In Reply to: Wow! 600mA choke...dunno if the rectifier will survive posted by Bas Horneman on January 29, 2004 at 01:36:17:
Bas, The choke is deliberately over-specified at 600mA. The mains tranny HT is nominal 359-0-350v, also rated at 600mA but the amplifier will not need all that juice: probably only 330mA or so. The 6.3v secondary windings can tolerate between them 20 amps but the load (including the 6D22S rectifiers) will only be 12 amps. So, I'm playing safe regarding power supply capacity.I agree with you that I could just try using a resistor instead of a choke and I probably will, but I don't want to wreck the 6D22S by using too high a capacitance so I thought I'd ask first. Actually, I'll probably split the power supply at that point; following the rectifier and 50uF smoothing capacitor, I'll use two 47 ohm resistors, each followed by 220uF smoothing capacitor, one feeding the left channel and the other feeding the right channel.
This is going to be a class A P-P amplifier (EL34s strapped as triodes, about 15W per channel), so power supply "stiffness" (low impedance) is not a prime concern. If it were, I'd probably be using SS rectifiers. Fatbottle is probably right about the noisiness of a resistor-smoothed PS so I should really the choke anyway; but, with the massive power tranny, two big (50W) OPTs and this heavy choke I can hardly lift the chassis. I don't want to do myself an injury! Besides, I'm hoping that any noise in the PS will be largely cancelled out by the fact that every stage in the amp will be balanced, because the design uses push-pull topology throughout.
Rgds,
Ray
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Follow Ups
- Re: Wow! 600mA choke...dunno if the rectifier will survive - Ray Moth 19:14:20 01/29/04 (2)
- Triode amp's POWER SUPPLY, cheapen it and suffer. - drlowmu 09:07:33 01/30/04 (1)
- Re: Triode amp's POWER SUPPLY, cheapen it and suffer. - Ray Moth 21:03:21 02/02/04 (0)