Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Backwoods Joe on June 22, 2010, 09:38:22 pm
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Anybody have any general opinions about how 7027's compare to others (EL34, 6L6, etc) sonically? thx, joe
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I'm speaking from experience in terms of what I heard and did in the 1970s. I'll sum it all up as best I could and as short as I could.
The EL-34 was a great sounding tube with more warmth, a smooth high end and good raunchy sound when driven. The 6L6GC which was cleaner and brighter had more body and a kind of scooped mid compared to the EL-34. i tried the 6L6GC in a 50 watt and it was cool, like Fender meets Marshall.
A lot of guys here used V-4s and to me they sounded like someone breaking a glass with every note. Not a real pleasant sound at all. I had a 100 Watt Marshall that I brought to Denny Kager in about 1975 to mod and he really ruined it by putting in the 7027 tubes, that was his big mod....I wanted to go back and well ya know. I just sold the amp. So I am NOT a big fan of 7027s I never heard a guitar amp sound good with them, a lot of guys were using Ampegs around here of all kinds with those tubes and their tone was horrible. Although they seemed pretty good for bass. They just sound horrible to me but these were tubes from 1970 so I can't tell you how the new ones sound or even if they are truly 7027s.
If it's for a clone or new build there are so many other tubes that blow that away in that class, I think the JJ KT-77 is similar and sounded great in one of my SE creations. If it's for one of those Ampegs and you want to bring it back to spec that's another story. Just my opinion.
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The 7027A is essentially a hard vacuum 6L6GC and will sound similar, though it does have a different pinout. Check out this link for more info on it.
http://www.triodeel.com/7027.htm
Greg
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It didn't sound anything like a 6L6GC to me.......nothing like one. Like I said just my opinion from experience.
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The 7027A is essentially a hard vacuum 6L6GC and will sound similar, though it does have a different pinout.
Same pumping process, usually the same innards - some 7027A have a top set of fins acting as screen heatsink while the 6L6GC from the same period/brand/factory won't.
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I think the 7027As, at least in Ampegs, were running at higher voltage.
That could explain part of the difference from a 6L6 sound.
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Thanks guys, I remember the old ampegs with 7027's of the 70's myself....HARSH. I was just wondering if anybody had used them in something else with good results. Electrically they look similar to the 6L6 and that's not my fav tube either.
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My son uses them, 2 PP pairs, used old stock, in a vintage Stromberg Carlson Stereo 60 amp (ASR-444) which I rebuilt for him. The amp sounds fantastic, but note that the 7027's are run @ only 430VDC on the plates and are cathode biased.
I have a pair of used old stock 7027's in my Ampeg V4 (I pulled 2 of the 4 tubes) and love them. The amp arrived with 4X Groove Tube 6L6's which I detested -- talk about harsh; though the Groove Tubes sound great in my Ampeg RI Reverberocket, to my surprise. Anyway, I'm a fan of used old stock tubes. Nothing against NOS except the price.