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In Reply to: RE: Over my head posted by patmcsween on July 01, 2009 at 14:02:22
This board really looks to be made to turn on one transformer (a dedicated filament transformer to warm up the 300B's), then another (the high voltage trasnformer). I see it on the Sophia site that they say
"Q: I have an extremely (3) modded out Dynaco Mark IV style amps that use solid state rectification so there is no 5 volt filament for the rectifier.
A: Not a problem. You can use the relay between power transformer supply secondary winding."
The relay says 240v... The MK-IV has a 720V secondary. This is terrible advice, don't do this in the Paramount! This is some decent advice...
"A: We have used this relay (10A version) in amplifer (550V) without any problem. However, we would recommend you to seek the most efficient way:
1. If you can control the primary (120V AC) instead of secondary (usually high plate DC voltage).
2. You may consider to control the rectifier tube filament. So you would not get turn on jump."
I think the only "good" way to do this would be to switch the HV ground coming off the power supply PCB. I'm sure PJ will chime in on this.
If memory serves, there was some kind of feature built in to the Paramount Power Supply board to allow for switching something - a search of the forum might yield some relevant info.Found the link - see below.
Edits: 07/01/09
so I think I see where to connect the "switching" wires from the delay board into the psb (replace the jumper), but im at a loss as to where to get 6.3v AC for the board supply.
There is 6.3V AC going to the heater on the 12AT7, but I don't know if the transformer supports higher current than the 12AT7 uses. That is a question for Paul Joppa.
Remember, YOU are the only one who needs to be happy with the sound of your system
Grainger Morrison
There Is Only One (Grainger Morrison, it seems)
Both the Paramount and the Paramour II power transformers are rated for maximum 1.2A rms AC current.
The 6.3v winding should have close to 1A of AC current available (just enough for a 6DN7).
IIRC the stock driver draws 0.3A for the heater. That leaves 0.7A for the timing circuit.That is if you are using the 12AT7 for the driver.
And follow Caucasian Blackplate's advice concerning what to switch.
Remember, YOU are the only one who needs to be happy with the sound of your system
Grainger Morrison
There Is Only One (Grainger Morrison, it seems)
Edits: 07/04/09
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