T+A DAC 200

[OE333]

On 4/14/2023 at 12:55 AM, luisma said:

Hi, no rush or urgent but did you have a chance to look into the RS233 firmware update? Thank you, that will be awesome if it can be done that way.

 

The official update tool should have been available in the T+A webshopby now, but it seems T+A is a bit slow in getting this tool into their shop. But I think it will be available soon.

 

For all who consider doing a firmware update using DIY hardware, I have prepared a short instruction attached to this post.

This is only a pre-release, just to give an impression how it works. I will add some more details and information in the coming days.

 

I will release the update tool PC software and the final instructions next week.

 

DIY_TA_UpdateTool.pdf

[OE333]

On 4/16/2023 at 2:15 PM, OE333 said:

 

I will release the update tool PC software and the final instructions next week.

 

 

Well, as promised:

I have uploaded the Update Tool, instructions and the current firmware for DAC200 and HA200 to Github.

 

https://github.com/OE333/DAC200-HA200-Update-Tool

 

Have fun.

 

-OE-

 

[OE333]

Hi @jrsub,

yes your setup for DSD should work fine. Just for a test I would recommend to disconnect all other sources, just have the Sony player connected and try to play a SACD. If the static noise is gone, connect one source device after the other and find out when the static noise begins.

If you have noise with only tne Sony connected, it might be best to contact the T+A sevice dept ([email protected]).

 

Multichannel:

Obviously the Sony player outputs a multichannel audio stream on its HDMI out, not a 2-channel downmix. Such a multichannel stream can not be decoded and downmixed by the DAC as it only accepts 2-channel stereo streams. Try to setup the HDMI output of your player to output a 2-ch. downmix, then it should work.

If this is not possible, you could perhaps use the S/P-DIF output of the player - this should normally be capable to output a 2-ch. stereo stream.

[OE333]

1 hour ago, 1125FPS said:

I suspect volume is always only fixed on all HDMI outputs, but don't really know.  Said another way, I suspect volume is always post-HDMI cable and never pre-HDMI cable.   

 

Yes, you are right, volume control is done post-HDMI cable i.e. after surround decoding (which is done in your Pioneer receiver).

 

What might work is using a setup with separate connections to Pioneer (HDMI) and DAC200 (SP-DIF or TOSLINK):

For HT - volume control thru Pioneer Receiver, DAC200 set to constant "HT" volume setting:

BluRay_Player > HDMI > Pioneer -> Front L/R pre-out RCA > DAC200 analog in > 2-ch amp > L/R main speakers.

                                                    -> rear and side surround speaker outputs > 4 in-wall surrounds.

 

For Stereo music: (volume control thru DAC200 - Pioneer receiver can be switched OFF):

BluRay_Player > DAC200 digital in (SP-DIF) > 2-ch amp > L/R main speakers.

                                                        

 

Please note:

For HT use, the DAC200 needs to be set to a constant HT" volume setting which should always be used for HT.

 

 

 

[OE333]

22 minutes ago, jrsub said:

 

I must  not be seeing the option on the Sony to output a two channel only stream.   Although I have the down mix set to stereo on the player,  the DAC 200 still is receiving a multi channel signal - the DAC 200 display tells me so.   More experimenting is required.  

 

 

Have you tried the following audio settings:

[Digital Audio Output] -> PCM

[BD Secondary Audio] -> On

 

 

 

[OE333]

4 hours ago, jrsub said:

Still no luck,  I contacted T+A support regarding the issues I am having. 

 

 

Problem seems to be that the player does not send a proper 2ch. downmix.

[OE333]

20 minutes ago, jrsub said:

 

I posted a thread on Audiongon forums to get insight from the members there and the consensus seems to be that playing SACDs through T+A should not work at all due to SACD license requirements.   

 

 

Playback of a 2-channel SACD over the HDMI connection DOES work.

DAC200 and HA200 are licensed products - so don't worry about that.

[OE333]

On 4/25/2023 at 7:11 PM, jrsub said:

Great, hopefully T+A support will get back to me soon regarding the static I get when using 2-channel SACD over HDMI.  

 

 

I was in the factory today and discussed this with my colleagues from the service dept. We will aquire a UDB-X700 and do some tests. I wll give you further notice, when we know more.

[OE333]

22 hours ago, The Computer Audiophile said:

The T+A factory is sold out of DAC 200 units, in both colors :~)

 

Don't worry too much about that - T+A devices don't arrive in big containers - they are produced in-house in the T+A factory. So replenishment comes on a daily basis (as long as T+A gets enough electronic components from the suppliers).

 

[OE333]

16 hours ago, The Computer Audiophile said:

I just got back to the hotel after dinner with the T+A team. What a lovely group of people, who also happen to really know their stuff! I don’t think I’ve ever been out to dinner with a manufacturer and talked about HQPlayer, NAA, single board computers, DACs, upsampling, etc… like we did tonight. So much fun. 

