Deang Posted July 2, 2003 Share Posted July 2, 2003 This is a very good article. http://www.dc-daylight.ltd.uk/Valve-Audio-Interest/Articles-for-the-web/Ultra-linear-Hafler&Keroes/UL-H&K-Nov1951.html Quote Link to comment Share on other sites More sharing options...
Triode Pete Posted July 3, 2003 Share Posted July 3, 2003 I'd like to hear the amp! Pete Quote Link to comment Share on other sites More sharing options...
leok Posted July 3, 2003 Share Posted July 3, 2003 Dean, Very interesting. The amp looks almost exactly like the Heath W5M that I have completely rebuilt except that the Hafler/Keroes amp has a better phase splitter (critical). It turned out, as I tore the Heath apart I found numerous burned out and otherwise failed components, so it was obvious to me that I'd never really heard this amp as it was intended. Ultra-linear, with no feedback, is about 10 minutes worth of soldering .. I might give it a try. Thanks for the informative post. leok Quote Link to comment Share on other sites More sharing options...
NOSValves Posted July 3, 2003 Share Posted July 3, 2003 Ultra-linear, with no feedback, is about 10 minutes worth of soldering .. I might give it a try. Am I missing something here I sure see a feedback loop on that circuit. Craig Quote Link to comment Share on other sites More sharing options...
leok Posted July 3, 2003 Share Posted July 3, 2003 I wasn't trying to re-create the entire circuit, just refering to the ultra-linear part. There sems to be only a small increase in low level distortion, but large reduction in high level distortion. I think the first graph or two are simple tube/transformer circuits to show the value of the configuration. leok Quote Link to comment Share on other sites More sharing options...
Daddy Dee Posted July 3, 2003 Share Posted July 3, 2003 Dean, and others. I've got a Hafler 220 that I've been wondering what to do with. If there's somebody who would want to try this out, I'd sure be interested to discuss offering the amp and paying the cost of mods. Also, hope the builder would keep the amp for a season to enjoy their work. I could get it back whenever. That would be such a good deal for me, I hope no one would take offense that it may not be an actual win-win thing. However, I should add an additional disclaimer, without the skills to read a schematic, I don't know if this is a mod for a 220 or not. I sincerely appreciate the spirit of this forum in sharing the collective base of knowledge with folks who are rank lay persons in such. Maybe the forum should take Dean's suggestion of having a section of posts that are FAQ's. We could name it FAQ: Idiots Guide to Tubes or something. As always, best regards, Dee Quote Link to comment Share on other sites More sharing options...
Deang Posted July 3, 2003 Author Share Posted July 3, 2003 Silly me -- I thought the Dynacos used this circuit. What are the differences (generally, because anything too deep and I'm not going to get it). What is it about the original schematic/design that is "superior"? I now know leo's secret, he uses a propane torch to do his soldering! It would take me a couple of weeks to build that thing. Quote Link to comment Share on other sites More sharing options...
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