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Topic: THD Univalve |
Keith Cordell
From:
San Diego
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Posted 10 Oct 2007 11:20 am |
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I got one of these today in a trade, and was pretty skeptical; I have read reviews complaining of harsh, brittle tones that were unmanageable. I can't stand solid state amps for that very reason.
The trade went ahead as the values worked out so that if I didn't like it, I could recoup the funds. I used an open backed Mesa 1X12 cabinet, with a Black Shadow speaker. It had a GT EL34 and 2 12AX7EH preamp tubes when I got it. One of the great features of this amp is that you can change out the power tubes with no biasing needed. I had a blackplate 6L6GC sitting in a drawer, as well as an RCA Blackplate 12AX7 and a 12AT7. I installed these tubes and let the amp warm up for about 20 minutes.
I play lap steel exclusively, and I currently have a Loney labeled Supro Supreme. The guitar has a particularly strong pickup. With no effects in the signal, I cranked it up.
The EL34 was a bit grindy and harsh, a bit too tight. The 6l6 completely solved this issue, loosening up the bottom a little and making the notes more distinct and accurate. The "rock" input was overly gainy, so I used the "roll" input and dimed the knobs. Nirvana! This is a very Lindleyesque tone, though I tend to keep it a little cleaner.
One disadvantage to this amp is the lack of an effects loop. I use a Deluxe Memory Man, MXR Flanger and a vintage white label Proco Rat. The difference in the amplified signal was most evident when I cut in the Memory Man; the overdrive on the repeats were as sweet as any I've ever heard. I was shocked at the difference. The Flanger sounds more direct and cutting, and the Rat (gain almost at 0 and volume cranked for a clean boost) was what I expected. I doubt I will ever use the attenuator, as it is a 15 watt amp and really doesn't need it, especially in the low gain input.
All in all, the amp has a great tone, though the high gain input is effectively useless for me. The lack of a loop is a pain, but I can live with that. The flexibility of changing tubes is extremely useful, and along with the other tone features I'd say this one is a keeper. |
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Olli Haavisto
From:
Jarvenpaa,Finland
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Posted 10 Oct 2007 11:49 am
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I have one and I`ve been thinking of taming the rock input a little. Has anybody done that ? Using an 12AU7 or 12AT7 as the first preamp tube helps a bit but an overall decrease of gain would be better...
Keith, an EL 84 sounds wonderful on the Univalve,instant Bluesbreakers/Beano tone with a Les Paul !
_________________
Olli Haavisto
Finland
Last edited by Olli Haavisto on 10 Oct 2007 12:00 pm; edited 1 time in total |
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Dan Tyack
From:
Olympia, WA USA
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Posted 10 Oct 2007 11:57 am
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I own a couple of these plus a BiValve and a prototype for THD's next amp (a very sweet EL84 based combo). I actually own the first Univalve prototype that Andy Marshall built 4-5 years before they hit the market.
The roll input is more usable (IMHO) for steel with an AT7 or AU7. SOmetimes I use a low gain ax7 (I forget the make of this). I have one of these in a combo which is my current main amp. If I need to be louder, I use the line out and power another speaker with a cheapo Crate power amp (the powerblock).
I can't say enough praise for the THD 2X12" cabinet. It is by far the best sounding speaker cab for guitar or steel I've ever heard. It has a FAT low end with all the clarity and open-ness of an open back cab. |
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Dan Tyack
From:
Olympia, WA USA
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Posted 10 Oct 2007 12:08 pm
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Oh yeah, if you like the Univalve, you'll love the BiValve. It has an exf loop, it has a bright switch (the Univalve has the bright eq always on), and the two output tubes enable getting some of the fattest sounds you can imagine. I like matching an old, soft TungSol 5881 with a new KT88. It almost sounds '3 dimensional'.
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www.tyack.com
Capetown girls sing this wrong: "da doo, da doo" |
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Keith Cordell
From:
San Diego
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Posted 10 Oct 2007 3:18 pm
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| Good thought Dan, but I could barely manage to afford this one. As far as the tubes are concerned I was thinking about getting a good KT88 but I am unfamiliar with the better brands and vintages. |
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Keith Cordell
From:
San Diego
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Posted 10 Oct 2007 3:19 pm
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| BTW I put a blackplate 12AT7 in and it did have a great effect on the gain stage. |
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Rick Abbott
From:
Indiana, USA
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Posted 10 Oct 2007 6:01 pm
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5751? pre-amp tube for the lower gain ax7?