 

Yes, it was a wonderful evening, I enjoyed it very much.. Thank you again for your visit and the good discussions we had.

Have a safe trip home.

 

[OE333]

@LowOrbit answer really "hit the nail on the head". The DAC200 is a DAC with a fixed functionality so normally there will be no reason for software updates.

 

When designing this DAC one of the main design goals was to keep electromagnetic interference as low as possible. So for control of the device a microcontroller (TI MSP430) with extremely low electro magnetic emission was selected. This controller does not have USB or ethernet interfaces - if it had, the elm interference would be much higher...

 

However, updates are possible if required - either via the MP200 streamer or via an electromagnetically "clean" RS232 interface.

[OE333]

On 7/3/2023 at 12:56 AM, 1125FPS said:

 

I respectfully request Miska or anyone else explain the unique nature of DAC 200's DSD NOS modes.

 

 

The NOS mode in DAC200 is available for PCM signals only.

 

 

[OE333]

On 7/2/2023 at 10:02 PM, Shadorne said:

From the discussion above, is the reconstruction filter also part of the burr-brown 1795 chip?

 

Also from the discussion, is it advisable to always oversample at least x8 (on a high quality external oversampler) in order for the reconstruction filter to properly remove high frequency aliased artifacts?

 

I assume you average multiple 1795 signals after the reconstruction filter to improve Signal to noise? Is this the case?

 

 

The reconstruction filter in DAC200 is not part of the BB 1795. It is a discrete analog filter circuit following the D/A converters in analog domain.

 

If using an external upsampler for PCM my recommendation is to upsample 8x externally and use the NOS mode of DAC200.

 

The averaging of the multiple D/A converter outputs is done in the (discrete analog)  I/V stage following the converters. Purpose of this averaging is to minimize noise and converter distortion.

 

 

[OE333]

8 hours ago, jonniema said:

Can also someone point out if DAC200 supports DSD1024 (Native DSD) other than via the ASIO windows driver? I.e: could i have my NUC running linux or other OS

 

 

Native DSD via USB from a Linux PC is fully supported. - so no problems to be expected.

 

Regarding DSD 1024 with a I7 8559U CPU I don't think it will work, but of course you can try it.

Maybe DSD512 with one of the more sophisticated filters/modulators would be the better way to go.

 

I'm sure @Miska will be able to give more advice on this topic...

 

[OE333]

21 hours ago, agisthos said:

@OE333 How does the DAC 200 handle the single ended outputs? Second class citizen running through op-amps like most DAC's do? Or does it have its own discrete output stage? Taken from one leg of the balanced?

 

The DAC200 signal path for both - balanced XLR and unbalanced RCA outputs - is fully discrete.

i.e. there are no Op-Amos between the D/A converters and output. And this is true for PCM and DSD signal paths. Even the I/V (current/voltage) converter stages in the PCM path are fully discrete.

 

And yes, the unbalanced output is derived from the positive balanced leg.

With "derived" I mean, that not directly the positive pin of the XLR socket is used for RCA. The RCA output has its own decoupling and emc filtering network. So when connecting sinks to the XLR and RCA outputs at the same time, there is no cross influence.

[OE333]

On 9/4/2023 at 2:47 PM, Asdfgh said:

@OE333 - Can the DAC200’s relay volume be controlled by a computer connected via USB (like the MP200 does) rather than just DSP? If not, is this something that could be added as a firmware update, even just for Roon?

 

Volume (and all other DAC200 settings) can be controlled from a computer via RS232. If this is an option for you I can give you some advice on how to do that - please let me know.

 

 

[OE333]

6 hours ago, davidv100 said:

I am thinking about buying a Sennheiser HD800s.
But I have no idea if this is a good match based on power, impedance and stuff.
 

 

Of course, as @droffen suggested, the Solitaire P / P-SE are a perfect match with the DAC200.

But the Sennheiser HD800 is one of the headphones which is used regularly by the T+A development dept. for listening tests and it also works extremely well with DAC200.

[OE333]

11 minutes ago, SPAZ said:

I know T+A already has an HDMI addon card for the DAC200 so I am assuming something with that and a firmware upgrade.

 

I could imagine an add-on card like the HDMI card already available from T+A.

This card would be inserted into the DAC200 (or HA200) at the position of the HDMI add-on - so the use of HDMI and I2S cards at the same time would not be possible.

If there is enough demand for an I2S input card I would discuss this matter with my T+A colleagues and see what is possible...

 

[OE333]

There have been quite a few questions during the past days. Mainly about (Volume) control and about an additional I2S input for DAC200 and HA200.

I will try to give some answers to both topiccs in separate posts following.

