DAC plus Preamp or DAC-Preamp or DAC-Volume Control ?


I recently purchased a 2A3 amplifier. Preamplifier and Speakers have not been chosen.

This will be a ’learning / experiential’ system. My intentions and goals are that this ’JOURNEY’ to a new system be radically different than how I went about putting my current ’primary’ system together.

I will be leaving my front end (computer audio) system the same.

The ’secondary’ system will bifurcate post DAC at the preamp OR with a new DAC/Preamplifier combo component.

The purpose of this thread is to ask for your recommendations and suggestions for:

- Preamplifiers

OR

- DAC + Full Preamplifier // DAC + Volume Control Combo Components

to pair with Scott Sheaffer’s Found Music 2A3 monoblock amplifier. Scott advises that this amp is unfussy with respect to preamp pairings, solid state or tube, or digital volume controls.


Current system (general components): Small Green Computer Server > Sonore Signature Rendu SE > Denafrips Terminator DAC > T+A PA 3100 HV Integrated Amplifier > Tekton Design Double Impact SE Speakers.


Any additional thoughts and advice related to the topic are welcome.

Thank You!
Ag insider logo xs@2xdavid_ten
I had asked a similar question on mattnshilp’s ’Absolute top tier DAC for standard res redbook CD’ thread. Responses are copied below, since they apply. I also did not want to take Matt’s thread off-course.

Thanks to all whose responses are copied below.

[If there are any objections to my copying your posts, let me know and I will edit accordingly].

recommendations for an upper tier DAC with a very well implemented volume control

@toetapaudio "I suggest taking a look at the Mola Mola Tambaqui when it arrives later this month. Going by the Makua (pre with dac module) it should be extremely good. £9k in the UK."

@bill_k "If you like NOS PCM DAC designs (no DSD), I suggest you check out the Metrum Acoustics Adagio which is their top of the line. It incorporates a unique volume control implementation which varies the operating voltage of the DAC rather than adding in an additional stage or digitally implemented volume control. It provides a continuous volume control without typical losses or compression most other designs exhibit."

@ctsooner "I have finally gotten the Memory Player DAC integrated into their server. It’s special. They are still working on it and we are waiting on the Stealth Caps to arrive, but It will end up being in the discussion of top DAC’s built I think. Soon Matt will have one in his system to play with I think. It’s worth keeping an eye on as I think Mark (the designer) is onto something specially. It does have two small signal tubes in it, but the sound is impactful, tons of micro and macro info for that emotional pull on music and it’s got great totality so far and it’s not broken in and it has many upgrades to come. We will even be pulling it out of the server and it may become a two box DAC. Just not sure yet. I like how they have dealt with the digital volume control, but mine also has an analog one too and in time, we will build that up to a world class preamp. This way I’ll be able to run a great stereo or set of mono’s off the DAC ."

@guidocorona "If you like NOS PCM DAC designs (no DSD), I suggest you check out the Metrum Acoustics Adagio which is their top of the line. It incorporates a unique volume control implementation which varies the operating voltage of the DAC rather than adding in an additional stage or digitally implemented volume control. It provides a continuous volume control without typical losses or compression most other designs exhibit. Sounds like a perfect description of the volume control of my Jeff Rowland Aeris... Yes, not the newest DAC on the market by any stretch of the imagination, but particularly when powered by the external PSU power supply, an amazing maker of music."

@mitch2 "I can second the Metrum Adagio that was already recommended by @bill_k. I owned the Adagio as well as Metrum’s Pavane at the same time and after several weeks of side-by-side comparisons, I chose to keep the Pavane and have it upgraded by Metrum to their Level 3, which means the interior build is at the same level as the Adagio, but without the volume control.

The sound of the Adagio is very close to my upgraded Pavane but I already owned a preamp that I like very much and I liked the sound through my preamp just a little bit better than through the Adagio alone. This was probably due to some minor coloration, possibly caused by components in the preamp including AN tantalum resistors in the volume control, Jupiter copper foil caps, Lundahl transformers, or other circuitry. The Adagio had slightly better resolution and both sounded super clean with good staging, tone, bass, and plenty of drive. If I didn’t already own that preamp, I would have kept the Adagio and been perfectly happy. There is probably "better" in some way but for a simple solution that gets you off the merry-go-round the Adagio should certainly be on your list.

FWIW, Steve Nugent’s well-regarded Empirical Audio DACs also adjust volume by changing the reference voltage. I think there may be at least one more that does that but I cannot remember the name."

@georgehifi "I believe they still do it in their flagship model dacs or cdp. either by user programming or physical links or trimpots.
But Wadia, Mark Levinson and the Bricasti M1 used digital domain remote volume controls, but they also had the ability to set the max output gain of the analogue output buffer, so that you used the digital domain volume at or near full output, so there was no chance of "bit stripping" (lowering resolution 16bit 14bit 12bit the lower you go)
This is the perfect dac /cdp volume control."

@wideload "I’m at a much lower level than you’re looking for but who knows. I was very happy with an Exogal Comet Plus until I heard the Mojo Audio Mystique. No contest. The Mojo has an organic, palpable, engaging presentation that is intoxicating. The Exogal makes lovely sound, The Mojo makes music. Goosebumps."

