DAC directly into PowerAmp (MC275) - any reason why not?

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NKokemohr

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Hi all,

just hooked up my Summit X's to a McIntosh tube amp 275 ––*which has shot me into audiophile orbit.

I'm out of a preamp, so I hooked up my chain as follows:

Sonos Z90 --> Cambridge Audio DacMagic --> McIntosh MC275 --> SummitX

and it works absolutely great. Volume Control happens digitally in the Z90, running between 40% - 70% of the volume bar.

I have ordered a preamp and am thinking of trying to cancel. Why put an element in the chain if not needed?

What do you think?

Thanks in advance!

Nils
 
If it works absolutely great you don't need that preamp. As you said, why put an extra component you don't need into the chain.
 
Hi Bernard,

thanks for the quick reply. I'll see if I can still cancel the order of the preamp. I bought it on audiogon & my purchase is binding, but maybe I can bribe the guy with some percentage of the purchase to keep it, so it's a win-win for both.

One concern is the following: I am listening mostly to classic with a high dynamic range, that means that most passages have much less volume than the loudest possible passage. Therefore I assume mainly only 11-14 bit of the possible 16 are being used. If the Z90 is scaling this down to about 40%, it's at least 1-2 bits that get lost in addition, if the volume control is logarithmic, it'll be more.

So I am really throwing away quite some bits plus I'm having the not-so-audiophile Sonos system interpolate my bits. That's can't be good.

Long story short: What I actually need between DAC and power amp is not a pre-amp, but a de-amp... something that makes the signal weaker.

Couldn't I just put in a potentionmeter in between? Wouldn't that be the least messing-with-the-signal?

Nils
 
Hi Bernard,

thanks for the quick reply. I'll see if I can still cancel the order of the preamp. I bought it on audiogon & my purchase is binding, but maybe I can bribe the guy with some percentage of the purchase to keep it, so it's a win-win for both.

One concern is the following: I am listening mostly to classic with a high dynamic range, that means that most passages have much less volume than the loudest possible passage. Therefore I assume mainly only 11-14 bit of the possible 16 are being used. If the Z90 is scaling this down to about 40%, it's at least 1-2 bits that get lost in addition, if the volume control is logarithmic, it'll be more.

So I am really throwing away quite some bits plus I'm having the not-so-audiophile Sonos system interpolate my bits. That's can't be good.

Long story short: What I actually need between DAC and power amp is not a pre-amp, but a de-amp... something that makes the signal weaker.

Couldn't I just put in a potentionmeter in between? Wouldn't that be the least messing-with-the-signal?

Nils

Yes, you could use a passive preamp. There are some decent units priced pretty attractively or look on the 'Gon for used one.

This Creek unit even gives you remote volume control in a passive design
http://www.audioadvisor.com/prodinfo.asp?number=CKOBH22
 
Ideally, you want to keep the Sonos digital output at 100%, so something like the Creek would be great, or alternatively, replace the DACMagic with a Benchmark DAC1-HDR (or DAC1-Pre), and eliminate that extra set of cables (and get the headphone output as a bonus).
 
This is eminently dependent on your components. That is, ALL of them. Your amp (input impedance, etc), your DAC (its ability to drive a power amp directly) and your source. Try it by all means - but it definitely does not gaurantee better sound.
 
I've done this with my DAC to amp while waiting for my pre. While the sound was acceptable, I much preferred it with the pre in the chain.

Gordon
 
Hi Gordon,

thanks, that is good to know. Actually, I am waiting for a preamp (Krell KSL) that I am looking into reselling when I get it, but you'd say there may be a benefit?

If so, what was it? I'd think if all the preamp needs to do is _dim_ the signal, a resistor should do a much better job than a transistor circuit, no?

Thanks in advance

Nils
 
Nils, I thought there was a bit of a digital sound when going direct to amps. A very slight edge and raggedness. Not terribly bad, but noticeable. Once I installed my pre (tube) the edginess was gone and more pleasing to my ear.

I can't answer your question about putting a resistor in line. That is way over my knowledge level! I do know that when I had a pair of 275's in the room it was very tempting to keep them. I was afraid of getting on tube rolling and went with the 501's in an attempt to control myself!! HAHA!

Gordon
 
The passive preamp that JonFo referred to is in effect a resistor network. It is important to try it out first to ensure that it is compatible with the DAC, i.e. it does not load down the DAC.
 
Hi all,

just hooked up my Summit X's to a McIntosh tube amp 275 ––*which has shot me into audiophile orbit.

I'm out of a preamp, so I hooked up my chain as follows:

Sonos Z90 --> Cambridge Audio DacMagic --> McIntosh MC275 --> SummitX

and it works absolutely great. Volume Control happens digitally in the Z90, running between 40% - 70% of the volume bar.

I have ordered a preamp and am thinking of trying to cancel. Why put an element in the chain if not needed?

What do you think?

Thanks in advance!

Nils
You can go one step further and eliminate the sonos z-90 but that would entail you getting a different DAC. The PS Audio PWD DAC with the optional bridge will take a feed directly from a NAS and makes a huge difference.
You can also run the DAC directly into the 275 via balanced or single ended output. I have a Sonos system also and taking my FLAC files directly into the PS Audio DAC is a night and day difference. I also have a MC275 powering my CLS's but am using a Mac C2200 pre.
 

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