RB 981 recifier bridge

[Smiffy]

Hi All
The rectifier bridges in my RB981s are all bypassed with disc ceramic caps.
Presumably to remove rf noise or diode switching noise?
Is it safe to remove them and would there be any audio difference if I did?
Ta for any inf

Smiffy

[Mooly]

Don't know why you would want to remove them but yes it is safe to do so.

They really do work to supress bursts of rf energy as the diodes come into and out of conduction... whether it makes any audible difference is for you to try.

Once had an old Hitachi radio that had an annoying buzz on the audio and all it needed was a 0.1uf cap across the transformer secondary winding.

[Smiffy]

Thanks Mooly
I have 4 RBV981s.I'll try it on one and see if I can hear a difference
Smiffy

[lineup]

You wont hear a difference.
Those caps are good, to keep the power supply clean.
Serious power supply designs have got such ceramic caps.
I say, you should not remove them.

[ostripper]

To snubber or not ???

Depends on diode speed and load.
High load/fast diode = YES
Small signal-low load/slow diode = should (to be retentive), but not absolutely required.

On even multi- thousand dollar amps (genesis stealth) , main bridge = no snubbers - extra local HF decoupling at output board. Small signal PS was snubbered.

JVC AX series - just 1- .01uF between secondary at bridge.
Nikko alpha - NO snubbers at all ,2 slow bridges (not fast recovery) - 60-0-60v and 70-0-70V supplies.
Sony 5 channel HT - another with just 1 .01uF between secondary at bridge.

Most other japanese HT's - either none or just that one cap at secondary like mooly suggests.

Comment on chip amp builders ..... they use ultra fast recovery to-220 diodes , have to snubber all 4 plus secondary ???(retentive ??)Just USE "slow" bridge + just 1 cap. Many 20 year old Japanese amps with the same.
Can you hear the difference ? NO , but worst case (Fast diodes - MUR-XXX/to-220 + heavy load) , you just might ... or worse case ,( if the amp was marginally unstable) .... trigger oscillation in some cases.

Lots of $$$ + time , or are "stuck" with fast diodes fully "snubber" it.
(recommendation).
personally , I have my 2 supplies with just that 1 .01uF at secondaries and relative slow diodes/bridge (10's of uS)

Debate about it here : fast vs. slow rectifiers It is just a personal/economic design consideration- (3M = mostly mental masterbation)

PS - where a "fast diode" is really needed is at the amp OP (flyback suppression diodes = MUR 3A ultra fast rec.)
OS

[jaycee]

If the snubber caps are not used, it is usually due to cost cutting. There is no sonic gain to be had in removing them, and indeed you may even make the sound worse. Leave them in place.

[Smiffy]

Ta all for the inf.Think i'll leave them there.
Smiffy