MDAC First Listen (part 00110001)

[iansr]

Ian,

If you don't get anywhere, I can look at the schematic to try and understand where the problem might be

Thanks John, appreciated. I've sent the designer some pics of my crossovers to see if he can spot any obvious problems. If I get stuck I'll be in touch!

 

[fusion5]

Its a question of time and cost, I will do, but I just dont see as getting very far with "superior" updates due to the time it takes to rebuild each unit - its not practical, we just cannot make the money to justify the time spent on each unit.

At the end of the day, "Superior" is meant primarily as a development stepping stone - with a few "very special" MDAC's released into the wild. Once design is tested, then we will "open" the order books for a one-time special order, then sadly that's it for "Superior"

"Superior" owners will qualify for the Morphed "Superior" + XMOS Dac PCB "At Cost + 100GBP"

Thanks! It's a shame these caps keep causing so much trouble. Although I assume that getting rid of the old analogue stage and fitting/testing the Superior board is at least equally time-consuming.

Speaking of development stepping stone: Are the resistor values final?

 

[misterdog]

It's a shame these resistors keep causing so much trouble.

Wouldn't be much to look forward to if everything was cut and dried though.

I have been pondering the resistor values for my Paradise phono stage cartridge loading, for some months.

At £ 10 each for Charcroft Z foil

Been using some Vishay dale for listening tests, bought a bag of mixed values in 10 R increments.

Ended up soldering in series, to achieve alternative values..

 

[stephengrenfell]

No, I'll just build and test the "new" sections on the PCB then let China build say 10pcs "T0" production and confirm the design "fully" with these - then I can ship these T0 units to the first lucky few...

The Detox's Isolated USB supply circuit section is used on the FDAC Digital PCB so its was worth spending the unexpected few days optimising the circuits operation - part of the problem with the Detox redesign was trying to squeeze a more complex discrete circuit in place of a single tiny (but as it turned out expensive) IC on a PCB that was already packed / space limited. With the FDAC we will not have such a space limitation.

I'm currently spending a lot of time with Jarek "tidying up" the XMOS test PCB - over the past few days I've spent over 10 hours on Skype as we work thought the "tidy up", but we are both very happy with hows its coming together. Once Jarek "learns" my ways I'm certain he will need less support from me, I can already see the results of us working together.

Hi John,

I am interested in a Detox (to improve the sound from my CDQ).

Am I too late to join the list ?.

Many thanks.

Stephen

 

[sq225917]

Paul, buy Vishay melf as the loading resistor, difference between these and naked Vishay's is a gnats dick at 1/10 of the price.

 

[Bob L]

Hi John,

I am interested in a Detox (to improve the sound from my CDQ).

Am I too late to join the list ?.

Many thanks.

Stephen

Just a query on what you want to do here. Do you mean improve the sound from the CD section?

The Detox, like the Regen, goes in the USB input line to your DAC, so if you are using the CDQ as a DAC for an external source, OK, but I don't think it will improve the CD performance of the CDQ.

 

[stephengrenfell]

Just a query on what you want to do here. Do you mean improve the sound from the CD section?

The Detox, like the Regen, goes in the USB input line to your DAC, so if you are using the CDQ as a DAC for an external source, OK, but I don't think it will improve the CD performance of the CDQ.

I am using the CDQ as DAC for external source from iMac via USB with Audirvana+ as music player. Mainly for 44.1/16 (since I ripped my CD collection), but also 96/24 streamed from qobuz.

I have a (built from kit) galvanic isolator based upon the ADuM4160 with external 5v linear psu. This reduces the noise, but cannot do anything about the jitter or other effects that might be caused by what I think of as the "un-regulated" packet delivery.

The Detox interests me as it seems to address the various USB audio interfacing issues that other USB filters / isolators don't seem to o on thier own.

 

[GWM]

Paul, buy Vishay melf as the loading resistor, difference between these and naked Vishay's is a gnats dick at 1/10 of the price.

Have to agree with SQ I had Tantalum as loading and swapped out for the naked foils couldn't hear a blind bit of difference spend your money elsewhere.

 

[misterdog]

220 R Naked Foil resistors £ 9.60 EACH.

Or Vishay Precision MELF 220R £ 0.53 for 5.....

Both .25W and 0.1% tolerance..

Maybe Superior/FDAC/FDAC Lite could also benefit ?

 

[Bob L]

I am using the CDQ as DAC for external source from iMac via USB with Audirvana+ as music player. Mainly for 44.1/16 (since I ripped my CD collection), but also 96/24 streamed from qobuz.

I have a (built from kit) galvanic isolator based upon the ADuM4160 with external 5v linear psu. This reduces the noise, but cannot do anything about the jitter or other effects that might be caused by what I think of as the "un-regulated" packet delivery.

