Raspberry pi TDA1541a DAC up-sampled options or alternative DACS

[IDM]

Hi,

I have for some time been using a raspberry pi with a Kali re-clocker and non-oversampled TDA1541a DAC. The software control is Moode.

I was reading with interest the discussion about over-sampling and digital filters to block harmonics that might cause issues. I am therefore very keen to at least try a digital filter or oversampling. However, as far as I can tell the usual filter oversampling chip SA7220 used with the TDA1541a doesn’t accept I2S from the Kali or the pi. So I was wondering if anyone has any suggestions on how to convert the DAC to oversampling?

There are numerous DAC hats that work with the Pi that have digital filters, but the more I read the more confused I get as there are many reviews or statements on the relatively poor performance of the DAC chips compared to the TDA1541a.

Any advice gratefully received

Kind regards,

Ian

 

[chartz]

Why do you want to use a Pi in the first place?

The old X4 OS Philips chipset is good as it is. I don't see the point.

 

[IDM]

Have you heard a pi with kali FIFO board?

Also the non-os TDA1541a is by definition not 4x over sampled. I am trying to discover more about how to implement over sampling

Regards
Ian

 

[Julf]

there are many reviews or statements on the relatively poor performance of the DAC chips compared to the TDA1541a

That is interesting, considering most modern DAC chips are objectively, measurably way superior to the TDA1541a.

 

[MJS]

Oversampling is usually handled by something like sox behind the scenes in these sorts of players. If you look at the resampling options in the setup you can choose different bit depths and rates. Keep it at 16 bit and change it to 176.4KHz for 4x oversampling.

A lot of DACs perform better than the 1541A but it has a sound that many, including myself, like.

 

[IDM]

That is very interesting about SOX. I had wondered if that was what it could do but was struggling to find the information via google. Also someone had suggested in another thread that software like Moode could not handle over sampling.

With regard to newer DACs I read loads about some of the work by IanCanada on diyaudio using ess chips but found really contrasting comments as to whether the DACs sounded particularly good even though they measured well.

I would love to hear of experiences with all the options such as Ian’s DACs or Allo products.

I will try playing with the SOX options
Thanks
Ian

 

[cubastreet]

Let us know how you get on.

I once had a single crown 1541 in a Marantz that I reclocked and the sound really dazzled me, but I ultimately found the sound fatiguing and liked it less and less over time. This could be due to whatever it is that would be filtered out.

These days I use a pi with the hifiberry DAC which I like a lot, but I have some 1541 chips kicking around and wouldn't mind trying them again.

Chartz: Raspberry pi running kodi with the yatse app is the best interface for me. I haven't found anything I prefer, at any price.

 

[IDM]

It has also been suggested that I could try installing bruitfir or ecasound as digital filters. I don't know how these operate or how to configure, but will start reading round this.

It's really interesting what you say about the hifiberry DAC. Every time I convince myself that one of the new DAC's will sound good I then find negative reviews. I think I will need to bite the bullet and simply buy one and compare to my current setup.

Cheers
Ian

 

[cubastreet]

You might want to see if something better has come out, the hifiberry must be a few years old now. A lot of people seemed to prefer the ess dacs on the pi, but I've never heard one.

 

[John Phillips]

Oversampling is usually handled by something like sox behind the scenes in these sorts of players. If you look at the resampling options in the setup you can choose different bit depths and rates. Keep it at 16 bit and change it to 176.4KHz for 4x oversampling. …

I think this is correct. I did try Moode some time ago but I don't remember much about it. Sorry my comments below are just possibly relevant fragments but I didn't use it for long enough to try resampling myself. I have tried oversampling in PiCorePlayer instead and that does use SoX's resampling library.

I think Moode uses MPD (Music Player Daemon). If I have not had a brain-storm about that, this link has an example near the end of lines to put in file mpd.conf to do resampling with SoX. A more general description of what you can do with mpd.conf, including resampling, is at this link. There is some specific practical Moode / MPD documentation at this link which seems relevant.

 

[MJS]

If you're looking for a more contemporary DAC, Andrew Weekes' description of modifying the Cirrus (Wolfson) Card for the newer Pis is worth a look, and I can confirm it is very musical indeed.

https://pinkfishmedia.net/forum/threads/raspberry-pis-and-the-wolfson-sound-card.214004/

 

[Yomanze]

That is interesting, considering most modern DAC chips are objectively, measurably way superior to the TDA1541a.

Subjectively, there is a naturalness with the TDA1541A, and well-implemented true multibit DACs, which is missing with 'way superior' modern DACs, like the Sabre units.

 

[Yomanze]

That is very interesting about SOX. I had wondered if that was what it could do but was struggling to find the information via google. Also someone had suggested in another thread that software like Moode could not handle over sampling.

With regard to newer DACs I read loads about some of the work by IanCanada on diyaudio using ess chips but found really contrasting comments as to whether the DACs sounded particularly good even though they measured well.

I would love to hear of experiences with all the options such as Ian’s DACs or Allo products.

I will try playing with the SOX options
Thanks
Ian

I have tested using Moode & SoX resampling (which you can find in Moode settings) with my Pi / DigiOne into a DAC. For example, oversampling 44.1kHz FLAC files to 88.2kHz, which stops the treble droop. However, I can't say it sounds better, and have always switched back to using no DSP / filtering. You can notice the rolloff slightly with things like cymbal crashes & violin, but it's sins of omission, subtle, and doesn't get in the way.

On an aside, if playing 24/96 files (truncated to 16/96), then there is no treble droop, so ironically, higher res files can actually make a notable, and measurable, difference, to NOS DACs, side-skirting the criticisms of when they are used for 16/44.1 playback.

