RTZ SDM (DSD) DAC

[Ray P]

I got my FPGA-based PCM2DSD module up and running today.

I'm just doing a basic test using a USB OTG connection from my smartphone (running USB Audio Pro) as the source and my simple RC filter as the decoder, and playing through my headphone amp. Anyway, it obviously works and sounds pretty good.

[Ray P]

In other posts I mentioned that last Friday i got the train up to Yorkshire for the day and had the pleasure of listening to Steve C's new 6V6 amp in the company of Steve, Mrs. C and Simon. But, great though it was to hear the amp, it wasn't the main reason for my trip; that was to take the breadboard build of the RTZ DAC up to Steve's for him to audition. I think there was consensus that the RTZ, in partnership with Steve's 6V6 amp and Mission speakers, was a great combination that was very easy to listen to and Steve has now taken possession of the RTZ and asked Ant to build a box for it.

On the front-end of the RTZ is a Chinese Amanero-type clone and the FPGA-based PCM2DSD module; that means that, although the RTZ is a DSD DAC, it will work with any typical PCM based media player that outputs via USB, which will perhaps make it worth considering as a project if you're thinking about a new DAC. There's a thread over on DIY Audio with all the information required and the designer is very helpful - there's bit of noise on the signal on the DIY Audio thread but everything needed for the build is in the first couple of pages and I know Tony and I will be happy to help too.

https://www.diyaudio.com/community/thre ... st-6847540

https://www.audio-talk.co.uk/phpBB3/vie ... 15#p208415

https://www.audio-talk.co.uk/phpBB3/vie ... php?t=8633

[Ray P]

When I was testing the RTZ, one of the media player arrangements I used was Volumio and it worked very well - the base version is free.

https://volumio.com/en/get-started/

It is essentially a pre-packaged Linux distribution that you just load onto a USB thumb drive and boot from. I used an Intel NUC I have to hand but it will work on a Raspberry Pi too. I ran the NUC headless and controlled playback via a web browser and/or an app on my phone (there's also an option of using an add-on that turns the volumio device into a Roon endpoint). It worked well and might be worth a look.

You can sometimes pick up suitable pre-owned Intel NUCs on ebay for less than £50.

[Leon]

Nice job Ray
Tony's kindly sent me one to try out , it's been a while since I've done any diy but have built a few different dacs over the years . My preference has been a modified AYA2 I've been using for 16 years so looking forward to properly comparing the RTZ .
I can only listen to DSD files at the minute with the Amanero because it won't switch , Tonys also sent me a PCM2DSD so I just need to sort best way of feeding it .

[Ray P]

Nice job Ray
Tony's kindly sent me one to try out , it's been a while since I've done any diy but have built a few different dacs over the years . My preference has been a modified AYA2 I've been using for 16 years so looking forward to properly comparing the RTZ .
I can only listen to DSD files at the minute with the Amanero because it won't switch , Tonys also sent me a PCM2DSD so I just need to sort best way of feeding it .

Hi Leon.

Tony has mentioned that you're giving the RTZ a try so welcome to the club. I'll be interested to hear your thoughts/experiences in due course.

My own preferred approach to feeding my DSD decoders is via a Beaglebone Black, running a derivative of the Botic linux distro, and equipped with an isolator/reclocker board. The beaglebone acts as a network endpoint renderer for HQ Player, which does the heavy-lift reampling. All controlled with Roon.

Apart from the RTZ, I also have DSC2 and ValveDAC DSD decoders (you can find them on DIY Audio) and they all sound excellent.

I've also used a Beaglebone equipped with a resampler/isolator/reclocker based on the AK4137 chip, similar result to the PCM2DSD module but network connection instead of USB.

[Leon]

Nice job Ray
Tony's kindly sent me one to try out , it's been a while since I've done any diy but have built a few different dacs over the years . My preference has been a modified AYA2 I've been using for 16 years so looking forward to properly comparing the RTZ .
I can only listen to DSD files at the minute with the Amanero because it won't switch , Tonys also sent me a PCM2DSD so I just need to sort best way of feeding it .

Hi Leon.

Tony has mentioned that you're giving the RTZ a try so welcome to the club. I'll be interested to hear your thoughts/experiences in due course.

My own preferred approach to feeding my DSD decoders is via a Beaglebone Black, running a derivative of the Botic linux distro, and equipped with an isolator/reclocker board. The beaglebone acts as a network endpoint renderer for HQ Player, which does the heavy-lift reampling. All controlled with Roon.

Apart from the RTZ, I also have DSC2 and ValveDAC DSD decoders (you can find them on DIY Audio) and they all sound excellent.

