZZ |
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Posts: 2432 (12/23/08 15:45) |
I have also had two Hot Rod series amps, that have had their plate load resistors blown open with GT 12ax7's in them.
I dont trust GT tubes, or Mesa's. Even when the GT's are clearly Sovtek relabeled, they must be rejects that didn't make the cut. -andy-
It aint the years, it's the mileage...
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EMan |
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Posts: 5202 (12/23/08 16:32) Hell Yes, I'm from Texas |
I've only had one set of GTs, and they were stock in the ( new ) HRDlx I bought back in '00 (?). Played the shite out of it, and never had any issues
with the tubes. Mayhaps, I got lucky with that one.
"I haven't failed, I've just found 10,000 ways that don't work."
- Thomas Edison - |
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retrorod |
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Posts: 18 (12/23/08 17:03) |
Very interesting info. There seems to be SO much hype when it comes to tube marketing these days. It helps to get some actual 'use experience' to cut
through the crap. It seems that 'back in the day' the main players actually made a great, long-lasting product....without all the hype. Rod
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SG123 |
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Posts: 8017 (12/23/08 20:24) |
My take on the reason Fender used GT was because they were the only ones at the time that could supply the quantity of homogeneous product they needed
with some QC pre-screening. I think they got tired of trying to source their own and label them "Fender" once GE, Sylvania/ECG/Philips and the others
closed shop.
I wonder why Fender at some point ('70s) suddenly felt the need to put their name on tubes. Leo didn't mind they said RCA, Mullard, Telefunken, Amperex, etc. [ I really know why - so they could sell "official" Fender replacements at a markup.]
So many
frequencies, so little time...
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jbmojo |
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Posts: 175 (12/24/08 04:29) |
Bob over at Eurotubes told me, years ago (90's), that GT was getting their tubes from JJ with GT logos on 'em. I don't think they are anymore,
though.
Ninty-nine percent of failures come from people who have the habit of making excuses.
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SG123 |
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Posts: 8019 (12/25/08 12:12) |
The suffix on G-T tubes is the key. EL84S, EL84R, etc..., 6L6C
"S" is from Slovakia [JJ]. The "R" suffix are Russian - from the New Sensor/Sovtek/Reflektor folks. "C" is China G-T has used everyone's tubes at different times throughout their history. They have contracted with different vendors to make a few of their own designs, and even assembled a repro of a GE 6L6GC using some parts from old stock material. As I recall, that may have been the only tube they actually manufactured here in the States. I lost my respect for them when they relabelled Russian 6L6 that didn't pass spec as 6V6-HD [ as in Heavy Duty ]. They're all about the marketing.
So many
frequencies, so little time...
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EMan |
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Posts: 5205 (12/25/08 19:33) Hell Yes, I'm from Texas |
"...and even assembled a repro of a GE 6L6GC using some parts from old stock material. As I recall, that may have been the only tube they actually
manufactured here in the States..."
SG - you have a pair of those in proto-type configuration. Did you ever plug them in to anything?
"I haven't failed, I've just found 10,000 ways that don't work."
- Thomas Edison - |
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SG123 |
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Posts: 8020 (12/25/08 20:47) |
Oh yeah - [ that's one of the reasons I mentioned them ] - got them from you. They're in the 6G6-B blonde Bassman. Sound really good, but I don't
use the amp a lot, so it's not a good candidate for longevity data. They'll probably last forever - for me.
So many
frequencies, so little time...
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- The Break Room
- Fender Amps
- Tech Bench
- Tubes
- Speakers
- The Instrument Room
- Mesa Amps
- Marshall Amps
- Small Amps
- Boutique Amps
- For Sale
- Other Major Amp Brands
- Introduce Yourself
- Solid State Amps
- Effects
- Other British Amps
- Sound Reinforcement
- Recording
- Important Announcements
- Hammond Organs & Leslie Cabinets
- Shameless Promotion
- The Boiler Room
