More 'Audiophile' bullsh*t
Discussion
TonyRPH said:
That's an interesting video.
As I understand it - it's oversampling that smoothes the stair steps.
Here's a screenshot of my 'scope - one channel is an oversampling DAC, the other is a non oversampling DAC.
The stair step effect is clearly visible with the non oversampling DAC.
What's that ? A four bit DAC or a very small signal? Or maybe its a bigger signal but very high frequency, the kind of thing that's not exactly common in music apart from Ted Nugent overdoing the feedback?As I understand it - it's oversampling that smoothes the stair steps.
Here's a screenshot of my 'scope - one channel is an oversampling DAC, the other is a non oversampling DAC.
The stair step effect is clearly visible with the non oversampling DAC.
It's meaningless without the amplitude and frequency being known.
If you put a 'non oversampled' DAC output into an ideal analogue filter, all the little stair-steps will be filtered out.
They are above the audio frequency range.
An over-sampled DAC basically just makes the DAC artefacts higher in frequency making them easier to filter out with a simpler analogue filter which will have less effect on phase towards the top of the audio band.
Where it gets interesting is when a DAC with little or no oversampling has a poor analogue filter after it, allowing high frequency artefacts or spurious or whatever to enter the amplifier. A lot of amps don't seem to be well specified for rejecting such signals which may have effects on how the amp behaves in the audio band.
Maybe this explains why some amps which are near-perfect in there paper specs in the audio band sound different?
OutInTheShed said:
What's that ? A four bit DAC or a very small signal? Or maybe its a bigger signal but very high frequency, the kind of thing that's not exactly common in music apart from Ted Nugent overdoing the feedback?
It's meaningless without the amplitude and frequency being known.
It's a 16 bit DAC (TDA1543) and the signal was a 1kHz -1dB (the level is from memory but is the level I usually test at).It's meaningless without the amplitude and frequency being known.
OutInTheShed said:
If you put a 'non oversampled' DAC output into an ideal analogue filter, all the little stair-steps will be filtered out.
They are above the audio frequency range.
This particular DAC (using a TDA1543) uses a simple (passive) I/V converter which consists of a resistor and capacitor, which does little to 'smooth' the waveform.They are above the audio frequency range.
There is no digital filtering / oversampling.
OutInTheShed said:
An over-sampled DAC basically just makes the DAC artefacts higher in frequency making them easier to filter out with a simpler analogue filter which will have less effect on phase towards the top of the audio band.
Where it gets interesting is when a DAC with little or no oversampling has a poor analogue filter after it, allowing high frequency artefacts or spurious or whatever to enter the amplifier. A lot of amps don't seem to be well specified for rejecting such signals which may have effects on how the amp behaves in the audio band.
Maybe this explains why some amps which are near-perfect in there paper specs in the audio band sound different?
NON O/S DACs do output a lot of high frequency junk, which is known to upset some amps.Where it gets interesting is when a DAC with little or no oversampling has a poor analogue filter after it, allowing high frequency artefacts or spurious or whatever to enter the amplifier. A lot of amps don't seem to be well specified for rejecting such signals which may have effects on how the amp behaves in the audio band.
Maybe this explains why some amps which are near-perfect in there paper specs in the audio band sound different?
I can't think I've ever seen a well designed 'modern' DAC outputting HF junk, unless there is some fault somewhere.
Additionally, most modern DACs ultimately use an analogue filter to buffer the DAC and define output levels whilst tailoring the frequency response to the manufacturer's optimum desired response curve (and in some cases even tailored to provide a 'house' sound).
A couple of my DACs have switchable digital filters, and whilst the effects are easily measured, it's quite difficult to hear a great deal of difference.
EDIT: Found the schematic for the DAC I built. The digital data was provided by a CS8412 SPDIF receiver chip. The DAC was simplicity itself.
It sounded nasty though!
Edited by TonyRPH on Friday 9th June 17:53
conkerman said:
I have a Gyrodec, It's lovely and is by far the best thing in my system. I have wanted one since I first saw them in the 80s/90s. It truly is a thing of beauty. (I had a big birthday so treated myself).
Currently running a T3 arm and VM540, and I have no desire to upgrade.
Yeah for now.Currently running a T3 arm and VM540, and I have no desire to upgrade.
I give it six months before you’re eying up an SME 309 and wondering which of the AT-OC9 range to go for.;)
(Fellow Gyro SE owner here - with a 309 and a Clearaudio MC Essence on it, usually!)
said:
It's a 16 bit DAC (TDA1543) and the signal was a 1kHz -1dB (the level is from memory but is the level I usually test at).
