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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ramtubes's avatar
ramtubes OP
451 posts
 
@khiak  Can changing the power cord to the amp changes the musicality of sound at the speakers.


Some think so.
ramtubes's avatar
ramtubes OP
451 posts
 
@prof1   I also wonder how the introduction of a subwoofer alters the load to an amplifier. So say if you have a powered sub and you crossover to the sub from the mains at maybe 80 or 60 Hz. Once one has off-loaded much of the low frequencies to the sub, I wonder how much the main amp "sees" and if that, in effect, is like adding a more powerful amp in to the equation
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I assume you are using some crossover to rolloff the main speakers. Is that via and electronic crossover or the series caps found on some subs?  Makes a difference as to voltage the main amp still has to produce and thus clipping and IM distortion. The correct way is to rolloff the main amp at its input so it never sees the bass voltage. 
ramtubes's avatar
ramtubes OP
451 posts
 
@fleschler  ramtubes - So, you don't believe power cables make a difference other than connectors and isolation transformers are worthless? Is that correct?


Do I detect a little nudge there?  I think isolation transformers are great when needed. I like balanced power which also isolates. These things have a good chance of reducing noise if one has noise.

My stand on power cords is entierly intellectual from an amplifier designer and transformer makers point of view. I know what is inside a transformer and how it works. When you know about transformers, house wiring etc. we can further discuss this interesting topic. 
bdp24's avatar
bdp24
4,908 posts
 
"Musicality" is one of those oh-so-subjective terms with no agreed-upon meaning. But the same can be said about the incomplete sentence by khiak above ;-) . The "can" implies it is a question, but the "changes" negates that. Should the sentence read "Can changing the power cord to the amp change the musicality of the sound at the speakers?" (a question), or "Changing the power cord to the amp changes the musicality of the sound at the speakers." (a statement) ?
ramtubes's avatar
ramtubes OP
451 posts
 
@ atmasphere
In one post Roger says it doesn’t make much difference, OTOH in the very same post describes the power cords that he made up special and how anyone can do it. I have to assume that he felt it was worth doing
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Ralph, what is OTOH mean? Im a newbee.The cords with diodes make a difference when needed. I think I have been clear and consistant here.

Your amp draws heaps of current when played hard. Something heavy ga might help a little at full power. At idle Im not so sure. I note the current draw of the M-60 goes up quite a lot at full power testing.

How long can I run an M-60 sinewave at 60 watts into 8 ohms before the tubes get unhappy?
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