A NOS 192/24 DAC with the PCM1794 (and WaveIO USB input)

Hi Folk,
A couple of updates:

1. I tried Chan's choke input tweak and it does seem to add a small but worthwhile improvement.

2. I tried a tube anode follower balanced to single end stage to follow the i/v resistor. It made a big improvement in SQ. More space, presence and bass depth. The circuit is almost exactly a Lampizator one.

But with this deck I'm having hum problems as soon as I connect balanced out, notwithstanding that the output stage has blocking caps on both pos and neg connections.

Any ideas anyone? It was there with the standard psu, and disappears when I connect from common to either negative or pos, with or without a blocking cap.
David
 
Hi Folk,
A couple of updates:

1. I tried Chan's choke input tweak and it does seem to add a small but worthwhile improvement.

2. I tried a tube anode follower balanced to single end stage to follow the i/v resistor. It made a big improvement in SQ. More space, presence and bass depth. The circuit is almost exactly a Lampizator one.

But with this deck I'm having hum problems as soon as I connect balanced out, notwithstanding that the output stage has blocking caps on both pos and neg connections.

Any ideas anyone? It was there with the standard psu, and disappears when I connect from common to either negative or pos, with or without a blocking cap.
David

If you have enough gain say 2 volts min o/p why not stick with single instead of balanced. Maybe you have an unknown earth creating a loop or you have disconnected an earth by floating pos and neg output.

Lampizator claimed his i/v SVRP valve buffer was the best and direct coupled to grid better than i/v transformer. Later he seemed to have put caps in both +ve and -ve.
 
CCS?

Chanh,

Your 11 DDDAC stack is one of the 7 technical wonders of the world which all of us in the forum bow down to and lust after.

Time to take your DDDAC stack apart and install CCS mini-boards. Everyone I know who has replaced the 6K resistor to pin 20 with JFET CCS's feels that the sound quality improved - more detail and dynamics. The total cost of all parts would be much less than for one assembled Acko S03 board.

I would happily sponsor the next revision CCS mini-board design and production run to accommodate the 2SK208 SOT-23 JFETS if I knew someone needed 22 of them. The board would be about 15mm X 15mm and not have provisions for a cascode transistor - unless you want this. The special price to you for 22 of these boards would be $60 plus shipping, etc. The most expensive part is the Bourns trimmer pot at $2.32usd. The 2SK208 "O" or "R" price is $0.36ea and the Susumu RG SMD resistors are $0.32ea in the quantities you need. So for $126 plus shipping and VAT you would have all you need.

The 2SK208 "O" or "R" versions have a very low temperature coefficient with the "O" version current changing no more than 1% when I heated it from 25C to over 40C with a hot air gun. These can be adjusted to 0.40ma in a breadboard and installed with no further adjustments or concern about heat. In fact you could measure the resistance needed for each 2SK208 and purchase the SMD resistor pair that gives you 0.40ma which would be even more compact and temperature stable.

I have a bare Acko S03 board and plan to buy a BBB computer board and S03 parts. What is the easiest way for me to find out what else I need and the software skills required to make this thing work?
 
If you have enough gain say 2 volts min o/p why not stick with single instead of balanced. Maybe you have an unknown earth creating a loop or you have disconnected an earth by floating pos and neg output.

I do have enough gain but still need to get to the bottom of this hum before any more experimentation. As it was there with the standard layout /psu and stayed when I migrated to separate analogue and digital supplies with common earth I don't think it is an earthing issue
David
 
"Is the blue mainboard a better choice when playing only via usb ?" smooth dancer
Unless you plan to add a 1/2 clock delay circuit and change the Vreg to 5V on the red main board, then get the blue board which has this circuit. It makes a HUGE difference in sq.

"with this deck I'm having hum problems as soon as I connect balanced out" juancho
Try connecting the power supply ground of your tube stage to the DAC 8V power supply ground. The only hum problem I ever had with the DDDAC was solved by additional ground connections between power supplies.
 
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I do have enough gain but still need to get to the bottom of this hum before any more experimentation. As it was there with the standard layout /psu and stayed when I migrated to separate analogue and digital supplies with common earth I don't think it is an earthing issue
David

Is the hum, mains hum or a generated noise which is a hum. Surely if it disappears on earthing out either output, then it is a mains loop. Is it a back traceable interconnect screen. There are so many possibilities.
 
Is the hum, mains hum or a generated noise which is a hum. Surely if it disappears on earthing out either output, then it is a mains loop. Is it a back traceable interconnect screen. There are so many possibilities.

