Oh-m'-god--bought a pair of MA-1/3.1s thru USAudiomart.

Dec 16, 2018
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Phoenix, Arizona USA
#1
https://www.usaudiomart.com/details/649467350-atmasphere-ma1-mk-31-amplifiers/

If that $16,900 retail price is correct, my delivered price is only 38% of RR.. The seller was anxious to get them OUT of his house and shipped them yesterday.. I expect these will sound a bit more 'comfortable' driving the Quad 2905s.. I have more than a complete set of Winged-C 6H13C output tubes on hand and, of course, more than a dozen Tung-Sol oval-plate 'N7s for the input and driver section.

2016731-atmasphere-ma1-mk-31-amplifiers.jpg
2016737-atmasphere-ma1-mk-31-amplifiers.jpg
 
Likes: tima

audio.bill

Well-Known Member
May 27, 2013
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Chicago suburbs
#2
Congrats on those amps which should sound exceptional driving the Quads! :) They do generate quite a bit of heat though... I have a buddy who used to own similar Atma-Sphere amps and he got used to listening in his underwear (and I'm not kidding!) :eek: All the best in the new year!
 
May 25, 2010
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SF Bay Area
#3
https://www.usaudiomart.com/details/649467350-atmasphere-ma1-mk-31-amplifiers/

If that $16,900 retail price is correct, my delivered price is only 38% of RR.. The seller was anxious to get them OUT of his house and shipped them yesterday.. I expect these will sound a bit more 'comfortable' driving the Quad 2905s.. I have more than a complete set of Winged-C 6H13C output tubes on hand and, of course, more than a dozen Tung-Sol oval-plate 'N7s for the input and driver section.

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Very impressive looking! Are you the Jeffrey who owned (owns) an audio shop? Welcome to WBF.

Larry
 
May 25, 2010
1,113
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SF Bay Area
#5
Owned, initially with another Jeffrey, Two Jeffreys Audio, a very parttime effort in my musicroom.. From TAS issue 36:

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Long gone, fortunately.
Thanks, I remember buying some records from you back in the latter part of the last century! Larry
 
May 30, 2010
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Portugal
#8
TYVM, Tim; now I have a name to connect to 'tima'.

Your observations on the MA-1 parallel the seller's of 'my new' MA-1s. It'll be hard waiting until Jan. 08 when the '-1's are scheduled to arrive. :rolleyes:
Just to point that even if you wrote that " Ralph Karsten claims that the Mk 3.1 MA-1 is the lowest-distortion tube amp he has encountered. And after thirty years in business, Ralph has encountered a lot of tube amps. " the mk 3.3 version has significantly lower distortion due to a small modification in the biasing scheme!
 
Dec 16, 2018
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Phoenix, Arizona USA
#9
Just to point that even if you wrote that " Ralph Karsten claims that the Mk 3.1 MA-1 is the lowest-distortion tube amp he has encountered. And after thirty years in business, Ralph has encountered a lot of tube amps. " the mk 3.3 version has significantly lower distortion due to a small modification in the biasing scheme!
...and running the input-gain-stage triode sections in parallel, and using a solid-state (MOSFET) current source, and maybe more I don't remember. :)
 

Gregadd

WBF Founding Member
Apr 20, 2010
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Metro DC
#10
It should be noted Ralph has some different ideas on distortion.
 

Ron Resnick

Site Co-Owner, Administrator
Jan 25, 2015
7,989
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Beverly Hills, CA
#11
Congratulations,! I am sure you will love those amplifiers!
 
May 30, 2010
16,732
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720
Portugal
#12
...and running the input-gain-stage triode sections in parallel, and using a solid-state (MOSFET) current source, and maybe more I don't remember. :)
I think that some MA1 mk3.1's already incorporated the parallel triodes and as far as I know the current source is still tube in the amplifiers. The only solid state I know about in the amplifiers was a HV regulator. But the information on the mk3.3 is scarce.

BTW Ralph Karsten is a frequent poster at Audiogon - see https://forum.audiogon.com/users/atmasphere/posts
 
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Dec 16, 2018
57
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Phoenix, Arizona USA
#13
I think that some MA1 mk3.1's already incorporated the parallel triodes and as far as I know the current source is still tube in the amplifiers. The only solid state I know about in the amplifiers was a HV regulator. But the information on the mk3.3 is scarce.

BTW Ralph Karsten is a frequent poster at Audiogon - see https://forum.audiogon.com/users/atmasphere/posts
The current source went MOSFET--the tiny circuit board just right of center...
2016Arp26_2 prs Platinums_1800w.jpg
...and the input triodes doubled with the 3.3s.
 

tima

Industry Expert
Mar 4, 2014
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1,264
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the Upper Midwest
#14
Just to point that even if you wrote that " Ralph Karsten claims that the Mk 3.1 MA-1 is the lowest-distortion tube amp he has encountered. And after thirty years in business, Ralph has encountered a lot of tube amps. " the mk 3.3 version has significantly lower distortion due to a small modification in the biasing scheme!
Are you really saying a newer version that was not available at the time of the article has lower distortion than the older release??
 
Dec 16, 2018
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Phoenix, Arizona USA
#15
The first of the pair arrived yesterday. Pulled the bottom cover, looked around, shot some pics, installed the (nineteen!) tubes, and installed it in place of one of the M-60s.
2019Jan07_bottom open caps down_1500h.jpg 2019Jan07_bottom open caps up_1500w.jpg

The second should arrive this afternoon.