[OE333]

Question1 - Control of DAC200/HA200 from a PC

As already mentioned, it is possible to control the DAC/HA 200 via a serial RS232 connection.

The RS232 control interface is used internally by T+A for production and QA tests in the factory but it could be used to implement a remote control of the DAC from a PC. Unfortunately there is no official T+A documentation of the RS232 interface pulicly available.

 

For further information I have made a short list (see attachment) of commands implemented in the DAC that could be used to control the DAC.

 

As you can see, the commands are plain ASCII text commands. These commands can be sent from any computer with the help of a terminal program (eg. "Putty" or Windows "Hyperterm").

Sending for example the command VOL 50 will set the volume control of the DAC to 50%.

In the same way all the other functions (input switching, output ON/OFF etc.) can be controlled.

 

Currently there is no APP with graphical user interface available for controlling the DAC - just the ASCII text cammands from a terminal.

It would be quite easy to make a simple graphical user interface for the basic control of the DAC.

Question: Is there a demand for such a GUI control application ????

 

Control over USB instead of RS232

Technically it would be possible to send the commands over USB instead of a separate RS232 connection. To achieve this the USB receiver firmware needs to be extended to handle control commands. Such an extention of the firmware might be quite expensive and I don't think that it will be implemented in the near futrure.

 

DAC200_RS232_Commands.pdf

[OE333]

Question 2 - Additional I2S input for the DAC200/HA200

 

First of all some basic facts regarding the I2S inteface:

I2S (= "Inter IC Sound") was developed as an internal interface between audio circuits (DSPs, codecs, ADCs, DACs). This interface was never meant to be used as an external interface between devices.

 

Standardized external audio interfaces are S/P-DIF, TOSLINK, AES-EBU, HDMI, USB, etc. These interfaces are standardized and in general provide good compatibility between devices which use there interfaces.

 

Some companies have started to (mis-)use I2S as an external interface between a digital source (e.g. SACD player) and DAC.  The reasons for this might be that

1.) the audio data needs to be encoded and packaged into a S/P-DIF, HDMI, USB stream and be decoded at the receiving end

2.) some of the above external interfaces are not capable of very high sample rate PCM or DSD signals

3.) additional costs for encoder/decoder, license fees (eg. HDMI, HDCP)

 

So some companies may have chosen to directly send the internal I2S data straéam to the external DAC. This saves expenses for electrical components and the (really very expensive) license fees.

 

A common claim is that I2S is sonically superior due a very "short" and direct signal path and the elimination of encoding/decoding hardware.

Well, I am a fan of short signal paths, but in case of I2S I have my doubts. I completely agree with the arguments of @barrowsabove. I2S is a synchronous inteface needing to transport the clocking signals from the source device to the sink. I think, who has ever seen clocking signals in the multi-Megahertz region after travelling over a 1-2m distance and over some plugs, cables and inteconnects would not think any more that I2S over external cables is a very good idea...

 

Audio over an asynchronous interface such as USB with clocking sgnals generated directly at the D/A converters is technically (and commonally sonically) superior.

 

Anyway - I2S as an external interface exists and it is used by some source devices. My personal advice would be that if the source has some other interface like USB or HDMI which supports the wanted audio formats, always use this interface.

 

Are there any source devices which ONLY have an I2S output ?

In this case it would of course be desirable to have an I2S input option for the DAC/HA200. As I have stated earlier, it would be possible to create a I2S input module for the DAC/HA200 which could be used instead of the HDMI option. So this would be a hardware add-on - a pure software based solution is not possible.

 

So my question: is there a need for such a I2S input board and for which source devices shall it be used.

The latter question is quite relevant, because there exists no standardization for an exteral I2S inteface. Different sockets/plugs (HDMI, RJ45..) are used, the pinnings differ from manufacturer to manufacturer and also the electrical parameters of the interface are different.

 

So, these things will have to be discussed.

 

An other interesting question was to have an additional USB input on the DAC/HA200. I will come to this question in my next post.

 

 

[OE333]

Additional USB input for the DAC/HA200

 

The DAC/HA200 comes as standard with two USB inputs, one of which (USB-SYS) is reserved for the MP200 streamer.

 

Technically it would be possible to make the USB-SYS input available for general use if no MP200 is connected. In this case it would be possible to connect two USB source devices to the DAC/HA200.

 

I am not sure if T+A would approve such modification but if there is a broad demand for it I could discuss it at T+A and see what I can achieve...

[OE333]

2 hours ago, davidv100 said:

My question is more generic. I looked about a ton a headphone/amp pairing YT videos, especially regarding the "Impedance" question, and came out more confused than ever before. Some say high impedance headphones (say 300 Ohms) demand more current than lower impedance headphones (says 16 Ohms), and some say the exact opposite.

