Hiraga upgrade - Bypass capacitors

[farflungstar]

Ok so I'm thinking of really pimping up my Hiraga class A 20 watter by swapping out all caps etc for the best i can afford - daft question, can you put bypass caps on power supply caps in a SS amplifier. Is there any point?

[RothwellAudio]

Ok so I'm thinking of really pimping up my Hiraga class A 20 watter by swapping out all caps etc for the best i can afford - daft question, can you put bypass caps on power supply caps in a SS amplifier. Is there any point?

You can put any caps in parallel with any other caps as long as they're rated for the voltage. I like a 20% error margin on the voltage, so for example for 80V across the caps I would use 100V rated caps.
Is there any point? A matter of opinion. Can't do any harm though.

[Infinitely Baffled]

Ok so I'm thinking of really pimping up my Hiraga class A 20 watter by swapping out all caps etc for the best i can afford ... Is there any point?

The question at the end is the important bit. See these very topical quotes from another recent thread on here ...

"Indeed. Audiophiles obsess far too much on "component quality" and "boutique capacitors" etc. The design of the circuitry itself, the ground layout and the correct provision of power at Point Of Load completely swamps any effects from fancy components. "

"Amen, and to make matters even more interesting, a super-cheapo component can *outperform* boutique components in the right place. Sometimes, in certain places, a boutique component can help, but it does pain me when I see people just adding in expensive components everywhere, not considering how each component works, assuming there'll be an upgrade - sometimes it'll be a downgrade."

Might be a waste of time money and effort. I'm guessing it sounds pretty good as it is?
IB

[Arkless Electronics]

You can put any caps in parallel with any other caps as long as they're rated for the voltage. I like a 20% error margin on the voltage, so for example for 80V across the caps I would use 100V rated caps.
Is there any point? A matter of opinion. Can't do any harm though.

I'm afraid it can..... If two caps are put in parallel then the self inductance of one can form a parallel tuned circuit with the capacitance of the other, thereby causing the ESR to go through the roof at those frequencies and be worse than just one cap by an order of magnitude. One needs to be very careful to avoid this.
Parallel caps are gradually going out of favour due to the above...

[Arkless Electronics]

The question at the end is the important bit. See these very topical quotes from another recent thread on here ...

"Indeed. Audiophiles obsess far too much on "component quality" and "boutique capacitors" etc. The design of the circuitry itself, the ground layout and the correct provision of power at Point Of Load completely swamps any effects from fancy components. "

"Amen, and to make matters even more interesting, a super-cheapo component can *outperform* boutique components in the right place. Sometimes, in certain places, a boutique component can help, but it does pain me when I see people just adding in expensive components everywhere, not considering how each component works, assuming there'll be an upgrade - sometimes it'll be a downgrade."

Might be a waste of time money and effort. I'm guessing it sounds pretty good as it is?
IB

+1

If doing anything to his amp I would be looking at quantity not quality!... of smoothing caps. Or better still a regulated supply.

[southall-1998]

+1

If doing anything to his amp I would be looking at quantity not quality!... of smoothing caps. Or better still a regulated supply.


I couldn't agree more!

This is why I stay well away from sites, like Head-Fi. Too much bullshit polluting the place.

S.

[farflungstar]

Thanks guys - my problem is Jez or some other guy I'd trust is in the UK - it would be great if i knew what components to change - but I don't, hence the change all approach. Thanks Jez for warning me. But what next....

[Arkless Electronics]

Use polystyrene for the pF value caps and just put as many uF as you can afford into the PSU (be artistic... you can nylon tie wrap or hot melt glue plenty of extra caps to the main ones!) and that should sort it:)

[Radford Revival]

Don't forget that with large PSU capacity the more you have to worry about inrush limiting.

[Spectral Morn]

Assuming the Hiraga is as was designed and not already bastardised why would you want to mess around with an amp designed by a legend, designed to be what it was mean't to be.

Its a piece of audio history, its value lies in what it was mean't to be. Mess with it and it ceases to be a Hiraga.

