The nice thing with McCormack is that you can send it to SMc Audio and have it upgraded. Letting know what is in your system can help them customize the upgrade.
The person is not a tech professional, he said his MacCormack kept resetting when connected to BAT VK-5i and he bought a different tube power amp. I wonder if it was a current draw issue etc, hence I am asking if you experienced any issues or had to do something special, as I am glad you have the set up working well for you.
If you like what you’re hearing and the 0.5 has enough power, I’d strongly consider sending it to SMcAudio for upgrades as it will be a surefire huge improvement over what you have now. Older DNA amps will eventually experience input board failure, which is basically fatal and requires a complete rebuild so beware. I have no idea about the BAT amp. Hope this helps, and best of luck.
There is nothing about BAT gear that makes it incompatible with my DNA amp designs. I know of quite a few people who run this combo happily. However, the original DNA-1 and 0.5 amps have a protection circuit that monitors the output for excessive DC levels. This circuit has a cut-off frequency around 5Hz and it can be "fooled" by high amounts of infrasonic noise, such as that produced by some noisy tubes (triggering the protection circuit clamps both inputs to ground so the amp goes silent). I have run into this a few times over the years, and the solution was to either find quieter tubes, or reduce the sensitivity of the protection circuit.
The upgrades I offer change a lot of things in the amps, and one of them is to eliminate both the DC servo and protection circuit for performance reasons, which also eliminates this problem. (There is no downside to this - your speakers are still well protected.)
There is no reason to expect that you would run into this issue with a BAT or any other tube preamp, but it can happen. If you have any more questions about this or a possible upgrade, please contact us directly.
Steve McCormack - SMc Audio (please note the new .net domain)