Hi Folks -
I had a nice opportunity to purchase a Gates SA-39B in beautiful condition this past spring and I am just now getting around to ordering some parts and putting it on the bench to try and breath some life back into it. When I purchased it, the previous owner said that when he last used it, it was in working condition but this was a number of years ago. I have been combing through the forms and am trying to put a little list together of what I should be checking before firing the thing up (Big thanks to EMRR et al). Perhaps you have something to add to the list?
I am wondering also about terminating the output - do I need to terminate the output with a 600 ohm resistor. I don't really have much experience with 600 ohm gear. It will be headed to the input of a fairly modern set of a/d converters.
-replace all power supply filter capacitors
-replace all film caps
-clean and verify all the shorting jacks for current balancing
-clean and inspect all tube sockets
-check tubes and perhaps order some matched sets of 1612s and 6V6s if needed.
-consider the Zener diode mod to replace neon bulb…
-verify R44 (33K/2W)
-consider mods for attack and release controls and moving them to the front of the faceplate - This seems like a nice touch.
-power up with current limiter to check for shorts
-power up and check all voltages
-verify tube balance at zero compression
-verify tube balance at no gain reduction, -5 and -10 db GR
-pull 6H6 and listen as a straight amp
- find a rack that will fit with a few spaces above and below for air circulation and then record something through it
What else b'ys?
I had a nice opportunity to purchase a Gates SA-39B in beautiful condition this past spring and I am just now getting around to ordering some parts and putting it on the bench to try and breath some life back into it. When I purchased it, the previous owner said that when he last used it, it was in working condition but this was a number of years ago. I have been combing through the forms and am trying to put a little list together of what I should be checking before firing the thing up (Big thanks to EMRR et al). Perhaps you have something to add to the list?
I am wondering also about terminating the output - do I need to terminate the output with a 600 ohm resistor. I don't really have much experience with 600 ohm gear. It will be headed to the input of a fairly modern set of a/d converters.
-replace all power supply filter capacitors
-replace all film caps
-clean and verify all the shorting jacks for current balancing
-clean and inspect all tube sockets
-check tubes and perhaps order some matched sets of 1612s and 6V6s if needed.
-consider the Zener diode mod to replace neon bulb…
-verify R44 (33K/2W)
-consider mods for attack and release controls and moving them to the front of the faceplate - This seems like a nice touch.
-power up with current limiter to check for shorts
-power up and check all voltages
-verify tube balance at zero compression
-verify tube balance at no gain reduction, -5 and -10 db GR
-pull 6H6 and listen as a straight amp
- find a rack that will fit with a few spaces above and below for air circulation and then record something through it
What else b'ys?
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