Jimbos Audio ramblings

[Puffin]

I was listening to my Topping D30 today which was gifted to me recently out of the blue by a mate in exchange for some Pass Amp boards I gifted to him. Nice performer and is "up my street". Googled what is inside it and it is a CS4398. Years ago there was a thread on here about modding a cheap Dac board with a CS4397 in it. I only dug it out the other day and thought that I should give this more air time

[Jimbo]

well you can see from measurements taken from the analogue outputs (so that includes power supply, analogue output stage, in fact everything) that noise and distortion is negligible at all audible frequencies. So it's not a guess, by those parameters performance is indeed as perfect as it needs to be. The signal going to pre or power amp is accurate to the source.

So in fact all the additional "clean" power supplies and analogue output stage (op amps) actually count for nothing when analysed?

[Barry]

That's the difference between being "objective" and being "subjective".

[Macca]

So in fact all the additional "clean" power supplies and analogue output stage (op amps) actually count for nothing when analysed?

There are some DACs with internal power supplies that bleed noise into the signal. So it's possible that sometimes a better power supply will help

Better just to buy one that's been designed with some care to such things in the first place though.

I know op amp 'rolling' is a thing but then so is astrology. Maybe in some circumstances improvements can be had, but again, just get something that doesn't need improving to work optimally.

[Gazjam]

There’s a saying.
“Music is just squiggly air”

In Hifi terms I'd add to that and say music is squiggly VOLTAGE.

Voltage being analogue,
It’s privy to noise, variances in impedance and all the other electrical stuff.

Digitals never been just about 1s and 0s, or what type of Dac chip you have fitted.
it’s a SYSTEM, and as such it’s down to implementation and synergy even at a component level.
Its easy (relatively speaking) to throw together a Dac that “works” (or measures well ) but getting one to play music that can move you is another thing I think?
I’ve owned a fair few dacs over they years, all different price points and heard differences in them all.

As James alludes to,
what is it that makes a good Dac sound the way it does?
Its a system, everything depends on everything else.

In my experience there are three main aspects.
Assuming 'good enough' case dampening and no leaky RFI/EMI,
Its the quality of the Power Supply, Analogue output stage and competancy of the digital design.
In that order.

Power supply is the big ticket item for me, I've upgraded PSU's and improved the quality of incoming AC in a fair few bits of kit now and always a significant step up.
The latest is with a separate linear PSU powering separately the analogue output stage of my Dac.
Also upgraded the Dacs output transformers on the analogue board - I.e. better quality power - to great effect.

The Music that hits our ears is “wiggly voltage”, and it terms of the Dac if power supply quality and quality of the analogue output bit isn't done right the music suffers - far more (imo) than what conversion chip in in your Dac may or may not do.

Anyways
As always, its just a thought.

[Macca]

voltage isn't analogue it's just voltage. Digital information is represented by a varying voltage, as is an analogue waveform.

A DAC just converts one to the other.

Yes there's lots of ways that can get screwed up. But the analogue output of the DAC is the end point of that process. We can see at that point if anything got screwed up or not.

[Gazjam]

voltage isn't analogue it's just voltage. Digital information is represented by a varying voltage, as is an analogue waveform.

A DAC just converts one to the other.

Yes there's lots of ways that can get screwed up. But the analogue output of the DAC is the end point of that process. We can see at that point if anything got screwed up or not.

Your right Martin.

Though voltage is also a varying voltage.

Its analogue...conceptually speaking (which wot I waz)
I.e. its not 'on' or 'off'

Its ALL analogue.
It's a waveform.

My point was that voltage (of any flavour) is subject to external factors, electrically speaking.

And yup,
The output stage just reflects what's came before, kinda like Ivor Tefunbruns's 'garbage in garbage out' analogy...

(i'll get my coat)

[Jimbo]

I always run my DACs with a linear power supply as I have found it is generally good practice to use the best power supply you have with a DAC as it prevents most unwanted electrical noise polluting the digital circuits.

It is a measurable and quantifiable thing that noise can be generated from the PSU and feed into whatever piece of kit you are using and corrupt the overall sound quality to some extent. Now I don't have the ability to run my current DACs analogue stage separately with a LPS but at least the digital section should be OK.