 

[misterdog]

With regard to newer DACs I read loads about some of the work by IanCanada on diyaudio using ess chips but found really contrasting comments as to whether the DACs sounded particularly good even though they measured well.

Sq and myself both using Ians DAC's with LifeP04 battery supplies and dual mono ESS 9038Q2M chips.

From stock they need 3 rail supplies for the DAC AVCC,DVCC and VCCA, better clock crystals on the FIFO (NDK SDA series in my case) and better I/V stage op-amps to really shine.

We have both ended with Lundahl transformers on the output stage, better soundstage and more organic sounding than op-amps, though a little loss of dynamics.

The great thing about Ian's boards is that they are so configurable.

At the end of the day it is all about quality versus price, not everyone wants to pay £ 180 for a Tx output stage, having said that they sound great with OPA 1612 for C £ 20 .

I have a spare I/V board if you are interested and some batteries.

In Sheffield if you want a listen.

 

[IDM]

Oversampling is usually handled by something like sox behind the scenes in these sorts of players. If you look at the resampling options in the setup you can choose different bit depths and rates. Keep it at 16 bit and change it to 176.4KHz for 4x oversampling.

A lot of DACs perform better than the 1541A but it has a sound that many, including myself, like.

Having been out of the Country all week I got to make these changes within Moode this afternoon and my initial thoughts are extremely positive. The music seems to present a better 3D image with vocals really stepping forward. Also cymbals sounding more realistic. I am yet to have any negative comments, indeed I really cannot think there is any reason to move away from the TDA1541A DAC. It seems quite amazing to me that using the Pi as a streaming source it is possible to select your oversampling rate, or to try no oversampling!

The DAC has been extensively worked on and consists of I2S from raspberry pi through a kali reclocker and then to a double crown TDA1541A. the PSU for the DAC chip consists of 3X ALWSR and local supply decoupling includes most if not all the recommended tweaks. I/V is by means of a pair of AD844 with signal taken from pin 5 (TZ). The output stage is by means of OPA627. Both the AD844's and OPA627's have their own ALWSR's.

I love fiddling on and refining projects but I think I am close to being done with this. The only thing I am tempted to try is:
1) stacking 2 or 3 AD844's as some people report improvement.
2) An Allo Isolator board between the Pi and the FIFO reclocker.
3) resistors to feed the I2S signals into the DAC chip, if this is done I think I also need to add low value decoupling caps (though I am not clear on this one).

Cheers
Ian

 

[IDM]

I have a spare I/V board if you are interested and some batteries.

In Sheffield if you want a listen.

I have been wondering about Ian's Dacs and the offer to listen and possibly provide some of the parts is really kind. If I am down your way I will certainly be in touch.

Thanks

 

[darrenyeats]

I do bit shift, over-sampling, volume control and dither in one SoX call for maximum precision.

I've hacked LMS so I can control the volume via LMS web UI and apps, including changing volume mid-track.

Without the initial bit shift, the over-sampling can digitally clip with highly compressed recordings.

 

[Dowser]

Having been out of the Country all week I got to make these changes within Moode this afternoon and my initial thoughts are extremely positive. The music seems to present a better 3D image with vocals really stepping forward. Also cymbals sounding more realistic. I am yet to have any negative comments, indeed I really cannot think there is any reason to move away from the TDA1541A DAC. It seems quite amazing to me that using the Pi as a streaming source it is possible to select your oversampling rate, or to try no oversampling!

The DAC has been extensively worked on and consists of I2S from raspberry pi through a kali reclocker and then to a double crown TDA1541A. the PSU for the DAC chip consists of 3X ALWSR and local supply decoupling includes most if not all the recommended tweaks. I/V is by means of a pair of AD844 with signal taken from pin 5 (TZ). The output stage is by means of OPA627. Both the AD844's and OPA627's have their own ALWSR's.

I love fiddling on and refining projects but I think I am close to being done with this. The only thing I am tempted to try is:
1) stacking 2 or 3 AD844's as some people report improvement.
2) An Allo Isolator board between the Pi and the FIFO reclocker.
3) resistors to feed the I2S signals into the DAC chip, if this is done I think I also need to add low value decoupling caps (though I am not clear on this one).

Cheers
Ian

Is there a thread with more details of what you have done please Ian? I also love the 1541 sound and have a DAC I’d like to start playing with

Thanks, Richard

 

[IDM]

Hi Richard,

I got all the background for the I/V conversion from this rather long thread on Diyaudio, it is certainly worth scan reading. The best I/V schematic uses pin 5 TZ as the output to feed the buffer, don't use pin6. The OPA627 buffer is also shown in the thread:
https://www.diyaudio.com/forums/digital-line-level/227677-using-ad844.html

The ideas I used for the TDA1541a supply pin decoupling cam from here:
https://pinkfishmedia.net/forum/threads/arcam-and-the-tda1541.29579/

The I2S pin outs on the raspberry pi are shown here:
https://raspberrypi.stackexchange.c...irming-the-i2s-pins-on-raspberry-pi-3-model-b

The Allo FIFO board has the same pins outs for the I2S signals

I built the DAC itself from scratch and is extremely straightforward. The rough schematic is the third schematic here:
https://www.tnt-audio.com/clinica/tnt1541_e.html

However, I used ALWSR for the PSU's and don't fit resistors R310 and R311 if you use the AD844 I/V stage.

Hope that helps a bit

 

[misterdog]

The I2S pin outs on the raspberry pi are shown here:
https://raspberrypi.stackexchange.c...irming-the-i2s-pins-on-raspberry-pi-3-model-b

Though in the first table for the GPIO there are two pins numbered 37, there seems to be some confusion.