Most other electronics fault finding channels show logical, relatively easy, trouble-shooting and fixes. Your amps always seem to have the weirdest problems! I admire your tenacity and skill, my friend!
Thank you. Yep, I did, 3% Ag. I have four Tek 500 series scopes, worked on them for years & have a few precious rolls of Tek solder but also have another four different types of Ag solder too. I have spare ceramic wafers if you need any. TFW.
Andy- Sometimes just the way components and wiring is located can cause oscillation. I have seen a bug get in between pins on a tube not fully seated and become a "resistor". (Carbonized bug). In transmitters and some oscillator circuits, especially at high and VHF freq we used to take a jewelers saw and cut a slot in between tube pins to reduce capacitance, possible leakage, or arc over. Weird but it worked. I see your tube uses "coin bases" , which was used typically towards the end of tube production to cut down the cost of making Bakelite bases.
No idea what caused the issue, I tested them when I bought them. Anyhoo, the valve is KO'd, I'm sure it has heater cathode short too. The thin bases are a pain, nowhere near as good as a proper base, care needed when swopping valves. TFW as always.
Most other electronics fault finding channels show logical, relatively easy, trouble-shooting and fixes. Your amps always seem to have the weirdest problems! I admire your tenacity and skill, my friend!
It's mainly this amp, but yes, my amps have odd faults. Thanks for your kind words, there's more weirdness to come with this amp. TFW.
I think you should call on Paul Carlson, he'll come flying over the Atlantic wearing his cape and underpants outside his tights and sort your problem!
Thanks for your IP. Used to watch Mr C but no longer. I can sort the problem but like to share my FU's as well as my successes. TFW.
Nice amp. I like the Tektronix ceramic terminal strips there - I hope the maker used a lead-free solder with silver (common Sn97Ag3 should do).
Thank you. Yep, I did, 3% Ag. I have four Tek 500 series scopes, worked on them for years & have a few precious rolls of Tek solder but also have another four different types of Ag solder too. I have spare ceramic wafers if you need any. TFW.
big green monster has come back nice amp
Looks nice, now I have to get it to sound nice. TFW
Andy- Sometimes just the way components and wiring is located can cause oscillation. I have seen a bug get in between pins on a tube not fully seated and become a "resistor". (Carbonized bug). In transmitters and some oscillator circuits, especially at high and VHF freq we used to take a jewelers saw and cut a slot in between tube pins to reduce capacitance, possible leakage, or arc over. Weird but it worked. I see your tube uses "coin bases" , which was used typically towards the end of tube production to cut down the cost of making Bakelite bases.
No idea what caused the issue, I tested them when I bought them. Anyhoo, the valve is KO'd, I'm sure it has heater cathode short too.
The thin bases are a pain, nowhere near as good as a proper base, care needed when swopping valves. TFW as always.
Tin whisker is by guess on the tube . Lead free solder is more of a problem than many think .
Could be right, though there is no lead free solder used on this amp. It's all 60/40 or 3% silver solder on the Tek wafers. TFW.
@@diabolicalartificerIronically you just stated the likely cause of the problem
Amplifiers do oscillators don't. My corollary to Murphy's Law.
Sounds like a Zen Koan, thou hath uttered great truth brother : ) TFW.
@@diabolicalartificer, all oscillators are amplifiers and all amplifiers are oscillator-wannabe's!
@@goodun2974 Yep, another truism. They're endlessly fascinating and frustrating at the same time, bit like some women I've known. TFW.