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

jeffreybehr

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Dec 16, 2018
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Congratulations on these incremental improvements!

TY, Ron.

I ran into Upscale's Brimar CV1988/6SN7GT tubes and bought a quad; Upscale has sold out of the two better (preamp) grades and have only poweramp-grade versions left.. The first quad had blacked glass and original cartons/protectors and sounded quite good in the 1st-Voltage-gain postions--maybe not quite as warm as my old Tung-Sol oval-plates but excellent none the less.

Bought six more which turned out to be two different plate styles; none had blacked glass, two had common-type rectangular-cross-section black plates, and four had curved gray plates.. I left four T-S OPs in the V1 postions, put four original-black-plate versions in the Vs 2 and '3 positions, and put the rectangular-plate pair in the V4 cathode-follower postions.. THIS combination sounds EXCELLENT and made the amps sound better than ever.
2019Feb10_Brimars_1200h.jpg


I'm now working on amppads and shelves for my equipment stand, using 3cm granite.. IF anyone is curious, see
https://www.audioasylum.com/audio/tweaks/messages/20/208063.html
for details.. Got the amppads finished yesterday and applied some sheets of Dynamat damping material to both today.
https://www.audioasylum.com/audio/tweaks/messages/20/208116.html

2019Feb09_amppads1_1500w.jpg
 
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chungjh

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@jeffereybehr

I am thinking about MA-1 3.3 for soundlab speakers (may be 545), which is very similar in size to your Quad. How do you like them? Does MA-1 have enough headroom for your room? What is your room size?
 

jeffreybehr

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Dec 16, 2018
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@jeffreybehr

I am thinking about MA-1 3.3 for soundlab speakers (may be 545), which is very similar in size to your Quad. How do you like them? Does MA-1 have enough headroom for your room? What is your room size?

I LOVE the sounds coming thru these things; I think they're the best amps I've ever had.. One thing that convinced me to keep the MA-1s instead of the M-60/3.3s is their versatility; I'm now using them with only three pairs of output tubes in each amp to drive my 96dB-sensitive Serenity Super-7s.

I have a largish room (about 3200CF) and LOVE large-orchestra Classical and film music, but I don't listen at very high average levels. . The amps always had PLENTY of power for my needs, but I could only guess at whether they have enough power for you.

I'm using the Winged-C 6H13C output tubes instead of the Chinese version of the 6AS7G and a combination of Tung-Sol oval-plate 'N7s and BRIMAR CV1988s in mine; see pic above.

I wish you well; pls let us know what your results are.
 

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Kcin

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I bought a stash of the Brimar CV1988 tubes from my dealer friend 25 years ago - he was an Atma dealer.

The difference they made on the MA 1s was profound when he installed them in the showroom. Mine have sat in their boxes for years unused.. I have nothing that uses them now. They look cool. IMG_1347.jpg IMG_1338.jpg IMG_1337.jpg
 

jeffreybehr

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Dec 16, 2018
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Kcin

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chungjh

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@jeffreybehr

You had a picture of MA-1 driving Quad 2912 with subs. Did you replace your 2912 because of the lack of bass/slam, which is common in ESLs?
 

chungjh

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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!


Can't you switch MA-1 to class AB from A to reduce the heat generation during summer?
 

jeffreybehr

Well-Known Member
Dec 16, 2018
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Phoenix, Arizona USA
@jeffreybehr

You had a picture of MA-1 driving Quad 2912 with subs. Did you replace your 2912 because of the lack of bass/slam, which is common in ESLs?
Can't you switch MA-1 to class AB from A to reduce the heat generation during summer?

The Quads are 2905s.. I replaced the Quads with their predecessors, Serenity Super-7s, hybrid open-baffle planar magnetics with double-12" bass drivers...
https://www.audiocircle.com/index.php?topic=141060.0
...because the Quads' bass tended to drone a bit in my room.. The S7s sound EXCELLENT with Atma-Sphere OTLs and the S7s' servo-controlled OB bass systems.


Earlier versions of A-S OTLs had switchable bias, but these later versions do not.
 
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jeffreybehr

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Dec 16, 2018
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Phoenix, Arizona USA
I guess what goes around, comes around. 1-1/2 years later, I'm back to the Serenity Super-7s and the Atma-Sphere MA-1s.. Both pairs of these have been resting in my musicroom, gathering dust.. This WE I reinstalled both and am very happy.. Without remembering that I had done it and wrote about doing so here, I installed the amps with* 3 pairs or output tubes in each amp, and the amps and speakers sound excellent again.
2022Jul10_DSC0205_M-160s & S7s_2000w.jpg

* Doing so (1) increases output impedance; (2) reduces maximum power output, and (3) reduces output Voltage.. My system tolerates all three very well.
 

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