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DAC as preamp

I have been pre-ampless for several years with no issues.

But I always triple check my volume is at zero before powering up the amp (the DAC uses an LED that changes colour to indicate relative volume which to these old eyes is hard to see).

The DAC has two features that negate digital volume decimation, which is the major concern when using a DAC as a pre-amp:

(1) - the internals run at 32 bit, which provides 48db of attenuation (6db per bit) before you affect 24bit music data
(2) - 4 levels of output attenuation so you can match that to your power amp and keep digital attenuation in the right range


If you have lots of 24bit music then at least check that if the DAC under consideration does digital attenuation, it does this internally at the 32bit level.

If your 16bit CD music only, then 24bit internals will be ok given you will have 48db of attenuation before issues arise (which is bascially any modern DAC) BUT if the DAC outputs lots of juice you might ride close to this so having output attenuation is a plus.

Peter
 
I'm considering setting up another room for music, and due to left-over components available, might have a power amp I can use and a Raspberry Pi, but no preamp.

I was idly musing about buying a DAC for this system that would handle preamp duties also. I believe the RME ADI-2 FS can do this, and also the Matrix Mini I Pro 3, and the Topping D90. Any others at a similar price point?

I'd be really interested to hear from anyone who does this. In particular, my concern is that if for some reason the digital gubbins decides to go for max volume, I could get a terrible shock (unlikely with an analogue potentiometer). Also, presumably the attenuation is occurring in the digital domain, so are you sacrificing quality at lower volumes?

Anyway, definitely interested to hear any real world experience.


I've been running various RPi combos with active and passive pre-amps (with or without DACs in the chain) into a Quad 405-2 for a number of years and the common problem with all of them is the sensitivity of the Quad power amps from that era. In a nutshell, they are easily swamped by modern outputs and finding a solution that allows a decent bit of control via the volume knob becomes a goal in and of itself - let alone judging the quality of the sound that comes out of it.

If you are running the RPi with an analogue output of whatever kind then any reasonable quality passive will do - I have had very decent results with a 10k Alps blue as a simple 'pot-in-a-box' solution that gave me at least a little bit of volume travel to play with. In fact this more than adequately replaced the active pre-amps I had used at times before (Quads 33 and 34)

I have also used RPi sets with digital out to a number of DAC/preamp combos although I found those that relied on digital attenuation to be the least successful (particularly an Audiolab Q DAC I had)

Currently I have also been toying with buying one of the RME ADIs - preferring the one without the screen and equaliser though:

https://www.thomann.de/gb/rme_adi_2_fs.htm

The key difference for me is that this model also has analogue inputs - the dearer one doesn't :(
 
In particular, my concern is that if for some reason the digital gubbins decides to go for max volume, I could get a terrible shock (unlikely with an analogue potentiometer).

I think the chances of that happening are pretty remote, so I wouldn’t worry. Unless you sit on the remote control and don’t realise why your hifi is getting loud, or unmute the DAC after having it very loud, or pull a cable out - but these are things that could happen with an analogue pre as well. Some folk like to use their software player to control volume and have their DAC at 100% or use a DAC with no volume control. They are but one accidental touch of the volume bar on a phone app away from catastrophe. But if your DAC has its own volume control there is nothing to worry about.
 
Mytek Manhattan II here too, but if you just want digital, the RME is excellent and a lot cheaper (but no analogue preamp section). I have used two Mytek DACs and the RME without any additional preamp and have never had any "unfortunate" incidents. I did and still use the analogue volume controls in the Myteks, however (but these are electronically controlled). The RME has a hybrid analogue/digital volume control, which behaved faultlessly .
 
I use my Benchmark DAC2 HGC as a pre-amp. It has 5 digital inputs, 2 analogue ones, remote volume control and a pair of headphone outlets. Very comprehensive manual. I prefer it as a pre-amp than just using it as a DAC into my existing pre-amp. There are a number of DAC2's and the previous DAC1 available on the second hand market at sensible prices.
 
