Valve DAC

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pre65
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#46 Re: Valve DAC

Post by pre65 »

IslandPink wrote: Sun Aug 02, 2020 12:14 pm Good effort Ray - glad it's worked out so well.
+1. :D
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Ray P
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#47 Re: Valve DAC

Post by Ray P »

Thanks chaps.

Just gave myself a few minutes of panic and despondency! :ashamed:

I've just moved the DAC from the workbench to next to my work desk so it's easier to explore the HQP settings and to use it with my Noir HPA and BayerDynamic DT880 headphones - no sound! After a bit of head scratching I remembered to plug the 5V LDO reglator back in. :rolleyes:

Anyway, I'm now listening to a DSD256 stream through the Noir and DT880s - simply delightful - I've never heard Eva Cassidy sounding so good!

This morning I finished the assembly and added some bling! I just need to organise a top for the chassis to, literally, top-off the project.

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Wolfgang
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#48 Re: Valve DAC

Post by Wolfgang »

IMO this DAC deserves to be built by more people and it will be good, in due course, to expose some of you guys t
Great success, Ray. I had a feeling when I first read the article in audio x-press that it could be soemthing special.I would start this project if the parts could be ordered easily.
Could the CT7302TL or soemthing similar be used in combination with the valve-DAC or is the HQ player the best/only solution? The comments in DIYaudio don't sound so promising. https://www.diyaudio.com/forums/digital ... 302pl.html
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izzy wizzy
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#49 Re: Valve DAC

Post by izzy wizzy »

Great project Ray and fantastic build as usual. Efficient projects do not seem to be what this place is about :)
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#50 Re: Valve DAC

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Hi Wolfgang and thanks. The only difficult to obtain part for this project is the PCB - I'll come back to that.

IMO the best way of getting the SDM (DSD) needed for this DAC is, as you would expect me to say, HQ Player - this is based on my own very positive experience with it and others who've tried different mechanisms and come back to HQP. The other means of getting the SDM include (BTW, I've not tried any of them) in software both Daphile and Roon will resample/upsample to SDM (there may be others) and in hardware there is the AK4137 and the CT7032 you mention. Have you read the original aricle in Linear Audio (https://linearaudio.net/article-detail/2284)? I ask because this project is a derivative of the original design, just for SDM/DSD, whereas the original had onboard resampling from PCM - can't remember the details off hand as it wasn't of interest.

As I say, all the components, apart from the PCB, were easy to get hold of, mostly from mainstream suppliers, with just a few specialist suppliers (such as for the reconstruction filter inductors and the output transformers). I've not used 'boutique' caps or resistors in my build, the nearest thing might be the LCR polystyrene caps in the filters and Arcotronics Polypropylene output caps. The PCB is relatively sophisticated, four layer with a custom layer stack as specified by the designer, who also provided the updated gerber files (he knows his stuff BTW and has been very patient and helpful - https://linearaudio.net/authors/373). There was no real interest in a group buy for the PCBs, which would have made the cost more affordable, so a fellow UK based DIY Audio member and I shared the, not insignificant, cost and ordered a batch of 5 boards from PCBWay. I mention all of this because I do have a spare PCB that I'm willing to sell now I don't need it but it won't be cheap. Still interested? You might also want to be aware that there's a fair bit of small smd soldering involved - I paid a friend to do that for me as I wanted to maximise the odds of success!
Last edited by Ray P on Sun Aug 02, 2020 9:07 pm, edited 1 time in total.
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IslandPink
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#51 Re: Valve DAC

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izzy wizzy wrote: Sun Aug 02, 2020 6:04 pm Great project Ray and fantastic build as usual. Efficient projects do not seem to be what this place is about :)
Hey - not so fast. Some of us are building horn speakers !
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#52 Re: Valve DAC

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I've been re-exploring my music collection again this evening, thoroughly enjoying the experience and hearing pieces in a new light. Now, I know that in the scale of things I haven't listened to that many DACs, but what I can say is that of those I've listened to this is the best, bettering my previous baseline, a DSC2 (another DSD decoder) by a significant margin. My Buffalo 3SE sounds positively 'flat' in comparison.

This Valve DAC is just delightful to listen to; excuse my exuberance, but it is true. Oh for the Covid situation to abate so that I could pop up to Greg's to share the experience with the Brissle collective.

Next week I will complete the build of my 6C33C and 13E1 amplifiers and then we'll see what the combinations with this DAC can do with my Lowther horns.
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#53 Re: Valve DAC

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I don't know if there is any interest in building this DAC amongst you chaps but, for information, I have initiated a group buy for a batch of PCBs over on DIY Audio and invite you to sign-up if its of interest.

https://www.diyaudio.com/forums/digital ... ost6299387
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#54 Re: Valve DAC

Post by simon »

Your impressions sound most tempting Ray. But I'm PCM and I probably need a simpler job.
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#55 Re: Valve DAC

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simon wrote: Wed Aug 05, 2020 1:41 pm Your impressions sound most tempting Ray. But I'm PCM and I probably need a simpler job.
It probably looks more complex than it is Simon.

You could feed it PCM by bolting something like an AK4137 or CT7302PL on the front for a hardware based solution. Conceptually, that's what the designers original project did except it was implemented with an FPGA/code solution IIRC.
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#56 Re: Valve DAC

Post by Wolfgang »

The more I dive into the HQ -Player and its possibilities and DSD the more I like it.Could solve the DSP problem. That opens of course a whole set of new options . I really like the desktop-client option on one PC.
I hope I can get the valve-DAC to work following Ray's build. Some things are still not fully clear to me (the interface for instance).

Will be a in interesting journey.
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#57 Re: Valve DAC

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Ray P wrote: Wed Aug 05, 2020 1:37 pm I don't know if there is any interest in building this DAC amongst you chaps but, for information, I have initiated a group buy for a batch of PCBs over on DIY Audio and invite you to sign-up if its of interest.

https://www.diyaudio.com/forums/digital ... ost6299387
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#58 Re: Valve DAC

Post by steve s »

Ray P wrote: Fri Aug 07, 2020 7:50 am
Ray P wrote: Wed Aug 05, 2020 1:37 pm I don't know if there is any interest in building this DAC amongst you chaps but, for information, I have initiated a group buy for a batch of PCBs over on DIY Audio and invite you to sign-up if its of interest.

https://www.diyaudio.com/forums/digital ... ost6299387
Nobody?
Hopefully we could have a demo at next year's Owston Ray, for me I'm more than happy with my terradac and any old transport, or at least I was until I discovered a 90s technics cd player that really does match it on sound.

My next project is a phono kit, I bought it a few weeks ago for a winter project, I was quite pleased with how my ear sounded at one of daves meets, so it's based on that.. If it turns out OK my genuine one will be sold, well that's the plan.
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#59 Re: Valve DAC

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steve s wrote: Fri Aug 07, 2020 9:08 am ...for me I'm more than happy with my terradac and any old transport...
maybe best if I don't bring it to the next Owston then Steve :lol:
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pre65
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#60 Re: Valve DAC

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Ray P wrote: Sat Aug 08, 2020 10:44 am
steve s wrote: Fri Aug 07, 2020 9:08 am ...for me I'm more than happy with my terradac and any old transport...
maybe best if I don't bring it to the next Owston then Steve :lol:
Does it work with a plain vanilla SPDIF input Ray ?

My main means of music these days is a Cambridge CXC transport and an upgraded Beresford SEG DAC with a home brewed 15V power supply.
The only thing necessary for the triumph of evil is for good men to do nothing.

Edmund Burke

G-Popz THE easy listening connoisseur. (Philip)
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