Help with re-tubing an ARC VT100 MkII

Jea48

I retubed my VT100 MKII using the instructions above from Collins. A matched octet(8) from Upscale audio will cost about $240. A set of 8 low noise input tubes 6H23 (6922) will cost about $200. Total $420 plus shipping. You may want to speak to kevin Deal at Upscale. You must use input tubes with close tolerances.

that's a lot of money they charge, these ARC guys. I am considering this amp myself and curious what the outcome of this will be as far as what you can do yourslef vs what has to be done by ARC. As far as buying tubes for my ARC LS-15 pre, I had great experience with www.upscaleaudio.com
Kevin really knows his stuff and their tube matching is very reputable. So far the tubes I got from Kevin made my pre-amp sing and I tried a lot of tubes from lots of different stores. You may actually save some money with UpscaleAudio vs. ARC. Just a thought.

Jea48...yes there are bias adjustments for the input tubes as well as the output tubes.

Gmorris and Rlips...thanks for the input. I have the Collins site and have printed it. The biasing of the input tubes however, looks a little difficult. Any further thoughts?

Audphil1, thanks also, I'll give Kevin a call.

Louis:

The biasing of the input tubes is very tedious and requires several iterations to obtain the optimal settings. It is easier if you have two digital voltmeters and several clip-on cables for the test points. You must bias the input tubes first.

For the output tubes use a rough setting prior to burn-in. There will be some drift of the bias as the tubes burn-in. You need to repeat the final bias after the tubes are sufficiently burned in.