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Post by brando on Jan 26, 2007 17:34:18 GMT -7
I originally posted this in the Stingray section, but this is really a question for Z's non master volume amps... This has really peaked my interest, as I'm not a big fan of hauling a separate attenuator to gigs. The Suhr Badger has powerscaling built-in and I thought it was amazing sounding. I would seriously consider getting my 'Ray professionally modded with the London power box, but half-scared to death to introduce anything foreign with Doc's design. I would really love to hear your thoughts (especially DOC if you would chime in). Recent TGP discussion... www.thegearpage.net/board/showthread.php?t=203211&highlight=powerscalingLondonpower www.londonpower.com/kits/psbox.htm
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Post by DRZ on Jan 27, 2007 13:22:20 GMT -7
Hey Brando, I'm a little blurry from reading twenty pages of posts on Power Scaling from the TGP. Nice posts though, good info. But let me sum up my feelings about the subject.
First lots of attention will be drawn to this because of the release of Suhrs new amp with this feature.
Just let me say this and please don't read any sour grapes into my comments.
John designed the PS circuit into the IDEAL vehicle to carry it. A self biasing two EL-84 amp with no negative feedback. Don't think that it will be able to be used with such success in other amp platforms.
A well designed two EL-84 amp will sound excellent, no matter how it's created, look at any PV , Fender, VOX and Marshall Clone, or any of the THREE DR.Z 2 EL-84 amps, or any of the other dozens of amps based on 2-EL-84's.
The tubes have a natural musical sound and distortion, they are one of the few Output Tubes capable of generating gain, they are pentodes for nice tone detailing. They are currently made in pretty nice quality and at a very low price. I could go on and on about two EL-84' amps, jeez I based my company on my original amp now called the Carmen Ghia. Trust me the PS design will not work as easily in a Fixed Bias amp ( i.e. and adjustable grid biased Class A/B amp ). Were just lowering the plate voltage must also adjust the bias voltage along a dissipation curve for that particular tube, as tubes are not linear devices, fuzziness and tube clamping will result if drive signal exceeds bias level, hence the separate Drive control on the PS installed amps. Lower drive ( output tubes drive signal ) as you lower plate voltage to keep the total operation and distorted tones SMOOTH.
Also the pre-amp needed to be excluded from Power Scaling as excessive distortion ( i.e. MUDDY Tones ) prevailed. John did additional work to accomplish this on his design, so the PS isn't quite a Plug -N-Play device. Also the comments about it costing $50.00 I don't think so John, a license fee is paid , parts bought, marked up retail sales, additional Warranty dealings, and so on, more like $ 200.00 realistically.
And it was noted in the 20 pages of posts the a MAZ 18 JR. NR with it's Master Volume and $700.00 less price tag is more attractive to some .
So there you have it rant off. I think the PS has some merit, I believe it needs to be tailored to each amp design, a well designed Master Volume will get you 95% there in may amp designs, and it's usefulness is only truly noted in very low volume applications . But that's NOT ROCK-N-ROLL to me............
DR.Z
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Post by brando on Jan 27, 2007 14:58:57 GMT -7
Doc, Sorry to put your eyes through the HUGE Gear Page thread. For those of us who aren't technically inclined, it's great to have THE expert clear the air on the subject. Very big thanks for the informative response. (imaginary) karma for you! -Brandon
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Post by John on Jan 27, 2007 15:50:04 GMT -7
uh Doc.... THREE Dr. Z 2-EL84 amps? Ghia Maz Jr. What's the third? Something out of production and no longer on the website? Oh, and while I'm at it, WHAT ABOUT A STANGRAY JR?? Just knock off two of those EL84's and stick in an appropriate OT?? 30 watts in a cathode biased amp (especially with a pair of 100db Blues) with no master volume will blast me out of any club I play.
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Post by billyguitar on Jan 27, 2007 19:58:29 GMT -7
Gain ain't my thang but when I do want to scratch that itch at low volume my Maz 38's master volume does such a great job that I would have to believe the 95% there that the Doc states. For me it's 100% there. I can't conceive of it being done any better PS or not. If I was still doing rock bands my Maz 38 could've easily handled the Aerosmith, AC/DC and the Cars stuff we used to do.
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Post by ruger9 on Jan 28, 2007 13:23:15 GMT -7
Oh, and while I'm at it, WHAT ABOUT A STANGRAY JR?? Just knock off two of those EL84's and stick in an appropriate OT?? 30 watts in a cathode biased amp (especially with a pair of 100db Blues) with no master volume will blast me out of any club I play. And while you're busy removing tubes, take a couple out of the RxES as well, will ya?
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Post by mward on Jan 28, 2007 15:01:45 GMT -7
This has really peaked my interest, as I'm not a big fan of hauling a separate attenuator to gigs. If having another piece of equipment to haul to gigs really bothered you you could mount the airbrake inside the cabinet or on the back of it. It's not THAT big. Don't know if that's an approved mounting but I can't conceive that it'd hurt it. It's built like the brick house.
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Post by Jim @94 Amps on Jan 28, 2007 16:01:45 GMT -7
"THREE Dr. Z 2-EL84 amps?"
Ghia Maz Jr. Maz Jr. NR
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Post by ruger9 on Feb 1, 2007 4:52:48 GMT -7
A related question:
Alot of comparisons between a "good master voulme" and power scaling, been reading up a little on post phase inverter MVs (which are supposed to be the "good" ones, I guess?) ...
And i know alot of people rave about the Doc's MV circuits & how well they work, SO... curious, are Z's MVs PPIMVs?
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jesse
New Member
Posts: 34
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Post by jesse on Feb 1, 2007 12:19:51 GMT -7
Oh, and while I'm at it, WHAT ABOUT A STANGRAY JR?? Just knock off two of those EL84's and stick in an appropriate OT?? 30 watts in a cathode biased amp (especially with a pair of 100db Blues) with no master volume will blast me out of any club I play. And while you're busy removing tubes, take a couple out of the RxES as well, will ya? You know, I would have agreed with that a while back, but I'm moved by Z's comment about ROCK-N-ROLL. Maybe Z's are meant for stages. I've been using the RxES flat out at gigs and it's just about right for a mid-size bar. (With my style of music.)
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