Is a preamp needed?

[Novak]

Hi all
I hope this thread find you enjoying some music on your couch!
Well, I am planning to run an X Sabre Pro Mqa directly into a power amp (Purifi 1ET400A) using the X-sabre pro as dac/preamp.
Would there be any advantage having a specific preamp between those two? Like a benchmark la4 for e.g.? Or another well measured product? Aside of performance, do you see any practical advantage?
N. B. I don't use analog sources only digital.

 

[LuckyLuke575]

If the DAC has a pre-amp function, then it would be fine to run it directly to the power amp, and then use it as a digital receiver and volume control to control the power amp.

And yes, I'm enjoying listening to my vinyl copy of Ted Nugent Double Live Gonzo! on the couch right now

 

[Novak]

If the DAC has a pre-amp function, then it would be fine to run it directly to the power amp, and then use it as a digital receiver and volume control to control the power amp.

And yes, I'm enjoying listening to my vinyl copy of Ted Nugent Double Live Gonzo! on the couch right now

Thanks for your reply, I am in the same position but with something more quiet playing,as kids are sleeping

 

[VintageFlanker]

Would there be any advantage having a specific preamp between those two?

None. Most of the time, it is even quite the opposite.
An active electronic gear between would ad noise and distortion (over the stellar X Sabre), not to mention pentionaly mismatch between channels.
Of course, the Benchmark is a State Of the Art product and will be transparent. But since you don't need any analog inputs...
If I was you, I would miss a rotary volume knob and would go for the Element X or M.

 

[Novak]

If I was you, I would miss a rotary volume knob and would go for the Element X or M.

Less is more
Volume range control is important to me. But I leave my boxes on a rack (protection against kids ) and use almost only the remote control. So no need of the knob (nor a streamer), but I fully understand your point.

 

[Berwhale]

I've been thinking about this myself. Is there any risk that the DAC 'forgets' the digital volume level, defaults to 0dB and blows your speakers?

 

[restorer-john]

I've been thinking about this myself. Is there any risk that the DAC 'forgets' the digital volume level, defaults to 0dB and blows your speakers?

I've mentioned this many times for people. Go away for a holiday, come back, sit down to listen to music and your D/A has defaulted to 0dB. Boom! Power cuts can do this also. There's no substitute for a real volume control in my opinion, especially if you have a lot of power on tap and expensive speakers.

 

[VintageFlanker]

I've mentioned this many times for people. Go away for a holiday, come back, sit down to listen to music and your D/A has defaulted to 0dB. Boom! Power cuts can do this also. There's no substitute for a real volume control in my opinion, especially if you have a lot of power on tap and expensive speakers.

Am I the only one...to always check volume before turning on my power amp?!

 

[Berwhale]

I've mentioned this many times for people. Go away for a holiday, come back, sit down to listen to music and your D/A has defaulted to 0dB. Boom! Power cuts can do this also. There's no substitute for a real volume control in my opinion, especially if you have a lot of power on tap and expensive speakers.

Thanks, I guess on the flip side, a physical volume control can also be a liability if you have young children. I've lost count of the times I've had to extract wooden balls out of the bass port in the Yamaha sub in the family room - I blame the shape sorters.

 

[restorer-john]

I've lost count of the times I've had to extract wooden balls out of the bass port in the Yamaha sub in the family room

Just tell them a big snake/rat/weasel (whatever suits) lives in the subwoofer and he doesn't like wooden balls blocking his entrance...

 

[Novak]

I've mentioned this many times for people. Go away for a holiday, come back, sit down to listen to music and your D/A has defaulted to 0dB. Boom! Power cuts can do this also. There's no substitute for a real volume control in my opinion, especially if you have a lot of power on tap and expensive speakers.

That's one of the reason, I was asking this question. Thanks for your relevant remark. But I am surprised that in preamp mode default would be zero. Does anyone know if this is the case with the x sabre pro mqa?

 

[restorer-john]

But I am surprised that in preamp mode default would be zero. Does anyone know if this is the case with the x sabre pro mqa?

Ask X Sabre what it defaults to out of the box or after a hard rest/crash. They may have a better answer for you.

 

[pma]

I agree on the possible issue of the FS level sent to the power amp. However, my main reasons why I use the preamp even if I have the DAC with volume control are:

1) good analog volume control has less distortion for low level set and does not create digital spuriae in spectrum,
2) very good preamp may have lower output noise then digitally controlled DAC volume

ad1) digital volume control reduces resolution, ENOB, and output noise remains same as at 0dBFS
ad2) when DAC sends full volume swing into the preamp, it utilizes its own dynamic range completely. If the preamp has very low output noise, which may be made better than -120dBV, DAC dynamic range is better utilized than with DACs digital volume control. Output of both measured devices was amplified by measuring amplifier with gain of 30dB to see noise, otherwise measuring system would mask it by its own noise.

