Subject: Re: Preamp
Date: Sun, 13 Sep 1998 12:05:33 -0700
From: Atma-Sphere@ManicReader.com
Organization: SMTEK
To: Atma-Sphere@ManicReader.com
On 1998/09/13 at 12:05:32, BLAYER@SMTP {blayer@uswest.net} wrote:
Hi Bob,
>> My question is what's the difference between the MP-1 and MP-3. Other
>> than cost other than cost of course!!
The MP-1 and MP-3 are very close cousins. The topolgies are nearly
identical, and what works in one works in the other. The both have
direct-coupled Circlotron output sections as well.
Differences are mainly low-end frequncy response, gain in the phono section
and noise. As much as I hate to say it, the MP-1 is a tad more musical as
well. This is largely due to the giant headstart in development the MP-1
has; the MP-3 has only joined the ranks in the last year or so. Another
important consideration is the tube-regulated supply in the MP-1's second
chassis.
I'm sure within another year or two, Ralph will be having to tweak the
MP-1's even harder to keep them a step ahead of the very capable MP-3.
If you intend to run the puniest of MC pickups, and your wallet is feeling
about $7500 too light, just buy an MP-1 and be done with it.
Else, you'll never be disapointed with the MP-3. Also remember, that in the
long run, the MP-3 has a few (5 or so) less $tubes$.
Hope this helps; let me know if you need more specific info.
Bill Layer
St.Paul, Minnesota USA
Charter member, The International Brotherhood of Jazz Dancers, Pastry Chefs
and Nuclear Technicians.
Subject: BBS Back on-line
Date: Mon, 14 Sep 1998 8:43:12 -0700
From: Atma-Sphere@ManicReader.com
Organization: SMTEK
To: Atma-Sphere@ManicReader.com
On 1998/09/14 at 08:43:11, MARK.GIL@SMTP {mark.gilmore@smtek.com} wrote:
Dear ASOG Members,
My thanks to Steven Cole for reporting a problem with our BBS. The ASOG BBS
is now back and working well.
Best regards,
mark gilmore
Subject: Message to Steve Cole
Date: Mon, 14 Sep 1998 9:09:52 -0700
From: Atma-Sphere@ManicReader.com
Organization: SMTEK
To: Atma-Sphere@ManicReader.com
On 1998/09/14 at 09:09:52, B.LAYER@SMTP {b.layer@vikingelectronics.com} wrote:
Hi Steve,
I got an email from you the other day, but I scuttled the darn thing before
I could reply to your questions. Sorry!
Could you re-send it today? Either work or home would be fine.
PS Hi to everyone else. First article for the Ex-Factory page is coming
soon... Could someone send me some schematics of their modded ASMS
equipment for posting? I'm especially intereted in details of the SRPP mod
that Jennifer Crock was working on.
BTW, The Ex-Factory now has it's own 600dpi 30 bit color scanner... Send
the photos!!! Now if I could just get my g-friend to finish those graphics...
Bill Layer
Sales Technician
----------------------------------
Viking Electronics, Inc.
1531 Industrial St.
Hudson, WI. 54016 - U.S.A
715.386.8861 ext. 210
----------------------------------
"Telecommunications Solutions for the 21st Century"
Subject: Fi Review on ASOG Page
Date: Wed, 7 Oct 1998 7:45:44 -0700
From: Atma-Sphere@ManicReader.com
Organization: SMTEK
To: Atma-Sphere@ManicReader.com
On 1998/10/07 at 07:45:36, MARK.GIL@SMTP {mark.gilmore@smtek.com} wrote:
Dear ASOG members,
The most complimentary Fi Magazine review of the Atma-Sphere MA-1 MK II is
now in the reviews section of our page. Please let me know if I made any
glaring errors.
Best regards,
mark gilmore
Subject: The importance of impedance matching
Date: Sat, 10 Oct 1998 10:14:17 -0700
From: Atma-Sphere@ManicReader.com
Organization: SMTEK
To: Atma-Sphere@ManicReader.com
On 1998/10/10 at 10:14:16, HARPER@SMTP {harper@q3-consulting.com} wrote:
(Copy of mail sent to Ralph Karsten)
The other day I came across your piece about the importance of output current
(http://www.atma-sphere.com/myth.htm). At first I was sceptical.
Everyone knows that lower impedance gives better damping factor and
is generally a good thing... but we just accept compromises with
tube amps in general (OTL or not).
Then I started to think about the math. And of course you're quite
right. I asked Mathematica to think about it too, which produced the
attached graph. The Y-axis is in dB relative to the level at nominal
impedance (which I took as 8 ohms, but it makes no difference),
while each curve shows the relative power level for a given source
impedance. 0.1 ohms shows dramatic fall of power with impedance.
