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MDAC First Listen (part XXVIII)

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wintoid said:
I've been holding off posting about my Premium Toy because I have had some concerns about it. John had previously talked about the bass on the Toy model being pretty amazing, so when my Toy arrived and I found the bass sadly quite lacking, I was surprised and concerned. I was worried that this was the emperor's new clothes. Mine was shipped mid-week, and didn't arrive until the following week, so it probably had a nice cold weekend in some storage warehouse somewhere. I can only speculate that this is why it took at least 2 full days to be listenable(!). I had contacted John and we were trying to work out what was going on.
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Funny, I had a very similar experience. I thought that initial ~6 hours of heating up were enough. Apparently not.
 
sq225917 said:
Is sorting out your lack of power amp inputs really the job of a dac?
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John's offered the concept of an av bypass for at least a year now, which has no other function than 'sorting out power amp inputs'. So I'm surprised you haven't raised this question before.

Power amps generally only have one input, so they always need 'sorting out'
 
ChrisPa said:
John's offered the concept of an av bypass for at least a year now, which has no other function than 'sorting out power amp inputs'. So I'm surprised you haven't raised this question before.

Power amps generally only have one input, so they always need 'sorting out'
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No doubt John will be along any second to tell you he can fit 2 Xlr, 2 RCA all the digital inputs of the standard Mdac plus the additional 2 Xlr you require on to the back panel. Or maybe he won't.

Pix, why don't you read every post from John on the topic of additional back panel sockets, like I have, then you'll know the answer.
 
sq225917 said:
No doubt John will be along any second to tell you he can fit 2 Xlr, 2 RCA all the digital inputs of the standard Mdac plus the additional 2 Xlr you require on to the back panel. Or maybe he won't.

Pix, why don't you read every post from John on the topic of additional back panel sockets, like I have, then you'll know the answer.
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Good. So we all understand that the mdac is a preamp and that for some time John has been trying and intending to enhance its capabilities in a preamp function. And because of the features he's been proposing, that it can used to sort out power amp inputs.

I didn't ask about fitting additional xlrs on the rear panel. Or maybe I did. Oh no, I didn't. And when I did ask about balanced inputs your first reply felt more like 'how dare I ask the question' and had nothing to do with space on the back panel, you've only given this reply now.

At the time of pix's post you had made no mention of back panel connectors, only a hint at the functionality of the mdac. So he wouldn't know to read about space for rear panel sockets because that wasn't your first answer (and that wasn't the question)

I asked John a straight and simple question for good engineering reasons and as part of that question, before your response, acknowledged the commensurate engineering problems. In this case I'm sure he can reply, or choose not to reply, for himself

Sq, it feels like there is sometimes a tone of scorn to the way you reply which could possibly be interpreted as superior or antagonistic. I'm sure you don't intend it that way. Unfortunately I seem to have interpreted a couple of your recent replies in this way, which seems to be resulting in us both wasting our time in the subsequent responses. I'm more than happy to continue with a discussion where we both correspond in a straight and level headed tone.
 
ChrisPa said:
John

Any chance the av bypass can be balanced?

I quite understand about space constraints on the back panel but from a system point of view this would provide full flexibility for an existing balanced system

Balanced circuit on the motherboard allowing a diyer to use a balanced connection instead of rcas?
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The AV bypass is simply "Passive" so that when powered off (or selected by the user) the AV input is routed via Relay to the XLR / RCA output.

The reason an Balanced (XLR) input AV bypass is not added is due to MDAC rear panel space - there is no room for the 2 extra XLR's. As its currently stands, MDAC2 will have the AV bypass RCA input mounted ABOVE the RCA audio outputs, with the Balanced headphone output (4Way XLR) mounted between the existing XLR's.

The header cable that links the Top mounted PCB with AV Bypass RCA's has the full balanced signals with the Negative phase of the XLR connected to the Ground pin of the AV bypass at the RCA connector thus correctly "Ground sensing" the AV signal.

You could simply remove the PCB assembly complete with the AV Bypass input RCA's and have XLRs attached via flying leads - with the leads poking though the holes where the AV bypass RCA used to be mounted on the rear panel - and soldered to the PCB (I'll leave Solder pad positions) - a simple but Mickey Mouse job :D :cool: :p

Maybe we can find a large Gromit that will clamp the XLR cable and still fit within the rather large RCA hole :) then it would look rather less Mickey Mouse - but you would still have a pair of Cable mounted XLR's dangling from the rear of the MDAC2 - but hey a practical working solution! you can then even make an XLR to RCA adaptor cable for single-end inputs :)
 
Thanks. I think that would work for me :)

I couldn't remember if you were thinking of buffering the av bypass on the mdac2. Either way you've given me the answer I was hoping for
 
[QUOTE=
The header cable that links the Top mounted PCB with AV Bypass RCA's has the full balanced signals with the Negative phase of the XLR connected to the Ground pin of the AV bypass at the RCA connector thus correctly "Ground sensing" the AV signal.


There are miniature balanced XLR's available I believe these could be fitted in the RCA holes instead giving true balanced pass through.
Geoff
 
I'll look into it - It would be good if they could be fitted - shame the Mini XLR is not a more common standard .....
 
Chris, sounds like you might have issues that are causing you to 'project' onto other people's posts and infer meaning and tone to them that simply isn't there. I imagine you're doing it now.
 
sq225917 said:
Chris, sounds like you might have issues that are causing you to 'project' onto other people's posts and infer meaning and tone to them that simply isn't there. I imagine you're doing it now.
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FWIW sq, I have (mis)interpreted the same tone from some of your posts - hence the ribbing.
 
JohnW said:
I'll look into it - It would be good if they could be fitted - shame the Mini XLR is not a more common standard .....
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While digging for the headphone 4pin thing, I noticed that 3-pin miniXLRs are quite fine. There's only one way to do it - 3 pins forming an equilateral triangle. It's the 4+ pin versions that differ - variations like miniaturized version of Neutrik's large 4W XLR (4 pins on a curved line) or triangle with 4th pin in the middle, ...

3 pin miniXLR is fine, it's standard enough to be used by (at least) AKG for detachable headphones cables. It can be therefore easily bought on ebay or even almost any local "radioshack".

edit: When it comes to ready-made products (and not DIY), there's not much to choose from, though.
 
Normal h/p output from my L3 Toy on Saturday sounded excellent via a pair of Grados.

Their owner, a musician, preferred the Optimum Spectrum setting to all other Filters. He likes the "air" that this setting brings to the party.
 
pix said:
FWIW sq, I have (mis)interpreted the same tone from some of your posts - hence the ribbing.
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Oh don't get me wrong, I am a prick, and the ribbing to be expected it's part of any reasonable discourse between grown adults.
 
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