Posted by Art Grannell

February 29, 2012 - 07:53 pm

Bill, 1/2 watt resistors should be fine. I used whatever I had on hand, which in this case, was 100ohm, 1 watt carbon composition on the screens, and 1Kohm 1/2 watt metal film on the control grids.

Posted by Bill

February 29, 2012 - 01:58 pm

I have checked this and other sites about this mod and can't seem to come up with the wattage for the new 100 ohm screen stability resistors. I have 1/2 watt, but it looks like 1W in the picture. On Dave's installation, it looks like 1/2W size. I have all the other values. Thanks.

Posted by Bill

February 17, 2012 - 09:35 pm

Thanks Art. I have the cathode resistors on 2 lug terminals outside the amp on either cooling slot. Looks like it was meant for that.

Posted by Art Grannell

February 17, 2012 - 09:16 pm

I see no reason why a "conventional" 3/4 or 1 turn "pot" should not work just as well as the "trimmer" style that I use. The adjustment really doesn't require the precision that many multi-turn trimmers provide. If you want to adjust the bias from outside the chassis the conventional style should be easier to mount, however keep in mind that you will still need to access a cathode resistor to measure the voltage drop.

Posted by Bill

February 17, 2012 - 08:28 pm

I'm in the process of doing this mod and wanted some way of adjusting bias from outside the ST35. I have a 1/2W 5K linear pot that looks similar to the one Dave G. used in his amp. It only has one turn however. Does this allow enough flexibility to nail the bias? I also have a Bourns encased pot like Art uses, which has 24 turns, but is difficult to mount to provide outside access. Is one better to use than the other?

Posted by Lydia

February 10, 2012 - 01:58 am

Thanks Art, steve, I understand this and I truly appreciate the info! Lydia