A very high value (I took 1000 ohms), i.e. a current source, is the
same in reverse.
The smoothest value, taking into account the characteristics of
real-life speakers (long flat minima, with impedance peaks of twice
or more the nominal value), is around 1.5 times the nominal speaker
impedance. The M60s at around 9-10ohms are a perfect match for
an 8 ohm speaker! In fact, as the curves show, 16 ohms would probably
be even better.
Of course this is supposing that the most important thing is constant
power output. It seems reasonable, but it would be interesting to
make some SPL measurements for different sources (I don't have
the equipment for that).
And whither damping factor? I've never fully understood what this
figure is supposed to mean (I know what it means electrically
and how to calculate it). I suspect that it relates to the ability
of the amplifier to overcome the Back EMF of the speaker. To do this
the ideal output impedance is slightly more than minus the speaker
impedance (i.e. a negative impedance). I spent a lot of time a while
back trying to come up with the perfect controller for model trains,
where this problem arises. I shudder to think however of the other
consequences of an audio amp with negative output impedance. (It
would be easy to build one, in fact I guess my negative resistance
train controller could be readily adapted!).
So I suspect that the quest for good DF is misplaced anyway.
But my big question is, how come other people haven't spotted
the negative effects of low output impedance? Seems to be you should
push your white paper a bit harder.
John
======================================================================
John Harper Specialising in the application of
Q3 Consulting Information Technology to
BP32, 06560 VALBONNE, France Telecommunications
phone: (+33) 493 12 24 70
fax: (+33) 493 12 09 89 E-mail: harper@q3-consulting.com
-----------------[ Uuencoded File Attachment: Image17.gif ]-----------------
[Image]
Subject: Re: The importance of impedance matching
Date: Sat, 10 Oct 1998 17:12:10 -0700
From: Atma-Sphere@ManicReader.com
Organization: SMTEK
To: Atma-Sphere@ManicReader.com
On 1998/10/10 at 17:12:09, ASEK@SMTP {asek@uswest.net} wrote:
Dear John,
My experiences with the Magnepan MG-20s show the importance of damping
in achieving the illusion of soundstage. Since I wrote the article on
the ASOG web site, we have moved to Phoenix. Our new house has a large
listening room with all hard surfaces. We spent a lot of time placing
rugs on the floor and front and back walls. With each new placement of
carpet or furniture, the reverberation time decreased and the soundstage
improved. However, it was not until I hung some Sonex acoustical panels
across the backs of the Maggies did the soundstage approach what we had
in Boise. We have two panels on each speaker, spaced with rolls of
toilet paper, and have about reached the optimum level of damping.
The speaker and room together store energy. The mechanical and
electrical damping of the speaker interact with the room's acoustical
damping to determine the overall response. Overdamped room/speaker
combinations sound dry, while underdamped combinations destroy the
soundstage. The speaker drivers act as generators to convert the room's
reverberant sound into emf that the power amplifier has to absorb. This
suggests that high feedback amplifiers would apply too much of the
delayed room response to the signal, and cause the sound to be muddied.
However, high output impedance amplifiers do little to dampen the
mechanical and reverberant sound energy. Unless the mechanical damping
is adjusted to compensate, underdamped speaker/room combinations will
suffer.
I don't think a universal rule can be applied to amplifier output
impedance. Each room/speaker combination is different. The advantage
of Atma-Sphere amplifiers driving underdamped speakers is that one can
optimize the total damping with room treatments. A voltage source
amplifier driving an overdamped speaker will deliver sound
'dead-on-arrival.'
Regards,
Al Sekela
Subject: Re: The importance of impedance matching
Date: Mon, 12 Oct 1998 8:08:03 -0700
From: Atma-Sphere@ManicReader.com
Organization: SMTEK
To: Atma-Sphere@ManicReader.com
On 1998/10/12 at 08:08:02, RALPH@SMTP {ralph@atma-sphere.com} wrote:
>On 1998/10/10 at 17:12:09, ASEK@SMTP {asek@uswest.net} wrote:
>
>Dear John,
>
>My experiences with the Magnepan MG-20s show the importance of damping
>in achieving the illusion of soundstage. Since I wrote the article on
>the ASOG web site, we have moved to Phoenix. Our new house has a large
>listening room with all hard surfaces. We spent a lot of time placing
>rugs on the floor and front and back walls. With each new placement of
>carpet or furniture, the reverberation time decreased and the soundstage
>improved. However, it was not until I hung some Sonex acoustical panels
>across the backs of the Maggies did the soundstage approach what we had
>in Boise. We have two panels on each speaker, spaced with rolls of
>toilet paper, and have about reached the optimum level of damping.