I understand that not many here have probably had a possibility of own experience to verify this. I am attaching the plot comparing distortion vs. level for DacMagic+ with the digital volume control set to -40dB (red line), vs. DacMagic+ in full volume set and signal going to analog preamp set to -40dB (blue line). The preamp is
http://pmacura.cz/sympre2.htm

The plots clearly show much lower noise with analog volume control. Please note that plots show just noise which is much higher than distortion. And, noise/distortion "hump" of the DAC at low level set?

 

[Novak]

Ask X Sabre what it defaults to out of the box or after a hard rest/crash. They may have a better answer for you.

I just did, I will let you know

 

[Novak]

Just found in user manual that there is a volume memory function.
This basically say that after a restart, if volume was set below zero it will get back to the volume set last time... So no issue if well implemented

 

[Novak]

I agree on the possible issue of the FS level sent to the power amp. However, my main reasons why I use the preamp even if I have the DAC with volume control are:

1) good analog volume control has less distortion for low level set and does not create digital spuriae in spectrum,
2) very good preamp may have lower output noise then digitally controlled DAC volume

ad1) digital volume control reduces resolution, ENOB, and output noise remains same as at 0dBFS
ad2) when DAC sends full volume swing into the preamp, it utilizes its own dynamic range completely. If the preamp has very low output noise, which may be made better than -120dBV, DAC dynamic range is better utilized than with DACs digital volume control. Output of both measured devices was amplified by measuring amplifier with gain of 30dB to see noise, otherwise measuring system would mask it by its own noise.

I understand that not many here have probably had a possibility of own experience to verify this. I am attaching the plot comparing distortion vs. level for DacMagic+ with the digital volume control set to -40dB (red line), vs. DacMagic+ in full volume set and signal going to analog preamp set to -40dB (blue line). The preamp is
http://pmacura.cz/sympre2.htm

The plots clearly show much lower noise with analog volume control. Please note that plots show just noise which is much higher than distortion. And, noise/distortion "hump" of the DAC at low level set?

View attachment 40823

Thanks for this very valuable feedback.
I don't know dac magic+ but can it compare to x sabre pro mqa? Do you think the same kind of behavior can be expected?

 

[Rja4000]

I agree on the possible issue of the FS level sent to the power amp. However, my main reasons why I use the preamp even if I have the DAC with volume control are:

1) good analog volume control has less distortion for low level set and does not create digital spuriae in spectrum,
2) very good preamp may have lower output noise then digitally controlled DAC volume

ad1) digital volume control reduces resolution, ENOB, and output noise remains same as at 0dBFS
ad2) when DAC sends full volume swing into the preamp, it utilizes its own dynamic range completely. If the preamp has very low output noise, which may be made better than -120dBV, DAC dynamic range is better utilized than with DACs digital volume control. Output of both measured devices was amplified by measuring amplifier with gain of 30dB to see noise, otherwise measuring system would mask it by its own noise.

I understand that not many here have probably had a possibility of own experience to verify this. I am attaching the plot comparing distortion vs. level for DacMagic+ with the digital volume control set to -40dB (red line), vs. DacMagic+ in full volume set and signal going to analog preamp set to -40dB (blue line). The preamp is
http://pmacura.cz/sympre2.htm

The plots clearly show much lower noise with analog volume control. Please note that plots show just noise which is much higher than distortion. And, noise/distortion "hump" of the DAC at low level set?

View attachment 40823

Yes, but you need a really good quality preamp to beat some of the best DACs out there.
Not the first lambda low cost one.

 

[Soniclife]

Thanks, I guess on the flip side, a physical volume control can also be a liability if you have young children.

Physical controls can also be easily knocked whilst the system if off, e.g. when cleaning. There isn't a perfect solution, unless the digital system implements well thought through safe guards.

 

[Soniclife]

Just found in user manual that there is a volume memory function.
This basically say that after a restart, if volume was set below zero it will get back to the volume set last time... So no issue if well implemented

Worth testing if you buy it. Sounds like the correct solution.

 

[Novak]

Worth testing if you buy it. Sounds like the correct solution.

Yes agreed, sounds like the solution.
But let's say, I want a preamp with a knob. What to go for? Apart from the benchmark la4 (which is not that cheap), I have not noticed so many well measured preamp. Any thought?