It first appeared when I moved from 4 boards back to one. It appears to be a mains hum, like an earthing loop but connecting or disconnecting either output when running balanced out makes no difference. Swapping back to single ended out I get absolute silence, so of course that's the easy fix. But from my tube output stage experiment it comes back with balanced out even into a buffer and I want to try the JFET buffer plus Cinemags. There are lots of possibilities but it's not the psus.
David
 
It first appeared when I moved from 4 boards back to one. It appears to be a mains hum, like an earthing loop but connecting or disconnecting either output when running balanced out makes no difference. Swapping back to single ended out I get absolute silence, so of course that's the easy fix. But from my tube output stage experiment it comes back with balanced out even into a buffer and I want to try the JFET buffer plus Cinemags. There are lots of possibilities but it's not the psus.
David

You can apply asort of 5 why's. I think you are on to a real 'cause and effect' scenario as it did work previously with 4 boards. So you could do the easy bit first. Look all over the board for any broken earth or other damage. I would look for damage caused by removing the other boards. If that finds nothing try one of the removed boards instead. then start adding boards to see if it works with the 4 boards. I think when you go single output you are putting back i.e replacing the missing i.e possible damaged earth.

When you have got it going I will be pleased to see how you like the Cinemags. The Sowter price has got me looking at making my own traffos, but cap out is pretty good.
 
You can apply asort of 5 why's. I think you are on to a real 'cause and effect' scenario as it did work previously with 4 boards. So you could do the easy bit first. Look all over the board for any broken earth or other damage. I would look for damage caused by removing the other boards. If that finds nothing try one of the removed boards instead. then start adding boards to see if it works with the 4 boards. I think when you go single output you are putting back i.e replacing the missing i.e possible damaged earth.

When you have got it going I will be pleased to see how you like the Cinemags. The Sowter price has got me looking at making my own traffos, but cap out is pretty good.

I tried the Cinemags with two decks and was a bit underwhelmed compared to two boards direct or via a cap but I am keen to give it another go with a JFET buffer as I loved the sound with the valve output stage.

Thanks for the tips. I have checked and double checked all the obvious tho. I am already on my second board and the main board was swapped for the later one with the clock mods, so it's a bit of a mystery!
 
I tried the Cinemags with two decks and was a bit underwhelmed compared to two boards direct or via a cap but I am keen to give it another go with a JFET buffer as I loved the sound with the valve output stage.

Thanks for the tips. I have checked and double checked all the obvious tho. I am already on my second board and the main board was swapped for the later one with the clock mods, so it's a bit of a mystery!

Sleep on it.

It seems the best line transformers are required. At least the Cinemag showed it was not a win win. I nearly bought some to try. Thanks

The LL1684 may be one of the better ones, and is used by many. It seems however, as many take them off, as put them on, but the valve buffer is more universally favoured.

The core of the transformer should ideally take some DC without saturating. So without introducing a dc zeroing circuit into the +-i out this is a problem unless you use a big low saturation core transformer. Very expensive.

I guess the Cinemag core may be better suited to v out DAC chips where +- are at same voltage. The transformer should smooth out the treble, but if the treble is really good IMO does not need transformer, only a decent cap. Money otherwise probably better spent on the buffer.
 
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Chanh,



Time to take your DDDAC stack apart and install CCS mini-boards. Everyone I know who has replaced the 6K resistor to pin 20 with JFET CCS's feels that the sound quality improved - more detail and dynamics. The total cost of all parts would be much less than for one assembled Acko S03 board.



I have a bare Acko S03 board and plan to buy a BBB computer board and S03 parts. What is the easiest way for me to find out what else I need and the software skills required to make this thing work?

Hi Carlsor,
Many thanks for your kind words!

Frankly, I very am over joyed with my current setup. I fear with JFET CCS might just be too much of a good thing...! Nonetheless, I certainly am craving for more improvement despite the gap is getting narrower as it elevates further up the sonic ladder. Currently, I have no desire for further tweaking because the current SQ is simply too engaging, loving it!!! In the same token, I really look toward to your excellent works for future upgrade if is ok? Please count me in for those 24 boards, I will reserve a set for my mate here, Tuyen! Hopefully we can have some fun in the early 2015?
Will pm you.

