Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: JustMike on July 27, 2021, 08:19:31 am
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Somebody wants to sell me an unopened tube of 4 GT EL34's from 1986. I don't know if there's any way of telling who the OEM is. He says they're rated 3-4 which he also says was desireable. He wants $100 for the quad which I think is a decent price for a quad of any EL34's. Just wondering if the "vintage" of these is a premium.
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Without knowing which OEM was the supplier, I'd say this is not a bargain.
New low end EL34 can be had for $15, with new mid-grade tubes less than $25 (quick peak at AES).
I frankly don't know what "rated 3-4" means. So what if they are from 1986? Does anyone remember anything great from that year?
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acheld Grove Tubes (GT) rate their tubes according to current draw at idle, going from 1 to 10 - Cold to Hot. So the 3-4 would put these on the mild side.
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Grove Tubes (GT) rate their tubes according to current draw at idle, going from 1 to 10 - Cold to Hot.
Oh, you're absolutely right. I'd forgotten that fact -- it's really just a method of "matching" tubes so that you don't have to re-bias when you're replacing tubes. So said the Fender dealer to me some years ago.
I have nothing against Groove Tubes -- they seem fine in my limited experience. I just doubt that $100 for a quad of 1986 EL34s (without a guarantee I would guess) is a good deal. Maybe I'm wrong . . .
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acheld Grove Tubes (GT) rate their tubes according to current draw at idle, going from 1 to 10 - Cold to Hot. So the 3-4 would put these on the mild side.
GT also says that 3,4 number is the "hardness of the tube" (whatever that means?) with 10 having the most headroom and 1 early break-up. So they say at Groove Tubes.
For what it's worth, GT's in the eighties matched American made tubes with their red logo, such as GE, etc. I have a set of GT 6L6's I got back in that time and you can clearly see GE markings on the tubes along with the GT's red logo, tubes are excellent sounding, matched well. I don't think GT's erased the manufactures identification markings, so if no other markings but red, probably a Chinese tubes or the like. I'd pass.
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They’re worth looking into, might be relabelled Siemens or Tesla.
But are they 3 or 4 rated, can’t see how they can be both; maybe one pair ‘3’, another ‘4’?
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You’re correct, GT’s only has one digit.
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They're all rated "S4". And in the pic I see GT-EL34C.
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They're all rated "S4". And in the pic I see GT-EL34C.
Ah..., C stands for China in most cases. Not worth $100
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Deservedly or not, Chinese valves had a rather bad rep back then.
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The 4 rating means that the tubes will start to distort sooner when turning the amp up than a higher number. Also, the distortion is supposed to be less harsh than the higher number tubes. Back then, the metal bands were using the high number tubes for that hard edged distortion that came from the high number tubes.
The #4 rated tubes would probably give you a more blues sounding distortion...
Back in the early 1990s, I had a quad of #7 rated 6L6s in my Fender Bassman 100 because they didn't break up as easily as some of the other tubes that I had used. I wanted a set of #8s, but I couldn't afford to buy them at the time.