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
1,201 posts
 
Jim B did Dynaco 400, SAE, GAS and SUMO products. Brilliant guy.
clio09
3,346 posts
 
@bdp24 - Eric this has truly been an eye opener. Roger can now do A/Bing on any number of amps. Fritz Heilor lives in the area recently donated a pair of speakers to us to use in a biamping experiment (Roger is impressed with his designs), so besides the Quads we have some box speakers available to us as well. The more the merrier I say. However, this listening stuff is really hard. After an hour or so I really needed a break. While some of the  differences were not subtle, in may cases you really had to focus to hear the differences, and at least to my ears, there were cases where there was no difference at all.
cardiffkook
12 posts
 
I put the proper cord on my RM-9 but now people want me to put an IEC on there so they can use theirs. I did opimize but thats not good enough for the PC and fuse people. May I also offer that a captive cord has one less pair of connections

That is what I suspected you would say. I have tested expensive upgraded power cords in my system and never noticed any improvement or difference. I notice large differences between amps, preamps, cartridges, cartridge loading and even in minor changes of speaker toe in. But in my system, I have yet to hear any difference between pc's. I am not saying there are no differences, just that I haven’t heard any so far in my system, compared to the cord included by the manufacturer. 

mrdecibel
3,029 posts
 
We need to stay away from the power cord debate here, imo. However, I have stated in other cable threads the subtle, to dramatic differences pcs make, to these ears. Cannot explain why, and I do not really care. But in my listening room, with my equipment and system, and with every one of my familiar recordings, I hear it immediately. I am talking about IEC cords, and those I have replaced with hotwiring. Sorry Roger, I will try and stay on point. Enjoy ! MrD.
pryso
1,913 posts
 
A point on comparison testing which I suspect Roger may agree with.  It is something I've learned after long years in this hobby.

That is a simple A-B is not adequate, even though you may find differences.  I believe at a minimum you need to have A-B-A.  That means any connection improvements (cleaning from friction) as well as differences from something new (possibly a detail not heard in A so B seems better, but it becomes diminished in the overall picture) can be accounted for.
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