Hi all...
I am looking into a home-brew vari-mu comp and there is a heater arrangement with mixed AC and DC for different tubes.
The power transformer is a decent model capable of delivering 3.5A @ 6.3VAC... according to data sheet.
The mix between AC and DC is that the V1's are supposed to have DC and the rest AC. To get the DC there is a rectifier bridge (1000V/ 8A) that is brand new and all new capacitors.
According to the tube data sheets the tubes getting AC are two 6AL5's and two 12AT7's... a total draw of 1.2A @ 6.3VAC and the tubes getting DC are two ECC85 with a total draw of 0.87A @ 6.3VDC. All according to the attached schematic.
And there is also a 200mA/6.3V light bulb connected to the VAC.
When all hooked up it proves that the transformer delivers 6.0VAC but after the rectifier bridge it is only 6.15VDC which makes it hard to filter with a "normal" C-R-C filter.
My question, before tearing the supply apart, is if the total current draw is too big or if I should look into the rectifier bridge or the capacitors... or what else? Is it normal behavior or not?
Any advice is helpful I guess.
Best regards
/John
I am looking into a home-brew vari-mu comp and there is a heater arrangement with mixed AC and DC for different tubes.
The power transformer is a decent model capable of delivering 3.5A @ 6.3VAC... according to data sheet.
The mix between AC and DC is that the V1's are supposed to have DC and the rest AC. To get the DC there is a rectifier bridge (1000V/ 8A) that is brand new and all new capacitors.
According to the tube data sheets the tubes getting AC are two 6AL5's and two 12AT7's... a total draw of 1.2A @ 6.3VAC and the tubes getting DC are two ECC85 with a total draw of 0.87A @ 6.3VDC. All according to the attached schematic.
And there is also a 200mA/6.3V light bulb connected to the VAC.
When all hooked up it proves that the transformer delivers 6.0VAC but after the rectifier bridge it is only 6.15VDC which makes it hard to filter with a "normal" C-R-C filter.
My question, before tearing the supply apart, is if the total current draw is too big or if I should look into the rectifier bridge or the capacitors... or what else? Is it normal behavior or not?
Any advice is helpful I guess.
Best regards
/John