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MDAC First Listen (part 00011110)

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giannitom,

I while back you asked for modifications to your Arcam FMJ A18 which is based on a pair of LM3886 Amplifier IC's - well it turns out that the Audiolab MPWR is practically the same power amplifier circuit with just a single resistor valued changed. I strongly suspect that whoever design the MPWR obviously also worked on the Arcam - or had access to its circuits.... the Arcam has an "oddity" with its circuit design, which has found it way into the MPWR - which is very unlikely to be by coincidents.

Sadly due to internal circuit design - there is a good chance the MPWR will sound better via the singled ended RCA inputs then via Balanced XLR's, not making the best use of the higher quality balanced signal available from the MDAC.

What the MPWR lacks in design it makes up by being very solidly and nicely built - and a cute form factor :)
 
John
I would like to get onto the MDAC 2 queue (I already have the original MDAC) - do I just need to pay only the first £100 instalment at this stage or the first two instalments together?
 
banjoman said:
John
I would like to get onto the MDAC 2 queue (I already have the original MDAC) - do I just need to pay only the first £100 instalment at this stage or the first two instalments together?
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banjoman,

We are at the second stage - so the first 2 instalments :)
 
JohnW said:
giannitom,

I while back you asked for modifications to your Arcam FMJ A18 which is based on a pair of LM3886 Amplifier IC's - well it turns out that the Audiolab MPWR is practically the same power amplifier circuit with just a single resistor valued changed. I strongly suspect that whoever design the MPWR obviously also worked on the Arcam - or had access to its circuits.... the Arcam has an "oddity" with its circuit design, which has found it way into the MPWR - which is very unlikely to be by coincidents.

Sadly due to internal circuit design - there is a good chance the MPWR will sound better via the singled ended RCA inputs then via Balanced XLR's, not making the best use of the higher quality balanced signal available from the MDAC.

What the MPWR lacks in design it makes up by being very solidly and nicely built - and a cute form factor :)
Click to expand...

What a coincidence!! Does the different resistor may affect the sound quality? If I'm not mistaken even the new Arcam A19 is based on the same IC.
So no chance to improve my amp with XLR inputs? And what about the closed loop gain of the MPWR ? Is the same of the A18? Once you tell me that reducing it in my amp would improve the bass.
 
Hi John hope you're over the worst of the flu.

Been listening to both quads I have and there are differences , with the xlr input and output connections of the non serviced one , the bass has more control , but the treble is not as refined . The one with speakon and RCA outputs which has been serviced seemed to have a smoother more defined top end but not so much control or definition in the lower end.

Edit 2nd swap I think perhaps the xlr non serviced one has just more bass not necessarily more control as I first thought.

I,ll be packaging up and sending the non serviced one to you , think I still have details on a saved email.

Cheers for now.
 
giannitom said:
What a coincidence!! Does the different resistor may affect the sound quality? If I'm not mistaken even the new Arcam A19 is based on the same IC.
So no chance to improve my amp with XLR inputs? And what about the closed loop gain of the MPWR ? Is the same of the A18? Once you tell me that reducing it in my amp would improve the bass.
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Yes - the Resistor that has been changed has reduce the overall gain on the MPWR by 1.6dB (So 29.6dB via RCA and 35.6dB via XLR balanced).

Your Arcams power Amplifiers stage is set to 31.2dB (hardly any gain difference between your Arcam and the MPWR).

It is possible to have a true balanced input with the LM3886 IC - its just that whoever designed the MPWR seem to have based the design on the Arcam schematic and thus its not truly balanced.

I'm going to modify the MPWR to see how much performance I can get from the LM3886. Jeff Rowland in the "Rowland Model 10" dual-monorail" utilises six of these LM3886 power amplifier devices per channel.

You do have to question the Value for money when the device's cost something like US$1.30 each in bulk - to be honest maybe you could stretch it for a GBP500 Power amplifier but the Rowland Model 10 sells for thousands of dollars and thats really pushing it IMHO...
 
PhilCTTE said:
Hi John hope you're over the worst of the flu.

Been listening to both quads I have and there are differences , with the xlr input and output connections of the non serviced one , the bass has more control , but the treble is not as refined . The one with speakon and RCA outputs which has been serviced seemed to have a smoother more defined top end but not so much control or definition in the lower end.

Edit 2nd swap I think perhaps the xlr non serviced one has just more bass not necessarily more control as I first thought.

I,ll be packaging up and sending the non serviced one to you , think I still have details on a saved email.

Cheers for now.
Click to expand...

Ok Phil,

I'll look out for it and advise you once it arrives...

I just bought a unit for myself of Ebay... Anyone located near Coventry who might be able to pick it up if I cannot convince the seller to ship it to me to Czech Rep?
 
JohnW said:
Ok Phil,

I'll look out for it and advise you once it arrives...

I just bought a unit for myself of Ebay... Anyone located near Coventry who might be able to pick it up if I cannot convince the seller to ship it to me to Czech Rep?
Click to expand...

I pop back to Coventry regularly (hometown) so if you struggle to convince the seller, I'll sort it out - drop me a PM.
 
Nick1881 who I I've been in previous contact on Pfm and an MDAC owner (no 104 on list for mdac2) comes from Nuneaton, let me know what the seller commits to. I can always do a quick sprint over from Halesowen if needed and send both units over .
 
John they are in good company the Abingdon Research AMR77 is similarly chip amp based, but with an epic valve front end. That had the softest bass of any amp I've ever owned.
 
PhilCTTE said:
Nick1881 who I I've been in previous contact on Pfm and an MDAC owner (no 104 on list for mdac2) comes from Nuneaton, let me know what the seller commits to. I can always do a quick sprint over from Halesowen if needed and send both units over .
Click to expand...

Hi Phil,

Thank you, I'll see what the seller says... I did a quick Google and noted that its still 40 minutes to an hour drive for you... Lets hope the seller agrees to ship direct :)
 
sq225917 said:
John they are in good company the Abingdon Research AMR77 is similarly chip amp based, but with an epic valve front end. That had the softest bass of any amp I've ever owned.
Click to expand...

I just feel its "cheap" to design a Chip amp - its OK for budget equipment but for a Hi-end design its pretty amateurish...IMHO...

That said, I'm going to mod my MPWR to see what it can do...
 
JohnW said:
Hi Phil,

Thank you, I'll see what the seller says... I did a quick Google and noted that its still 40 minutes to an hour drive for you... Lets hope the seller agrees to ship direct :)
Click to expand...

Collecting something from Coventry wouldn't be much of a problem for me, could be as little as 10 minute drive depending where abouts.
 
EIffel said:
Besides the similar look to the M-DAC, I'm not sure what the M-NET brings compared to, say, a SBT. It seems it is lacking most of the features which we'd want (USB async output, open system/customisation/apps, user interface -colours, album art, etc.-).

I also noticed no mention of things such as gapless playback or HD support
Click to expand...

True.

Not to mention that a streaming device requires constant firmware updates...
 
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