 

 

A low impedance HP will require higher current than a high impedance HP for a given sound pressure level - provided both headphones have the same sensitivity in dB/mW.

On the other hand the high impedance HP will require a higher voltage.

 

 

2 hours ago, davidv100 said:

So, since there is such a huge impedance difference between the HD800S (300 Ohms) and the Arya Organic (16 Ohms), and as you said the HD800S would be a good match with DAC 200, would that mean the Arya Organic (16 Ohms, 92Db Sensitivity) would be a poor match ? Or not at all ?

 

 

Even though I personally have no experience with the Arya headphone, I don't see any problems for the DAC200 driving it.

 

The DAC200 can deliver about 0.64 W into the 16 Ohms of the Arya and about 0.35 W into the 300 Ohms of the HD800S.

In both cases more than ever will be needed...

 

[OE333]

22 hours ago, Apollo said:

Is there any potential harm when starting HDMI audio (and video) whilst the DAC200 is in Nos2 position?

 

Reason for asking as there is only information on the (small) display of the DAC200, it is easy to forget or make a mistake with filter (OVS) setting when switching input.

 

My request would be to have the Nos1/Nos2 modes disabled when switching to HDMI.

 

I don't see any potential harm when using HDMI with the NOS2 oversampling setting.

You will of course have some more digital artefacts (mirror-frequencies etc) in the output signal but this should be more annoying than harmful --- I even know some people who love the sound with the additional artefacts...

 

Maybe the settings of the oversampling and analog reconstruction filters should be stored for each source independently - perhaps we can add such a feature in a coming firmware version. 

[OE333]

21 hours ago, Shadorne said:

My observations. Two cents. Depending on your setup results may vary.

 

Good -> Better -> Best

1) Redbook native files with the DAC200 upsampling filters FIR1,2, etc (similar to many other chip DACs but the DAC200 definitely has a slight edge)

2) Redbook native files with the DAC200 upsampling and NOS1 or 2 (audibly hard to distinguish from 1 above on my setup but this may be system dependent)

3) Redbook to PCM 88 or 96Khz on PC to DAC200 any filter (slightly better soundstage, more relaxed, clean lower noise floor)

4) Redbook to PCM 172 or 193  on PC to DAC200 any filter(even better soundstage - focussed but natural)

5) Redbook to PCM 705 or 756 on PC to DAC200 any filter(superb hard to tell between 5 and 4)

6) Redbook to DSD64 on a PC low pass analog output filter only (better yet - can’t put a finger on it - everything is just relaxed yet detailed)

7) Redbook to DSD256 on PC to DAC200 either analog low pass final filter only (best natural sound and soundstage from a DAC that I have heard - laser focus - easy to hear or pinpoint anything)

 

The biggest step in improvement is the jump in upsampling from 44.1 to 4x oversampling on a PC. (Between 4 and 1) This step in improvement is probably true for many chip-based DACs, as the low latency first stage filters aren’t great on any chip and this stage probably has the biggest detrimental impact to sound. The DAC200 is better however fed native 44.1 than I have ever heard from other chip-based DACs. So a great choice even for those who don’t like PC.
 

The icing on the cake is going to DSD256 and although the jump is very subtle, I think this is what sounds to me better than vinyl in every way and every dimension for the first time.  I believe digital has for years already been better than vinyl in many ways but it came with a digital glare and less soundstage than vinyl (so if you could live with all other deficiencies of vinyl then vinyl was still the sweetest and most impressive holographic sound)

 

I don’t have a chord TT2 or May to compare. I cannot say. What I can say is that upsampling is necessary to get the very most out of this DAC, probably due to simple low latency filters used in the DAC chip (like every DAC chip) compared to a powerful PC. That said the DAC-chip in the DAC200 (which processes all PCM) has been implemented in such a way that even simple straight 44.1 sounds slightly better than many DACs I have heard. (T+A seem to know what to do to get the most out of BOTH PCM (from a DAC chip) and also via their bespoke DSD 1 bit converter - they are unlikely to share their in depth understanding of the audibility of filter issues, as it is a competitive advantage/trade secret but a hint could be their use of bezier smooth filters as an option)
 

I believe that pre-echo from the low latency simple equiripple tap filters used in digital upsampling is the primary problem with most chip-based digital (there are other issues too but I hear an effect very much like baffle edge diffraction from these chip-based filters).
 

I am a convert to @Miska way of thinking. FWIW that might influence my views and biases. 

 

 

 

@Shadorne: thank you for sharing your detailed observations.

 

I just would like to add that T+A does not use the chip based filters from the DAC chips. All filtering is done by proprietary algorithms in a DSP.

Besides the FIR filters the DAC200 offers the choice of two BEZIER filters. These filters are no FIR filters, they use Bezier polynominal interpolation instead and these filters do not have any pre-echoes or any pre- or post ringing.