dirtmudd Posted November 26, 2017 Share Posted November 26, 2017 On 10/22/2017 at 9:01 PM, theoman said: I blew out my diaphragms on my horns in my Altecs and replaced them with the ones from china. is there much difference in the US models? https://greatplainsaudio.com Quote Link to comment Share on other sites More sharing options...
erik2A3 Posted December 28, 2017 Share Posted December 28, 2017 Moth Audio kits: Bruce, Moth Audio did not sell kit versions of their products. We (specifically my wife) contacted Craig U. to make an offer for the Si 2A3 in the form of an unassembled and unwired parts package, including output transformers, power transformer, and all passive parts and hardware (including chassis and custom wooden shipping crate) to build the amp. I already had an assortment of driver and output tubes to choose from. And that's what he agreed to sell us, based on the understanding that I can read schematics and know how to build. The regulated DC filament supply on the output stage doesn't use hum null pots; however, I have converted the 2A3 heaters to AC, balanced with pots for minimal hum. Even with AC on directly heated triodes, it's still a fairly quiet amp in terms of 60 cycle hum. I just prefer the sound of AC over DC filaments, which is probably also partly related to the fact that I simply also prefer that more historically traditional approach (such as a grounded center-tapped filament transformer, etc.) The zero-cap-in-signal-path design was inspired, as he explained to me, by an amp designed by his dad. I am responding here for clarification. erik 1 Quote Link to comment Share on other sites More sharing options...
Marvel Posted December 30, 2017 Share Posted December 30, 2017 @erik2A3 Thanks Erik... I tried finding your old posts but was searching using my phone and just not coming up with anything. I hope you are doing well. I've got my Moondogs out for diagnosis/repair, too crowded under the there. The magic smoke got out of one, and I don't feel confident figuring it out. Bruce Quote Link to comment Share on other sites More sharing options...
erik2A3 Posted December 30, 2017 Share Posted December 30, 2017 Hey Bruce, Absolutely. I couldn't find my old posts on this either, and decided I was probably going about it the wrong way...or something along those lines, and gave up. It's great you still have your old Moondogs! They are such great amps! I agree they are a bit busy under the hood as originally designed. That's of course NOT a reflection of the efficacy of the circuit, itself, but rather related to the fact that it enabled the kit builder to more easily keep track of what's what during construction - despite the fact that each mono block subsequently used a bit more hook up wire to and from the terminal boards than if caps and resistors (etc.) were wired directly to tube pins and other terminal points. That puff of smoke should be really easy to track down and fix; I'm sure they'll be howling at the moon again very soon! I rebuilt my own pair around 300Bs, but was just thinking the other day that 'llI put the separate 2.5V filament transformers back in for 2A3 use. When I bought mine, Welborne Labs and Lowther America had gotten together to sell a large kit package for a significantly lower cost. It consisted of the pair of Moondog kits, very large, back-loaded horn enclosures (unbuilt flat pack), and Lowther PM2A drivers. Maybe I imagined this Bruce, but do you no longer have your La Scala? Am I thinking of someone else, maybe? Hope you and your family are well, too. After a 3rd major back surgery and move from Houston to AZ last year, things are getting better. I also had four separate surgeries on my hips to repair torn cartilage (that's what running on concrete got me), but have been once again been able to do some hiking. Very thankful! erik Quote Link to comment Share on other sites More sharing options...
Marvel Posted January 6, 2018 Share Posted January 6, 2018 I sold my first pair of LS to Dean, but found some cabs for $100. I still had the crossovers I built, added other parts. It's been three years, but not quite done with them. I'm doing Dennis' bass mod. I have no workshop or garage, so it's been slow. I've said it often, but soon... I will be listening again. Just had the Heresy IIs and JBL 4311s for the past three years, but that's ok. Been too busy to sit and listen much anyway. The getting older can be rough, but at 68 I find myself in pretty good health. Here's the wife and I at a wedding this past Dec. Bruce 2 Quote Link to comment Share on other sites More sharing options...
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