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.


128x128ramtubes
lightfighter2018
75 posts
 
I hope this question is appropriate for this thread.  

In comparing 'only' power supply VA ratings - can one judge the capability of an amp to drive a set of speakers when all other specifications are the same except the number of channels including the power supply?

Real world example:

I am comparing a 5ch and 7ch amp.  Same brand and specs exactly the same except for one difference -- one is a 5ch and the other a 7ch.  Same rating of Tor power supply ( 2 total valued at 1,230VA and 1,025VA)

All things being equal - will sound quality be relatively the same?  Dynamics? ... or is one better than the other?

Also -- ideally how big of a power supply is best suited for an amp rated at 200wpc at 8ohms driving speakers that dip to low 3ohms?

Thx in advance.

fleschler
766 posts
 
ramtubes   I poorly wrote that line about the EAR 912-  My pre-amp has subminiature tubes rated for 100,000 hours, the EAR 912 can use 7DJ8s or 6DJ8s rated for 10,000 hours as you stated.  My old EAR 864 NOS 12AX7s and 12AU7s only lasted about 3,000 hours before replacement.  However the EAR Acute has 6DJ8s at over 7,000 hours and going strong.  Depends on the tube and design of course.  My Audio Research gear back in the 90s had power tubes last about 2,000 hours or less, not really good but better than my Dynaco IIIs which lasted about 9 months, 1,000 hours or less.
grannyring's avatar
grannyring
4,637 posts
 
I would look into Electra-Print output trannys and talk with Jack.  Nice output trannys for sure. 
utrak
12 posts
 
Thanks grannyring.  I'll check those out and talk to Jack.
utrak
12 posts
 
I've got another question for the tube amp designers.  Does it matter whether the filament supply is AC or DC?  I've heard arguments both ways.  I think that it would be great if one could get away with an AC filament supply because it requires less current from the power transformer and reduces cost to build.

Thanks  
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