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MDAC First Listen (part 00100110)

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The only way to know if amps are truly balanced is to look at the schematics.
For your Resteks a quick search did not yield schematics result. The manual states that in bridged mode one of the inputs is used symmetrical (balanced) so my guess would be that your on the right track. Again no way to know for sure if it is without the schematics.
 
JohanH,
You have something based on ncores. Dis you follow any guide/instructions?
Would you recommend such an amp with the mdac? :)
 
Yes, followed Hypex instructions; as I almost never play loud I used 1 smps600 for 2 nc400.
Would definitely recommend
 
tunkejazz said:
JohanH,
You have something based on ncores. Dis you follow any guide/instructions?
Would you recommend such an amp with the mdac? :)
Click to expand...

I'm using Ncore monoblocks with the MDAC. So one NC400 and one SMPS600 per monoblock. Followed the wiring advice very closely, and got great tips from this forum. Very happy with them, though have nothing to compare to. If you do decide to build there's some useful tips in this thread, just in case you didn't see it.
 
For the VFET's Current Dumping Inductor I'd like to use a flat foil Air Core.

I've opened tooling for the inductors former - these inductors will be an "At Cost" extra over the standard inductors - I'm not sure what difference they will make sonically, but "Flat Foil" Aircores are the "Perfect Inductor" - its this type of attention to the details engineering that adds the cost to the VFET design.

https://dl.dropboxusercontent.com/u/86116171/VFET Air Core Inductor.jpg

Air cores are available, but with a wooded dowel core which I don't consider professional enough for a statement design like the VFET amps.
 
Thanks for the tips! Just one last question, perhaps out of place now (sorry for that). Where did you get the case? ;-)
 
JohnW, if you consider eventually designing an affordable amp, I think you would be surprised abour how many people may want to join!
 
Hi guys, hi John.
I am new here as in a hifi community :)
I have tried to send JohnW privete msg, but his inbox is full so I will ask a question here. Sorry for any inconvenience.

I have recently bought M-DAC, second hand but it looks like brand new. Works almost perfectly, apart from the power button which seems to be used only with top part of it, I can`t turn device on by pressing it bottom part, its getting "blocked". Once Ive done that it showed no comms error. Other than that its perfect (upgraded soft to a.10).
I am strongly considering an upgrade to M-DAC2, would that (£400 from basic version) also solve button problem?

Regards,
Lucas.
 
Here's a the outline of the VFET / TDAC & MDAC2 full width chassis front panel profile looking from above.

https://dl.dropboxusercontent.com/u/86116171/VFET A02b 150mm.jpg

The front Panel Window area is wide enough for the TDAC / MDAC display panel - while on the VFET amp you can see the Plasma Tube Bargraph module (you can see the glass Envelope "Pip" projecting into the rear of the amplifier, between the PSU Caps).

The VFET, TDAC & MDAC2 will have touch buttons on the glass central window area, with a nice machined solid "Volume knob" mounted on the right hand section on the TDAC / MDAC2.
 
Lucas,

"No comms error" indicates a pending Crystal failure - it could continue working for weeks, months or Years - or could fail altogether tomorrow.

The MDAC2 will replace the internal electronics - so will solve the issue and the power switch just needs re-aligning which is a simple job.

The MDAC2 development cost starts at £400 for the L2 version with an extra £100 for the L3 Version - but then you ALSO have to purchase the PCB "At Cost" + Shipping etc. The PCB cost for the L2 version will be around £300 to £400 (subject to final build cost).

I'll repair your MDAC for free should it completely fail irrespective if you join the MDAC2 project so don't worry :) , so long as you cover the return shipping costs to Czech Rep.
 
Thanks for quick answer JohnW, will stay in touch.

p.s.
Regarding to "No comms error" would you recommend to send the unit back?
I still have 2 months warranty left.
 
JohnW said:
For the VFET's Current Dumping Inductor I'd like to use a flat foil Air Core.

I've opened tooling for the inductors former - these inductors will be an "At Cost" extra over the standard inductors - I'm not sure what difference they will make sonically, but "Flat Foil" Aircores are the "Perfect Inductor" - its this type of attention to the details engineering that adds the cost to the VFET design.

https://dl.dropboxusercontent.com/u/86116171/VFET Air Core Inductor.jpg

Air cores are available, but with a wooded dowel core which I don't consider professional enough for a statement design like the VFET amps.
Click to expand...
Your attention to detail is very much appreciated.
I will of cause want the no compromise option.
 
efski said:
Thanks for quick answer JohnW, will stay in touch.

p.s.
Regarding to "No comms error" would you recommend to send the unit back?
I still have 2 months warranty left.
Click to expand...

Lucas,

Hard to say it depends how much you paid for the MDAC, its a common MDAC issue, Postage from Czech Rep to the uK is about GBP35 - and about the same to ship to me...

So if worst happens, the "repair" will cost you about GBP70 in postage - the repair work itself is for free.
 
Hi,

Does anyone know if the M-Dac if the XLR and RCA outputs on the M-Dac are both live at the same time? I have some unusual speakers (Gallo Ref 3.5s) which uses a separate amp for the bass.

Thanks
 
CrazyindianZA said:
Hi,

Does anyone know if the M-Dac if the XLR and RCA outputs on the M-Dac are both live at the same time? I have some unusual speakers (Gallo Ref 3.5s) which uses a separate amp for the bass.

Thanks
Click to expand...

Yes, both outputs are active together, so you can use both at the same time.
 
JohnW said:
tunkejazz,

Yes sadly the VFET amplifiers are an expensive project, but they are design to be the best...

I'd like to design a more affordable design, but I hate to compromise and I cannot see at this time how to meet the performance of the VFET design.

I'm hoping that the development of the VFET amplifier will give help in designing a lower cost unit.

The problem with amplifiers is that once you have factored the cost of a correctly designed the PSU, Chassis / Heatsink and output devices its hard to design a "Budget version", as any cost saving would be a compromise.
Click to expand...

I'll take 8 :cool:
 
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