This is not quite the same but I use a Topping E30/L30 DAC/HeadphoneAmp combo with their dinky little phono connectors and custom stand. The L30 acts as a (good) headphone amp for the dac(also good) but also a pass through pre-amp w/physical volume control to my NAP140 power amp - I have great confidence in the volume control which gives a fine and continuous analogue control.
I get more than acceptable results with this setup. IMO better than if I incorporate the NAC62 pre-amp which adds in another set of switches, volume control and noise.
The L30 has physical switches and a nice -9db/0db/+9db switchable gain. I have other schemes for having more input sources e.g. I have already added a turntable.
This E30/L30 replaces an Aune X1s - which I have passed on but did similar tricks and if anything was even more versatile.
 
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Mytek Manhattan II here too, but if you just want digital, the RME is excellent and a lot cheaper (but no analogue preamp section). I have used two Mytek DACs and the RME without any additional preamp and have never had any "unfortunate" incidents. I did and still use the analogue volume controls in the Myteks, however (but these are electronically controlled). The RME has a hybrid analogue/digital volume control, which behaved faultlessly .

I had it happen with a Brooklyn running as a preamp. I don’t know what setting I accidentally pushed, but I got Max volume for a second. My heart stopped but my drivers somehow survived

I’ve used the Project S2 Digital prebox too. It’s fine as a preamp, but I knew it wasn’t a keeper in that spot. I like it a lot as a DAC, though. I just thought it was a little sterile as a pre.
 
I had it happen with a Brooklyn running as a preamp. I don’t know what setting I accidentally pushed, but I got Max volume for a second. My heart stopped but my drivers somehow survived

I’ve used the Project S2 Digital prebox too. It’s fine as a preamp, but I knew it wasn’t a keeper in that spot. I like it a lot as a DAC, though. I just thought it was a little sterile as a pre.

Oof, nightmare! That's what I'm afraid of. It's looking like the little Tisbury is coming out of retirement then.
 
I had it happen with a Brooklyn running as a preamp. I don’t know what setting I accidentally pushed, but I got Max volume for a second. My heart stopped but my drivers somehow survived

I’ve used the Project S2 Digital prebox too. It’s fine as a preamp, but I knew it wasn’t a keeper in that spot. I like it a lot as a DAC, though. I just thought it was a little sterile as a pre.
Thought I would try my schiit eitr into dac magic using the balanced cables to amp from dac..full volume for one second too..leema speakers survived! Lol...I might bring the dac magic back into the main kit using the eitr as the spdif/ usb converter...just to see how good it actually is? I took it out of my main kit years ago before I streamed music and before I realised what a difference a spdif/ usb converter can make..
 
I had it happen with a Brooklyn running as a preamp. I don’t know what setting I accidentally pushed, but I got Max volume for a second. My heart stopped but my drivers somehow survived

I’ve used the Project S2 Digital prebox too. It’s fine as a preamp, but I knew it wasn’t a keeper in that spot. I like it a lot as a DAC, though. I just thought it was a little sterile as a pre.

I have a Brooklyn and a Manhattan ii. You can set both to bypass the volume controls and give an unattenuated output, for use with a separate preamp or integrated amp. However, it take a series of button pushes to achieve this and it is virtually impossible to do it by accident. Obviously it can be done, but the displays (especially on the Manhattan) very clearly show what is going on. I have never done this by accident and I suspect that the probability of it happening by mistake is lower than that of inadvertently leaving the volume control on a separate preamp at max, or sufficiently high to drive the power amps into clipping.

However, it is possible to inadvertently push the volume increase button on the remote and send it to maximum (by sitting on it for example!) when nothing is playing and then to be startled by the ensuing full output when pressing play, but the same applies to any preamp with a remote control!
 
I would add that I have been running both Myteks for years without mishap. They certainly do not suddenly decide, on a whim, to go to max volume!
 


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