Upscaleaudio is right.
The ARC amp requires closely matched tubes and you have to remove the lid and use a digital voltmeter to set the bias correctly. The CJ Premier amps on the other hand are open chassis designs and bias is independently adjustable for each tube using a built-in LED indicator for each adjustment. It's a more forgiving design and also easier if you enjoy "tube rolling".
Here's me screwing around with the ARC VT100MKII earlier today. I just retubed it replaceing all 16 tubes. Ouch!
http://mycollins.net/audio/vtcj4.html
The ARC amp requires closely matched tubes and you have to remove the lid and use a digital voltmeter to set the bias correctly. The CJ Premier amps on the other hand are open chassis designs and bias is independently adjustable for each tube using a built-in LED indicator for each adjustment. It's a more forgiving design and also easier if you enjoy "tube rolling".
Here's me screwing around with the ARC VT100MKII earlier today. I just retubed it replaceing all 16 tubes. Ouch!
http://mycollins.net/audio/vtcj4.html