>
>The speaker and room together store energy. The mechanical and
>electrical damping of the speaker interact with the room's acoustical
>damping to determine the overall response. Overdamped room/speaker
>combinations sound dry, while underdamped combinations destroy the
>soundstage. The speaker drivers act as generators to convert the room's
>reverberant sound into emf that the power amplifier has to absorb. This
>suggests that high feedback amplifiers would apply too much of the
>delayed room response to the signal, and cause the sound to be muddied.
>However, high output impedance amplifiers do little to dampen the
>mechanical and reverberant sound energy. Unless the mechanical damping
>is adjusted to compensate, underdamped speaker/room combinations will
>suffer.
>
>I don't think a universal rule can be applied to amplifier output
>impedance. Each room/speaker combination is different. The advantage
>of Atma-Sphere amplifiers driving underdamped speakers is that one can
>optimize the total damping with room treatments. A voltage source
>amplifier driving an overdamped speaker will deliver sound
>'dead-on-arrival.'
>
>Regards,
>
>Al Sekela
>
>
A simple speaker damping rule is to measure the reaction to square wave
inputs to the speaker. Being an electro-motive device, it will exhibit
critical damping characteristics, just like a phono cartidge or an audio
transformer. Critical damping is acheived with many speakers when the
damping factor is less then 15. Obviously, IMMV. Controlling the room will
usually pay off better then the application of negative feedback.
-Ralph
- You'll be hearing more from us! -
Subject: Input Stage Constant Current Source
Date: Sun, 1 Nov 1998 18:42:21 -0800
From: Atma-Sphere@ManicReader.com
Organization: SMTEK
To: Atma-Sphere@ManicReader.com
On 1998/11/01 at 18:42:17, PI$TUBE@SMTP {pi_tube@hotmail.com} wrote:
Hello:
Just down loaded the input stage diagram from the ASOG page. Being a
novice at this, I need a little more help in applying this mod.
Any chance for a more complete schematic.
Thank you ,
Marcial
______________________________________________________
Get Your Private, Free Email at http://www.hotmail.com
Subject: Re: Input Stage Constant Current Source
Date: Mon, 2 Nov 1998 9:34:23 -0800
From: Atma-Sphere@ManicReader.com
Organization: SMTEK
To: Atma-Sphere@ManicReader.com
On 1998/11/02 at 09:34:22, B.LAYER@SMTP {b.layer@vikingelectronics.com} wrote:
High Low All,
>
>Just down loaded the input stage diagram from the ASOG page. Being a
>novice at this, I need a little more help in applying this mod.
>Any chance for a more complete schematic.
Which diagram is that? For the power amp or preamp?
Bill Layer
Sales Technician
----------------------------------
Viking Electronics, Inc.
1531 Industrial St.
Hudson, WI. 54016 - U.S.A
715.386.8861 ext. 210
----------------------------------
"Telecommunications Solutions for the 21st Century"
Subject: RE: Input Stage Constant Current Source
Date: Mon, 2 Nov 1998 12:22:56 -0800
From: Atma-Sphere@ManicReader.com
Organization: SMTEK
To: Atma-Sphere@ManicReader.com
On 1998/11/02 at 12:22:55, MARK.GIL@SMTP {mark.gilmore@smtek.com} wrote:
>Just down loaded the input stage diagram from the ASOG page. Being a
>novice at this, I need a little more help in applying this mod.
>Any chance for a more complete schematic.
Dear Marcial,
The constant current source schematic update is complete. If you have
specific questions, I believe I might be of help.
Best regards,
mark gilmore
Subject: Re: Input Stage Constant Current Source
Date: Mon, 2 Nov 1998 12:26:27 -0800
From: Atma-Sphere@ManicReader.com
Organization: SMTEK
To: Atma-Sphere@ManicReader.com
On 1998/11/02 at 12:26:27, PI$TUBE@SMTP {pi_tube@hotmail.com} wrote:
The power amp (M60II) driver stage.
>Date: Mon, 2 Nov 1998 9:34:23 -0800
>From: Atma-Sphere@ManicReader.com
>To: Atma-Sphere@ManicReader.com
>Subject: Re: Input Stage Constant Current Source
>
>On 1998/11/02 at 09:34:22, B.LAYER@SMTP {b.layer@vikingelectronics.com}
wrote:
>
>High Low All,
>>
>>Just down loaded the input stage diagram from the ASOG page. Being a
>>novice at this, I need a little more help in applying this mod.
