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Lots of noise in my system... MDAC/ Quad 909 / ATC SCM40 - what's the cause?

F

funtime

pfm Member
So following on from my weekend of tinkering with my 909 I've had a chance to do some serious listening now...

The sound has definitely improved, replacing the caps and fitting the Dada upgrade kit has taken the harshness off the sound and brought some warmth into the mix.

My main gripe with the system now is as follows...

Noise - some tracks are worse than others, but every track I play has a lot of noise. On some tracks you can only here it when the music starts to play, and others you can hear it the whole way through the song, from the moment it starts - if that makes sense?

I'm not sure if the cause of this is my MDAC, the Quad 909, or just the fact that the ATC's are so transparent that every recording I have has had far to much gain applied to the track when producing the CD.

All of my music is from original CD's put onto iTunes in Apple lossless format. It's then played through my SBT using the asynchronous USB and this passes the Bit Perfect test on the MDAC.

So what's to blame?

Also as I mentioned in an earlier thread, the listening volumes tend to be around -15db to -10db on the MDAC which is not far off full volume - I'm still convinced that this may be the cause of the noise as the input signal is amplified so much.

Please help.... almost nearly very happy with my system :)

Regards,
James
 
It can't be too much gain in your system. The hiss would stay static and on whilst you don't play music. Unless it does? If it does, purchase some attenuators to sit inbetween the MDAC and 909.

Otherwise since you tinkered on your power amp, I am guessing it is something there. Put your ears up to the tweeter and woofer - listen to whats going on. If it hums and not hiss turn it off and get it looked at professionally.. It will be oscillating and can damage your speakers and DAC.

At 15-10db you either have the ideal gain levels or you are listening at some crazy volumes!
 
Sebbyp said:
It can't be too much gain in your system. The hiss would stay static and on whilst you don't play music. Unless it does? If it does, purchase some attenuators to sit inbetween the MDAC and 909.

Otherwise since you tinkered on your power amp, I am guessing it is something there. Put your ears up to the tweeter and woofer - listen to whats going on. If it hums and not hiss turn it off and get it looked at professionally.. It will be oscillating and can damage your speakers and DAC.

At 15-10db you either have the ideal gain levels or you are listening at some crazy volumes!
Click to expand...

Oh right OK well that's encouraging. The hiss doesn't stay static, in some songs when there's no singing it's silent (but as soon as the singing starts you can hear the noise in the background, in others it's constant throughout the whole song.

It is definitely a hiss and not a hum though - it also did it before I fitted the upgrades to the amp... I had hoped that the upgrades would increase the S/N ratio and remove the hiss but it hasn't :(

Not happy :(
 
Nope - might try this, although playing through iTunes it won't be Bit Perfect - mind you I suppose it will see whether its the Squeezebox that's the source of the noise - is that what you're thinking?
 
Yerp just try to eliminate things step by step till you get to the most simplest setup possible. Why won't it be BitPerfect via iTunes directly into MDAC BTW?

I assume you've got all the setting correct in iTunes preferences? are you mac or windows?
 
funtime said:
So following on from my weekend of tinkering with my 909 I've had a chance to do some serious listening now...

The sound has definitely improved, replacing the caps and fitting the Dada upgrade kit has taken the harshness off the sound and brought some warmth into the mix.

My main gripe with the system now is as follows...

Noise - some tracks are worse than others, but every track I play has a lot of noise. On some tracks you can only here it when the music starts to play, and others you can hear it the whole way through the song, from the moment it starts - if that makes sense?

I'm not sure if the cause of this is my MDAC, the Quad 909, or just the fact that the ATC's are so transparent that every recording I have has had far to much gain applied to the track when producing the CD.

All of my music is from original CD's put onto iTunes in Apple lossless format. It's then played through my SBT using the asynchronous USB and this passes the Bit Perfect test on the MDAC.

So what's to blame?

Also as I mentioned in an earlier thread, the listening volumes tend to be around -15db to -10db on the MDAC which is not far off full volume - I'm still convinced that this may be the cause of the noise as the input signal is amplified so much.

Please help.... almost nearly very happy with my system :)

Regards,
James
Click to expand...

Hat you tried the MDAC Direct with headphones?
 
makes sense. iTunes processes the sound and as far as I know there's no way of changing any settings to make it play Bit Perfect. I thought that that's why the MDAC instructions say to use the foobar media player or whatever it is called.

I will give it a go, just didn't think you could achieve this with iTunes... Im running it on Windows 7 - if you could tell me what I need to do that would be great! :)

Regards,
James
 
Welcome to the world of high resolution and low playback system noise floors !

I have the same noise symptons you describe. As I tweaked by system with vibration control, better speaker cables, Supra Lorad mains cables, I can hear more and more detail which includes recording venue background noise, noise of the mixing console etc. This noise is even more apparent with 24/96 recordings. In my case I have gotten used to it and can enjoy the closer connection to the music

Foobar > Audiolab 8200 CDQ > W4S ST-500 > B&W 805D
 
It seems as I have the same problem too with my NVA P50SA and A60 combo. It's blown my DAC up twice!

I was scratching my head wondering what the hell was going on.

Bunsen is now on the case, with my pre/power being sent back down to him for a solution.

Thanks Richard!
 
i'd say its unlikely to be transparency making these tracks sound bad. Theres something amiss here. Have heard setups capable of far far more resolution than a 909 / SCM40 being played from apple lossless tracks with no issue at all.

In fact recently, i have been listening to an Eastern Electrics DAC+ (same chipset as m-dac) into marantz reference series preamp, MA9 monoblocks and 99db/w klipsch palladium P39F speakers. All on the back of a digital out from a squeezebox. Sounded pretty spot on to these ears with no noticeable background noise beyond what was clearly identifiable as the source material.

Likewise have also heard recently a squeezebox touch, feeding antelope zodiac dac feeding directly a pair of ATC SCM100's. Same as above, just clean, defined and with no obvious issues with background noise.

So I can safely say, its not because your system is too resolving, and its unlikely to be the DAC/Speakers.
 
Don't need to. They are owned by two of my best friends. I Can listen to them any time I like ;)
 
i think it would be unfair of me to come down too heavilly on one side :)

the system with the marantz reference pre and monoblocks + klipsch, costs considerably more, probably by a factor of 3-4 times. So you have to weigh in the value for money aspect. But that said, I just cant engage with the big ATC actives at all. I find them thin and uninvolving at low levels, but then shouty and hard at higher levels. The bass is too controlled to the point of stiffness.

If i had to have one system, the sheer dynamic ease and fluid sound of the marantz / klipsch would be it. Its probably the best setup ive ever heard. 300w monoblocks into 99db/w speakers of that size, results in almost limitless dynamics, plus the resolution and projection of the horn mid/treble units. It's a winner for me! It sounds full and clean at low levels, but tight punchy and rich at high levels. It never sounds dull, or forward, and never loses control even when approaching PA levels of sound pressure. not a bad way to have spent about £60k i reckon ;)

anyway, sorry about the thread detour!
 
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