Whatever theories of other peoples experiences maybe with DACs I can appreciate they may not hear any difference but my own listening experience is such that running a DAC with a LPS brings about a more fluid and smoother sound which also has slightly more ability to show imaging and spaciousness in the sound stage. Conversely removing an LPS and using a SMPS brings about a slight coarsening/hardening of the sound and flattening of the soundstage.

It does not bring about anymore detail or transform the DAC massively but I can hear the difference none the less. Why it does this and how maybe a complicated theoretical but measurable actuality. I presume that electrical noise somehow alters some electrical components so they are adversely affected. I am not sure about how it affects the actually digital signal as such as I think the PLL circuit compensates for any corruption of data and so the packets of data are always reconstructed accurately in order to produce the final audible sound. However something is going on and power supply has a big influence somewhere in the chain.

Regarding a DACs performance I think as Gary has mentioned it is system dependant and therefore any given DAC can sound and perform quite differently depending on what it is hooked up to. The higher performing and resolving your system is maybe the more noticeable the differences maybe between different DACs.

It must also be recognised that the person listening subjectively hears the DACs performance or not as the case maybe. Some people maybe very sensitive to the sound a DAC produces where as some cannot hear any difference at all. This is purely down to their listening/ aural ability, their system and their subjective opinion.

So I don't dispute there are differences between DACs, however I have a highly resolving system and bat like ears and notice incredibly small changes in whatever I am listening too but my experience in listening to all the DACs I have heard would suggest there is not a massive night and day difference between any competently designed DAC just marginal differences in presentation and detail retrieval. Again this may come down to system synergy and how you hear a DAC in your room. This often gets blown out of proportion I feel and is not as significant as differences in other components.

[Puffin]

I use linear PSs with all my Dacs all made by me. I was a member of many fora years ago where the DIY threads were very busy. On EDIT there was interest in well designed regulators for critical low noise use and 2 types of reg were designed by Teddy Pardo the Teddy Reg and the Power Reg for amplifier circuits and were the subject of a group buy.

"Teddy Pardo Audio is the world leading provider of high quality linear power supplies for audio equipment. Our vast experience in modding and building high-end audio equipment, taught us a major lesson: always start with the power supply!"

https://teddypardo.com/#:~:text=Tedd...power%20supply!

Another group buy was for a JLH Ripple Eater (John Linsley Hood) on the Rock Grotto forum

https://www.rock-grotto.co.uk/rock-g...pple-eater.pdf

EDIT Pink Fish Media - not Wigwam! https://pinkfishmedia.net/forum/thre...eddyreg.39990/

If these are any interest to you I still have a board or two and some of the 2SA1930's and 2SC5171's the other transistors are readily available.
2SA1930's and 2SC5171's are for current limiting but if you don't need them they can be left. Details are in the build guide.

I put one of these in a separate box with DC connectors at both ends so that I can insert it between the PS and what ever I am powering, some others are built in.

[Jimbo]

I use linear PSs with all my Dacs all made by me. I was a member of many fora years ago where the DIY threads were very busy. On EDIT there was interest in well designed regulators for critical low noise use and 2 types of reg were designed by Teddy Pardo the Teddy Reg and the Power Reg for amplifier circuits and were the subject of a group buy.

"Teddy Pardo Audio is the world leading provider of high quality linear power supplies for audio equipment. Our vast experience in modding and building high-end audio equipment, taught us a major lesson: always start with the power supply!"

https://teddypardo.com/#:~:text=Tedd...power%20supply!

Another group buy was for a JLH Ripple Eater (John Linsley Hood) on the Rock Grotto forum

https://www.rock-grotto.co.uk/rock-g...pple-eater.pdf

EDIT Pink Fish Media - not Wigwam! https://pinkfishmedia.net/forum/thre...eddyreg.39990/

If these are any interest to you I still have a board or two and some of the 2SA1930's and 2SC5171's the other transistors are readily available.
2SA1930's and 2SC5171's are for current limiting but if you don't need them they can be left. Details are in the build guide.

I put one of these in a separate box with DC connectors at both ends so that I can insert it between the PS and what ever I am powering, some others are built in.

Good to get another confirmation LPS is a worthwhile upgrade to use with a DAC. I know from amplifier design it also one of the most crucial aspects in their construction.


I was watching an interesting review of a number of power supplies recently used to power a DAC, these include SMPS and Linear and the results were similar to what I experience. It also may explain why I am getting such good results with my SMSL SU-1 DAC which relies totally on an off board PSU to power it.