Air Tight ATM2 PLUS

[cuntigh]

Hello,
Just received my ATM2 new version today. I can only say it is promising as it has to burn in a bit more...
I wonder if someone here has experienced this beast and could help or advise on tube rolling.
The ATM2 Plus comes with the rebadged Air Tight Platinum tubes from EH. They are said to be adjusted for this amp, but from past experiences with nos tubes I know nos can be (in most cases) beneficial for sound quality.
Any opinion to share ?

Tubes are 4 KT88, 2 12AX7 and 4 6CG7/6FQ7.

 

[cuntigh]

A few photos

 

[dan31]

Sweet amp! I really like Airtight products. They are always on my list. Enjoy!

 

[Zeotrope]

Nice amp!
I’m considering this or the EL34 ATM-1S to power a desktop Wilson TuneTot (83dB sensitivity) system. Since I sit about 1m away from the speakers, I don’t need any more than about 18W, even for peaks, but curious how the two amps would sound relative to each other?

 

[cuntigh]

It’s difficult to answer because the KT family tubes is different from the EL one. It depends on what you like and listen. The KT has more slam, more bass, (I simplify) and the EL are more global and sweet sounding. That’s what you can notice firstly when you listen side by side these 2 amps.
So some could consider the EL for classical and KT for rock but it’s not true. I’ve known an opera singer who did prefer the ATM2 over the ATMs 1 and 3. He founded the KT88 superior on voices and he even used 2 ATM2 in mono for driving his ATC speakers ! As a professional singer, soloist with an international career and audiophile I think we trust his opinion.
So the sounding preferences and the rest of your system should be your judge.
For both amps you can go further if you change the tubes. I found the KR Audio KT88 better than the AT and the nos pre tubes are recommended in my opinion.

 

[Zeotrope]

Thanks! For my main system, I listen mainly to classical and jazz. For this system, I plan to listen to mostly rock/electronic.
Since the TuneTots are light on low end anyway, perhaps the ATM-2Plus will be better than the ATM-1S?
I know the price delta is 2X, but trying to leave that out, at least for now.

 

[cuntigh]

I think the same. In my opinion the ATM1 « s » is below the original 1 in SQ. I think the PS’s tube regulation is the mane reason for that.
A power supply regulation is expensive and difficult to do well. All the best and most expensive tube amps have a regulated tube power supply. In the 1 you have 2 GZ34 (5AR4) in the power supply.
The sound one the « S » compared with the original version is less dense, more ethereal, a bit thin. When the S version came out, Air Tight did propose for some time to the customers to choose between the old and new one, but the price was higher and the delay longer for the original one.
It means something.

 

[Zeotrope]

Interesting, thanks. And the 2 Plus power supply is not tube rectified?

 

[cuntigh]

No.

 

[Zero000]

Nice, solid, well built amp. I owned the original for some years i.e. the non-plus version.

I spent a serious amount of time finding the best tube combo for it.

For power tubes, Tesla KT88. So far ahead of anything else it was unbelievable. Last marketed as E.A.T. for a massive price hike. Find a quad and you will understand what I am saying.

The sound quality for me was so upper echelon nothing could beat the Tesla but the Air Tight used to literally eat them for breakfast (excuse the pun).

Next best NOS Tung Sol 6550. Nice, no question. It is extremely rare to find current production tubes that sound better than NOS ones I reckon after 40+ plus years of playing with the things. The Tesla KT88 managed it, with the massive compromise of not being reliable in the Air Tight. At the time, £80 a tube for the frequent failures wasn't an issue. Then Absolute Sounds and E.A.T. took over and fucked it all up as far as I was concerned with massive price hikes for the tube. If still available and you don't mind paying the price, try a quad. In that amp, as it was, in my system as it was, it was amazing. As they might be made now, which could be different, I cannot say.

My advice would be to take the risk, then sell them on if not happy.

However, if they still are what they were... you'll love this post for a very long time

 

[Zeotrope]

Nice, solid, well built amp. I owned the original for some years i.e. the non-plus version.

I spent a serious amount of time finding the best tube combo for it.

For power tubes, Tesla KT88. So far ahead of anything else it was unbelievable. Last marketed as E.A.T. for a massive price hike. Find a quad and you will understand what I am saying.

The sound quality for me was so upper echelon nothing could beat the Tesla but the Air Tight used to literally eat them for breakfast (excuse the pun).

Next best NOS Tung Sol 6550. Nice, no question. It is extremely rare to find current production tubes that sound better than NOS ones I reckon after 40+ plus years of playing with the things. The Tesla KT88 managed it, with the massive compromise of not being reliable in the Air Tight. At the time, £80 a tube for the frequent failures wasn't an issue. Then Absolute Sounds and E.A.T. took over and fucked it all up as far as I was concerned with massive price hikes for the tube. If still available and you don't mind paying the price, try a quad. In that amp, as it was, in my system as it was, it was amazing. As they might be made now, which could be different, I cannot say.

My advice would be to take the risk, then sell them on if not happy.

However, if they still are what they were... you'll love this post for a very long time

Well the "Plus" model has significantly changed how it uses the tubes, so I'm not sure if any of this applies...

Anyone tried replacement tubes for the 2Plus?

Also, I assume it still has a characteristic "tube sound", but to a lesser extent than an EL34, for example?

 

[Zero000]

Well the "Plus" model has significantly changed how it uses the tubes, so I'm not sure if any of this applies...

Anyone tried replacement tubes for the 2Plus?

Also, I assume it still has a characteristic "tube sound", but to a lesser extent than an EL34, for example?

How, precisely, does it change the use of the tubes?

 

[Zeotrope]

How, precisely, does it change the use of the tubes?

Air Tight did a good job describing this on the website - the "Plus" is a completely different design than the original model.

ATM-2P_AIRTIGHT

This website is AIRTIGHT official homepage of precision tube amplifiers manufacturer A&M LIMITED.

www.airtight-anm.com

 

[cuntigh]

You can change the tubes and re-bias the KT88. The Air Tight rebadged EH tubes are not the last word for SQ, far from it.
The KR Audio are in another league. Also the 6CG7 (I tried the GE) are far better. For the 12AX7 it is one own choice. I tried Valvo I60 and they were very good, but the RCA 5751 give another taste. Some Telefunken or Amperex will sound different for sure but I only tried Valvo and 5751. I can live with both.

 

[Zero000]

Air Tight did a good job describing this on the website - the "Plus" is a completely different design than the original model.

ATM-2P_AIRTIGHT

This website is AIRTIGHT official homepage of precision tube amplifiers manufacturer A&M LIMITED.

www.airtight-anm.com

Just read it. On the basis of that link, I would ask them what modern tubes they optimised it for.

I had a chat with the designer of Air Tight stuff at Munich a few, but not many years ago. Unfortunately he was in a wheelchair. Liked his high power 211 monos quite a bit. Not gonna buy a pair, though

 

[Zeotrope]

I think it’s more for the modern tubes, not the NOS which are now very hard to find.

 

[ava1962]

Hello
What is the price of the atm 2plus?

 

[cuntigh]

In Europe I think about 18000€.

 

[cuntigh]

Thé ATM2 plus comes with its own tubes (selected Electro Harnonix). When you switch with NOS and KR KT88, the sound is better.

 

[cuntigh]

At that time I also had ATM1 and my old ATM3. Except that the 3s fitted the M40.2 Anniversary better, I much preferred the EL34’s sound. But that’s me.