50Hz hum DIY project
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Re: 50Hz hum DIY project
(deleted)
Last edited by matt h on Fri Mar 27, 2015 4:40 am, edited 1 time in total.
Re: 50Hz hum DIY project
Ok, i've split the busbar in two parts, so i grounded the power bus at the screen side, and the signal bus at the input side. I'm not shure this is the correct way.
Then i connected the unused pins of one half of the PI valve, and grounded them. I also scoped the HT at the PI and the recovery stage V3 with no noticeable abnormalities.
I also placed a ,01 cap in parallel with the V3 cap, with no noticeable difference.
V7 does not exist by the way, i just overlooked it
I also pulled all the other valves before the PI, with no difference.
Then i connected the unused pins of one half of the PI valve, and grounded them. I also scoped the HT at the PI and the recovery stage V3 with no noticeable abnormalities.
I also placed a ,01 cap in parallel with the V3 cap, with no noticeable difference.
V7 does not exist by the way, i just overlooked it
I also pulled all the other valves before the PI, with no difference.
Re: 50Hz hum DIY project
(deleted)
Last edited by matt h on Fri Mar 27, 2015 4:37 am, edited 1 time in total.
Re: 50Hz hum DIY project
The heaters are full ac right now.
The voltage between cathodyne cathode and ground is 40V.
I'm thinking of elevating the heaters to a 20V reference.
Maybe it could help.
At rehearsal the hum is barely noticeable, but at home it disturbs me a little
And practice makes perfect, so it has to be solved!
At the end it wil work!
Thanx
The voltage between cathodyne cathode and ground is 40V.
I'm thinking of elevating the heaters to a 20V reference.
Maybe it could help.
At rehearsal the hum is barely noticeable, but at home it disturbs me a little
And practice makes perfect, so it has to be solved!
At the end it wil work!
Thanx
Re: 50Hz hum DIY project
(deleted)
Last edited by matt h on Fri Mar 27, 2015 4:45 am, edited 1 time in total.
Re: 50Hz hum DIY project
I tied them all to ground.
Re: 50Hz hum DIY project
(deleted)
Last edited by matt h on Fri Mar 27, 2015 4:45 am, edited 1 time in total.
Re: 50Hz hum DIY project
Made a ground reference at 40VDC. There is less hum, still a little bit, but acceptable!!!
My AC30 heritage is a lot noisier!!!
I gigged it last weekend, before i did the elevated heater ground, with no issues at all.
Not even hum, i think. As there was some background noise.
I added the elevated heater to experiment, and am going to leave it there, cause it does improve the silentness of the amp.
Is it ok to connect it to the screen cap, and then to ground at the same cap??
Maybe a dumb question, but is it possible to connect the heater ground reference to the cathode of the phase inverter, or is that just asking for trouble?
Thanx for all the help guys,your the best!!!
My AC30 heritage is a lot noisier!!!
I gigged it last weekend, before i did the elevated heater ground, with no issues at all.
Not even hum, i think. As there was some background noise.
I added the elevated heater to experiment, and am going to leave it there, cause it does improve the silentness of the amp.
Is it ok to connect it to the screen cap, and then to ground at the same cap??
Maybe a dumb question, but is it possible to connect the heater ground reference to the cathode of the phase inverter, or is that just asking for trouble?
Thanx for all the help guys,your the best!!!
Re: 50Hz hum DIY project
(deleted)
Last edited by matt h on Fri Mar 27, 2015 4:43 am, edited 1 time in total.
Re: 50Hz hum DIY project
That's just what i wanted to know thanx.
Re: 50Hz hum DIY project
That's just what i wanted to know thanx.
Re: 50Hz hum DIY project
I kept searching to get the last little bit of hum out. It appeared to be
the bias supply after all.
the bias supply after all.