Thanks for the report Sonny - Marcel's DAC is very special DAC isn't it!
With the Covid situation I've yet to expose my DSD-only build to any similar type of event/audience - hopefully not too long now though.
Yes, the ValveDac is a very high performer. Am even considering building a second one for myself in order to be able to directly A/B between two in an effort to milk a little 'extra' with various small mods...or more precisely figure out if a few little changes actually contribute to a change in sound. I'm smitten with mine. Also am sure that once someone hears this thing I will be able to shift the extra dac without any trouble.
So interestingly, other people came to the same conclusion that Chaos is the one that can be reliably identified in a blind test vs the other two. Chaos sounds a little more rounded overall and perhaps slightly less microdynamic, but it's not necessarily "worse" depending on the song and gear. On my home setup, the smoothing over wasn't that desirable, but for example, the Focal Utopia which has fast attack and a really aggressive leading edge to things, Chaos kinda helped mellow it out and make it a more relaxed listen, but it wasn't necessarily worse. Overall PWM5 or 9 was used the most, as it sounds the most like "normal" DACs if that makes sense? The ValveDAC is still unique sounding, but the differences when using one of the PWM modes is more subtle.
Do let me know if you discover anything. I'm not sure if any of the"over the top" things I used in the build helped, so I'd be interested to know if you notice changes when switching parts, etc. My only real upgrade left would be the 6922 tubes. They are a bit expensive though for good ones, and needing 6 complicates things lol
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Well, the biggest thing for me to trial will be the analogue reconstruction filter. My system is perhaps a little unique in that my preamp is limited to about 200kHz bandwidth by the autoformer at output and my mono 6 channel amps have analogue line level filters (generally first order) at their inputs with the transducers directly driven by the amplifier output transformers (no speaker level crossovers) which means that my system is already bandwidth limited in some ways and a sixth order reconstruction filter on the dac may be overkill. I really need to get in and measure these interactions and do some controlled listening to see if I can hear dac filter differences. Sigh.
Other than that, I will try different B+ power supplies and a special low voltage power supply for the clock circuit. Maybe even try some different caps at the end of the process, but perhaps not. To be sure these are not changes just for changes sake the ideal situation is to be able to A/B between a control unit and the modified, which means the second ValveDac.
Marcel may or may not have a laundry list of potential improvements, but to me the design as-is is quite comprehensive and well thought out. Not sure if there is anything to be gained by any of the above changes but time will tell...I'm in no rush as it sounds great right now.
Other than that, I will try different B+ power supplies and a special low voltage power supply for the clock circuit. Maybe even try some different caps at the end of the process, but perhaps not. To be sure these are not changes just for changes sake the ideal situation is to be able to A/B between a control unit and the modified, which means the second ValveDac.
Marcel may or may not have a laundry list of potential improvements, but to me the design as-is is quite comprehensive and well thought out. Not sure if there is anything to be gained by any of the above changes but time will tell...I'm in no rush as it sounds great right now.
Ah I don't know enough about the reconstruction filters to mess with that, so I'm using the stock ones with the recommended Jensen's.
I've already got a Neurochrome Maida reg for the -300V and a Pete Millett filament supply for 6.3V. I've got some fancy regulator in the on-board 5V supply, but otherwise that's stock. My output caps are 18uF instead of 10uF which was the biggest I could fit and wanted to spend extra on.
I think the only reasonable upgrade for mine would be the tubes. I'm using JAN Phillips 6922 that I got for $150, so nothing special. Knowing what tubes can do for amps, I'm curious to upgrade the DAC
I've already got a Neurochrome Maida reg for the -300V and a Pete Millett filament supply for 6.3V. I've got some fancy regulator in the on-board 5V supply, but otherwise that's stock. My output caps are 18uF instead of 10uF which was the biggest I could fit and wanted to spend extra on.
I think the only reasonable upgrade for mine would be the tubes. I'm using JAN Phillips 6922 that I got for $150, so nothing special. Knowing what tubes can do for amps, I'm curious to upgrade the DAC
I have a second build to do sometime too so will be interested in any discoveries you guys make.
I have a spare DSD-only version PCB with all the smd parts mounted. First thing I need to do is utilise the revised parts around the noise adjustment pots but beyond that it will be good to try some parts upgrades.
I have Maida reg for the B- supply, a DC filament supply and low-noise 5V regulator so I think there will be little milage in messing with the power arrangements.
I would also like to try the AK4137 and FPGA upsampler boards against my current HQ Player set-up.
I have a spare DSD-only version PCB with all the smd parts mounted. First thing I need to do is utilise the revised parts around the noise adjustment pots but beyond that it will be good to try some parts upgrades.
