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Hi,
I just finished my first amp build. I ordered the parts from Mojotone and have primarily used a triode electronic layout to get it together. Starting it up for the first time, I put in the rectifier tube, turned it on & nothing unusual. I put in the preamp tube, turned it on, nothing unusual. I put in the power tube, plug in the speaker and 6-7 seconds later it makes a loud, high-pitched squeal so I unplugged it quickly. I then expressed my frustration in a very profane way after which I began to wallow in self-pity.
From what I have read in other posts that have experienced a similar sound the recommendation was to swap the OT blue & red wires. The OT from Mojotone (part NOS771) had a note specifically stating that "polarity is reversed from most originals - use the blue lead to B+ and red to output tube for correct polarity." I had followed this instruction as directed when putting it together.
I also have read in other posts to ignore the warning and swap the wires .... so I tried that and when I plugged it back in the pilot light didn't come on. So I assumed this was incorrect and that the sound must be something else so I swapped them back again. I gave it another attempt and the same squeal is there.
Any thoughts would be very appreciated. I have gone over all the connections a couple of times and was pretty sure I didn't miss anything. Pictures attached if that helps.
Cheers,
Matt
I just finished my first amp build. I ordered the parts from Mojotone and have primarily used a triode electronic layout to get it together. Starting it up for the first time, I put in the rectifier tube, turned it on & nothing unusual. I put in the preamp tube, turned it on, nothing unusual. I put in the power tube, plug in the speaker and 6-7 seconds later it makes a loud, high-pitched squeal so I unplugged it quickly. I then expressed my frustration in a very profane way after which I began to wallow in self-pity.
From what I have read in other posts that have experienced a similar sound the recommendation was to swap the OT blue & red wires. The OT from Mojotone (part NOS771) had a note specifically stating that "polarity is reversed from most originals - use the blue lead to B+ and red to output tube for correct polarity." I had followed this instruction as directed when putting it together.
I also have read in other posts to ignore the warning and swap the wires .... so I tried that and when I plugged it back in the pilot light didn't come on. So I assumed this was incorrect and that the sound must be something else so I swapped them back again. I gave it another attempt and the same squeal is there.
Any thoughts would be very appreciated. I have gone over all the connections a couple of times and was pretty sure I didn't miss anything. Pictures attached if that helps.
Cheers,
Matt
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