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
atmasphere's avatar
atmasphere
11,861 posts
 
No- I liked the styling of the Marantz. I was also influenced by ARC. Both of these can be seen on the front panel of our old M-50 amplifier. But people wanted the tubes on the front, so we turned the chassis around when we introduced the MkIIs. The MA-2s still have a front panel though.


We still do our anodized finishes at the same place ARC used to do them.

I think the model 8 was a better sounding unit too. The 9 IMO only worked acceptably in Triode mode. Side note: when I was first showing my employees what I wanted for hand-wiring quality, I showed them the insides of a model 8b we were renovating at the time and told them this was the quality of workmanship we had to meet and beat.
fleschler
2,021 posts
 
I forgot the great Leak and Quad amps, low powered but wonderful.
bdp24's avatar
bdp24
9,868 posts
 
Ralph, your champagne anodizing is a MUCH better version than that of ARC. When I got my SP-3, D51, and D75, I was disappointed with the rather garish gold anodizing of their faceplates. Your champagne is more like that of Conrad-Johnson, understated and elegant, very tasteful. And your build quality is far higher than that of ARC, imo. Plus, no circuit boards!
grannyring's avatar
grannyring
6,511 posts
 
The inside of Ralph’s amps are pieces of art! Love the layout and skilled construction. 
ramtubes's avatar
ramtubes OP
460 posts
 
@atmasphere To the third, a correct answer requires a correct question- the **response** is not raised; the **pre-emphasis** is, and by about 5 db (so the simple answer is thus 'no'). Remember that the curve is just that and is the amalgam of three timing constants. The range of frequencies to which you refer is the area where the response is relatively flat compared to the rest of the curve. It isn't flat because of the ordinates of the timing constants. So its a gentle curve in that range, and the **pre-emphasis** is 'lifted' by about 5 db over that range, not 12.

 
There are plenty of images on the web. Fig. 2 of the article at the link below is pretty good- you can see the 5 db or so rise in the pre-emphasis in the range of frequencies about which you asked:


We are talking about just two time constants that are at 500 HZ and 2200 Hz. Surely you know that time constants or frequency corners are defined points where the response is 3 db up or down. Since these are first order they eventually (within the audio range) come to be 6 dB. Thus 6 db rise for the first pole and 6 db loss for the second. 6+6 = 12 dB.

This is also confirmed by graph you presented from Stereophile. 

I am simply trying to tell readers that the high end of a disc is cut 12 dB higher above 2200 Hz. Also that the RIAA playback curve they are accustomed to seeing is for a magnetic (velocity) cartridge and the one for a displacement (strain gague) would be only 12 dB top to bottom as apposed to 40 dB.

How can you disagree?


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