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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OP do you believe in the burn in process of an amp that over time the sound will settle and finally focus on a cohesive musical experience or is it to your opinion all in our brain that is adjusting to the sound of the component?  When I mention burn in process its regard to periods of 300hrs and more (eg Naim or Simaudio Moon amps).
Hi,
My Nakamichi Compact ! Receiver has a FM tuner. How do I connect it  to my Rotel A14 integrated amp? The Nakamichi has Pre output , main input and Aux available. Rotel has aux and pre output/ 
@ramtubes. 

I measured the impedance of my passive across the input to the output as you requested. It measures 1.21kohm, which is as written on the bottom of the case. I opened the case and found an Alps volume pot, two resistors, and wiring. I played lots of music through it, using my phono preamp as the source, and I periodically placed my preamp back in the system for comparison. My verdict, with this passive unit, in my system is as follows: The system with the passive has clear high and mid frequencies, good space, and sounds spacious... but it is a bit brighter, a bit leaner, and is less pleasant to listen to than with the preamp. I’d call the sound with the preamp “smoother” and “warmer”. The vocals through the preamp were slightly veiled compared to the passive though, which annoyed me. So.. after this exercise, I believe that either a better quality passive, or a more transparent preamp, is what I’d want. What design elements could improve the sound of a passive device? Clio wrote about a phono preamp with passive level control and aux inputs. What a great idea!
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krelldreams
my passive across the input to the output as you requested. It measures 1.21kohm, which is as written on the bottom of the case.
If your Alps pot’s passive pre, input to output measures 1.21kohm then you have a 5kohm Alps pot.
Your source may well be doing it hard into this 5k load, and making things "leaner".
Passives should be at least 10kohm to suit "most" situations. Or higher (>10kohm) if the amp is also >50kohm or more.

Cheers George