I've also used a Beaglebone equipped with a resampler/isolator/reclocker based on the AK4137 chip, similar result to the PCM2DSD module but network connection instead of USB.

Hi Ray,

Thank you , could we use this as a discussion thread for this dac or maybe start something separate ?
I'll have a read up on what your using as a source thanks , certainly be way better than what im currently using .

The Amanero is playing fine now, its plugged into the PCM2DSD I'm not sure what the issue was before.It would only play DSD files but is now playing anything .

I'm so behind with this stuff things have moved on a lot since I was last playing around with diy years ago. Many dacs diy and commercial designs have come and gone in my system over the years . AYA2 has been my favourite and remained, it's been modded as far as it'll go but it's around 16 years old now so im hoping the RTZ can replace it .

BTW If there's anything you can see I'm missing, can be improved etc please give me a shout

I mainly use Amazon music unlimited as a source , it's convenient but not sure how it compares against against the other options out there regards sound quality . I also have Foobar for content saved on the hard drive but rarely use it now .
There doesn't seem a lot of choice for playing Amazon music , Its currently just the app on a win laptop and my MacBook Pro feeding the Amanero both set using exclusive mode . With the AYA2 I use a Douk U2pro USB with external psu feeding spdif . I was looking at the JLsounds to use with the RTZ and AYA2 , interesting that it can run the TDA1541A I2S in simultaneous mode although not sure if it will offer much over the Amanero for the RTZ dac . I was looking at those Wiim pro servers but not sure if they are any good , unfortunately they only offer spdif output . I'm not sure if they can e modded or even worth it .

So far

I have a pair of PH shunt regs running the RTZ +/-15v , shunt reg running the RTZ 5v, shunt reg running 5v pcm2dsd . Later today I'm going to disconnect the USB supply and run Amanero from an external 5v shunt reg too. All supplies have separate transformer windings and grounding wires running straight to dac.
I'm using the Dac3filter wired as SE going to my headphone amps , Headphones HD800 , HD250 linear and modified HD650. I like to use the HD800's for testing . The Dac3filter uses NE5532's for u5,6,12,13 but Tony's kindly going to send me some OPA1678's so I can swap them over .

At the minute it sounds great , compared to AYA2 I find the RTZ soundstage a little smaller , bass is warmer the sound is a little compressed compared against my AYA2 .My AYA2 has had a lot of work done to it though , the OPA861 output stage with passive I/V is quite simple so the parts and regulation used has quite a big influence on the sound . I'm looking forward to seeing what else can be squeezed out of the RTZ, I'd imagine the source is the main thing holding it back so far though. It shows a lot of potential Marcel did a great job .

[simon]

Hi Leon,

I also Amazon Music Unlimited too. I don't know how it compares to other streaming services either but it sounds pretty good to me, and HD music is included not an extra cost option. (Perhaps the other streamers don't charge now either?)

I'd hoped to use Linux, which I can through the Web rather than app, but it's limited to SD only. HD is available on Windows as you say but I've had issues with the JLSounds driver dropping out for no obvious reason.

TBH I use the app on my Android phone most of the time. It's easy and works, but it powers the USB side of the JLSounds card so is ultimately limited how long I can use it for. I should add an extra PS for it inside the DAC chassis but there isn't the space.

[Leon]

Hi Leon,

I also Amazon Music Unlimited too. I don't know how it compares to other streaming services either but it sounds pretty good to me, and HD music is included not an extra cost option. (Perhaps the other streamers don't charge now either?)

I'd hoped to use Linux, which I can through the Web rather than app, but it's limited to SD only. HD is available on Windows as you say but I've had issues with the JLSounds driver dropping out for no obvious reason.

TBH I use the app on my Android phone most of the time. It's easy and works, but it powers the USB side of the JLSounds card so is ultimately limited how long I can use it for. I should add an extra PS for it inside the DAC chassis but there isn't the space.

Hi Simon ,

It's just nice having the huge amount of content with Amazon music unlimited . The sound is good with both my dacs I'm just not sure if there's more to be had .I have tried it with my iPhone and iPad but only with a portable usb dac and it can be a little finicky , I mainly use the laptop and MacBook with the main dacs . I notice some tracks show HD and others ultra HD a lot are at 44.1 with fewer 48, 96 and 192
I was hoping there was more options to use Amazon , those Wiim devices look to be one of the few streaming devices that has an app available for it . They are cheap but no point getting one if its no better than what im using now

[Ant]

I have 2 wiim minis and you can only output to an external dac via optical. It says it will do 192 down the optical, but one dac i have will pick it up and the other wont. My topping e30 will pick up the 192 test signal it outputs but my jds labs dac wont. That one only accepts it via usb which the wiim dossnt have

[Leon]

I have 2 wiim minis and you can only output to an external dac via optical. It says it will do 192 down the optical, but one dac i have will pick it up and the other wont. My topping e30 will pick up the 192 test signal it outputs but my jds labs dac wont. That one only accepts it via usb which the wiim dossnt have

Thanks Ant , those Wiim pro's have coaxial out too by looks of it , just a shame no I2S . Other thing I was looking at is Bluesound Node

[Tony Moore]

Welcome Leon!