The Detox interests me as it seems to address the various USB audio interfacing issues that other USB filters / isolators don't seem to o on thier own.

Sorry if it seemed a rather silly question!

I'm doing almost exactly the same as you, with my ripped CDs on a Mac Mini running off an LPS, into an unmodified MDAC. I already have two Regens running in series on the USB input and I can confirm that hey make a big improvement to SQ, at least when I run them off the LPS.

I'm hoping for an even bigger improvement with he Detox!

 

[JohnW]

220 R Naked Foil resistors £ 9.60 EACH.

Or Vishay Precision MELF 220R £ 0.53 for 5.....

Both .25W and 0.1% tolerance..

Maybe Superior/FDAC/FDAC Lite could also benefit ?

Paul,

I've just changed x8 Vishay MELF resistors to Vishay Bulk foils on the Superior PCB and there's a really big step improvement in Macro detail (texture), sound stage (ambiance of the recording) and Firmer Bass.

https://dl.dropboxusercontent.com/u/86116171/Superoir Basic Vishay.JPG

I was pondering Simon's & GWM comments as the difference is so significant in my system atleast and recalled we also experienced much the same at Pink Triangle where we would offer a "Vishay'ed Bulk Foil" PIP II (Pre-amplifier / Phono Stage) upgrade - again with much the same results as I hear with the Bulk foiled MDAC / Superior.

As it happens, Aurther Khoubesserian and I where having much the same discussion at Munich about the SQ benefits of the Vishay bulk foils and how expensive they are !

I'm kinda worried alittle as I used the polystyrene capacitors on Simon's & GWM the recommendation and not sure where that leaves me now

So basically at the end of the day you need to listen and judge for yourself.

 

[JohnW]

John, any updates on the 8200 (I think) amp custom PCBs, please? Everything on track?

Thanks.

Jiri,

I completed the amplifier schematics and happy with the design but have left it at this stage due to limited engineering resources, we are concentrating on FDAC with the Superior / XMOS developments - its been a productive month, but we do wish we could progress the amps!

 

[music fiend]

Hi John,

Good to know the Superior and FDAC are progressing well.

Do you have any updates regarding the Detox?

Cheers!

 

[sq225917]

John, I've no idea how much your designs benefit from Vishay foils, you make them sound so amazing it's a wonder any hifi can be designed without them.

Perhaps I'm a little more balanced re the change they deliver?

It's a modest step up in resolution, Ime of using them in various phonostages, in preamp, stepped attenuators and dap.

Maybe they reap much greater rewards in the new DAC...

As to the styrene caps, obviously you need to decide what sounds best and what works in production, cos of course you can't robot place styrenes.

 

[fusion5]

So basically at the end of the day you need to listen and judge for yourself.

I think we should still try the full 52 pcs package or we'll always ask ourselves, 'what if?'.

Would it still be premature to order them now?

 

[timola]

Back in late/mid 80s I bought a Pink Triangle Pip preamp...it was a great improvement over my then meridian 101 and a couple of other pre-amps i tried including a Naim....one of the best sounding pre-amps of its day in my opinion...I was only about 21 years old then, but I still remember how the pip improved things.....I had no idea whatsoever it might have been the caps or your design...I wish I still had it, but it was an expensive purchase and a couple years later I sold it and the HiFi for a car (Cortina mk3)..
Happy days!

 

[GWM]

're bulk foils I have some in various parts of my system they were an advantage in feedback positions in my power amps and preamp in signall positions including phono stagel I can't say I heard a lot of improvement despite wishing it seeing as how bloody expensive they are.
Personally I like the Dale Brown boys they get the party going so to speak but maybe my ears are to old.
Styrene caps are the most neutral and transparent the only thing better are RTX teflons I have them as signal caps in my phono but they are ridiculous prices but its a mater of taste at the end of the day.

 

[JohnW]

I think we should still try the full 52 pcs package or we'll always ask ourselves, 'what if?'.

Would it still be premature to order them now?

I'm really keen to hear your Fusioned Superior MDAC we will be able to direct A/B between our "Std" Superior unit.

 

[JohnW]

I can't say I heard a lot of improvement despite wishing it seeing as how bloody expensive they are.

While Ian was here, I added the x8 Vishay bulk foils in place of the Vishay MELF's to the rats nested "superior" MDAC, and was pleasantly surprised at the improvement - they repeated my earlier experiences of the MDAC Toy / Fusion upgrade.

Personally I like the Dale Brown boys they get the party going so to speak but maybe my ears are to old..

The Light Brown Dales have a very full bodied sound - trading fine texture resolution / sound stage for Bass "Body" - but we had PLENTY of tight firm Bass with the Vishay bulk - one track was incredibly impressive,it left both Ian and I pretty much speechless for a "reproduction" audio system

 

[fusion5]

John,

Can you please give me final order details with Nick?