This larger, bent-aluminum (?) chassis vibrates significantly worse than those of my M-60s did before I damped them; I imagine I'll use two full sheets of SoundCoat the Thicker on the chassis ceiling and transformercover. Seems to have the same Voltage sensitivity as the M-60, so one M-60 and one MA-1 work plenty OKly as a pair. ... :)
 

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Dec 16, 2018
57
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Phoenix, Arizona USA
#16
The second amp arrived Tuesday afternoon in a new outer carton; one upper corner of the original A-S carton was slightly wet, but everything inside was OK. This time I removed the transformer cover to see what the big PS caps were--Corn.-Dub. 27000/160s, which Ralph says is or at least was the upgrade option. Got the tubes (including Chinese output tubes and four Tung-Sol oval-plate 'N7s) sorted, nulled, and the amp running. Over the evening, I installed tube dampers and VPI Magic Brick and other vibration dampers.

The amps sound excellent playing a movie, and that's as ambitous as I got.

Current upgrade plans are to install Cardas binding posts (the 'all-rhodium' CCRR Ss) and XLR inlets (the CM F), apply a substantial amount of 'SoundCoat the Thicker' on the chassis ceilings and transformer cover, replace the coupling caps with those glorious-sounding Miflex KPCA (copperfoil/paper & 'propylene/oil), and add PS-bypass caps. The latter will be, on each of the huge main-supply caps, a BlackGate* 470/160 and a 1uF SoniCap Platinum**. At least the BGs (and probably the Platinums, too) will go under the transformer cover. On the frontend supply, I'll use one Miflex 0.47 per amp.
2019Jan09_R ch running_1500w.jpg
Soon I'll determine what size dampingbars can be used atop the amp in the 4 'aisles' between the rows of tubes. I'm hoping a 1"w.-X- 1-1/2"h. bar will fit, front-to-back, from the meter panel to within an inch or so of the front edge of the amp. I HATE VIBRATING CHASSIS!!!!!!!!!!!!!!!!!

* I have 6 left in my now-very-small stash.
** Teflon-alloy film and tinfoil. I find these to be extremely resolving and tonally balanced.
 
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Dec 16, 2018
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Phoenix, Arizona USA
#18
Parts are here!

Since everyone is out of my preferred, thicker Soundcoat, lucky me I still had three new sheets in inventory, and that's the FIRST thing going into the amps.. Black caps are 1uF SoniCap Platinums for main-PS bypassing, large brown ones are Miflex KPCU-copper frontend-PS bypasses--and WOW these 600VDC copperfoil caps are BIG!--smaller Miflexes are 0.1uf couplers, bindingposts are Cardas CCRRs, XLR connectors are Cardas CM-Fs, and hookup wire is Neotec UPOCC 18g. copper from my inventory.
 

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Likes: Sablon Audio
Dec 16, 2018
57
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Phoenix, Arizona USA
#19
Update.. Got the Miflex KPCU (copperfoil/'propylene&paper/oil) frontend-PS-bypass and coupling and the 1uF SoniCap Platinum main-PS-bypass caps, the Cardas CCRR binding posts, and LOTS of SoundCoat the Thicker damping material installed.
2019Jan19_Bypass & coupling caps_1500w.jpg 2019Jan18_Transformer cover & SoundCoat_1700w.jpg
The chassis rings LOTS less. :)


The music thru the system sounds a bit warmer and even-better resolved than before.. In fact, this is the best-sounding, overall, that my system has ever sounded AND better than ANY system I've ever heard*. When I listen to multichannel SACDs, I run 5 channels (and not the '.1' channel) and run the CC level rather low. The surround effects are VERY subtle, as sounds being heard as coming from the sides and rear are very distracting for me.
2019Jan23_Room front w MA-1s & Quads_1500w.jpg
I moved the amps one position inboard (and about 6" closer to the listening position) and the Rythmik 15" SWs one position outboard to get the amps' heat away from the Quads, and I've reinstalled one of my Butler TDB 5150 5-channel amps (and removed one of my inexpensive Emotiva A-700 7-channel amps) to drive the 4 surround and one centerchannel speakers, the latter a Vandersteen VCC-1. The six ceiling speakers are driven my the M-700 in the middle of the center stack.


Yet to arrive is new custom-wound speakercable required by the amp moves, and yet to install in the amps is a pair of BlackGate 470/160 main-PS-supply caps. I'm highly likely NOT to replace the presumed-OK-sounding original main-PS caps, as much as I fantasize about doing so. I guess 'best-ever' is good enough. :) ...:) ...:)

Will be conditioning the incoming, maybe-2-dozen new Winged-C output tubes in my M-60s and then combining those with my own and then installing in the MA-1s.

As the former owner wrote, he was going to return these amps to A-S for upgrading to version III.3s, but they sounded so good with his Soundlabs that he didn't**. Me too with my Quads.


* Do userstand that I do not hunt for excellent audio systems to audition.
** He bought a pair of MA-2s. :D
 
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Ron Resnick

Site Co-Owner, Administrator
Jan 25, 2015
7,989
2,370
680
Beverly Hills, CA
#20
Congratulations on these incremental improvements!
 

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