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needsp  
#1 Posted : Sunday, September 27, 2009 2:42:29 AM(UTC)
needsp

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Hi

What's more important for VACC- speed or noise?

I've removed the buffer op amps and RC filters,and fed 3.3V from to each chanel from shunt regulators (fed by the analogue's circuitry's supply). The regulators- made by Paul Hynes here in the UK, and which have performed miracles for me in the past- are supremely fast, and low noise. I could instead try ultra low noise series regs here (a little slower I think, but still damnfast).

I've also replaced the ceramic decoupling caps with 47u Black Gate NX HiQ caps in parallel with Panasonic 0u1 ECPU SMD film caps

And I like what I'm hearing!

Paul

Dan Giovanni  
#2 Posted : Sunday, September 27, 2009 1:20:23 PM(UTC)
Dan Giovanni

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Hi Paul,
The Paul Hynes shunts have a very good rep, so personally I'd just stick with them. I'm using a couple of regs of my own design, and I agree that the analog supply to the DAC benefits from some special attention. BTW, my understanding is that the standard caps on the Buffalo are films already.
Dan
Brian Donegan  
#3 Posted : Sunday, September 27, 2009 1:27:55 PM(UTC)
Brian Donegan

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This is the idea behind the Placid supply... a super low-noise, high performance shunt regulator primarily for the analog sections of the Buffalo.
needsp  
#4 Posted : Sunday, September 27, 2009 1:41:34 PM(UTC)
needsp

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Hi Dan

The ultra low noise alternative series reg I mentioned is also a Paul Hynes design. I just wondered which to optimise in this particualar application- low noise or speed

Brian- I'll certainly be trying high performance shunt regs on the analogue circuitry

Paul


Dan Giovanni  
#5 Posted : Sunday, September 27, 2009 2:49:45 PM(UTC)
Dan Giovanni

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Personally I'd go for lowest noise, as the decoupling caps will keep impedance low at very high frequencies. Ultimately though whatever sounds best to you. Do the PH series regs have lower noise than the shunts then?

Dan
needsp  
#6 Posted : Monday, September 28, 2009 4:49:31 AM(UTC)
needsp

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Hi Dan

Not the standard models, no. I was just thinking ahead

Paul
sureshm  
#7 Posted : Wednesday, September 30, 2009 5:12:34 PM(UTC)
sureshm

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Guys,

I would like to get an idea where the biggest benefit is gained. With an Opus (WM8741) + S/PDIF Receiver (WM8804) setup, there are 4 voltage regulators between the two modules (5v and 3.3v for the DAC and two 3.3v for the receiver). If I was to replace one of them with the placid, which of the four would I replace to get the greatest audible difference? My guess is the 5v analog supply to the DAC?

Thanks
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