Freds in 6X5 psu?

[Brit01]

I'm referring to Bas's Hornemans psu for the Aikido. Don't have the schematic handy at this moment but I'm sure most of you know it.

It has 2 diodes and an 6X5.

Just wondering if a couple of Freds in place of the standard diodes would make any improvement here.

[Soonerorlater]

H Brit01,
According to my schematic (version 1), it states that you use 600v 1a fast diodes presumably instead of standard ones.

HTH Bill

[Soonerorlater]

Just wondering if a couple of Freds in place of the standard diodes would make any improvement here

Hi Brit01,

Just wondering if a couple of standard diodes in place of the Freds would make any difference at all here.


Is the necessity of using fast diodes instead of standard ones the issue your really getting at


Brgds Bill

[Brit01]

According to my schematic (version 1), it states that you use 600v 1a fast diodes presumably instead of standard ones.

HTH Bill

I was using 1N4007's.

I might give the FREDs a go then. Not sure if it will make a noticeable difference but always like to experiment.

Thxs

[Soonerorlater]

Normally I would go for Freds, UF4007'S etc instead of IN4007's to avoid switching noise.

I'm not sure though what happens to switching noise in a Graetz bridge, perhaps someone more knowledgeable could comment on this.

Brgds Bill

[Eli Duttman]

Performance of a hybrid bridge rectifier is dominated by the vacuum diodes. SS diode switching noise is blocked from entering the B+ rail. The reason for using good SS diodes is to ensure switching noise doesn't sneak into the signal path via the heater supply. UF4007s are easily snubbed into near silence (parallel with 10 nF. high WVDC caps.) and are quite inexpensive. There's no need to pay for FREDs or deal with the mechanical issues TO220 cases present.

[Soonerorlater]

Eli D.

Many thanks for your concise reply.

Brgds Bill

[Brit01]

Thxs Eli.


I've already got some FRED's in stock so no harm in experimenting I guess.