Air Tight ATM2 PLUS
- Thread starter cuntigh
- Start date
In my opinion the fact that the ATM2 « eats » the tubes comes from the non tempo applied on the power tubes when you switch it on.
Don’t understand why they did it on the ATM3, but not on the ATM1S and both the 2 and the 2+.
Another problem for such a high priced amps is there is no rectifier tube(s). When you switch the amp on, these tubes protect the power tubes and so they last longer and the electron flow is regulated.
We all understand a diode is less difficult to build and less costly for the manufaturer…
The first generation ATM1 (non S) was built with 2 5AR4 / GZ34. The S generation took them off. First the sound is changed, less body, and second : power tubes are literally eaten and don’t last as long as they should. I still have my ATM1, and not willing to sell it.
Don’t understand why they did it on the ATM3, but not on the ATM1S and both the 2 and the 2+.
Another problem for such a high priced amps is there is no rectifier tube(s). When you switch the amp on, these tubes protect the power tubes and so they last longer and the electron flow is regulated.
We all understand a diode is less difficult to build and less costly for the manufaturer…
The first generation ATM1 (non S) was built with 2 5AR4 / GZ34. The S generation took them off. First the sound is changed, less body, and second : power tubes are literally eaten and don’t last as long as they should. I still have my ATM1, and not willing to sell it.
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Install a ntc thermistor type cl 60 in the primary side of maintransformer and the eating of tubes is over.
Shematic exsample
Shematic exsample
I would not feel comfortable fitting a CL60 to a class A/B 2x80W high-end tube amplifier amplifier.
of course yes, an ntc resistor cl60 has 10 ohms when cold, limits the inrush current of the amplifier for 2 seconds, after that the ntc has about 0.15 ohms. This protects the filaments and cathodes of the tube.
I would recommend for all amplifiers that work with ss retifer (diodes).
i have svetland el 34 in my push pull amp in service for eight years no failure until now.
A technical video
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As far as I remember this NTC has such resistance (around .2 ohm) at maximum current (5A) . At 25% the load it is around 1 ohm and this resistance modulates with the current - it is why I do not recommend them particularly in class A/B. .
That's right, you have to adapt an ntc to the amplifier if you want it to be perfect. Most amplifier nameplates show the contoured power consumption in watts. Dividing the wattage by the mains voltage gives the current. You may need to choose another NTC type. They should be in the range of 80-100%, then this has no audible influence. Since I don't know the power consumption of the amplifier, safety comes first with this NTC. it's easy on your wallet, especially when very good tubes are in use.
Unfortunately a measurement will be needed , the power consumptions listed can't be trusted. And it is not possible to use them in the 80-100% zone with class A/B, that often have a dynamic range of current around x3 or x4.
IMO such adaptation should be left to experts in electronics.
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