Hello DX community,
I'm trying to set my Plate voltage on a homebrew 4cx300 amp. I'll take any voltage from 1.5 to 2kv but I'm also having a measurement issue. I'm getting higher voltage than expected post-V. Doubler. I'm feeding 920-30 AC into it and getting about 2.5 out, which is too high. I presume my meter is reading peaks? I should have about 875vac max, is that right?
Both my plastic VOM and RCA Voltohmyst w/ HV probe display the same values in & out. How can I adjust for load when measuring pre-completion (no tubes inserted)? Transformer is from an AL572 amp (w/ buck boost) but I don't have the jumper board pictured in the Ameritron paperwork/manual (instructions premised upon the wires being assigned letters A, B, etc). I can only judge by the color of the buck boost wires (Orange, Blue, Grey).
Currently the Blue is disconnected; AC fed to: 1.) Grey and; 2.) Striped Brown & Black wires together. The solid Brown & Black wires are tied to the Orange wire. This yeilds about 930vac which is better than the 1100v I got previously. I'm still about 75vac too high. Is this as low as I can get it given my 120vac input?
neil, NYC
I'm trying to set my Plate voltage on a homebrew 4cx300 amp. I'll take any voltage from 1.5 to 2kv but I'm also having a measurement issue. I'm getting higher voltage than expected post-V. Doubler. I'm feeding 920-30 AC into it and getting about 2.5 out, which is too high. I presume my meter is reading peaks? I should have about 875vac max, is that right?
Both my plastic VOM and RCA Voltohmyst w/ HV probe display the same values in & out. How can I adjust for load when measuring pre-completion (no tubes inserted)? Transformer is from an AL572 amp (w/ buck boost) but I don't have the jumper board pictured in the Ameritron paperwork/manual (instructions premised upon the wires being assigned letters A, B, etc). I can only judge by the color of the buck boost wires (Orange, Blue, Grey).
Currently the Blue is disconnected; AC fed to: 1.) Grey and; 2.) Striped Brown & Black wires together. The solid Brown & Black wires are tied to the Orange wire. This yeilds about 930vac which is better than the 1100v I got previously. I'm still about 75vac too high. Is this as low as I can get it given my 120vac input?
neil, NYC
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