Dared VP-845 Bias Adjustment? 845W Tubes?

Ok, Thanks. I'm just going to spend a couple hundred on some pairs of 6sn7's and see what I like best. I'm going to get the 845's upgraded first so I can see which 6sn7 I will like best with them. I'll update what I'm buying. Thanks.

Brian

I have an older version of dared 845 and have been contemplating about getting 845M. But I was worried about low dissipation power rating of 845M than stock 845. Ken do you see, any redish glowing on the plate of 845M on your dared under room light off? thanks.

What year is your VP-845 Rdk845?

To hijack an old thread, I have to agree that the Chinese Shuguang 6N8 (6SN7) is a damn nice sounding tube in the VP-845. I got into "tube rolling" pretty hot and heavy for a while with this thing; using old used, NOS, the ones that people recommend. Much to MY surprise, I keep coming back to the stock Chinese Shuguang 6N8. When the best sounding brand of tube in your amp is still in production and costs $20 - $25 a set, that's a pretty good problem to have!

I have had a VP-845 for a couple of years and I have learned a few things about this amplifier (not everything). I'll cover some bases. For the 6sn7 NOS tubes I have only tried RCA GTB black ladders and Sylvania chrome dome black base green print. While they were nice, much to my surprise the Shuguang 6n8 offered a more dimensional performance. It came time to replace these and I purchased (off ebay) some Shuguang 6n8 T which is supposed to be the top grade of this basic tube $25 for the pair. I got the same results. This tube works very nicely in this amp. I replaced the output tubes with Shuguang 845b tubes and these are quite nice, doing practically everything better than the basic 845. The stock Shuguang 12ax7 is......junk. I had the opportunity to try several current production 12ax7 tubes because a friend has a preamp that uses these and he has LOTS of current production tubes. I found of his tubes the Tung Sol Russian made 12ax7 sounded best. Now, I am using Psvane Treasure cv-181 for 6sn7 duty and Psvane Treasure 12ax7 in my amp and they handily stomp what I was using before. Greater transparency yet more liquid and luscious.

Regarding bias, there are 2 adjustable pots on the inside of the amp. Leave you speakers hooked up, tip your amp on it's side and place something solid under the transformer so it doesn't tip over. It should be pretty solid now. Remove bottom plate. Locate the pots. The bare shafts are small and slotted. Get a small screwdriver with a PLASTIC OR RUBBER handle. Turn amplifier on and let it warm up for 30 minutes. Now keep in mind that you need to be VERY careful when working in the amp because there is voltage inside of that thing that is as high as 1000 volts and the could very easily be fatal. The left channel pot is on the left side of the amp. Listen VERY closely to your left speaker. Adjust pot back and forth until you find the spot with the LEAST amount of noise (buzz, hum, hiss). Repeat with the right channel. Shut the amp off and reassemble. It is not a bad idea to do this whenever you change output tubes. One last thing; before putting in the 845 tubes lightly polish the pins with 2000 grit paper. Clean the pins with a 90% or greater solution of alcohol. LIGHTLY (and I mean lightly) coat the pins with Permatex Dielectric Grease. WITH THE AMPLIFIER DRAINED, OFF AND UNPLUGGED clean the 845 sockets with a Q Tip and alcohol. Let it all dry and reassemble. The alcohol and Permatex works for the other tube pins and sockets too. Just remember, too much and it will cause sonic degradation. A SUPER thin coating on JUST the tube pins will due.