I have Maida reg for the B- supply, a DC filament supply and low-noise 5V regulator so I think there will be little milage in messing with the power arrangements.
I would also like to try the AK4137 and FPGA upsampler boards against my current HQ Player set-up.
Since I’m also interested in building this Dac, what is roughly the amount of money I’ll need to invest in this project.
Hans
Hans
It depends on how far you want to take certain aspects. My total cost was upwards of $2500, though I don't know the exact amount. But I spent $500+ on just the casework, etc. Could definitely do it cheaper than I did.
Also I did external power supply boards. Using the on-board stuff would be much cheaper.
If I had to guess, you could build a "stock" version in the $1,500 range.
Also I did external power supply boards. Using the on-board stuff would be much cheaper.
If I had to guess, you could build a "stock" version in the $1,500 range.
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I think mine was a bit over 1000 euros excluding the output transformers, but I didn't keep track of it very accurately. The raw DSD version is less expensive than the original version.
As this is just a hobby I felt no need to keep an accurate track of the outgoings so I can only give a rough estimate - I reckon my DSD-only version cost up around £1000 all in.
As Sonny says, there is no set recipe so YMMV.
As Sonny says, there is no set recipe so YMMV.
Marcel,
As much as I like your Valve Dac’s technical concept and although I gave it some serious thoughts, I’m not a tube guy for several resaons.
But your Valve concept could be very well translated to semiconductor technology, giving individuals a choice for one of both worlds.
All semiconductor would result in a rather big PCB size- and cost-reduction and eventually the option to use a FirDac with (much) more taps and a simpler analogue reconstruction filter.
Your design would then come quite close to Bruno’s Mola Mola Dac, a Dac that was received very well, but with far less filter options as yours.
Mola-Mola Tambaqui | HFA - The Independent Source for Audio Equipment Reviews
Have you considered this option ?
Hans
As much as I like your Valve Dac’s technical concept and although I gave it some serious thoughts, I’m not a tube guy for several resaons.
But your Valve concept could be very well translated to semiconductor technology, giving individuals a choice for one of both worlds.
All semiconductor would result in a rather big PCB size- and cost-reduction and eventually the option to use a FirDac with (much) more taps and a simpler analogue reconstruction filter.
Your design would then come quite close to Bruno’s Mola Mola Dac, a Dac that was received very well, but with far less filter options as yours.
Mola-Mola Tambaqui | HFA - The Independent Source for Audio Equipment Reviews
Have you considered this option ?
Hans
Hi Hans,
I did build a configuration-file-compatible solid-state version once, I mainly use it for debugging new configuration files:
74AHC02 and 74AHC08 DAC with 97 dB(A) dynamic range
I'm sure you can improve it by making a longer FIRDAC or doing something with more clock phases for the NRZ function. (I mean a circuit that has a larger and better-defined delay between the transitions of the flip-flops and the logic gates to ensure you get no data dependence of the bit weights.)
Regards,
Marcel
I did build a configuration-file-compatible solid-state version once, I mainly use it for debugging new configuration files:
74AHC02 and 74AHC08 DAC with 97 dB(A) dynamic range
I'm sure you can improve it by making a longer FIRDAC or doing something with more clock phases for the NRZ function. (I mean a circuit that has a larger and better-defined delay between the transitions of the flip-flops and the logic gates to ensure you get no data dependence of the bit weights.)
Regards,
Marcel
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The Mola Mola Tambaqui has some serious processing power. It has three ADSP-21489 SHARC DSP chips.
The XC6SLX45 (as used for valve DAC version 3) has 58 and the XC6SLX75 (version 2.1) has 132 18-by-18 bit multipliers with 48 bit accumulators, I use them at 189 MHz (version 3) or 216 MHz (version 2.1). I haven't a clue how that compares to DSP chips.
It's been a bit quiet on the thread of late, how are other people getting along with their Valve DAC projects?
Since completing mine I have been slowly acquiring a small collection of DSD media files, purchased from Native DSD. I now have 16 albums, mostly DSD256 and covering a variety of genres, and they've all been of consistently high quality, musically and sound quality wise, if a little expensive. I'm currently enjoying the current album of the week (their albums of the week are offered with 20% discount)
Rimsky-Korsakov selection
Since completing mine I have been slowly acquiring a small collection of DSD media files, purchased from Native DSD. I now have 16 albums, mostly DSD256 and covering a variety of genres, and they've all been of consistently high quality, musically and sound quality wise, if a little expensive. I'm currently enjoying the current album of the week (their albums of the week are offered with 20% discount)
Rimsky-Korsakov selection