[Roger A. Modjeski]

Do you hear too much noise from your speakers? We have solved many a problem with this simple box. http://tubeaudiostore.com/prnoandvore.html

In a quiet room with sensitive speakers one can often have noticeable noise at the listening position. This is due to the fact that the power amplifier simply amplifies the output noise of the preamp driving it. The volume control of the line amp is at the input not the output so the noise of the line amp is always there. Some designers seem not to consider this potential problem no matter what the cost of the preamp. This is something we will discuss in the upcoming amplifier class. BTW is it virtually impossible to find a 12AT7, 12AX7, 12AU7 or 6SN7 quiet enough to make a single stage line amp without feedback that will be quiet in most situations.

Are some recordings too bright or too dull? Is there too much or too little bass.? We can add a passive EQ for high or low frequency modification.  A simple addition to the attenuator is a 3 position toggle switch with two choices of EQ plus and "out" position. This is a far more effective way to tune your system than trying to do it with cables and do-dads. In a larger box EQ can be up to 5 positions of boost or cut, bass or treble or both.

[nature boy]

No price listed on the website.  Any idea here?

NB

[opnly bafld]

http://www.ebay.com/itm/PreAmp-Volume-and-Noise-Reducer-/261411052499?pt=US_Home_Audio_Amplifiers_Preamps&hash=item3cdd501bd3

[fastfred]

How much for the larger unit with 5 positions of eq?

[tubegroove]

Could someone at MR please put up prices and functionality/specs of all the available versions?
Thanks

[Roger A. Modjeski]

The 5 position unit is $250 in a plastic box, $350 in metal, but I like the plastic box better.

for more info  [email protected]

[nnck]

The 5 position unit is $250 in a plastic box, $350 in metal, but I like the plastic box better.

for more info  [email protected]

Is there a picture somewhere of what this tone control looks like? A little more info of how to use it and more specifics on what we can control with this?

Thanks.

[mresseguie]

Have you got a three channel preamp noise and volume reducer for my AVA 3 channel amp/Nuforce pre/pro?

Email sent.....

[Roger A. Modjeski]

we can make one for you. Contact [email protected]

[bdp24]

we can make one for you. Contact [email protected]

This simple statement reminded me of something that I, at the time and now, found and find funny, and tells you a lot about "High-End" "designers" (they need to be called that because they are not EE's.). I went to the closing of the retail store owned and operated by The Mod Squad couple, Steve McCormick and Joyce Fleming. Haven't heard from them lately? It's just as well, because when I asked her if they could make me a Mode Switch (you know, like the one that was included in every Pre- and Integrated Amp since the beginning of Hi-Fi, including those found on the faceplates of Fisher, Scott, Dynaco, Marantz, McIntosh, even Audio Research, fer cryin' out loud. That is, until perfectionists decided that an extra knob in the sacred signal path of their "straight-wire with gain" Pre-Amp would make the Pre sound veiled.). She got a perplexed look on her face, and asked me what a Mode Switch was! I swear to God!! I told her, and apparently she had never looked at the front of the Audio Research SP-6 that Steve was selling (it in fact had one of them new-fangled controls labeled Mode), because she told me (without a hint of embarrassment on her face, after needing me, a layman, to explain to her what a Mode Switch was. I even took her over to the SP-6 to show her. Even then, no embarrassment, or even an "Oh yeah".) "We would need to do some R & D work on that", said she. Not just clueless, but shamelessly so. Remember now, this is the team who brought us the Tiptoe, made out of.....aluminum. What would she have thought if I had told her that doing some R & D on a Mode Switch would be just like re-inventing the wheel? I'm sure I would have seen only more of that perplexed look on her face. Why would ANYONE buy ANYTHING "designed" by this R & D Team?!

[Roger A. Modjeski]

I believe there are fewer than a dozen EE's in the High End industry. Perhaps we should compile a list. You can put me on it, BSEE University of Virginia 1973. Many years ago I attacked a leading designer of cables inaccurate yet imaginative white paper on cable theory. The paper demonstrated a significant lack of understanding of electrical theory. He heard from someone that I had dissed his paper. I asked him what kind of technical education he had, he didn't have a degree but his son did. He  then said  "I've heard you don't even have a degree" I told him I was looking at it as we spoke. We got into a discussion of how he did his research and he described a particular HP Network analyzer and how he was using it. I told him that his application was outside the ability of the machine and the numbers he was getting were not truly what was going on. He told me the salesman had assured him the $25,000 machine was just what he needed. I looked up the specs and it obviously wasn't. To this he replied "You really ought to get out of your backyard with your voltmeters and oscilloscopes and get some real test equipment, I have over  $100,000 of HP equipment"

I am not surprised at the Mod squad experience, I recently had one of their phono preamps in here that was unbelievably noisy. The problem was clearly in the design. The circuit board was nicely laid out but no attention was given to serviceability. Replacing any part would be a major effort.

