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.


128x128ramtubes
maplegrovemusic's avatar
maplegrovemusic
1,113 posts
 
Roger - What brand of speaker wires and interconnects do you use ?
clio09
3,346 posts
 
If I am a good guesser I would have to say that since wolf_garcia plays guitar and he has mentioned the Grateful Dead in a few of his posts the reference would be to the Doug Irwin Wolf guitar (known for the Dire Wolf inlay) made for Jerry Garcia. I’ve seen Garcia play it a number of times and the current owner of the guitar has made it available to be played by others, most notably Steve Kimock who Garcia really respected as a guitarist. You can see it here:

https://liveforlivemusic.com/features/a-brief-history-of-jerry-garcias-five-most-well-known-guitars/

[Side Note: Upon Garcia’s death some of the Irwin guitars made for him were auctioned off to help pay for Doug Irwin’s medical expenses, and it got a little gnarly with the Grateful Dead asking for a piece of the action since they contended none of the equipment ever belonged to Garcia, but was purchased under the Grateful Dead corporate umbrella. In essence the guitars weren’t Garcia’s to give away. So the band got to keep a couple of the guitars in the legal settlement. So much for that community thing.]

As for the Dennis Had Inspire amp, I have a lot of respect for Dennis having owned and enjoyed very early Cary equipment, but knowing someone that measured one of these amps I couldn’t ever bring myself to buy one. If anyone wants to have their amp measured Roger is game to do it (even brought his equipment to Burning Amp one year to measure amps). He keeps notes on all the amps (and some preamps) he has measured. I think Roger has measured most of my equipment and even I was surprised at some of the results.

ieales's avatar
ieales
1,201 posts
 
@cakyol

I predict that these capacitors will be in a vicinity with a temperature of about 60 - 65 C most of the time
  • Definitely use 105°C parts.
  • Cap ESR goes up with age, so while the C may still be good with old parts, the increased ESR will play havoc with Z.
  • Dielectric degrades with time and more so when not charged.
  • A small DC fan could cool the temperature by 30°C. 12VDC fan on 3V is inaudible from 6 inches. Two 60mm fans operating push pull will keep things very cool.

You may find this link interesting. "Determining end-of-life, ESR, and lifetime calculations for electrolytic capacitors at higher temperatures"
https://www.edn.com/design/components-and-packaging/4326347/Determining-end-of-life-ESR-and-lifetime...
wolf_garcia
6,644 posts
 
My name has zero to do with Jerry Garcia...I borrowed the last names of two people in my office (Tom Garcia and Dave Wolf) around 20 years ago for an open mike thing I was doing, and I kept the name for professional use and to disguise my identity as an international celebrity. As far as the Dead goes, I recently found a ticket I didn't know I had kept (I don't keep stuff like that) in a bag of papers from my late mother's stuff...3 bucks for a Dead show I saw in Honolulu on Jan 3rd 1970...framed it! There's a recording of that show someplace that I should try harder to find, just to complete the set.

I like the fact that my Dennis Had amp is relatively "unmeasured," although I'm sure somebody has looked into that...if measurements for the thing were available, I still would not care one iota as the thing simply reproduces music so beautifully among my gear pile it's earned its place several times over.
tomic601's avatar
tomic601
12,869 posts
 
With some affinity for The Dead, corporate or not
in the old days before they had to feed the wall of sound monster, they used 4 x MC240 in bridged mode to run the PA
those are 50# each, so that was an ungainly bit of plywood all four were attached to....
Roger - one of my first memories is also at age 4 watching the MC240 and Bozaks arrive in my parents house
no $ for furniture, plenty for music and HiFi

i still have the 1961 MC240 / MX110 Z

have you measured a 240 ??????


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