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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ieales's avatar
ieales
297 posts
 
The whole idea of tuning a system with cables seems rather weak to me.
The missus once said "Those wires are the only ones where the clarinet sounds like a clarinet." [She had perfect pitch and played the clarinet.] We had decent amp and speakers, so the "wires" were the final tweak.

Unless one subscribes to the idea that cables do not alter the sound, surely it makes more sense to replace bad cables than a good amplifier to correct system deficiencies.
ramtubes's avatar
ramtubes OP
451 posts
 
@devilscucumber

 Hi Roger,I have some old Martin Logan Sequel II's which when repanelled no longer sounded pleasant with my Plinius Integrated 9100 (100w), they became overly bright and shouty. I ended up bi-amping with a Perreaux 6000B (300w mos-fet) running the panels, while the Plinius now drives the subs, my question is can you recommend a cost effective tube amp to drive these speakers, (which dip down to 2 ohms?) I live in NZ (240V/50Hz). I must admit most of the discussion on this thread is well over my head, but your experience in these matters is invaluable to help novices such as myself


First I wonder what happened to the speakers? Were they repanelled at the factory? Did some fool with the crossover? 

Thats a hard speaker to drive and a 100 watt integrated mignt not be up to the task. The Perreaux is much larger and probably more tollerant of the low impedance. 

An RM-200 will drive your speakers from the 2 ohm tap to some reasonable level. How loud do you listen, at what distance and what is the sensitivity of the speaker?

The best amp for you would be a Direct Drive to the ESL. Thats what I use.

I have a keen interest in ESL speakers and have measured many. What I have found is that the hard part of driving them is often the transformer, not the panel. Going direct to the panel makes a big difference. My DD amplifiers produce about 1200 VA into a capacitive load. 
tomic601's avatar
tomic601
2,164 posts
 
RM I have a dead pair of ESL-63, pretty low serial numbers...thoughts on rebuild upgrade steps at same time?Ashamed to admit I dont really have a budget in mind....
ramtubes's avatar
ramtubes OP
451 posts
 
@tomic601 5:38pm

RM I have a dead pair of ESL-63, pretty low serial numbers...thoughts on rebuild upgrade steps at same time?Ashamed to admit I dont really have a budget in mind....
My friend here has a dead pair too. Are your panels bad? Panels are harder to fix than the electronics. Panels go bad, its a shame they didnt use better glue. Do yours have the black grids?

DD amps stereo amps are $6,000. its up to you. 


ramtubes's avatar
ramtubes OP
451 posts
 
@ieales
Unless one subscribes to the idea that cables do not alter the sound, surely it makes more sense to replace bad cables than a good amplifier to correct system deficiencies.


If a system is not broken and has serious deficiencies cables will likely not correct the problem. How can they?

As I said in a previous post, sometimes a listener does not realize his system is broken and somethig needs to be fixed. 
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