Around the Blog-Fire

I suppose I could say the system is pretty sorted now, but as with anyone suffering from audionervosa one is always keeping a lookout at various bits of kit.


The Metrum Musette Dac piqued my interest as it is an R2R dac and I like R2R dacs.
It is from 2015 originally but this has the updated Transient modules in it, the Transient Dac2. It is supposedly 24 bit with a bit of jiggery pokery to the bit sequence to lower the noise floor.
Internal view showing the two plug in modules:



Now these modules are all potted so there is no chance to make any direct modifications so I have been looking at the power supply arrangements.

There is a large LM317 regulator and I discovered two smaller LM317/337 regulators underneath the modules. Question is what is powering what?
I fitted a sense resistor in series with the larger LM317 so I could measure the current in different modes and with the modules and USB board removed.

It turns out the larger LM317 is just for housekeeping duties, the smaller LM317/337 regs are powering the modules. Now I can get down to business and replace these with something with a lot lower noise. Fortunately I have a twin psu board available.
I am going to give the dac a good listen before doing any mods, it does sound very good as is. Comparing to the Holo Spring 3 there is less air and a narrower sound stage on some recordings.

From searching it seems there is an FPGA chip in each module plus other chips, would be interesting to know which R2R chips it uses.
Here is a view of the latest Dac3 module pcb:


Anyone else using Metrum Dacs?

See if it has the Dac1 or Dac2 modules in it. Dac2 are supposedly a lot better.

The later modules Alan are good step up in perfomance, improved bass control, greater depth of field and more open upper frequencices.

You could go to town on this one Alan some very positive gains to be made.

I had a Metrum Octave (I think), allegedly their first ever DAC. It was alright. Mostly harmless.

I've heard that their later models were much better.

Yup, I can't fault the damn thing.
I'll keep trying.

A couple of new preamps should be with me over the next few weeks, and I look forward to trying those with my Theta DSPro Prime DAC.

After further investigation it seems the main 5V regulator is powering the digital part of the Transient modules, the FPGA chip for sure.
I had to have a signal playing to see the increased current through the regulator.

I have now ordered a low noise regulator board to fit to power the modules 5V.
The other two smaller regulators are set at +-6V and I am sure power the analogue output stages, also inside the Dac2 modules.

I shall ask, as it is €600. I also won’t be modifying it, as a little knowledge is dangerous…

What's your budget K?

The Metrum mods are yielding excellent results, I have fitted an ultra low noise regulator feeding the Dac2 modules 5V.

It's close to the Holo Spring3 performance now, well chuffed.

OK I've been thinking the system is now at a pretty stable state, I have rebuilt the Neurochrome 286 into a larger case with a linear supply (400VA transformer) along with all copper connectors and TripleC internal cabling. Performance is exquisite.

New speakers arriving tomorrow should/will put the cherry on the top. System sorted, or is it?

Something took my fancy, not expensive but prompted the question - could this improve the digital? Only one way to find out, buy it and try it.

As a certain individual will say, you know who you are, the Innuos Zen only having a USB output is letting the system down.
So a SOtM (soul of the music it stands for) DDC to convert from USB to AES/coax/optical has been installed.




I had to make a new AES interconnect, fortunately I had some XLR plugs so used some cat6a cable to make it.
The Zen now connects to the DDC and then via AES to the Mutec

Well blow me down it has actually worked in my favour with a greater clarity and attack.
We have been listening to a lot of different tracks and I am really pleased with how they sound.

I have now put together a Test Tracks playlist in readiness for tomorrow, whoo hoo!

Strange this hobby Allen, you have found adding another element into the digital, chain has increased SQ. Whereas for me it was the opposite and the reason I pulled and sold my Mutec. I found for me, once I had the ZenITH 3, that the Mutec killed the flow and put the music in a straitjacket.

Alan I would certainly agree that using a DDC works and sounds an improvement on a direct USB connection . In my case it got worse because using two DDC units daisy changed improved the sound again .

I will be getting my Mutec to you soon so you can remove the SMPS power supply and install a barrel input so I can use an off board LPSU . Given what I have read here I will be very hopeful of getting a decent sound quality uplift . Only issue at the moment is that I have no better box for the Mutec been looking for one .If anyone near me has something get in touch quite happy to pick it up .

I think it comes down to the quality of the source feeding the DAC, as my Node2 definitely benefitted from the inclusion of the Mutec in the chain as did an ifi Zen Blu2.

I'd agree with that if I didn't have a circa £5k (RRP) streamer feeding the Mutec.

I am quite notorious at this point for finding issues I don't like with devices, especially when I whip the lid off stuff, but the Aria uses pretty much exactly what I'd put together in terms of storage devices, power supply and output.

Obviously there are PSU related things that could be upgraded to more modern devices, but as it is, it's a bit of a beast.

Don't forget, I also had an Aurelic Aries G2 here too for a while, and that also cost around £5k (RRP). The result was the same with and without the Mutec with that too.

The obvious difference is that I do not (will not) use USB. I have never tried a Mutec via USB.