@nitewulf "I’d highly suggest the Chord Dave or the Metrum Adagio. Conversely, I believe you have the Denafrips Terminator which is a high end dac, perhaps you could add a well regarded passive attenuator between the dac and the amp."
I'll get the Preamplifier list going with an audio friend's recommendation that I consider Dave Slagle's Emia Remote Autoformer.
Let's leave budgetary considerations out of the discussion. All options are welcome.
Hi david_ten,

FWIW, I would vote for a separate DAC and preamp. 

A preamp is really a heart of a system and DAC technology keeps changing.

The ability to keep the preamp that you like and just change the DAC, I think, provides more flexibility. 

Thanks for listening, 

Dsper
@dsper  Thank you. Agreed. It's also the most versatile option and will allow for optimized pairings.
Everyone: Thoughts on Ed Schilling’s The Truth Preamp (from the Horn Shoppe)? The T-3 version is an option.
david_ten,

I have not heard The Truth, but I have recently acquired an Axiom II with the Taylor upgrade. Half the price of the Hornshoppe piece.

The Axiom has been used with about ten CDs so it is not broken in yet. 

It appears a bit bright at this point but is worth listening to further to decide if it will give my Conrad Johnson Premier LS17 - 2 a run for its money.

Thanks for listening,

Dsper
@dsper   I was holding off on updating the thread for another week or two. I wanted to have my system settled, prior to doing so.

In essence, I followed your advice and went with an active preamplifier/linestage.

There were a number of consultations 'behind the scenes' with a number of folks on whether the DAC+Volume Control, Passive Pre, or Active Pre would be a fit. A number of brands and models, of each type, were also discussed and considered.

I came very close to going forward with a Nagra HD DAC (which has a volume control) but the general and specific advice was that it would not be the best fit. That (process) also clarified the reasons and need to eliminate DACs with volume controls. 

Given my experience with driving the 2A3 amps with the T+A Pre-outs, and my future speaker choice (and again after a ton of consultation), passive preamps have also been eliminated.

I settled on going active with sufficient gain. The Robert Koda Takumi K-10 and the Grandinote Genesi were my top choices. The third choice was the CJ GAT 2.

This has been the most exhaustive (and exhausting) and time consuming process for a single component I've personally been through.

I chose to go with the Grandinote Genesi, at this time. 

It is in system, but since it is truly / fully balanced (only) I have a properly configured female XLR to male RCA  IC on order.
@david_ten


 

FWIW its possible to set up an SET to accept and process balanced signals in the differential domain- so no need for an adapter. The mod can be done to any SET and is really quite simple!
Hi david_ten,

You ended up in some rarefied atmosphere🤑!

My sincere hope is that you truly enjoy your choice.

It will be interesting to hear your listening impressions once things meld together a bit.

Thanks for listening,

Dsper
@atmasphere  Thanks, Ralph. How would I go about doing so?
@dsper  Thank you!  I will be sure to update in a few weeks.
Thanks, Ralph. How would I go about doing so?
You could take the amps to any competent technician, have them contact us (651-690-2246) and we can tell them how its done (instructions are below). Otherwise you could also ship it to us.
Any SET has an input tube. Normally the signal comes in on the grid of the tube. This is the center pin of the RCA connection and also pin 2 of the XLR that will have to be installed. Pin 1 of the XLR is the ground of the RCA.


Pin 3 is where its different- that is connected through a coupling cap to the cathode of the input tube. If the tube has a cathode bypass cap, the ground side of the cap is lifted and connected to pin 3 (and when the RCA connector is in use, pin 3 is connected to pin 1 via a jumper you place in the XLR connector). If the amp lacks a cathode bypass cap (which will be an electrolytic), you sort out the value needed and connect it between the cathode of the input tube and pin 3, with the plus side to the cathode.This connection is not balanced, but it **is** differential. The amp’s character doesn’t change, while being able to process both phases of the balanced connection.

Plan B: install an input transformer to make the conversion. At least with our preamps, plan A above sounds better.
@atmasphere  Thank you very much. I'll run it by both the amp's designer and Richard Gray, who is local to me and would do the work.

For clarification, are you saying:

Your Plan A (Post above) is superior to > Plan B (Input transformer) Both of which are superior to > What I am doing with the cable approach (Keeping Pin 3 'Open/Not connected')?

Thank you.
David,
Plan A option  per Atmasphere is a very intriguing proposition 
.Charles 
@david_ten
Your Plan A (Post above) is superior to > Plan B (Input transformer) Both of which are superior to > What I am doing with the cable approach (Keeping Pin 3 'Open/Not connected')?
I've listened all three ways. The transformer has to be pretty good to keep up- it tends to have less bandwidth and detail and this is measurable (at least its bandwidth and distortion is). I prefer to use the signal that is presented by the balanced source- it tends to be more accurate than if you only use one phase as in an adapter. This is probably because the single-ended connection is more susceptible to noise and the like.

I've been running this sort of connection for about 10 years in one of my prototype amps and have modified many amps with this connection since. I first read about it when researching some of the works of George Philbrick, who is often credited (inaccurately, but he was certainly an early pioneer) with building the first opamps, which were vacuum-tube.
Ralph, I will follow through on this. Your guidance is appreciated. Thank you.