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Vintage threads from the first ten years

Hiwatt

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4/28/2003 7:01 PM
Ben N	Hiwatt Can someone explain how V3b (V3a is the post-MV gain stage) in the classic DR103/504 preamp works, and what is the difference, in sound or utility, between the original use of that stage as a cf, and its use in most permutations of this amp, which I do not get. Thanks, Ben

4/29/2003 4:25 PM
Ben N	No Hiwatt mavens? Then how 'bout a suggestion for a book? I know TUT I doesn't deal with this, maybe there is something else. Thanks, Ben

4/29/2003 4:55 PM
Chris ( CMW amps )	Re: Hiwatt Hi Ben Sorry I can't help you with that , still haven't figured it out myself . But ..... they're GREAT amplifiers , did play an early 70s one ; very punchy , tight & dynamic amp . Great OT too ! Chris

4/29/2003 8:49 PM

Chris:
Thanks for the response. Hey, if you haven't figured it out, I don't feel like such a dummy. Yeah, I think that incredible Live at Leeds tone is IT--incredible articulation and power.

I would like to get close to that with my Traynor YSR-1, which already shows promise, although it is a little bit loose and get flubby in the bass when you turn it up, especially with humbuckers. No Partridge trannies, but it does have those big Hammonds that are considered indestructible. I'm thinking that some simple steps will definitely help: tightening up the power supply with bigger caps and maybe a choke, like the original '60s YSR-1; putting a lower gain tube in the PI instead of the 12AX7; replacing the 4M volume pots with 1M is also supposed to tighten things up, although I don't quite understand why.

Then there are the other things I don't understand, and/or that involve more surgery. The pre-PI stage is one of them, although I can certainly appreciate the extra gain after a lossy tone stack, like the Traynor's. I don't love the Traynor's tremolo much, so I can either try to improve it, or recycle the tube a la Hiwatt, with MV and presence controls instead of speed & intensity. I think Kevin O'Connor has posted a mod like this somewhere.

Besides that strange non-cf, I'm also wondering about the channel mixing. Why does the Traynor have the mixing C+R (.1/100k) on the plates of V2, instead of just hooking them together like the Hiwatt? Can I lose them, and will this be beneficial?

Last, I think, would be putting MOSFET source followers on the power tube grids--this is supposed to kill all flubbiness, right? But I'm pretty intimidated about the power supply aspects of this.

4/30/2003 1:23 AM
jbrew73	that section is a voltage source to bias the PI sort of a voltage regulator to control the bias by applying DC to the grid of the PI

4/30/2003 2:50 AM
Ben N	Hey, Jbrew, thanks. i never heard of something like that in a triode--can you explain what the advantage is over the usual plate-biasing? Does it have anything to do with that special Hiwatt killer sound? Thanks, Ben

5/1/2003 3:30 AM
Richie{~}==:::	Ben You might go over to Mark Huss page.. hes got one of the best hiwatt pages,and owns a hiwatt along with many other amps... He visits here too sometimes.. Or shoot him an e-mail from his page.. hes helped many people over on our 18 forum.. http://mhuss.com/ Richie

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