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MDAC First Listen (part 00110001)

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I have noticed that my setup is quieter when using XLR compared to RCA. I have my MDAC connected to Focal CMS 50 monitors. I would have expected the XLR connection to be louder.

I'm trying to find out if this is due to the MDAC, the amplifier gain on the monitors, or the cables. The RCA cables I use are Techlink Wires XS, I have two sets of XLR cables: a pair of Van Dammes and a pair of Fisual Havanas. If I could eliminate the MDAC as the cause that would be something. Does the MDAC have a lower output on the balanced XLR? According to the manual it would seem that it has a higher output on XLR. Could someone confirm this?

Many thanks
 
mrflibble said:
I have noticed that my setup is quieter when using XLR compared to RCA.
Click to expand...

Is this in a good way or in a bad way ?

It should be quieter in a 'less distortion way'.

I'm assuming that you are looking at the voltage output of RCA Vs XLR being 2.25 and 4.5 Vrms respectively and thinking that more voltage should equal more dB (louder volume) output.

There is more to fully balanced dual differential signals than that.

Over to someone who can explain the concepts in a concise manner......
 
fusion5 said:
Full (52pcs) kit's performance.

For me it is important to find out now, so everyone else can made up their mind for the final FDAC (or Superior) order.
Click to expand...

Michael,

I have the "Package" pricing back from Nick with discount and its £372.06 + vat and he will create a specific order code for us :)
 
wintoid said:
A question for John, showing my complete ignorance.

I recall there was some discussion about performance of the MDAC being degraded if signal was taken from both the XLR and RCA outs at the same time, I think for people running subs.

I want to have my MDAC plugged in to an amp on the XLR, and a headphone amp on the RCA. If I turn off the amp/headphone amp which is not in use, will my performance on the device I'm using be degraded? I'm guessing the answer is no.

Thanks,
Click to expand...

Switching off a connected device might be even worst as any Opamp on the devices input will then present a non linear "back to back" diode type load which is not good sonically or for the Opamp....
 
davidjt said:
Two more questions for John: BobL mentions that his Regen(s) are more effective with a better psu. So it makes sense to take the Regen's +7.5V from my new 5-rail MDAC box.
IIRC the Detox will require +12V. Is that correct?
Click to expand...

The Regen requires 9V DC - (Centre Pin positive)

davidjt said:
Second, using the Regen when the laptop is acting as a Radio or TV source always results in a loud burst of white noise sooner or later, so it has to be taken out of the chain every time, which is a pita. Is this likely to be a pathetic BT bandwidth issue and will I therefore have the same problem with the FDAC + Detox? Thanks
Click to expand...

You will no issue with Detox's as it very well shielded and filtered.
 
adamdea said:
is the idea that a few prototype units are produced beforehand, these are tested and approved and then (assuming they are OK) the (mainstream) production units are produced?
Click to expand...

TO means units that are manufactured on the production line but in say 10 Pcs Qty (normally you might produce say 100 to 1K Pcs) - just to confirm design and production stability and weed out any remaining issues.
 
mrflibble said:
I have noticed that my setup is quieter when using XLR compared to RCA. I have my MDAC connected to Focal CMS 50 monitors. I would have expected the XLR connection to be louder.

I'm trying to find out if this is due to the MDAC, the amplifier gain on the monitors, or the cables. The RCA cables I use are Techlink Wires XS, I have two sets of XLR cables: a pair of Van Dammes and a pair of Fisual Havanas. If I could eliminate the MDAC as the cause that would be something. Does the MDAC have a lower output on the balanced XLR? According to the manual it would seem that it has a higher output on XLR. Could someone confirm this?

Many thanks
Click to expand...

Each phase of the MDAC's output is 2Vrms - (3Vrms with +3dB), I suspect the lower level is related to gain scaling on the speakers balanced inputs.
 
misterdog said:
Is this in a good way or in a bad way ?

It should be quieter in a 'less distortion way'.

I'm assuming that you are looking at the voltage output of RCA Vs XLR being 2.25 and 4.5 Vrms respectively and thinking that more voltage should equal more dB (louder volume) output.

There is more to fully balanced dual differential signals than that.

Over to someone who can explain the concepts in a concise manner......
Click to expand...

I meant quieter volume wise :)

Yes, I was looking at the Vrms values in the manual and assumed it equated to dB levels. Thanks for pointing out that it is not that simple.
 
Interesting so that's about £8 each a lot better than the £16 I have paid in the past on another issue how many rsisters are in the MC stage that might need to be bulk foils as well?
 
I suspect the MC stage to be even more sensitive of Resistor types due to the Gain and EQ circuits...

In the next few weeks I'll be starting the "Latest" MC design based upon the experience gained with the Superior PCB - I'll answer that soon...
 
JohnW said:
Michael,

I have the "Package" pricing back from Nick with discount and its £372.06 + vat and he will create a specific order code for us :)
Click to expand...

I'll order as soon as I get the order code. I couldn't find anything in the shop yet.
 
Yes, I've been playing in the shop for the last 15 minutes :)

Shipment via FEDEX Int. Priority Courier -Trackable & Secure, 1 day
 
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