_________________
RICK ABBOTT
Sho~Bud D-10 Professional #7962
Remington T-8, Sehy #112
1975 Peavey Pacer 1963 Gibson Falcon |
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Rick Abbott
From:
Indiana, USA
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Posted 10 Oct 2007 6:31 pm
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5751? pre-amp tube for the lower gain ax7?
What the....? Must have hit a wrong button!
_________________
RICK ABBOTT
Sho~Bud D-10 Professional #7962
Remington T-8, Sehy #112
1975 Peavey Pacer 1963 Gibson Falcon |
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Dan Tyack
From:
Olympia, WA USA
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Posted 10 Oct 2007 8:57 pm
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| Rick, I think that's what I'm using in the Univalve. |
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T. C. Furlong
From:
Lake County, Illinois, USA
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Posted 12 Oct 2007 2:38 pm
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Dan, do you have any experience with a THD Flexi-50?I got one in a trade a while back. It is a really sweet head and sounds to me like it is voiced for electric guitar.
TC |
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Jim Sliff
From:
Lawndale California, USA
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Posted 12 Oct 2007 6:19 pm
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| Quote: |
| The lack of a loop is a pain, but I can live with that. |
Welcome to the world of tube amps.
I've never used a loop even when I had one, and none of my current amps have one. All the warm stage tones of the 60'/70's were done without effects loops (in the studio most time-based effects being added at the board or in remix).
I've just never had any problem - signal loss, excessive noise, etc. - running evverything into the front end.
Regarding preamp tubes - 5751's are a good lower-gain sub for the 12AX7. The 12AY7 is also excellent, and is the tube used in almost all early (tweed) Fenders (12AV7's are a little less common but also often nice tubes, very close in specs to the 12AY7). The 12AU7 likes some amps and not others, as it has quite a bit less gain, but I like the nice warm soud when running clean and turning up the power section in some amps - in others it just does not have enough punch.
OTOH, generally most 6-stringer tube amp jockeys (and tube sellers) will not recommend 12AT7's as preamp tubes. The make good oscillators for tremolo and excellent phase inverter (or driver) tubes, but as a rule tend to be pretty harsh sounding when used in audio circuits (i.e. carrying the actual guitar signal). There are a few exceptions - some high-end NOS ones like Bugle Boys sometimes work out fine, but most day-to-day current production 12AT7's just have a nasty, ratty bite to them when used as the first preamp tube (especially when hit with a boost or distortion pedal).
_________________
No chops, but great tone
1930's/40's Rickenbacher/Rickenbacker 6&8 string lap steels
1921 Weissenborn Style 2; Hilo&Schireson hollownecks
Appalachian, Regal & Dobro squarenecks
1959 Fender 400 9+2 B6;1960's Fender 800 3+3+2; 1948 Fender Dual-8 Professional |
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Keith Cordell
From:
San Diego
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Posted 13 Oct 2007 8:27 am
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| I have the RCA black plate 12AT7 in there now, and it could be better; I would love to try a KT88 or KT77 if anyone has one they could be persuaded to sell or trade for the power tube. I have a blackplate 6L6 and an old 6V6 that tests to 85%;the 6V6 gets the vote for my style of playing- very crystalline cleans and when I engage my Rat it gives the overdrive a really distinct tone. |
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Dan Tyack
From:
Olympia, WA USA
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Posted 13 Oct 2007 9:10 am
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Keith I actually am not a huge fan of the KT88 by itself. They sound great in the BiValve in conjunction with a 6L6.
I actually never use my efx loop. Most of the efx one might put in the loop would be time based effects (reverb, echo), but IMHO the efx loop doesn't help that much because it's still before the power amp section. I just don't like the sound of reverb before the driven power amp section.
If you don't mind hauling extra equipment around, you can take the line out of the THD, and use one of the other amps that are sitting in your garage and use it for a 'wet only' amp. It doesn't need to be a great sounding amp, because most of the sound will come from the THD.
_________________
www.tyack.com
Capetown girls sing this wrong: "da doo, da doo" |
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Keith Cordell
From:
San Diego
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Posted 13 Oct 2007 9:20 am
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Other amps? Where? The only thing in my garage are old clothes and furniture...
I only really use an effects loop for my Deluxe Memory Man. For some reason it just has a better sound there; I can use it without a loop though, it still sounds pretty incredible. |
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