DAC DIRECT IN TO AMPLIFIER OR TO PREAMPLIFIER

@blisshifi “…T+A SDV 3100 HV (which in all fairness has a true preamp stage built in)…”

That is really interesting. Perhaps what that means over time as digital becomes more dominant… DACs will include preamp stages… and really ultra high will continue to require separate preamp functions. 

@ghdprentice Perhaps… but I am in the camp of associating T+A with ultra high end. The SDV 3100 HV is a $38,750 component. While T+A does offer the standalone reference DAC at $36,500, they integrate the power supplies, analog output and volume control from their $22K reference preamp for an additional $2,250 into the SDV. The SDV unit does have a lesser feature set than the dedicated preamp - less inputs and outputs; no option for built in phono, no room correction or EQ - all so it can fit in one chassis, but also to reduce any culprits that may result from combining analog and digital circuits closely together.

I am a big believer of isolation and agree that typically it is best to have separate circuits in separate chassis’, but in a few manifestations such as the SDV 3100 HV, I think world class results are possible in integrated offerings. 

@carlsbad2 “…My summary of this thread would be that there are 2 camps, one likes adding a preamp, and one doesn’t..”

I get a different take all together. It seems there is consensus that most of the time a real preamp is required, it can be built in, or separate, or the music looses some really important characteristics. While there are exceptions… generally very high end, they are that… exceptions.

This brings up the problem to those assembling systems… especially if they are not auditioning extensively along the way. You put together a system without one and you don’t know what you are missing. And this missing stuff is often the most important stuff… what allows you to enjoy the music vs the system. So, without a preamp you often get amazing detail but somewhat flat lifeless presentation. This is a recipe for listening to the guy in the third row of the symphony move his foot as opposed to getting lost in the music you are listening to.

Us old times tried this by removing their preamp, so had the advantage of noticing the difference… then for whatever reason put it back in. Folks these days my never put one in.

Some really great points have been brought up in this string. Different systems will adapt better to change and others will not. Really measurements will play a small part in this process and yes cables or lack there of, can make a difference regardless of what your crusade/religon.I have listened to systems that on paper measured well, but in application sounded like buffalo chips. Expand your Third Eye and give some things a try, you maybe suprised. I love this and I am quoting @ghdprentice

This is a recipe for listening to the guy in the third row of the symphony move his foot as opposed to getting lost in the music you are listening to.

@ghdprentice 

You put together a system without one and you don’t know what you are missing. And this missing stuff is often the most important stuff…

Very true, both wrt to preamps and with other stuff too.  In my case it was dual subs, which I should have added years ago.

So, without a preamp you often get amazing detail but somewhat flat lifeless presentation. 

Not everyone has the same experience with loss of depth and dynamics, but it was mine with the 4 or 5 resistive passives I have tried in my system.  The internal volume control of the Metrum Adagio DAC was better sounding and certainly not flat or lifeless, but it leaned more toward a clean/detailed sound without providing the degree of body and rich tone I enjoy.  In addition to the Adagio, the only other passive solutions I have tried where that "somewhat flat lifeless presentation" didn't occur used Slagle autoformer volume controls (AVC) but those two units had their own sound that, while nice, I ultimately moved on from.

Regarding DAC volume controls and loss of bits, here is some reading material explaining how bits can be lost in some situations.  The article also includes a couple of illustrations by ESS showing how analog volume controls lower both the signal and the noise while digital volume controls can lower the signal while leaving the noise unaffected, which has the effect of reducing the S/N ratio.  

Not all DAC volume controls are the same.  The approach practiced by Cees Ruitenberg at Metrum and at Sonnet (now together under one roof!) involves changing the volume by varying the reference voltage of the converters, which, in conjunction with an algorithm they employ, preserves S/N.

In the end, as mentioned by others here, you really need to try things out for yourself and preferably in your own system with the music you listen to.