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
ramtubes's avatar
ramtubes OP
460 posts
 
@georgehifi



https://www.stereophile.com/content/leben-cs300-integrated-amplifier-measurements

JA does make mention of the ultrasonic resonance, but "maybe" because they’re an advertiser, didn’t make too big a deal of it.


Thanks for the link. When saw the picture again my mind went.. Ah, is this Luxman? Looks like Luxman. Does perform like Luxman. Must not be Luxman.

This amplifier is a strange combination of thoughts and performance. While the bass rolls off with out the boost, the boost is enormous when used and nothing in between.

Of course it didnt do the Quads well, "no bass grip". What did you expect when the output impedance is so high and I did not say damping. I want the word damping to go away as it is a most misleading term.

Look at horrible distortion curves at even low power. The only reason anyone could like this amp is on high sensitivity speakers like Art’s and at low levels. After a watt this amp is a mess.

I have been waiting someone who really wants to know ask me why damping is such an outdated term.



ramtubes's avatar
ramtubes OP
460 posts
 
@mapman 

Back in the 70s selling most popular receiver lines from Pioneer to sansui to Tandberg the more powerful models in a line  (generally up to 120 w/ch or so) ALWAYS sounded better at least at moderate or higher levels.
Clipping is always public enemy #1 to good sound. Avoid at all costs. Better to have overkill than clip on that great sounding full range dynamic recording.
Modern louder recordings are more prone to clip as well being louder overall so that ups the ante even more when it comes to how much power might be needed.
Also music not reproduced at lifelike volumes is not accurate reproduction rather a scaled down one. Nothing wrong with listening at lower levels but one is not even attempting to reproduce real music accurately that way.


I agree with you. I worked on a lot of pioneer and such. Receivers are value products. I respect them, have worked on possible 500 in 3 years as a busy beaver. After about 80 watts I see no good reason to buy a big receiver, thats the time to go separates. 

I have found the following. Using a scope to determine clipping I find that most people do not hear clipping till it reached 10 % of the time and those are just little Millisecond clips. Longer clips are more notiable because they block the signal for a long time. So how much overkill is needed? Recievers are not designed for overkill. I use a nice Marantz 2235 in my lab for background music. Way more than I need for my Rogers LS3/5As.

I would say louder recordings are prone to less clipping because they are more compressed. Your ideas?

What is a lifelike SPL for you? On what music?
ramtubes's avatar
ramtubes OP
460 posts
 
@almarg 

It would help to quote the original question so we can follow this. 

It appears to be an answer but im not getting it.
bdp24's avatar
bdp24
9,874 posts
 
Roger, why is damping such an outdated term? ;-) I have heard you speak of how even a low output impedance amp doesn't, contrary to common believe, "damp" a woofer. You have quoted Paul Klipsch on the subject, as I recall.
ramtubes's avatar
ramtubes OP
460 posts
 
@donjr 

A friend of mine loves Accuphase. I have seen inside and its beautifully built, measures well but its just too many parts. Their preamp has something like 600 transistors and 1200 diodes. Im into simple circuits. 

Sure would love to see the specs and a review but only with measurements.
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