Hi all, brand new member. I've had Dynaco equipment for years, but I've always hired technicians for repair and upkeep. I've decided to learn some rudimentary electronics during the "Covid break"... I appreciate your patience, as I'm only taking my first steps into this world!
I traded a pair of Dynakit MKiii mono blocks for a nice VTA ST70. It worked fine except for occasionally blowing fuses more and more frequently. After some digging around online, I decided to replace the rectifier tube with a SS one from Weber. I fired it up and it worked.
After adding the SS rectifier, I wanted to bias the tubes. I noticed that only one bias pin on the front socket was reading any voltage. Everything I see says there should be two, one for each tube... from my understanding, one of the luxuries of the updated board is so that you can bias each tube individually!
When adjusting both pots on one channel, I see the voltage goes up and down. It seemed like both tubes are hooked up to one pin on the front socket.
I opened up the amp, and sure enough, the front bias socket only has one wire heading to the tubes, which appear to be connected. Has anyone seen this done before? I really would rather have it set up the "right" way... but I'm afraid i'm not willing to experiment on this valuable piece of equipment. Any advice is much appreciated.
I've attached a photo, hopefully it makes sense. Thanks a bunch.
EDIT: I'm not allowed to post a photo for a few days. I'll try again soon.
I traded a pair of Dynakit MKiii mono blocks for a nice VTA ST70. It worked fine except for occasionally blowing fuses more and more frequently. After some digging around online, I decided to replace the rectifier tube with a SS one from Weber. I fired it up and it worked.
After adding the SS rectifier, I wanted to bias the tubes. I noticed that only one bias pin on the front socket was reading any voltage. Everything I see says there should be two, one for each tube... from my understanding, one of the luxuries of the updated board is so that you can bias each tube individually!
When adjusting both pots on one channel, I see the voltage goes up and down. It seemed like both tubes are hooked up to one pin on the front socket.
I opened up the amp, and sure enough, the front bias socket only has one wire heading to the tubes, which appear to be connected. Has anyone seen this done before? I really would rather have it set up the "right" way... but I'm afraid i'm not willing to experiment on this valuable piece of equipment. Any advice is much appreciated.
I've attached a photo, hopefully it makes sense. Thanks a bunch.
EDIT: I'm not allowed to post a photo for a few days. I'll try again soon.
Last edited by rollinlikemarcbolan on Mon Jul 20, 2020 10:51 am; edited 1 time in total (Reason for editing : image not displayed)
