2. amps-preamps
  3. 140029-80294

Does anyone care to ask an amplifier designer a technical question? My door is open.

I closed the cable and fuse thread because the trolls were making a mess of things. I hope they dont find me here.

I design Tube and Solid State power amps and preamps for Music Reference. I have a degree in Electrical Engineering, have trained my ears keenly to hear frequency response differences, distortion and pretty good at guessing SPL. Ive spent 40 years doing that as a tech, store owner, and designer.
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Perhaps someone would like to ask a question about how one designs a successfull amplifier? What determines damping factor and what damping factor does besides damping the woofer. There is an entirely different, I feel better way to look at damping and call it Regulation , which is 1/damping.

I like to tell true stories of my experience with others in this industry.

I have started a school which you can visit at http://berkeleyhifischool.com/ There you can see some of my presentations.

On YouTube go to the Music Reference channel to see how to design and build your own tube linestage. The series has over 200,000 views. You have to hit the video tab to see all.

I am not here to advertise for MR. Soon I will be making and posting more videos on YouTube. I don’t make any money off the videos, I just want to share knowledge and I hope others will share knowledge. Asking a good question is actually a display of your knowledge because you know enough to formulate a decent question.

Starting in January I plan to make these videos and post them on the HiFi school site and hosted on a new YouTube channel belonging to the school.


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analogluvr
859 posts
 
@unrecievedogma I also have settled on a remarkably similar system. I use Altec 604E’s  run full range from a pair of atmosphere M60s.  Then off of a second Output  on my preamp I run a dahlquist crossover to a pair of 12 inch subs.  I usually have it set at about 60 hz. 
 I also have a pair of fostex T 900 super tweeters augmenting the top end. 
 I have owned a lot of gear including high end Tannoy‘s, apogee Divas, reference 3a grand veenas.  I find this to be the most enjoyable and best for me. No plans on changing anything. 
 When I go to the shows I find my rig to sound better than pretty much everything there, to me. 
unreceivedogma's avatar
unreceivedogma
984 posts
 
analogluvr,

I’ve been curious about the Atmospheres.

I have a 3 disc LP set of Theodorakis’s “Canto General” that Atmosphere produced, and I found the engineering to be disappointing. It has been muddy, and there has been no bass to speak of. I have yet to listen to it in the new environment with the sub. Maybe it will sound better.

As for setup, I run the signal through the preamp, then into the Velodyne servo, which splits the signal and sends above 70 to the Futtermans and below 70 to a 300 watt ss amp within the servo and then to the sub, which is also connected to the servo by another line that as I believe they say in their literature “digitally corrects for phasing” in order to reduce distortion from that source.

By cutting off the signal to the Altecs below 70, it gives them much less work to do and they sound clearer.

When I go to shows, the way I would put it is that I almost never hear anything that I would prefer, and never ever hear anything that I would prefer that’s within 300% of what I have spent on my system.

Nice to meet you. It’s nice to know that there is somebody out there who thinks and hears similarly. By hearing, I mean that my ears, from an early age, grew accustomed - maybe trained is the word - to hearing audio a certain way. My system no doubt sounds very colored to many, but it suits me fine.
fsonicsmith's avatar
fsonicsmith
962 posts
 
Roger, I have two questions though the second is a doozy. 

1) What do you think of the Tungsol KT150?

2) What are your top 5 criticisms of the ARC Ref series components (i.e. the Ref 75SE or Ref 150SE amp and the Ref 6 preamp)?

I ask because I own and am proud to own the Ref 150SE and Ref 6 and more importantly, they deliver untempered joy and because while you said some negative things about Bill Johnson, you passed over the fact that Ward Fiebiger was the mind behind the latest designs. 


ramtubes's avatar
ramtubes OP
460 posts
 
@russellstone

Hi. I was turned off tubes when a Mac 2275 couldn’t properly drive my ML Summit X’s (yep, ‘soft’ bass’). After some searching I found an Accuphase E-600 matched beautifully. My question is: how can Accuphase make a class A amp that runs cooler than many A/B amps, and substantially cooler than other class A amps that can give you serious burns when touched?


The Mac could not handle the low impedance. The Accuphase has lots of current. I looked it up, its 30 watts at 8 ohms, therefore low voltage supplies. A 30 watt class A amp can run cool, but not a 100 watt Class A. thats the difference. 

Here is a great example where 30 watts at 8 ohms is better than 75 watts from the Mac. Did you try the 4 ohm taps on the Mac? 
ramtubes's avatar
ramtubes OP
460 posts
 
Is there a particular Direct Drive Amp you can recommend to drive the panels? (Again I’m in a 240V 50Hz country).


I dont know of anyone making DD amps but myself. It a rather special thing.

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