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Post by brando on Jan 26, 2007 11:07:56 GMT -7
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 Hohn on Jan 28, 2007 16:52:58 GMT -7
A separate attenuator like a Hot Plate isn't much of a carry burden, IYAM.
I also wouldn't be inclined to mess with Doc's designs.
I think the Ray would benefit least from power scaling because it's such a clean amp. It also happens to sound really good even at low volume levels, so it's probably not the best amp for this type of mod.
I can see how this might be a good option for a different amp design, though.
jh
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Post by brando on Jan 28, 2007 19:45:16 GMT -7
It's not really that much of a hassle I know. Just wanted to investigate the technology. There was NO WAY I would do something that evasive without the Doc's consent. Sounds like a surgery analogy. Actually Doc gave me a terrific answer about this in the Ask the Experts section. Here's his answer... 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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