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I've been checking this forum out for a while but as I have only built one amp until now have had no reason to post. I just finished assembling a second Champ kit that I have built previously without incident. It is basically a 5F1 with the addition of a tone control and master volume. The first kit was a single 6V6 whereas this is running two 6V6's in parallel with the help of beefier transformers.
The symptoms are:
1) When first fired up it worked as it should but the normal operational hum seemed a bit too noticeable.
2) After some time playing through it - couple hours - the fuse blew. The fuse was a 1 amp and may have been a bit small. Replaced with 1.5 amp.
3) After the fuse blew the volume output became very low - full on the amp sounds like it's on 1. Some crackles/pops that accompany the output increasing for an instant then back to low volume. edit: the volume creeps back toward normal with some crackles as the note decays - so, (i'm guessing) when the signal voltage is at it's highest something is failing and as the voltage decreases it approaches normal operation - would this indicate anything?
-I've tried various tube substitutions with no improvement.
-I've checked and rechecked the wiring and all seems good.
-I've taken numerous voltage readings but am unsure what measurements would help in diagnosing. edit: the most noticeable voltage variation from normal is pin # 6 12ax7 (the plate voltage driver stage according to the manual). Normal voltage is listed @ 145v-180v. Measures 107v - what might this indicate?
My knowledge of amp-speak is limited but I have built numerous guitar effects and am not a complete noob to electronics but neither do I have an EE degree or alot of amp experience.
I'm trying to figure out if it might be something minor like a cap or major like a transformer.
Any and all help is much appreciated.
The symptoms are:
1) When first fired up it worked as it should but the normal operational hum seemed a bit too noticeable.
2) After some time playing through it - couple hours - the fuse blew. The fuse was a 1 amp and may have been a bit small. Replaced with 1.5 amp.
3) After the fuse blew the volume output became very low - full on the amp sounds like it's on 1. Some crackles/pops that accompany the output increasing for an instant then back to low volume. edit: the volume creeps back toward normal with some crackles as the note decays - so, (i'm guessing) when the signal voltage is at it's highest something is failing and as the voltage decreases it approaches normal operation - would this indicate anything?
-I've tried various tube substitutions with no improvement.
-I've checked and rechecked the wiring and all seems good.
-I've taken numerous voltage readings but am unsure what measurements would help in diagnosing. edit: the most noticeable voltage variation from normal is pin # 6 12ax7 (the plate voltage driver stage according to the manual). Normal voltage is listed @ 145v-180v. Measures 107v - what might this indicate?
My knowledge of amp-speak is limited but I have built numerous guitar effects and am not a complete noob to electronics but neither do I have an EE degree or alot of amp experience.
I'm trying to figure out if it might be something minor like a cap or major like a transformer.
Any and all help is much appreciated.