MAC Autoformers?


Someone is selling a MAC MA6500 Integrated claiming its superiority over the Ma6600 due to the fact that "it does not have the degrading autoformer design found in the MA6600". That is the first time I've heard a claim that the autoformer was a hindrance to better performance; I thought quite the opposite. What do you MAC Maves think?
pubul57

I posted this on the thread Roger (ramtubes) started to discuss transformers, but thought I would do it here as well.

Roger gave a 90 minute talk on tube amp design at the 2015 Burning Amp Festival. If you own a tube amp, or are thinking of getting one, you will be glad you watched the video. The video is on You Tube, but also on the Berkeley Hi Fi School website.

Go to "berkeleyhifischool.com" and put your browser over "RESOURCES". A drop-down screen will appear---click on "VIDEOS". On the right hand side of the page is a row of "ARCHIVES". Click on October 2015, and the video will appear. Prepare to learn a lot!

Paul was awesome. I had the pleasure at hanging out with him at RMAF several years ago. We met in Bobby P.’s room as Paul was a Merlin owner. It was there that I mentioned to him the Lightspeed and he bought it soon thereafter. In addition to the 9SE, Paul also loved his RM-10 and used the Lightspeed with that amp as well. I can't be certain but I have owned my Lightspeed for around 9 or 10 years.
I can't be certain but I have owned my Lightspeed for around 9 or 10 years.

Wow I think your right, the MkII, was released around 2006 when all MkI's were recalled and converted.
I think it's time for a MkIII, what do you think Anthony? Upset the active preamp brigade some more?

Cheers George 
@bdp24 

I checked out the Roger Modjeski YouTube video.  Awesome.  I've often observed that there are 3 types of smart people in the world, namely:  regular smart; very smart; and scary smart.  Roger is scary smart and down to earth at the same time.  

I think he might have tossed a tongue in cheek zinger at ARC.  Roger snickered that expensive ARC power tubes need to be replaced every 2000 hours.  In contrast, Roger said his early tube amps (RM-9 ??) could run their power tubes for years.  

Not being a EE, I can't say whether tube life in ARC amps is good, bad or neutral.  But I can tell you that ARC charges $200 for a single KT-150 tube.  My ARC Ref 150 SE takes two quads (8 tubes) -- for a total cost of $1,600.  Ouch!  I should mention that while I can buy the KT-150s from well know tube vendors for half that price, I have had problems getting closely matched pairs from one well know vendor.  

If Ralph (Atmasphere) picks this post up, ... what is the tube life is in your amps.  Btw Ralph, …. Roger mentioned a couple of times that negative feedback, *if used properly*, is not all that bad a design feature.  Not taking a position, just passing along what RM said.

BIF




I know BIF, Roger doesn’t look any different than a regular guy, but damn! It’s humbling to listen to him talk about amplifier design; I wonder how anyone can have so much knowledge in a normal-sized head. I talked to Bill Johnson a few times, and to Tim de Paravicini (EAR-Yoshino), David Manley, Keith Herron, Ralph Karsten, Frank Van Alstine, Max Townshend, and numerous other really good Hi-Fi engineers. They are all very interesting of course, but I have the distinct impression that Roger Modjeski understands amplifier design as well as any human in history. That he and his products aren’t more well known and widely owned actually doesn’t surprise me any more than the fact that most of my favorite music is made by artists known to only the hardest-core music lovers, like we here on AudiogoN.

The late Brooks Berdan was my Hi-Fi dealer for many years. He sold me Hi-Fi, I sold him vintage drums. He was a Music Reference dealer, and loved Roger and his amps. He told me his wealthier clients would pass up MR products because they didn’t cost enough (no bragging rights), or weren’t being reviewed or talked about enough in TAS and Stereophile, didn’t have the High End cashe’ of ARC, VTL, Jadis (Brooks sold a lot of Jadis), etc. Brooks had a LOT of used ARC amps in his pre-owned racks, their owners tired of the breakdowns, repairs, frequent tube replacement, updates, etc. His tech Tom Carione showed me all the burned circuit boards in the ARC amps he had repaired every time a tube blew. He had never seen a Music Reference amp come back for repairs---never. That’s my kinda amp!---Eric.