With regards to BBB and Acko S03, it is very simple. Please go to Twister Pears Audio and look for support Linux Botic driver from Miero. Alternatively Google the term "Botic driver". When purchase S03, Acko will email you the 12pages pdf manual on how to setup with schematic. Personally I went a step further by using JRiver to manage the 4TB audio library. JRiver does this efficiently better than MPD, which is the embedded player built in Botic driver. JRemote can wirelessly navigates JRiver which is managing the whole library at your fingers, extremely convenience and very user friendly. Those knowing JRemote will appreciate where I am coming from. The trick is to get BBB communicate to your PC with JRiver running. Here you can google "upmpdcli". This piece of code will allows JRiver to control your BBB under the protocol UPnP. Secondly, you need to manually modified the LAN IP address to static on both BBB and PC with JRiver, in order to have them communicate directly for purity of sound. If step 2 is a little too advance, you can simply connect both into a router. JRiver will detect as player namely UpMPD. Which also appears in your JRemote under Zones selection. If selecting UpMPD, it will send all data to BBB which MPD will play the file and I2S direct to DDDAC or S03. Please feel free to shoot me a PM if you are getting stuck? I can also assist the same interface with Raspberry Pi via Volumio 1.4. ;)

Hope Doede doesn't mind for this off topic?! :)

Cheers.
Chanh
 
RPi or BBB with DDDAC

Hi. Chanh
I am an happy owner of four deck DDDAC
As a source I use modyfied squeezebox receiver with superclock and shunt regulation, and I2S output stright from its Xilinx chip. It has to be really low jitter from Xilinx I2S outpu as the SQ from 44.1 kHz is perfect - much better then from HQ CD PRO source.
As the limitation of the sq. receiver is max to 24B48KkHz, SQ is not so good from HD files >48kHz. (On line transcoding by LMS server)
I am thinkig of changing the reciever to any ather solution as RPi BBB or wandboard, but I heard that RPi(19,2MHz) and BBB(24MHz) aro not strictly audio dedicated and have only one clock resonator.
As an experienced user of DDDAC, could you tell me which solution would be best for this DAC to have source with low jitter for 44.1 and more sampling rates files - to 192kHz or even more if possible.
regards
Andrzej



Hi Carlsor,
Many thanks for your kind words!

Frankly, I very am over joyed with my current setup. I fear with JFET CCS might just be too much of a good thing...! Nonetheless, I certainly am craving for more improvement despite the gap is getting narrower as it elevates further up the sonic ladder. Currently, I have no desire for further tweaking because the current SQ is simply too engaging, loving it!!! In the same token, I really look toward to your excellent works for future upgrade if is ok? Please count me in for those 24 boards, I will reserve a set for my mate here, Tuyen! Hopefully we can have some fun in the early 2015?
Will pm you.

With regards to BBB and Acko S03, it is very simple. Please go to Twister Pears Audio and look for support Linux Botic driver from Miero. Alternatively Google the term "Botic driver". When purchase S03, Acko will email you the 12pages pdf manual on how to setup with schematic. Personally I went a step further by using JRiver to manage the 4TB audio library. JRiver does this efficiently better than MPD, which is the embedded player built in Botic driver. JRemote can wirelessly navigates JRiver which is managing the whole library at your fingers, extremely convenience and very user friendly. Those knowing JRemote will appreciate where I am coming from. The trick is to get BBB communicate to your PC with JRiver running. Here you can google "upmpdcli". This piece of code will allows JRiver to control your BBB under the protocol UPnP. Secondly, you need to manually modified the LAN IP address to static on both BBB and PC with JRiver, in order to have them communicate directly for purity of sound. If step 2 is a little too advance, you can simply connect both into a router. JRiver will detect as player namely UpMPD. Which also appears in your JRemote under Zones selection. If selecting UpMPD, it will send all data to BBB which MPD will play the file and I2S direct to DDDAC or S03. Please feel free to shoot me a PM if you are getting stuck? I can also assist the same interface with Raspberry Pi via Volumio 1.4. ;)

Hope Doede doesn't mind for this off topic?! :)

Cheers.
Chanh
 
Hi Carlsor,
Many thanks for your kind words!

Frankly, I very am over joyed with my current setup. I fear with JFET CCS might just be too much of a good thing...! Nonetheless, I certainly am craving for more improvement despite the gap is getting narrower as it elevates further up the sonic ladder. Currently, I have no desire for further tweaking because the current SQ is simply too engaging, loving it!!! In the same token, I really look toward to your excellent works for future upgrade if is ok? Please count me in for those 24 boards, I will reserve a set for my mate here, Tuyen! Hopefully we can have some fun in the early 2015?
Will pm you.

