2. amps-preamps
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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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almarg
9,670 posts
 
I have no particular question to ask at this time, Roger, but I want to take the opportunity to express my appreciation for your participation here. As with Ralph (Atmasphere) and a few other audio designers who participate here at least occasionally, I always follow your posts with interest, and I have learned from them. And I’ve learned from them even though I have BSEE and MSEE degrees myself, from excellent schools, as well as 33 years experience designing and managing design of sophisticated analog and digital circuits (not for audio), and nearly 40 years of experience as an audiophile.

Thank you, and best regards,
-- Al
nonoise's avatar
nonoise
10,616 posts
 
Even though I disagree with you on the efficacy of some things, like power cords and fuses, welcome. It's too bad you had to shut down the other thread but it was getting out of hand.

All the best,
Nonoise
ramtubes's avatar
ramtubes OP
460 posts
 
@mrdecibel

I will be the first. I never owned an amp of yours. I have owned other tube amps by several other manufacturers. I gave up on them, and this has been through a pair of modified and tweek’d pair of Klipsch Lascala. Why did I give up on them ? Noise, microphoncs, pretty often biasing, warm up time ( I leave ss amps continuously because of the superior sq ). and " timing " in the bass ( muddy ). I go passive through a Dac. Should I try an amp of yours, and why ? I listen loudly to rock and jazz. Thank you... Enjoy ! MrD.


First I’m not using this post to sell amplifiers, that is up to you. However I can understand and appreciate your frustration with the tube amps you have owned. Here is why.

Noise is simply due to designer who doesn’t hear or mind the noise, probably has no internal limits for what is low noise, or doesn’t know how to measure noise. It could be a noisy tube.

Microphonics are generally created in the first tube of the amp, the input tube. You just have to find a good one. I do grade tubes for noise and microphonics.

A good amplifier needs to have its bias adjusted perhaps twice a year or when you hear something change radically.

Good amplifiers warm up and are 99% there in about 5-10 minutes. There is no good reason to warm them up or leave them on. They play in the first 30 seconds and don’t sound bad as they come up slowly.

Muddy bass is generally due to low damping factor. Get a damping factor of at least 8-10. More than that wont make much difference and high damping tube amps are often unstable due to too much feedback.

BTW, I am believer in both pcs and fuses. Enjoy ! MrD
Thats fine with me. Just don't use premium fuses in the B+ circuit of any power amp. There is a lot of energy stored in the filter caps and it has to go somewhere. A high interrupting fuse does the proper job of leaving most of the energy in the filter caps rather than tearing a path of destruction through your amplifier..
atmasphere's avatar
atmasphere
11,640 posts
 
Roger, normally things go pretty easy on this forum unless certain individuals get involved as you've already sorted out. When they jump in, that's usually a signal that the usefulness of the thread is over.
frogman
7,373 posts
 
An extremely generous offer. Thank you.

What is it, from a technical standpoint, that allows good tube amplification to reproduce micro dynamics in a way that is much closer to what I hear in live music? I refer to the ability to reproduce the seamless dynamic gradations in volume (especially very subtle gradations) that give music a sense of aliveness; not simply the ability to play very loudly. I know some will disagree, but to me tube amps generally do a better job of this than solid state. The attributes of tube amplification are often described in terms of tonality, dimensionality, staging, but the thing that draws me to tubes more than anything is the way they reproduce dynamics. I generally hear more dynamic nuance (realism) from tube amplification. Thoughts?
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