Seems to only contain 22 samples per cycle, that might explain why is looks a bit poorly!The TDA1543 is a 30 year old economy chip.
It's good for 4x oversampling and should deliver better than -70dBFS distortion when used properly.
https://pdf1.alldatasheet.com/datasheet-pdf/view/1...
If you use the application circuit intended for oversampling, but don't oversample, then it should be no surprise that it doesn't look very good.
Looking at the schematic for my Marantz CD player, it has a quite complicated analogue filter on each output, it looks like 3 poles of Low Pass and a band-stop. That's the kind of thing you need to separate 20kHz passband from 22kHz and upwards artefacts from 44kHz sampling.
That apparently gives 96dB of dynamic range, over 100dB of SNR.
Oversampling just makes those numbers easy to achieve, and with more modern ICs cheaper than chips so to speak.
It's a fundamental part of sampling theory that all the 'rubbish' from an ideal DAC is above half the sample rate so can be filtered off with an ideal filter.
Of course ideal DACs and filters only exist in 'theory'.
OutInTheShed said:
'stuff'
The waveform gets worse as the frequency rises too of course..!These were quite popular back in the mid noughties.
These and R-2R DACs (both still have a limited following, and a couple of manufacturers are actually making R-2R DACs).
I never bought into the sound of either however - especially the NON O/S DACs which always sound hard to my ears.
There are some hobbyists out there that even run the TDA1541 in NON O/S mode, thinking that it sounds better...
TonyRPH said:
NON O/S DACs do output a lot of high frequency junk, which is known to upset some amps.
I can't think I've ever seen a well designed 'modern' DAC outputting HF junk, unless there is some fault somewhere.
Additionally, most modern DACs ultimately use an analogue filter to buffer the DAC and define output levels whilst tailoring the frequency response to the manufacturer's optimum desired response curve (and in some cases even tailored to provide a 'house' sound).
A couple of my DACs have switchable digital filters, and whilst the effects are easily measured, it's quite difficult to hear a great deal of difference.
EDIT: Found the schematic for the DAC I built. The digital data was provided by a CS8412 SPDIF receiver chip. The DAC was simplicity itself.
It sounded nasty though!
I'd expect that to sound dire, unless you fed it to a preamp which did all the filtering for you.I can't think I've ever seen a well designed 'modern' DAC outputting HF junk, unless there is some fault somewhere.
Additionally, most modern DACs ultimately use an analogue filter to buffer the DAC and define output levels whilst tailoring the frequency response to the manufacturer's optimum desired response curve (and in some cases even tailored to provide a 'house' sound).
A couple of my DACs have switchable digital filters, and whilst the effects are easily measured, it's quite difficult to hear a great deal of difference.
EDIT: Found the schematic for the DAC I built. The digital data was provided by a CS8412 SPDIF receiver chip. The DAC was simplicity itself.
It sounded nasty though!
Edited by TonyRPH on Friday 9th June 17:53
That's a circuit which anyone with any sense would only build to crudely look at a DAC chip with no filtering.
But even so, it would probably sound better if you had the sample rate correct instead of apparently half-rate?
I'm sure there were some awful circuits implemented in things like CD ghetto blasters, but that's probably because circuit designers really don't like people who buy ghetto blasters, or only care about absolute minimum cost.
Just been listening to a couple of CDs on my Marantz, tomorrow it's live music, possibly a few of the same tunes.
I've just looked up the datasheet for the DAC in the Marantz, it's a SM5872, which has 8x oversampling and some clever digital filtering, all within the DAC chip. That's a chip released in 1993? So I was wrong about it not over sampling. Mea Culpa and all that. But the point remains, a DAC IC needs analogue filtering to make it a worthwhile audio circuit.
It's not just a numbers game, 16x over sampling won't necessarily be better than 4x if the circuit design is rubbish.
If you look at the datasheet for SM5872, it suggests it can pump out a fair amount at around 4x and 8x the sample rate, which is where audio amps are running out of feedback and not working according to simple theory.
But back in the late 80s, there was a huge market for things that sounded noticeably better than a worn record on a Garrard deck and cost less than a hundred quid. Later there was a big market for CD players to be listened to in Ford Escorts and Vauxhall Novas, where any SNR above 40dB was probably academic.
Those were actually good times with some fun music.
Most of the market is not about audiophiles.
Deranged Rover said:
Yeah for now.
I give it six months before you’re eying up an SME 309 and wondering which of the AT-OC9 range to go for.;)
(Fellow Gyro SE owner here - with a 309 and a Clearaudio MC Essence on it, usually!)
Haha. I give it six months before you’re eying up an SME 309 and wondering which of the AT-OC9 range to go for.;)
(Fellow Gyro SE owner here - with a 309 and a Clearaudio MC Essence on it, usually!)
