MDAC First Listen (part 00100001)
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JohnW
pfm member
That's fine, because whenever it arrives, Christmas will have come
I like buying myself Christmas presents. I know I'll get exactly what I want
Chris,
You requested an option for Balanced XLR AV Bypass input - looks like I can use the Mini XLR's (as used for the MDAC2's ADC input (3W) and the 4W Balanced headphone output) as an option in the position of the standard RCA AV input:-
https://dl.dropboxusercontent.com/u/86116171/Mini XLR Rear Panel.JPG
https://dl.dropboxusercontent.com/u/86116171/Mini XLR Plugs.JPG
My only slight concern I have is that the cable exit of the mini XLR is tiny - it might require heatshrink or Snake skin for thicker cables in place of the plugs strain relief.
The Mini XLRS are really high quality connectors - more akin to the Swiss Lemo connectors than the cheaper feeling standard size XLRs.
Also, for the MDAC2 digital expansion port (for the streamer etc) looks like I can fit a standard HDMI connector - I've sourced some decent 30cm and 50cm flat cables (the type with the metal ends and "snake skin") which can be used for the interconnection between units. They look good on the TDR.
https://dl.dropboxusercontent.com/u/86116171/MDAC2 Expansion port HDMI Cables.JPG
JohnW
pfm member
An update on the VFET amps, earlier this week I ordered the new 8200MB's donor units, so they should arrive here by the end of the week - I'll feel more relaxed once they arrive.
Also the second batch of 30 VFETs have arrived in Czech Customs (as has my new Curve tracer)
I believe I've also thought up a circuit that will inherently protect the precious VFET devices - the Gate driver will be current limited thus preventing any chance of over driving them - inherent self protection. Dominik is creating the Spice Simulation model for the VFETs, once I have the models then I can simulate the circuit, rather then experimenting with the precious devices.
Also the second batch of 30 VFETs have arrived in Czech Customs (as has my new Curve tracer)
I believe I've also thought up a circuit that will inherently protect the precious VFET devices - the Gate driver will be current limited thus preventing any chance of over driving them - inherent self protection. Dominik is creating the Spice Simulation model for the VFETs, once I have the models then I can simulate the circuit, rather then experimenting with the precious devices.
Really? Because all the miniXLR I have are of decent quality, but nothing like full size Neutrik XLR. The ones that come close are the REAN ones (http://rover.ebay.com/rover/1/711-5...0001&campid=5338728743&icep_item=201142142719 - "Neutrik REAN" is *not* Neutrik, socket: http://rover.ebay.com/rover/1/711-5...0001&campid=5338728743&icep_item=201137708976). The ones on your picture seem like the cheapest / lowest quality ones.
Of course it's still the next best thing after normal XLRs, better than 3-pole jacks.
PS: The REAN ones can fit even larger cables, the strain relief can be shortened, IIRC.
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Yes I've been following the thread and seen your chosen option. Given the space constraint you have I think they're a fine physical compromise. Thank you. Only one pair of cables is required with those connectors and it will be relatively short - unlike the cables going to the power amp - and there's no inherent reason why they should have any adverse effect on performance.
It's all looking good. Carry on
JohnW
pfm member
Really? Because all the miniXLR I have are of decent quality, but nothing like full size Neutrik XLR. The ones that come close are the REAN ones (http://rover.ebay.com/rover/1/711-5...0001&campid=5338728743&icep_item=201142142719 - "Neutrik REAN" is *not* Neutrik, socket: http://rover.ebay.com/rover/1/711-5...0001&campid=5338728743&icep_item=201137708976). The ones on your picture seem like the cheapest / lowest quality ones.
Of course it's still the next best thing after normal XLRs, better than 3-pole jacks.
PS: The REAN ones can fit even larger cables, the strain relief can be shortened, IIRC.
I have the Rean type as well, they do fit but they have a "Screw thread lock" type latch - no problem with either using plug type with the connector fitted to the MDAC2 real panel.
I have Neutrik connectors on my test equipment, and without fail they have all oxidised - I'm not impressed with Neutrik.
This site contains affiliate links for which pink fish media may be compensated.
iansr
pfm Member
An update on the VFET amps, earlier this week I ordered the new 8200MB's donor units, so they should arrive here by the end of the week - I'll feel more relaxed once they arrive.
