About to buy MA-1 monos- how long do the tubes last and how easy are replacements to source?

Nuforce

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Please can someone tell me roughly how many hours I can expect from the 6as7g tubes and if replacements are easy to find?

Searching for 6as7g tubes doesn't show a lot of places that stock them, which concerns me.
 

LL21

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Congrats...sounds very exciting. I would have thought Ralph/Atmasphere should have sufficient stock that you could always buy replacement tubes from him?
 

microstrip

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Please can someone tell me roughly how many hours I can expect from the 6as7g tubes and if replacements are easy to find?

Searching for 6as7g tubes doesn't show a lot of places that stock them, which concerns me.
They are great amplifiers.

The 6as7g tubes are known to last for long - many thousands of hours. They russian tubes were inexpensive, now they are hard to find. We can get the GE 6080 in Europe, not sure if Ralph likes it.

Do not forget to run the 100 hour filament burn-in without B+ supply - it is reported to double tube life.
 
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ACHiPo

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I’ve had my MA1s less than a year, but M60s since ~1999. I lost a few (5?) power tubes the first month, but it’s been smooth sailing since then—no tube loss. In the M60s that preceded my MA1s I changed tubes after 5 years just because—there was no change in sound, and the tubes I removed I saved for back ups. The 6SN7s (I prefer 5692 NOS variant, but the KenRad VT-231s are outstanding as well) seem to last forever. On both amps I listen 2-14 hours/day 7 days/week.
 

tima

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Iirc, if a tube were to fail in an MA-1 you can remove it and another tube - rearrange so the back two sockets are empty - and the amp will play on, only with slightly less output. I have not faced the recent Russian export ban but in the past the tube expense was nice 6SN7s.
 
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Chorus

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Nufo, Respectfully, you may be considering the wrong product from Ralph.
Have you heard his latest contribution to the audio world? If not get to Schaumburg
this weekend.
 

ACHiPo

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Iirc, if a tube were to fail in an MA-1 you can remove it and another tube - rearrange so the back two sockets are empty - and the amp will play on, only with slightly less output. I have not faced the recent Russian export ban but in the past the tube expense was nice 6SN7s.
Tim,
That is correct. Ralph’s amps will run on as few as one power tube per side, and even when I lost the 5 on my MA1s the amps still sounded great, the dynamics were just more constrained on the side that lost the most tubes (I think I lost 4 on the right amp and 1 on the left amp, with 3 of the 4 dead tubes on the right bank and 1 on the left bank).

I bought a lifetime supply of the Russian 6AS7 equivalent tubes several years ago. I know things are crazy right now, but the Chinese tubes sound quite good. The power tubes go for about $12 each. As you say, 6SN7s go from $15 to >$100 depending on flavor.

Evan
 
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tima

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I bought a lifetime supply of the Russian 6AS7 equivalent tubes several years ago. I know things are crazy right now, but the Chinese tubes sound quite good. The power tubes go for about $12 each. As you say, 6SN7s go from $15 to >$100 depending on flavor.

Thanks Evan for the confirmation. I don't know if it was a lifetime supply but several years I bought a crate of the 6AS7 from Russia. I still have them and my 6SN7 collection if I should return to Atma-Sphere. My collection of quiet 12AT7s for the MP-1s phono-section are still here. I always try to keep the tubes.
 

microstrip

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Tim,
That is correct. Ralph’s amps will run on as few as one power tube per side, and even when I lost the 5 on my MA1s the amps still sounded great, the dynamics were just more constrained on the side that lost the most tubes (I think I lost 4 on the right amp and 1 on the left amp, with 3 of the 4 dead tubes on the right bank and 1 on the left bank).

I bought a lifetime supply of the Russian 6AS7 equivalent tubes several years ago. I know things are crazy right now, but the Chinese tubes sound quite good. The power tubes go for about $12 each. As you say, 6SN7s go from $15 to >$100 depending on flavor.

Evan
If you take tubes from one amplifier you should do the same from the other . Otherwise the system becomes unbalanced!

Just because of heat I sometimes operated the MA2s with half the power tubes.
 

Nuforce

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I must say I'm impressed that you can remove tubes in pairs without any amp fail.

Hopefully I'll be in a position to show what I've bought once I've finished price negotiation with tye dealer....

They are being mated to my magnepan 20.1 mid/tweeters via a sublime audio analogue crossover.
 

ACHiPo

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Thanks Evan for the confirmation. I don't know if it was a lifetime supply but several years I bought a crate of the 6AS7 from Russia. I still have them and my 6SN7 collection if I should return to Atma-Sphere. My collection of quiet 12AT7s for the MP-1s phono-section are still here. I always try to keep the tubes.
I think I have 3 crates of the Russian/Ukrainian power tubes plus at least a full set of Chinese tubes and probably 8 sets of 6SN7s. “nothing succeeds like excess!”
 

ACHiPo

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Feb 22, 2015
450
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Pleasanton, CA
I must say I'm impressed that you can remove tubes in pairs without any amp fail.

Hopefully I'll be in a position to show what I've bought once I've finished price negotiation with tye dealer....

They are being mated to my magnepan 20.1 mid/tweeters via a sublime audio analogue crossover.
That should be a great combo.
 

ACHiPo

Well-Known Member
Feb 22, 2015
450
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175
Pleasanton, CA
If you take tubes from one amplifier you should do the same from the other . Otherwise the system becomes unbalanced!

Just because of heat I sometimes operated the MA2s with half the power tubes.
Absolutely agree. My comment was meant to reinforce that the amps still operate safely and sound surprisingly good without a balanced number of operational tubes on each side, not that I would recommend it.
 

microstrip

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(...) I still have them and my 6SN7 collection if I should return to Atma-Sphere. (...)

Curious that your current Lamm's and Atmasphere are night and day sonically and technically and you still consider returning to Atmasphere. If it was not for heat I would still have the MA2's. I always admired the support and dedication of Ralph Karsten to this hobby - he even published schematics of his M60 and helped DIY people to build them and is always ready to share his knowledge with interested people.

Confession - I also still own a few boxes filled with 6as7g's ...
 

tima

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Curious that your current Lamm's and Atmasphere are night and day sonically and technically and you still consider returning to Atmasphere. If it was not for heat I would still have the MA2's. I always admired the support and dedication of Ralph Karsten to this hobby - he even published schematics of his M60 and helped DIY people to build them and is always ready to share his knowledge with interested people.

Different speakers make different amps more or less feasible.
Audio would welcome more people like Ralph.
 
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Nuforce

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Screenshot_20220421-084859.png

So I've successfully negotiated a fair price for these bad boys. They are the MK11.3 with self bias.

VERY excited to see how these fit into my system, compromising of :

Auralic Aries G2
Acuhorn R2R T with WE300 tubes
KR Audio P135 with EML 45 mesh globes
Sublime audio analogue crossover
Atma-sphere ma-1
Magnepan 20.1
Emotiva HC-1 for bass section
 
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LL21

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WOW! Congrats! Very exciting! When do they arrive?
 
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Nuforce

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WOW! Congrats! Very exciting! When do they arrive?
Next week. I'm trying to understand what each 6SN7 position does, I think the two nearest tube dial are the most important re sound impact. I've emailed Ralph to clarify but didn't get a response yet.
 

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