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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
ramtubes's avatar
ramtubes
460 posts
 
Ralhp,
 At least we agree that Paul was a good guy and liked to experiment with different things. 


bdp24's avatar
bdp24
9,816 posts
 

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!

clio09
3,355 posts
 
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.
georgehifi's avatar
georgehifi
10,312 posts
 
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 
bifwynne
2,206 posts
 
@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




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