Most of the products sold in the high end were not designed by EEs and many EEs hide their degree because it is thought that they do too much by the book or by the test equipment. The products designed by the layman may sound good but suffer from unreliability due to the lack of knowledge of electrical laws, tenants of good performance and attention to serviceability. They often perform poorly when tested by Stereophile or others who still test. It amazes me how many amplifiers are sent to Stereophile that measure poorly. Don't they know anything about minumum performance in the areas of noise, distortion, damping and frequency response. What also amazes me is how often the reviewer loves an amp that measures poorly.  Didn't he hear how different his tonal balance was (poor damping) or how it distorted massed strings or voices (high distortion, especially in SE amps)? One reviewer of a particularly noisy amp had tested it with a very sensitive speaker and commented that it was dead quiet. Has he got wax in his ears? It gives one pause.

[gab]

I believe there are fewer than a dozen EE's in the High End industry. Perhaps we should compile a list.

I'll add 3 of my favorites to your list:

Phil Bamberg - http://bambergaudio.com/bamberg/about-peb.php

Siegfried Linkwitz - http://www.linkwitzlab.com/about_me.htm

Jim Hagerman - haglabs.com

8 to go

gab

[Doublej]

You are talking niche firms no? I suspect that Harman, D&M Holdings, Lenbrook, Luxman, Pioneer, Sony, Sonos, Yamaha et al have a few. I am sure Bose has lots of them FWIW.

Dan D'Agostino - University of California, Berkeley

John Curl perhaps

 

[poseidonsvoice]

Bruce Rozenblit has a BSEE with at least 1 patent in OTL design
Amar G Bose had a bachelors, masters and PhD in EE from MIT but he died last year.
Keith Herron of Herron Audio has a BSEE from Iowa State
William (Bill) Dudleston of Legacy Audio has a BSEE from Univ of Illinois Urbana-Champaign
John Kreskovsky (designer of the NaO dipoles) has a BSEE but he took his personal info off his site
Drew Baird of Moon Audio has a BSEE
Bruno Putzeys has a BSEE and is the designer of Hypex amplifiers.

Earl Geddes has a PhD in Acoustics and 17 patents to his name, with 5 pending.
Nelson Pass' degree is in Physics as well!
Andrew Jones of TAD, his degree is in physics

I'm sure there are more but that's all I can think of now!

Best,
Anand

[Doublej]

Amar G Bose had a bachelors, masters and PhD in EE from MIT but he died last year.

Best,
Anand

Amar Bose did NOT earn a PhD from MIT! I'll bet anyone money on this.

[jtwrace]

Amar Bose did NOT earn a PhD from MIT! I'll bet anyone money on this.

http://en.wikipedia.org/wiki/Amar_Bose

[Doublej]

http://en.wikipedia.org/wiki/Amar_Bose

How much would you like to give me? You actually believe Wikipedia all the time?

[Roger A. Modjeski]

Bruce Rozenblit has a BSEE with at least 1 patent in OTL design
Amar G Bose had a bachelors, masters and PhD in EE from MIT but he died last year.
Keith Herron of Herron Audio has a BSEE from Iowa State
William (Bill) Dudleston of Legacy Audio has a BSEE from Univ of Illinois Urbana-Champaign
John Kreskovsky (designer of the NaO dipoles) has a BSEE but he took his personal info off his site
Drew Baird of Moon Audio has a BSEE
Bruno Putzeys has a BSEE and is the designer of Hypex amplifiers.

Earl Geddes has a PhD in Acoustics and 17 patents to his name, with 5 pending.
Nelson Pass' degree is in Physics as well!
Andrew Jones of TAD, his degree is in physics

I'm sure there are more but that's all I can think of now!

Best,
Anand

Thanks for the list. I was speaking of BSEEs involved in electronic design, not speakers but it is nice to know.

The only thing I know about Bruce R. is that he misrepresents the Futterman design. It doesn't work the way he says it does so I don't know if that is for a lack of understanding or marketing as he has a totally different amplifier.

[srb]

Amar Bose did NOT earn a PhD from MIT! I'll bet anyone money on this.

From the Amar Bose obituary published at the MIT News Office (newsoffice.mit.edu)

"Dr. Bose received his bachelor’s degree, master’s degree and doctorate from MIT, all in electrical engineering. He was asked to join the faculty in 1956, and he accepted with the intention of teaching for no more than two years. He continued as a member of the MIT faculty until 2001."

Steve

[tubegroove]

How about Ken Stevens at Convergent Audio Tech??