[farflungstar]

[emoji17] hmmm

[southall-1998]

Assuming the Hiraga is as was designed and not already bastardised why would you want to mess around with an amp designed by a legend, designed to be what it was mean't to be.

Its a piece of audio history, its value lies in what it was mean't to be. Mess with it and it ceases to be a Hiraga.


Amen.

S.

[Arkless Electronics]

Don't forget that with large PSU capacity the more you have to worry about inrush limiting.

A good point yes but a few of the schematics I saw already had 150,000uF per rail! There are large thermistors designed for just this job available and it would be a good idea to use one in the primary circuit yes:)

[Light Dependant Resistor]

Don't forget that with large PSU capacity the more you have to worry about inrush limiting.

And following the rush ( reminds me of the Neil Young song ) the ability of diode bridges to handle such capacitance is a major concern. The old rule of thumb, that is still immently sensible is 1000uf for every amp of current drawn. The LT4320 using 4x N channel hexfets at 50 amps each, might provide ability for such high capacitance, but are then limited by Rds on of the mosfet and voltage can be no higher than 70v.

[farflungstar]

I don't want to bastardise - but it's quite old and I'm sure some of the components must be out of spec - though I don't know. It sounds extremely good. In fact I was planning on a post about it compared to my Cary monsters.

[Spectral Morn]

I don't want to bastardise - but it's quite old and I'm sure some of the components must be out of spec - though I don't know. It sounds extremely good. In fact I was planning on a post about it compared to my Cary monsters.

I deliberately used that word as the initial post suggested more to me than a simple check up and more a modification. It is possible that components may be off spec and it would be worth getting them measured. If all still in spec and no bits known to fail suddenly then I would leave alone. Changing components out even if same values can change the sound unless they are identical parts but the problem will be that manufacturing changes to those parts might alter the sound.

I know some folks aren't precious about designers work and as long as they get a perceived improvement will happily alter a classic design but from a collectors point of view, and yours and any amp designed by that legendary designer fall under that heading then altering them will kill the collectors value, and ruin what that designer designed that amp to be.

Put it simply a Lectron amp or yours unaltered I would buy, but a messed with one, nope wouldn't touch it with a barge pole. That's me and others mileage will vary. You pays your money and makes your choice.

[anthonyTD]

I would first off' just replace the power supply caps for decent quality new ones, and posibly upgrade the diodes, or bridge rectifiers for better ones, and see how much it changes things first before going too drastic, you may end up turning something you currently like, into something somewhat diffrent to what you remember!
Just my ramblings.:)
A...

[Arkless Electronics]

I deliberately used that word as the initial post suggested more to me than a simple check up and more a modification. It is possible that components may be off spec and it would be worth getting them measured. If all still in spec and no bits known to fail suddenly then I would leave alone. Changing components out even if same values can change the sound unless they are identical parts but the problem will be that manufacturing changes to those parts might alter the sound.

I know some folks aren't precious about designers work and as long as they get a perceived improvement will happily alter a classic design but from a collectors point of view, and yours and any amp designed by that legendary designer fall under that heading then altering them will kill the collectors value, and ruin what that designer designed that amp to be.

Put it simply a Lectron amp or yours unaltered I would buy, but a messed with one, nope wouldn't touch it with a barge pole. That's me and others mileage will vary. You pays your money and makes your choice.

I don't class Hiraga as a good designer personally... Well known, yes. Good, No.

[farflungstar]

Thanks guys. I don't want to change the design so sorry if my initial post suggested otherwise. I do however need to investigate an issue and thought it might be a good chance to pimp up some components

The issue I have is that with it connected there is a grounding issue - touching the fingerlift causes a hum. If I float the ground on the preamp it goes away. Not sure if this is a design flaw or if something is wrong. It's not an issue with other amps.

Also the red neon rocker switch for power doesn't completely go out - it's always on albeit at a low level.

Saying this it sounds extremely good - in some areas beating my Cary 805c monsters.

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