Jubilee 2550 clone - better grounding or hum reduction advice
Posted: Fri Oct 19, 2018 1:35 am
I have had a Marshall 2550 for some years now and decided to build a clone and sell the original.
While the clone sounds very similar to the original, it also exhibits many of the same nuances, of which are the same in the Marshall - and I would love to address and resolve them if possible!
Firstly the hum and noise. With all 3 (gain volume and master) set at 1oclock + both amps hum, badly. Its not the house power, as ever room I have gigged at is the same with this amp.
I have heard a few YouTube jubilee clones that are quite, quiet. How was the grounding done to minimize this? I have a ground buss and the preamp section is separate from the power and all come to one ground point. The input is shielded, but the fx loop is not. Could this be a source of big hum @ high gain levels?
The input gain pot is the biggest culprit of deep hum, most likely 60cyl.
Has anyone built one of these and gotten them quiet at high gain and high volume?
Next is the pot taper on the 1 meg push/pull pots. Both amps are the same. The pot had little movement in perceived volume from 0 to 12 o'clock. Is there a different pot value and taper that could have the volume coming up sooner driving the preamp section earlier?
I would really love some advice and wisdom on how to minimize the deep 60cyl hum in this amp and Change all 3 volume pots!
Thanks for your time and wisdom, I am ready to try anything out at the moment.
Stephen
While the clone sounds very similar to the original, it also exhibits many of the same nuances, of which are the same in the Marshall - and I would love to address and resolve them if possible!
Firstly the hum and noise. With all 3 (gain volume and master) set at 1oclock + both amps hum, badly. Its not the house power, as ever room I have gigged at is the same with this amp.
I have heard a few YouTube jubilee clones that are quite, quiet. How was the grounding done to minimize this? I have a ground buss and the preamp section is separate from the power and all come to one ground point. The input is shielded, but the fx loop is not. Could this be a source of big hum @ high gain levels?
The input gain pot is the biggest culprit of deep hum, most likely 60cyl.
Has anyone built one of these and gotten them quiet at high gain and high volume?
Next is the pot taper on the 1 meg push/pull pots. Both amps are the same. The pot had little movement in perceived volume from 0 to 12 o'clock. Is there a different pot value and taper that could have the volume coming up sooner driving the preamp section earlier?
I would really love some advice and wisdom on how to minimize the deep 60cyl hum in this amp and Change all 3 volume pots!
Thanks for your time and wisdom, I am ready to try anything out at the moment.
Stephen