>>Any chance for a more complete schematic.
>
>Which diagram is that? For the power amp or preamp?
>
>
>
>Bill Layer
>Sales Technician
>
>
>----------------------------------
>Viking Electronics, Inc.
>1531 Industrial St.
>Hudson, WI. 54016 - U.S.A
>715.386.8861 ext. 210
>
>----------------------------------
>
>"Telecommunications Solutions for the 21st Century"
>
______________________________________________________
Get Your Private, Free Email at http://www.hotmail.com
Subject: New ASOG member
Date: Fri, 13 Nov 1998 15:03:01 -0800
From: Atma-Sphere@ManicReader.com
Organization: SMTEK
To: Atma-Sphere@ManicReader.com
On 1998/11/13 at 15:02:59, MARK.GIL@SMTP {mark.gilmore@smtek.com} wrote:
Dear ASOG members,
Please join me in welcoming Ashby Box to our listserver. Welcome aboard,
Ashby.
****************************************************************************
************************
Hi Mark,
My wife and I live in Sunrise Florida. We are currently listing to Speakers
system consisting of a Entec LF-20 self-powered sub-woofers redesigned
Opamps
and PS. A ZALYTRON speaker kit ( http://www.zalytron.com/ ) on top in a MTM
configuration 2 CABASSE 17DLB and a DOME 4 Tweeter with a ACCUTRON C2-12 as
a
Rear Firing Tweeter. All internal wire and speaker cable's is all silver
wire
KIT ( http://www.warrengregoire.com/ ). 44.1 is all I2S BUSS Audio Alchemy
Pro Transport - TWO PRO 32 in series - to I2S BUSS modified Class DAC-1. All
battery powered. Current amplifier is home made 4 6C33-C Tango Single-Ended
OPT driven by 6SN7 in a Differential Parallel Single-Ended Configuration.
The
phase splitter is the differential Ultra -Analog D/A in the CLASS DAC-1. A
BEDINI 25W Class A amplifier is driving the Rear Firing Tweeter.
Our next project is a Bi-Amped OTL based on the M-60 amplifier.
Regards,
Ashby
Subject: Ultimate M-60 Mk. II Tweak
Date: Thu, 10 Dec 1998 16:14:02 -0800
From: Atma-Sphere@ManicReader.com
Organization: SMTEK
To: Atma-Sphere@ManicReader.com
On 1998/12/10 at 16:13:54, WB6RHQ@SMTP {wb6rhq@loop.com} wrote:
Dear ASOG members,
I may well have gone over the edge now. I couldn't help myself this
time. Please take a look at a new tweak I added to the ASOG page under
the FAQ / Tweaks section. If you have an M-60 Mk. II, you could
conservatively get twice its output power with only minor
modifications. No, I'm not kidding, but I may be proving just how far
over the edge I've gone.
While you're there, take a look at the new M-60 Mk. II review from Glass
Audio. It's in the reviews section. I'll soon add an MA-1 TAS review,
from issue 71. Its amazing how far the MA-1 has evolved in the last 10
years.
Thank you for all your support as the ASOG page develops. It's been a
lot of fun. Happy holidays to you and your families.
Best regards,
mark gilmore
Subject: Re: Ultimate M-60 Mk. II Tweak
Date: Fri, 11 Dec 1998 4:48:01 -0800
From: Atma-Sphere@ManicReader.com
Organization: SMTEK
To: Atma-Sphere@ManicReader.com
On 1998/12/11 at 04:47:59, COLEPERF@SMTP {coleperf@visuallink.com} wrote:
Atma-Sphere@ManicReader.com wrote:
>
> On 1998/12/10 at 16:13:54, WB6RHQ@SMTP {wb6rhq@loop.com} wrote:
>
> Dear ASOG members,
>
> I may well have gone over the edge now. I couldn't help myself this
> time. Please take a look at a new tweak I added to the ASOG page under
> the FAQ / Tweaks section. If you have an M-60 Mk. II, you could
> conservatively get twice its output power with only minor
> modifications. No, I'm not kidding, but I may be proving just how far
> over the edge I've gone.
>
> While you're there, take a look at the new M-60 Mk. II review from Glass
> Audio. It's in the reviews section. I'll soon add an MA-1 TAS review,
> from issue 71. Its amazing how far the MA-1 has evolved in the last 10
> years.
>
> Thank you for all your support as the ASOG page develops. It's been a
> lot of fun. Happy holidays to you and your families.
>
> Best regards,
>
> mark gilmore
Mark,
I keep looking but don't see it! But I'd sure like to .
Easy,
Steve