I'm really glad you're onboard with the RTZ. This will spur me on also to try more upgrades and tweaks and try to see what is ultimately possible.

I am happy with my main DAC / Transporter combo but I do have the 2nd unit that is currently not really being used much so I have that to experiment on in parallel. Both units are almost identical in construction apart from the source which is a Squeezebox Receiver for the 2nd unit. To my ears they currently sound identical so I don't believe the source is making much difference in my case. However that might just be that my ears are not good enough to resolve the differences, which is entirely possible.

I am really interested in discoveries related to power supply types and quantity. My DAC supplies are LM317s but I've used a super-reg on the +/- 15v to the filter/output board with the thought that perhaps the analogue sections would benefit more but perhaps I should try the other way around. Or perhaps shunts on the DAC 5v and separate shunt on the PCM2DSD? I do have very limited room in my main DAC case though so it would be tough.

[Ray P]

...could we use this as a discussion thread for this dac or maybe start something separate ?

Just in from work so I'll read the posts properly later but for now, sure, it's as good a place as any.

Ray

[Leon]

Welcome Leon!

I'm really glad you're onboard with the RTZ. This will spur me on also to try more upgrades and tweaks and try to see what is ultimately possible.

I am happy with my main DAC / Transporter combo but I do have the 2nd unit that is currently not really being used much so I have that to experiment on in parallel. Both units are almost identical in construction apart from the source which is a Squeezebox Receiver for the 2nd unit. To my ears they currently sound identical so I don't believe the source is making much difference in my case. However that might just be that my ears are not good enough to resolve the differences, which is entirely possible.

I am really interested in discoveries related to power supply types and quantity. My DAC supplies are LM317s but I've used a super-reg on the +/- 15v to the filter/output board with the thought that perhaps the analogue sections would benefit more but perhaps I should try the other way around. Or perhaps shunts on the DAC 5v and separate shunt on the PCM2DSD? I do have very limited room in my main DAC case though so it would be tough.

Hi Tony ,

Its great to try these things, share tweaks and findings so I'm looking forward to it .
The shunt regs didn't make a huge difference , I find they added a little finesse to the sound , subtle details easier to hear just cleaner ,main downside is these regs run quite warm , I used 12v AC transformers for the +/-15v DC and 9v AC for the 5v so not to over heat them . My Lm317/337 regged supply was very basic for quick testing so certainly not the best. I have some ALW super regs somewhere so I can knock a couple up if I can find them to compare if it would help ? Might be smaller difference against the shunts with those

I've modded the Amanero , removed L1 and added wires to the onboard 3.3v reg input , cutting the track before L1 would have been better to keep the inductor and extra decoupling cap in circuit. Removing L1 makes it easy to revert back though . Just warming up but initial impressions are good and worth the effort . Its running from the PCM2 DSD shunt

[Leon]

...could we use this as a discussion thread for this dac or maybe start something separate ?

Just in from work so I'll read the posts properly later but for now, sure, it's as good a place as any.

Ray

Thanks Ray

[Ray P]

I don't know where this evening has gone!

I prefer the JLSounds USB board to the Amanero but it would complicate matters with connections to the PCM2DSD module. I made some interface boards to hook a JLSounds board to a ValveDAC that I bult for a friend (Marcel's designs use the Amanero pattern header on their inputs) and it worked really well but that used HQPlayer for upsampling. The interface board also has sample rate indicators for the DSD rate and whether the data is 44.1KHz or 48KHz family.

I have found these are very good power supplies for my Decoder projects, Salas shunt regulators didn't give any discernible improvement so I think in this context low-noise is the important thing to consider. These supplies are very space efficient too.

https://www.ldovr.com/category-s/114.htm

I think the most scope for exploring improvements with the RTZ is the output filter and when I get back to the RTZ (currently working on several amplifier projects) I want to try some different arrangements - top of my list is the circuit in post #7 of this thread, using 6SN7s.

Just some quick thoughts.