I have had it a year and still happy with it. Although I am looking at cartridge (Going to stick with MM) as my 540 has quite a few hours on it.
It plays through a NAD T778 AV Receiver/Edwards Audio phono stage to Q Acoustics Concept 40 and a B&W Sub. The T778 is fab piece of kit, and is ALMOST the ideal compromise for me. I am astonished by the capabilities of Dirac on an almost daily basis and its ability to tame my untreated room.
conkerman said:
Deranged Rover said:
Yeah for now.
I give it six months before you’re eying up an SME 309 and wondering which of the AT-OC9 range to go for.;)
(Fellow Gyro SE owner here - with a 309 and a Clearaudio MC Essence on it, usually!)
Haha. I give it six months before you’re eying up an SME 309 and wondering which of the AT-OC9 range to go for.;)
(Fellow Gyro SE owner here - with a 309 and a Clearaudio MC Essence on it, usually!)
I have had it a year and still happy with it. Although I am looking at cartridge (Going to stick with MM) as my 540 has quite a few hours on it.
It plays through a NAD T778 AV Receiver/Edwards Audio phono stage to Q Acoustics Concept 40 and a B&W Sub. The T778 is fab piece of kit, and is ALMOST the ideal compromise for me. I am astonished by the capabilities of Dirac on an almost daily basis and its ability to tame my untreated room.
I think there is something about turntables that just grabs you, it is so easy to fall in love with one and you then change other components to try to get the best out of it rather than upgrading the tt. I also have an old LP12, which sounds good, but I have never fallen in love with it! Just as well given the costs of upgrading LP12s...
robinessex said:
Meanwhile, getting firmly back on Terra Firma. Just been re-reading High Performance Loudspeakers by Martin Colloms, founder of Monitor Audio. Less than £10 on eBay. When you've finished reading it, with then some knowledge of the inadequacies of loudspeakers, you'll realise that they are about 1000 times more effective in screwing up your Hi-Fi sound than the rest of your system, bar the room you are in.
I often see rooms in “audiophile” magazines that cannot possibly sound good - hardwood floors, floor to ceiling windows, little fabric, 12’ ceiling and no ear for layout. It doesn’t take much to utterly transform the acoustic of a room without recourse to spending money on equipment. Similarly, I used to work in a music shop that would install grand pianos in houses where they would sound appalling, for similar reasons. Too much sound and too little furnishing to balance it. Was never going to turn down the money but if they got played it would be with the lid on and the quiet pedal engaged.
I'm no aficionado when it comes to all things hifi but I spotted these on FB Marketplace for a tenner and thought they looked interesting, I thought they were relatively modern but apparently they're 'vintage' and date back to the 90's.
I'm seeing them on ebay for £50 - £90 but none of those are complete, unused and still with their original box like mine.
Have I snagged a bargain or are the ones on ebay at delusional asking prices?
I'm seeing them on ebay for £50 - £90 but none of those are complete, unused and still with their original box like mine.
Have I snagged a bargain or are the ones on ebay at delusional asking prices?
Dylano said:
I'm no aficionado when it comes to all things hifi but I spotted these on FB Marketplace for a tenner and thought they looked interesting, I thought they were relatively modern but apparently they're 'vintage' and date back to the 90's.
I'm seeing them on ebay for £50 - £90 but none of those are complete, unused and still with their original box like mine.
Have I snagged a bargain or are the ones on ebay at delusional asking prices?
I see you have the user manual - would you mind posting a picture of the specifications page, so I can add the data to my Vintage Technics website?I'm seeing them on ebay for £50 - £90 but none of those are complete, unused and still with their original box like mine.
Have I snagged a bargain or are the ones on ebay at delusional asking prices?
Thanks!
No strictly audio but an iInteresting experience looking for a HDMI cable for a newly purchased Apple TV 4K.
It's a foot from the TV so you'd think any cable of adequate construction would be fine and I work in a field where I know that petabytes of data is shifted over perfectly normal ethernet cables but I still found myself overwhelmed by the quantity of cables on Amazon at all manner of price points.
Ended up with a 50cm Kenable cable at £3.50 as it's officially certified and they're a sensible reputable brand but it's easy to see how people get suckered into some of this stuff
It's a foot from the TV so you'd think any cable of adequate construction would be fine and I work in a field where I know that petabytes of data is shifted over perfectly normal ethernet cables but I still found myself overwhelmed by the quantity of cables on Amazon at all manner of price points.
Ended up with a 50cm Kenable cable at £3.50 as it's officially certified and they're a sensible reputable brand but it's easy to see how people get suckered into some of this stuff
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