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
Technical question: Do certain electronic components, e.g. capacitors, need to "form" before they operate at their best?
Amplifiers, only the tubes. When it comes to electronics and wire I believe the listener is becoming accustomed to the change.

I must admit that I personally in my limited experience of owning new HiFi components I never experienced this  marked change of sound during 'burn in process'.  When you confirm that in regard solid state amplifiers it is the listener who is becoming accustomed to the change thats quite an assertion  when you consider the host of people (professional and non professional) who claim to have actually heard and experienced the change of sound during the claimed burn in process.  Its fascinating that such a divide exists among normal music lovers.
If burn in exists in these devices why did we not know about it until recently. I find no references to burn in in the 50s 60s 70s.. when did it start?
It's my belief that connectors are the largest culprit. As components became more modular, more connectors. Once I have a system I plan to keep for a while, I remove ALL internal connectors. More than once I've rejuvenated a system by re-plugging ALL connectors, both internal and external.

In the studio, we regularly cleaned all connectors, patch cords. Tracking setup required every mic cable be re-plugged 3x to ensure an unoxidized contact. All multitrack cards and console modules were R&R'd. AFAIK, this was SOP in some places going back to the 50's for mics and 70's as consoles and tape decks became more modular.

Cable burn-in? Bunkum!
Technical question: Do certain electronic components, e.g. capacitors, need to "form" before they operate at their best?
It takes electrolytic capacitors no time at all to form (certainly not days or weeks) with the correct polarizing voltage, and if they have zero or don’t have the correct polarizing voltage, it was a bad design.

Cheers George
@prof  And if burn in occurs in cabling, why don’t we see people producing these measurable results between a new and burned in cable? The suspicious thing is that when most cable manufacturers are hyping either the technical reasons why their cables produce better sound, or telling you the cables need burn in, they are always appealing to some objective, technical phenomena whose existence is known because it was measurable. "Here’s a technical problem with cables you need to know about, that we have solved via our manufacturing process!"



Nicely done all of it. To the part quoted the reason we dont see measurable changes is that there arent any. Of course the people who believe in burn in and such will just go to the default "well you cant measure everything".  If you measure the things we can measure they will stay the same. 

We all need decent cables, thats fine. Decent cables need not cost much and are very easy to make. Up until Monster came on the scene most people made their own speaker cables out of zip cord, which is an excellent choice, very low capacitance, resistance as low as you want just buy more copper. High capacitance speakers have been known to blow up SS amps as they cause the amplifier to go into oscillation. Ive seen a Levinson smoke.