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MDAC First Listen (Part 00101010)

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The 4x 10HD is limited to 96KHz sampling we can goto to 192KHz (with MiniDSP) or higher with our own software.

Everything hinges on how far miniDSP can afford to support the FDAC with there software resources rather then hardware limitations of the FDAC platform.

With the x3 slave units then you can have 8 audio channels in total.
 
Ok thanks. Couple more questions. Is the DSP done in the FPGA, or is there separate circuitry required? Will the normal miniDSP plugins be used or wil the software be written specifically for the FDAC?
 
There are a pair of analogue device Shark DSP processors, the software is just a "Variant" of the miniDSP code, but depends on miniDSP's workload.
 
BigDog said:
...and see that one attribute is impedance matching
and the addition of resistance to the USB hub

http://uptoneaudio.com/blogs/news/2...-bass-all-unshipped-orders-will-be-the-latest

which supposedly improves sonics particulary in the bass region.

How would either of these 2 things be relevant to the DETOX?
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Sorry about the repost, JohnW, as I know you are busy but just curious if the 2 aspects of the REGEN operation are relevant to the DETOX...particularly the impedance matching since I have not seen this ever mentioned in discussions of USB devices.

BTW, will have opportunity to audition a friend's REGEN in my system shortly.

Thanks.
 
Hi John,
Just back from rather extensive boating travels in England, then Ireland, so only just up to speed with developments. £50 development payment sent for Detox, I will probably be interested in 2, as my MDAC + amp will now replace the rather squeaky NAD D 3020 digital amp in the computer room. I will also be interested in an Audiolab power amp if you still have any to unload.
As you predicted ATC won the bet :)
I managed to get my ATC 100A's into the factory, for full refurb and realignment, before I went to Ireland. Just picked them up after a rather extensive factory tour and being let loose in their listening room. Rather blown away with the difference, so can't wait to get the FDAC.
ATB
Neil A
 
John , just made a late night eBay purchase for a ex demo pair of 4m Nordost LS Red Dawn speaker cables in ready for the new Vfet Amps. I'm assuming it will accept banana plugs ?
 
BigDog said:
Sorry about the repost, JohnW, as I know you are busy but just curious if the 2 aspects of the REGEN operation are relevant to the DETOX...particularly the impedance matching since I have not seen this ever mentioned in discussions of USB devices.
Click to expand...

The impedance mismatch referenced to is the characteristic impedance of the USB connection - visually looking at the PCB design of the Regen I doubt it meets the 90ohm Spec. of USB2.0 but TBH its hardly important as the PCB tracks (such short tracks are called stubs) on the Regen PCB are so short I'd worry more about the USB Cable and USB connectors.

If the recovered eye pattern at the "Device end" is OK, then the impedance is good. The Eye pattern of the ReGen using the "direct Link" looks fine :) later, I might make some TDR measurement just to see what's going on but everything takes time... A couple of weeks ago I purchased software to download the TDR traces from the measurement system to my computer, when it arrives I'll try installing the software and saving taking some measurements just for fun :)

BigDog said:
BTW, will have opportunity to audition a friend's REGEN in my system shortly.

Thanks.
Click to expand...

That will be VERY interesting!! :)
 
Neil A said:
Hi John,
Just back from rather extensive boating travels in England, then Ireland, so only just up to speed with developments. £50 development payment sent for Detox, I will probably be interested in 2, as my MDAC + amp will now replace the rather squeaky NAD D 3020 digital amp in the computer room. I will also be interested in an Audiolab power amp if you still have any to unload.
Click to expand...

Welcome to the Detox project :)

Yes, I have a basement full of brand new "Donor" 8200MB's which are now surplice to requirement - I can convert them to true "balanced only" operation for your MDAC / FDAC :) - removing the cheap opamp in the design I hope will remove the "Brightness" that I so despise with these amps in there standard form!!!

GBP450 each (with basic mods) - for the money they will be a decent and VERY powerful amps - with Bass that's REALLY impressive, and I'll resolve there horrid harsh and "forward" brightness!

Neil A said:
As you predicted ATC won the bet :)
I managed to get my ATC 100A's into the factory, for full refurb and realignment, before I went to Ireland. Just picked them up after a rather extensive factory tour and being let loose in their listening room. Rather blown away with the difference, so can't wait to get the FDAC.
ATB
Neil A
Click to expand...

Yep, that was always going to be easy! :p
 
Neil,

I just tock a closer look at the 8200MB schematic and I can see more then a few "Simple" :) solutions to make these VERY decent amps for the money (For balanced input ONLY with MDAC / FDAC), if you wanted to have a little fun I could also add Vishay Bulk foil resistors into the input stage and feedback path - they made very impressive improvement to the Fusion MDAC's, I'd expect the same results here.

Certainly for the money you will have a hard time to beat them :) .... I'll use modified pair until the VFETs are ready :)

Soon (once the Detox is ready for listening) I'll be setting up my ESL's and this will be the time to quickly mod some Amps, I also need to have a first listen of the FDAC PCB....
 
Cheers John , got them at a reduced price thankfully as they do carry a bit of a premium. Took a punt and a bit of a risk using eBay . They sent me the serial number so will double check authenticity with Nordost.
 
John as previously discussed , I would also be interested in a pair of modded 8200mb to tie me over and to use in a surround setup afterwards .... But only if there is time between your busy schedule :)
 
PhilCTTE said:
John as previously discussed , I would also be interested in a pair of modded 8200mb to tie me over and to use in a surround setup afterwards .... But only if there is time between your busy schedule :)
Click to expand...

Phil,

I have a pair set aside for you already :)
 
JohnW said:
Neil,

I just tock a closer look at the 8200MB schematic and I can see more then a few "Simple" :) solutions to make these VERY decent amps for the money (For balanced input ONLY with MDAC / FDAC), if you wanted to have a little fun I could also add Vishay Bulk foil resistors into the input stage and feedback path - they made very impressive improvement to the Fusion MDAC's, I'd expect the same results here.

Certainly for the money you will have a hard time to beat them :) .... I'll use modified pair until the VFETs are ready :)

Soon (once the Detox is ready for listening) I'll be setting up my ESL's and this will be the time to quickly mod some Amps, I also need to have a first listen of the FDAC PCB....
Click to expand...

Dear Mr Westlake

Great news on these 8200MB amps for those who will be interested to take them.

Kevin at AUDIOCELLAR (Tag/AUDIOLAB repair specialist) inspected and repaired a few of these 8200MB now and many Resistors, like you have spotted are sub par compared to the Tag McLaren 250MR ...the board layout is practically identical, but performance wise the Tag was/is in another league - midrange energy is the most notably lacking with the cheapened AUDIOLAB spin-off :-(

If you can source larger, better quality transformers (like at least the 650 vs 380 that 250MR has) and bigger PSU capacitors you will probably quite like these amplifiers for their worth, or class :)

Kevin told many years ago that the 250 Tag modules (I had a few in my spending prime) were a respectable design, but just let down by their PSU a bit...if you can better the Tag PSU specs on these, I expect some more of us may be interested ;-)

Thanks and merely observational suggestions intended with respect as you know better than I !

Paul
 
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