MoFo

For the three and more legged things
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ed
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Re: MoFo

Post by ed » Tue Feb 05, 2019 11:43 pm

Ah pathos, I'd almost forgotten.
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Re: MoFo

Post by IslandPink » Wed Feb 06, 2019 11:31 am

Umm... OK...
So, what makes this more successful in high current solid state ?
Just remembering my last use of a by-pass in the shunt-reg supply, and what I simmed on LT Spice that seemed to explain why it might sound bad.
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Re: MoFo

Post by Nick » Wed Feb 06, 2019 12:39 pm

IslandPink wrote:
Wed Feb 06, 2019 11:31 am
Umm... OK...
So, what makes this more successful in high current solid state ?
Just remembering my last use of a by-pass in the shunt-reg supply, and what I simmed on LT Spice that seemed to explain why it might sound bad.
Its the best of the available compromise. If you could have a 22000uf film cap it would probably sound better, but you can't, so the next best thing in my experience is to use a 1uf or more cap across the electrolytic. It may be a regulator will work with just a small film cap on the output, but I have not tried that. Also, consider that the PSRR of a solid state amp may be very different to a valve one.

One of these things is not the same as the other.
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Re: MoFo

Post by IslandPink » Wed Feb 06, 2019 3:36 pm

OK - could be partly a difference between SE and PP, as it seem most solid state amps are PP or relatively low demand on the PS ? ( which I suppose is PSRR )
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Re: MoFo

Post by ed » Wed Feb 06, 2019 3:49 pm

I understand the bypass scenario(or at least the hf/spike rejection bit) but why would a film cap be better in the heavy duty section?

hold that question...I'm revising ESR and ESL
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Re: MoFo

Post by Nick » Wed Feb 06, 2019 4:35 pm

ed wrote:
Wed Feb 06, 2019 3:49 pm
I understand the bypass scenario(or at least the hf/spike rejection bit) but why would a film cap be better in the heavy duty section?

hold that question...I'm revising ESR and ESL
Yes, there is that, plus electrolytics tend to be less linear than film caps
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Re: MoFo

Post by little eddy » Thu Feb 07, 2019 9:45 am

Nick wrote:
Tue Feb 05, 2019 8:29 pm
Also try adding film bypass caps on the electrolytics.
As per Nick's Rankin valve book, rather than just add as a bypass cap, was thinking of adding the 4u7 film cap at the end of the filter chain as a small Pi filter with a 0.1R resistor.
Thorens TD-125 & 'Snail' phono/pre, NAS/SBT, CS4398 DAC, Rocky KT66 amp, still messing with OBs.

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Re: MoFo

Post by Nick » Thu Feb 07, 2019 10:15 am

Seems like a good way of increasing the impedance of your supply.
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Re: MoFo

Post by little eddy » Sat Feb 16, 2019 5:08 pm

Time to stop meddling and do some listening.

If this were a boxing match, I am quickly heading towards the heavyweight division at an unexpected 18kg for just 12.7W.

Additions include microwave transformers, moving original chokes into the power supply and film filter caps as suggested by Nick, (only had polyester MKT1813s to hand).

The only things I've left to consider at the moment is supplementing the heat sink capacity and trying different film caps both on the input, and also bypassing the 6800uF output electrolytic.
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Mofo film cap small.jpg
Thorens TD-125 & 'Snail' phono/pre, NAS/SBT, CS4398 DAC, Rocky KT66 amp, still messing with OBs.

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Re: MoFo

Post by IslandPink » Sat Feb 16, 2019 6:13 pm

If I can ever find a second Audyn 4.7u/100V KP-SN, I will send you the pair. I've been poking around while looking for other final bits for the amp, but so far no success.
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It's so easy to look down from above " (Wyatt)

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Re: MoFo

Post by little eddy » Mon Feb 18, 2019 11:43 pm

Distortion falls as bias current is increased but might a higher Idss also provide an audible difference (I remember increasing the current with 6SN7s in SRPP made a huge audible improvement, at least to my ears)?

More current means more heatsink so it's not a cheap/easy thing to do if it's unlikely to provide any sonic improvement.
Thorens TD-125 & 'Snail' phono/pre, NAS/SBT, CS4398 DAC, Rocky KT66 amp, still messing with OBs.

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