With regards to BBB and Acko S03, it is very simple. Please go to Twister Pears Audio and look for support Linux Botic driver from Miero. Alternatively Google the term "Botic driver". When purchase S03, Acko will email you the 12pages pdf manual on how to setup with schematic. Personally I went a step further by using JRiver to manage the 4TB audio library. JRiver does this efficiently better than MPD, which is the embedded player built in Botic driver. JRemote can wirelessly navigates JRiver which is managing the whole library at your fingers, extremely convenience and very user friendly. Those knowing JRemote will appreciate where I am coming from. The trick is to get BBB communicate to your PC with JRiver running. Here you can google "upmpdcli". This piece of code will allows JRiver to control your BBB under the protocol UPnP. Secondly, you need to manually modified the LAN IP address to static on both BBB and PC with JRiver, in order to have them communicate directly for purity of sound. If step 2 is a little too advance, you can simply connect both into a router. JRiver will detect as player namely UpMPD. Which also appears in your JRemote under Zones selection. If selecting UpMPD, it will send all data to BBB which MPD will play the file and I2S direct to DDDAC or S03. Please feel free to shoot me a PM if you are getting stuck? I can also assist the same interface with Raspberry Pi via Volumio 1.4. ;)

Hope Doede doesn't mind for this off topic?! :)

Cheers.
Chanh

Hi Chanh,

Nice that you got the acko board running. I am still waiting for the potato chips to finish my board :(

I am wondering why you would make all this extra trouble with jriver through mpd.
I am running volumio and runeaudio (the latter has the edge since the last update for rpi) I control mpd with mpad; this has an excellent GUI and I have no reason to look for alternatives.
I also find that the GUI of runeaudio is more stable and more tuneable than volumio.
Am I missing something here?

Regards,
 
Hi Chanh,
I am wondering why you would make all this extra trouble with jriver through mpd.
I am running volumio and runeaudio (the latter has the edge since the last update for rpi) I control mpd with mpad; this has an excellent GUI and I have no reason to look for alternatives.
I also find that the GUI of runeaudio is more stable and more tuneable than volumio.
Am I missing something here?
Regards,
Hi Stefan,

I have tried them all and including the Picoreplayer, If I must rank them interm of Sound Quality, RuneAudio is the best, follow by Volumio and then Picoreplayer. As for RuneAudio, I found the recent beta 0.3 has too many bugs. The alpha version worked more effortlessly and much stable. WebUI is also the better compare to Volumio. Picoreplayer with LMS sound worst, very muddy and no separation/focus but most importantly lack of clarity. Those are based on personal observations, not saying it will reflect to other setup as audio is very subjective with too many variables like system's synergy, listener's acceptance/hearing,....

With regards to your question, I assumed you are relating this to the Raspberry Pi only? None of the above player are I2S capable for BeagleBone Black just yet! My setup is purely for BBB, though it is also benificial with the Pi if your library is extensively large like 2TerraBytes and up. The Pi is a little sluggish when loaded up with such large audio library. The issue with either MPaD or MPoD is the cover art for each album, catalogue and also when is playing, is it will not display the album artwork. You must also consistently remand the artwork for each album to either "cover.jpg or Folder.jpg". Often that is also not working proper. Not to mention the slow respond when larger library loaded. Playing 24bit 192khz can sometime be stuggtering too...., I can talk about this all day long..... :D

With regards to my setup, the idea derived from JPlay dual PC setup which I have had appreciation for them before experiement with the Pi than BBB. More infor you can do some background reading on their website. Basically, I delicate a pc for a task that it does best to mitigate any untolerate jitters/noise...! Therefore BBB or pi does best when only play the music via MPD player and nothing else. MPD is an excellent embedded player but suck with file or database management, not to mention the sluggish processor in place. My practical experience proved having the usb hhd and Ethernet connecting to the Pi or BBB has negatively influenced the sound while having it simply Ethernet direct to a ControlPC has the positive effects, more micro-dynamic and better nuisance sound were obviously apparent, not to mention the darker black background.

Again, may I stress that the observation is system base with my hearing capability. Why not try it yourself and advise us if your findings are any differ? I spent more than 18months in search, experimenting, spent loaded of funds and efforts for an analog CA setup, a setup I could appreciate close to a proper setup-up of a TurnTable. I think with what I have, is getting close, dam close!

Presently, if one tried BBB with Acko S03 and with my dual pc setup idea derived from Jplay, I can assured you there will be no turning back! I put my reputation (if I have any! :D) on the line here but again pending on how revealing a setup is! Note all my setup is powered by decent audio grade linear powersupply like Doede ps and Per-Anders SSR03. Audio grade linear PS is an essential!

Happy Listening!
Chanh
 
Hi. Chanh
I am an happy owner of four deck DDDAC...

Hi Andreaj,

Hope you find some answers to part of your queries in my response to SuperSurfer.

The clock on the Pi isn't all that bad at all. It does better than BBB's built-in crystal. In that I mean Pi plays all sample frequencies from 44.1-192khz, without any irritating digital noises like the BBB for 44.1khz clock family. If you seek for the best then Acko S03 is an luxury item will contribute that attribute. There might be better one out there, which I am not aware? Personally I found the sound from squeezelite or squeezebox a little less refined than MPD. Experimented it and found not worth pursuing further.

Chanh