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Theo's picture
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DAC to Powr Amp
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I wanted to start a thread to collate your experiences running DAC directly to Power amp with no preamp. 

 

If we assume the DAC claims to have in-built pre-amplification  i.e. quality attenuation + a strong output stage for example, Benchmark DAC2 and NAD M51. Also let's assume our components down the line are sufficiently sensitive as to not need too much gain. We can also assume we are only interested in two-channel audio and have only one source i.e. source selection capability not required. Under these conditions, is there any real benefit in inserting a preamp.

 

Here are some thoughts I have gathered mainly in support of having a preamp in the path:

- A preamp can add some positive colour to the sound

- A preamp will improve dynamics and transient capabilities

- With a preamp in, bad recordings appear not so bad 

 

I can think of several advantages to not having a preamp but would really like your opinion as it seems many of us are opting to go direct these days.

 

Thanks!

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RE: DAC to Powr Amp

I’ve only tried my budget Beresford Caiman DAC (with variable output) as a pre-amp and didn’t like it at all, couldn’t live with it. The Caiman is fine as a DAC but doesn’t cut it as a pre-amp. It just does not have the drive or any life, the sound it flat. I guess a large part comes down to the quality, type and implementation of the volume control, no doubt that in the Caiman is pretty basic so sucks the life out, I really don’t know how people see it as a viable option.

 

I added a pre and returned the DAC to fixed (doing its primary function just as a DAC) and it improved things no end.

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RE: DAC to Powr Amp

I haven't tried using a pre-amp is in my set-up, but what I can say is that DAC -> Power amp direct is very good in my system.  Logically I would think that it is preferable to eliminate the pre-amp if you DAC is good enough (one step less, and less cables Smile )

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RE: DAC to Powr Amp

All of my amps are integrateds, so I dont do it this way, but a friend in the US has a Benchmark DAC1 (the original, so not even the 'Pre' version) plugged straight into a huge solid state McIntosh power amp, feeding Anthony Gallo reference 3's. It's a sickly good system for a single digital source (his computer) - the only thing it's missing, really, is a remote control for the volume (plus between you and me, he really needs a new living room, if you know what I mean - this setup is in a smallish apartment - his neighbors love him).

I must admit, though, that I have wondered whether it would or could sound better with a preamp. But he's doesn't have another source, so no real need for line switching, the Benchmark's volume control seems pretty heavily over-engineered as it is, and if anything, I feel the big Mac would be happier higher up in its power band, not lower (it's none too stressed in his living room or by those really agreeable, almost crossover-less speakers). I'm just not sure what he would gain - and of course, we'd be adding another power supply, more cables, more complexity, and more cost - a pretty compehensive set of cons with nary a pro in sight.

I would say that the only excuse to add a preamp in his system would be if it were a tube preamp. This would make the sound different - more distorted but perhaps more pleasing to some. But I don't see how it would make it inarguably better.

Bottom line: if you want to use a DAC as a preamp, it's probably fine if it's a really good DAC. But I would never commit to this setup unless I heard that specific power amp/DAC combo first, in person, for more than just a few minutes. The usual caveat in other words but it strikes me as especially important here. Find a dealer who's interested in honestly helping you. I'm sure he'd love to sell you a preamp but it isn't like you're talking about budget DACs here either.

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RE: DAC to Powr Amp

Hi

I run my M-DAC straight into my power amp's XLR inputs. My DAC's volume control is digital but it runs in 32 bits & is very well implemented. Some users don't like the idea of running a volume control well down in its range so use fixed attenuators but many have reported a loss of SQ in the process. Others have stated that they prefer the sound through a preamp stage.

The advantage of analogue volume control is that noise is also attenuated. Digital volume doesn't attenuate any noise present & there will be some point far down in its range where the signal to noise ratio will fall but the volume will be low enough to mask the effect. To answer your question directly: it depends on how individual DACs work. However, how did you arrive at the notion that adding extra circuitry would add "positive colour" rather than optimising levels?

I'd also point out that most analogue volume controls in either preamps or integrated are used well down in their range in most setups I've encountered. My take Is to remove preamp stages as a matter of preference unless your own experience has shown that using a preamp is better! One deal-breaker is whether or not you want analogue inputs or not though some DACs have them.

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RE: DAC to Powr Amp

Further insight into driving a suitable DAC into a power amp from the designer of the M-DAC:

http://www.pinkfishmedia.net/forum/showthread.php?t=130437&page=15

Post #223

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RE: DAC to Powr Amp

busb wrote:

One deal-breaker is whether or not you want analogue inputs or not though some DACs have them.

Hi busb,

Could you name a few? I' m looking for a "all-digital + FM" set-up, so one of these DACs with analogue input (just one would be fine) and "pre-ampability" (as if that were a word in English! :roll: ) might be just the ticket.

 

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RE: DAC to Powr Amp

In the Hifi world according to Naim, the preamplifier forms the most important component when it comes to amplification. So I believe the higher you go - from the NAC 282 to the 552 - the gains in sound quality are reportedly huge when paired with the same power amp.

Mind you, I haven't heard the whole range - certainly not the top of the line stuff - but in my limited experience with Naim amps, I have found the preamplifier to be crucial. Perhaps it's to do with having superior dedicated power supplies? Not sure if the same applies to other brands though.

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RE: DAC to Powr Amp

DocG wrote:

busb wrote:

One deal-breaker is whether or not you want analogue inputs or not though some DACs have them.

Hi busb,

Could you name a few? I' m looking for a "all-digital + FM" set-up, so one of these DACs with analogue input (just one would be fine) and "pre-ampability" (as if that were a word in English! :roll: ) might be just the ticket.