Also the second batch of 30 VFETs have arrived in Czech Customs (as has my new Curve tracer)
I believe I've also thought up a circuit that will inherently protect the precious VFET devices - the Gate driver will be current limited thus preventing any chance of over driving them - inherent self protection. Dominik is creating the Spice Simulation model for the VFETs, once I have the models then I can simulate the circuit, rather then experimenting with the precious devices.
Looking forward to hearing what your curve tracer reveals about the VFETS
travelfotografe
pfm Member
Hi John,
Like to ask what is the decision on the Balanced headphone output: 5-pin male miniXLR or 4-pin male miniXLR?
Leon
I really really hope the downloads will all be available in a Mac option.
JohnW
pfm member
JohnW
pfm member
JohnW
pfm member
Leon,
I prefer to use a 5W, but it might be very tight for the cable - do you have any experience?
JohnW
pfm member
Looking forward to hearing what your curve tracer reveals about the VFETS
I've got a simple "intelligent" curve traces and it identifies the Nch parts as JFETs
but gets is knickers in a twist with the Pch parts.I probed the Pch parts with a Huntron Tracker and they look good - like the Nch, but opposite!
misterdog
Not the canine kind
Also the second batch of 30 VFETs have arrived in Czech Customs (as has my new Curve tracer)
/QUOTE]
Will you not be needing a bigger Lab, with all this new test equipment ?
JohnW
pfm member
I'll be soooo grateful when I can move into my 4.6m x 4.3m Lab in the first instance!
Last week I had a company "spray" the foam roof insulation, amazing to see
In the next week, I'll have to take a day or two away from working on the MDAC2 / VFET projects to sort out the electrics as the concretes due to be poured for the floor + start work on finishing the walls.
Nice to see its getting closer - I need to complete it before the winter weather starts to set in and intime for MDAC2 "production".
Your components arrived yesterday from the UK, waiting of the last 7 items from the US...
Last week I had a company "spray" the foam roof insulation, amazing to see
In the next week, I'll have to take a day or two away from working on the MDAC2 / VFET projects to sort out the electrics as the concretes due to be poured for the floor + start work on finishing the walls.
Nice to see its getting closer - I need to complete it before the winter weather starts to set in and intime for MDAC2 "production".
Your components arrived yesterday from the UK, waiting of the last 7 items from the US...
Yes I've been following the thread and seen your chosen option. Given the space constraint you have I think they're a fine physical compromise. Thank you. Only one pair of cables is required with those connectors and it will be relatively short - unlike the cables going to the power amp - and there's no inherent reason why they should have any adverse effect on performance.
It's all looking good. Carry on
Following on from this, if you do manage to reclaim any more back panel space, I'd suggest donating it to the balanced headphone socket, as it does appear that that is more of a 'standard'. It's likely that headphones will be swapped/changed/upgraded much more often than analogue bypass inputs. Making a custom cable for the bypass isn't a big problem at all.
JohnW
pfm member
Chris,
https://dl.dropboxusercontent.com/u/86116171/MDAC2 rear panel conector arrangement.jpg
The top row of connectors is the proposed Digital connector arrangement (you can see the USB B connector above the Balanced headphone output which is mounted on the lower Analogue board).
Maybe I could fit a full sized XLR, but I'd have to use a Mini USB connector - we have already had a few people manage to break the full sized USB connector, I'm not sure I trust an even smaller, possibly more fragile "Mini" version + everyone getting upset about needing a new type USB cable...
I'm open to suggestions...
https://dl.dropboxusercontent.com/u/86116171/MDAC2 rear panel conector arrangement.jpg
The top row of connectors is the proposed Digital connector arrangement (you can see the USB B connector above the Balanced headphone output which is mounted on the lower Analogue board).
Maybe I could fit a full sized XLR, but I'd have to use a Mini USB connector - we have already had a few people manage to break the full sized USB connector, I'm not sure I trust an even smaller, possibly more fragile "Mini" version + everyone getting upset about needing a new type USB cable...
I'm open to suggestions...
fred sonnen
pfm Member
Please stay with the standard USB port. At least because of the new cable's...
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