Anyone using Airtight ATM 211 to recommend?

mtemur

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Mar 26, 2019
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Dear @BP4007 @Dante Choi @bonzo75 and @ogschile I hope you are biasing your amplifier every time you change 211 tubes cause output tubes need proper biasing. especially when you are tube rolling.
Additionally every tube (even the used old stock ones) requires at least 20 hours of burn in after a long unused period. I believe IOT accurately evaluate an output tube's sound, biasing and burn in period should not be skipped.

I hope your prior comments about sonic differences of various 211 tubes are based on regarding these considerations.
 
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cuntigh

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Dec 20, 2014
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Tube amps need to be biased regularly, not only when you change the tubes. Auto biased tube amps are ideal for that matter. With Air Tight it is very easy to do. If you biase high or low you can modulate the sound quality. With ATM3 and ATM1S we are several users who found the sound better when power tubes are biased lower than recommended by the manufacturer.
 
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mtemur

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Mar 26, 2019
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Tube amps need to be biased regularly, not only when you change the tubes.
thank you, output tubes also need to be biased when the line voltage changes. biasing in general is very important and needs to be done regularly as you mentioned but my prior comment based on tube rolling.
 

new2Krell

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Feb 9, 2020
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Tube amps need to be biased regularly, not only when you change the tubes. Auto biased tube amps are ideal for that matter. With Air Tight it is very easy to do. If you biase high or low you can modulate the sound quality. With ATM3 and ATM1S we are several users who found the sound better when power tubes are biased lower than recommended by the manufacturer.
I guess it all depends on where the manufacturer specified the bias level. I don't know anything about ATMs.
I have EL34's in my amps, the "usable" range is 50 - 70%. The manufacturer specifies 26-29 ma (52 - 58%), already at the lower end of the range. I have just settled on a bias level of 53% for my recently installed tubes. I find I get the best sound from my amps when biased "cool".
 

Dante Choi

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Feb 26, 2016
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Finally sold my ATM-211, have changed by Audio Note UK Ongaku Shinguru. If some one love 211, please consider ANUK…

I love Amperex 211D, but not possible to use with my Ongaku’ auto bias. I’m using with original WE-242C, incredible sound.
 
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BP4007

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Mar 7, 2018
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Mine are extremely quiet. Using with Horning (99db) and Zingali (98db) speakers. Your Altec's are a bit more sensitive, but I have not had an issue with background noise. Dead quiet. Using Air tight ATE 2001 pre.
 

Norway

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Mar 26, 2022
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Mine are extremely quiet. Using with Horning (99db) and Zingali (98db) speakers. Your Altec's are a bit more sensitive, but I have not had an issue with background noise. Dead quiet. Using Air tight ATE 2001 pre.
Thanks for your reply. My VOTTs are a bit more than a bit more sensitive.
 

Dante Choi

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Feb 26, 2016
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I have the possibility to get a pair ATM-211(at a very good price) but not sure that they will be quiet enough on my Altec VOTT s.
I have used to drive Vitavox CN-191, maybe 105db… was very good matching. Please try to found Amperex brass base with molibdeno plate 211 or Amperex 211D also brass base.
 

Legolas

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Dec 27, 2015
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I have the possibility to get a pair ATM-211(at a very good price) but not sure that they will be quiet enough on my Altec VOTT s.
Interesting.I do like the 211 tubes, and wildly available as well. One thing I notice about these monoblocks, they both have an attenuator. Is that for balancing the input level while using a preamp?
 

Maril555

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Jun 26, 2014
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Interesting.I do like the 211 tubes, and wildly available as well. One thing I notice about these monoblocks, they both have an attenuator. Is that for balancing the input level while using a preamp?
Its mostly for adjusting the overall gain structure of the system. For instance, if you have a high gain preamp and sensitive speakers, then you’ll have an opportunity to lower the power amp’s input sensitivity, etc.
Many older amps had that feature, all Shindo amps do to.
 

BP4007

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Mar 7, 2018
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Agree on the Amperex 211 tubes. I have tried many NOS tubes and found the Amperex to be the best. If buying new, consider the Elrog 242 (if you can find them), or the new Psvane 242's. I'm running the Amperex in my Air Tight 211 mono's, with the Air Tight ATE 2001 for a pre amp, Horning Eufrodite, or Zingali speakers. Love the set up.
 

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