 

I know of a few:

http://www.audiolab.co.uk/ProductDetail.aspx?lang=En&Tab2=8200DQ

http://www.benchmarkmedia.com/dac/dac1-series-overview

http://www.benchmarkmedia.com/dac/dac2-hgc

http://www.antelopeaudio.com/en/products/Zodiac-Plus-Mastering-DAC

http://www.msbtech.com/products/dac3.php

http://www.cyrusaudio.com/product/dacs/dac-xp

http://www.whathifi.com/forum/hi-fi/dac-pre-with-volume-control-and-analogue-input


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RE: DAC to Powr Amp

Theo wrote:

Here are some thoughts I have gathered mainly in support of having a preamp in the path:

- A preamp can add some positive colour to the sound

- A preamp will improve dynamics and transient capabilities

- With a preamp in, bad recordings appear not so bad 

I can think of several advantages to not having a preamp but would really like your opinion as it seems many of us are opting to go direct these days.

Thanks!

A preamp could add colour to the sound, but any good amplifier should not really colour the sound at all. Wether the colouration is to your taste would be for you to determine. Personally, if you want to add colouration, then the best way is to add a good EQ to the system. Trying to acheive some sort of tonal balance by swapping pieces of equipment seems like a fools errand to me.

I don't know how a preamp is going to 'improve dynamics and transient capabilities'. I also don't know how it would make a bad recording sound any better, unless distorting the sound in some way.

In short, a preamp should be a completely transparent method of amplifying or attenuating the signal and acting as a central hub for your sources. It could be digital, analogue or a combination.

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RE: DAC to Powr Amp

DocG wrote:

busb wrote:

One deal-breaker is whether or not you want analogue inputs or not though some DACs have them.

Hi busb,

Could you name a few? I' m looking for a "all-digital + FM" set-up, so one of these DACs with analogue input (just one would be fine) and "pre-ampability" (as if that were a word in English! :roll: ) might be just the ticket.

Also try the MATRIX Quattro DAC and Mini-iDAC

You could also consider an audio interface such as a UA-55 (USB powered) or Saffire Pro 24 (Firewire or Mains adapter power)

I don't know what sources you have, or how many, but if you feel that you needed more digital inputs, optical switches are available for not much money.

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RE: DAC to Powr Amp

I've had good results running my Benchmark DAC1 direct to power amps and active monitors. I'm a big fan of the combination of DAC and Pre as it means you have one less component and set of cables to worry about. More importantly it means you can dedicate the extra funds towards a better power amp. My belief is that rather than trying to get a pre to somehow "improve" the sound, it would be better to get a better amp. So start with the most neutral and accurate DAC/Pre you can find and then get a power amp to suit your tastes.

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RE: DAC to Powr Amp

busb wrote:

Further insight into driving a suitable DAC into a power amp from the designer of the M-DAC:

http://www.pinkfishmedia.net/forum/showthread.php?t=130437&page=15

Post #223

 

Good link and explains the pot in detail.

 

 

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RE: DAC to Powr Amp

The other thing about matching a pre with power is the output voltage of the pre. If the voltage is high you run the risk clipping the signal when you turn up the volume unless you have some control on either the amp or the pre. For example my dac outputs 8v over balanced and the power packs cant handle that signal so i reduce the input gain so thay dont clip, in this case by 10db's.

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RE: DAC to Powr Amp

shooter wrote:

The other thing about matching a pre with power is the output voltage of the pre. If the voltage is high you run the risk clipping the signal when you turn up the volume unless you have some control on either the amp or the pre. For example my dac outputs 8v over balanced and the power packs cant handle that signal so i reduce the input gain so thay dont clip, in this case by 10db's.

Before I bought my current power amp, I did some research into the input impedance & gain of power amps in general. It will come as no surprise that there's no standard. Most power amps are designed to be driven from a brand's own preamps where they choose where much of the voltage gain is done. How many people mix & match pre/power amps from different makes?

If less equals more, a DAC feeding a power amp (or active setup) is a good option, particularly where no analogue sources are needed. My power amp pushes out nearly 300W rms into my 4Ohm Arros which is probably only 3-6dB higher than average. This means that my DAC's output hovers around -30 to -40dB for average listening levels with a max of 3dB output. This mirrors how far down most folk use their analogue volume controls fairly well.

One option for those wanting both analogue inputs & fewer boxes is a multidisc player like the Oppo 105 feeding a power amp.

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RE: DAC to Powr Amp

busb wrote:

DocG wrote:

busb wrote:

One deal-breaker is whether or not you want analogue inputs or not though some DACs have them.

Hi busb,

Could you name a few? I' m looking for a "all-digital + FM" set-up, so one of these DACs with analogue input (just one would be fine) and "pre-ampability" (as if that were a word in English! :roll: ) might be just the ticket.

 

I know of a few:

http://www.audiolab.co.uk/ProductDetail.aspx?lang=En&Tab2=8200DQ

http://www.benchmarkmedia.com/dac/dac1-series-overview

http://www.benchmarkmedia.com/dac/dac2-hgc

http://www.antelopeaudio.com/en/products/Zodiac-Plus-Mastering-DAC

http://www.msbtech.com/products/dac3.php

http://www.cyrusaudio.com/product/dacs/dac-xp

http://www.whathifi.com/forum/hi-fi/dac-pre-with-volume-control-and-analogue-input

Thanks for the tips, busb.

The Zodiac is rather expensive. A mail to the Belgian distributor taught me MSB is way out of my reach (prices start at €7000).

But the Benchmarks look interesting. See if I can find out where to audition them.

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