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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Showing 4 responses by ffzz

@almarg 

Thanks again for your thorough explanation. As a big fan of SET amps, I am delighted to hear your experience of XA25. Should I ever endeavor into the ss world, it seems that XA25 would be the natural candidate to try out.


A couple tech questions for Roger. Others please chime in too.

Is it possible to estimate how much amp power will be enough (i.e. never clipping) simply based on speaker specs (assuming they are correct), and listening habit/situation (i.e. distance from speakers, loudness)? 

If so, how?
@almarg Many Thanks!

In your case, both your VAC and Pass amps are capable of producing 32w I presume. What gave XA25 an edge over the VAC amp with your speakers? Does XA25 have less distortion due to its class A operation in the first 25 watt?

My speakers are 93db sensitive (1w/1m) with 8 ohm impedance (7ohm min).

With a listening distance of 8 feet, it seems 15w will be more than enough to produce 100db or so loudness that Symphonic music peaks into from time to time.

Assuming 100db is my max need, will there be any advantage of using, say, a 30w amp rather than a 15w amp? What if the amp is class AB rather than A?