DS DAC Amp matching question


#21

I have the same problem when the DS is connected directly to the Amp using balanced connection. I tried four different Amps (Pass Labs, Hypex nc500 based, Symphonic Line, Merrill Veritas) and the result it same. Even when the DS volume is 0, I can hear it from 5ft distance at night. The only way the noise is reduced is the DS is put in a standby mode. I thought that its how things are but since now many are reporting it, I wonder why isn’t everyone seeing the same problem.


#22

Dev, I could be wrong, but … If you are hearing noise with the DS at zero volume then I think you have some sort of problem other than a gain mismatch. If it’s hum then a ground loop is likely, if it is hash/static/white noise then might be some RFI leaking in.


#23
Fmaspero said Hi, I just bought a Directstream Junior dac to use directly feeding mi Parasound jc1's amps. Connected directly through the amps I have a lot of noise through the tweeters, even when the dac has the volume ser to 0. I tried connecting the dac to a preamp and the noise lowers significantly, even it is not dead quiet as I would expect. My speakers are Paradigm Signature S8, which are very sensible, but tried with dynaudio speakers which aren't and have the same problem if running the dac directly to the amps. I wonder if this could be some mismatch between my amps and the Directstream Junior, so I would appreciate Eldrick any information regarding how does the same match sounds in your case. Thanks in advance
I seem to have exactly the same problem with my setup -pretty perceivable noise even at 0.

Federico -I have pretty different equipment from yours, if you want to stop by and check maybe we can find out what is it about the DSJ that is doing this to either system. Just let me know via PM.


#24
Dev said I have the same problem when the DS is connected directly to the Amp using balanced connected. I tried four different Amps (Pass Lans, Hypex nc500 based, Symphonic Line, Merrill Veritas) and the result it same. Even when the DS volume is 0, I can hear it from 5ft distance at night. The only way the noise is reduced is the DS is put in a standby mode. I thought that its how things are but since now many are reporting it, I wonder why isn't everyone seeing the same problem.
Hi Dev,

If you go RCA as opposed to balanced do you get the same result?

To me this is the one thing about the Junior that I’m finding increasingly frustrating.

Cheers

Fernando


#25

I know all to well how frustrating “noise” can be.

My horn speakers are 107dB sensitive and any little annoyance can be amplified quite readily.

But there is noise and then there is unacceptable noise.

A good example are the Classic Audio speakers that use field coil drivers.

At idle with no music playing you can hear noise, but from the first note of music played, that all goes away and the sound is glorious.

I have to ask if all of your electronics are on the same leg of your power ? ( if you are in the US )

Have you checked for difference of potential across all of your electronics ? ( that neutral and ground are not reversed, if in the US )

Last but not least, is everything PROPERLY grounded, not lifted or bypassed or run to another ground potential.

If you just have a bit of hiss when idle and the music still sounds dynamic, just listen, why worry, be happy!


#26

Hi Mr Derrick,

No unfortunately it’s not just a little bit of noise -it’s unacceptable noise and at night if you are trying to listen to low levels in order to not disturb the Missus, sometimes it just makes no sense to keep listening as the noise overtakes the voices :frowning:

I’ll look into the rest of stuff you kindly enumerated though. Interesting stuff that f.i. neither Mr fmaspero nor myself are in the US, in fact I believe we are both same country, same town really (!) so maybe there is something local going on, I don’t know.


#27

BTW my speakers aren’t that sensitive at all:

88dB spl (2.83V, 1m)

I wonder where the problem really lies. If it’s got to do with a certain lack of DSJ - power amp “affinity”, or radio frequence or ground loop interference, or just something inherently defective on this model, or our units (the 4 of us) in particular.

Real pity because I just love my DSJ -best dac I’ve ever had.


#28

I need to be careful here - I don’t intend to cast aspersions on any given piece of hardware.

The DS is different than most DACs - this has some benefits and some tradeoffs:

The single bit DSD output makes for a more linear DAC with the possibility of better time domain performance than other designs.

But it also involves a tradeoff that produces more ultrasonic energy than PCM or multibit DSD designs (e.g. DACs that are implemented on a chip.) The DS was designed to have less ultrasonic energy than the spec that SACD players are designed to. (i.e. that the ultrasonic energy is below -40dBFS - less than 1% of what it could be.

Still many preamps and or amps weren’t designed with SACD in mind let alone the DS in particular in mind.

Anytime a device is used in a new manner, a manner that it wasn’t explicitly designed to deal with there’s a chance for unforeseen consequences.

A simple example is that the VU meter on many preamps and amps is obviously wrong with SACD and/or the DS as an input. A VU meter is supposed to be a good indication of audio loudness, but if the VU meter pays attention to peaks instead of average weighted energy over the audio band or it pays attention to energy outside of the audio band it will be measuring something else than most of us expect. That doesn’t mean it was badly designed, but instead that it was designed for a purpose other than it’s being used for.

In any case, the tradeoff with the DS is that letting more ultrasonic energy thru makes the DS sound better for the vast majority of people, but it doesn’t sound better for everyone. Some amps/preamps and other components don’t react well to ultrasonic energy - they may fold some of it into the audio spectrum, it may cause some of them to clip in unexpected places in their circuits, … I could go on. But the point isn’t that those devices are badly designed, but instead that they weren’t designed for the DS and that the DS wasn’t designed for them.

I wish we could have a simple answer. Some of the early SACD players have a bandwidth switch which adds a, say, 50kHz low pass filter to the output to work with the systems that are sensitive to ultrasonic energy. Some other more consumer grade players simply always filter at, say, 50kHz.

In general adding optional signal paths to audio equipment degrades the audio output, sometime a lot and other times barely. In the DS’s case perhaps with 20-20 hindsight we should have added another optional filter for the systems that don’t react well to that ultrasonic noise.


#29

pmotz - no, its not a ground loop 60Hz hum. I know that sound very well since I have the problem with my HT setup. The noise is kind of loud hiss or similar to a noisy tube rush but louder in decibel. I use a Cary slp-05 preamp which has 3 pairs of 6SN7 and when connected to any of the Amps the hiss from the tweeter is normal (my tubes are quiet).

@EfeTe - I have to experiment on the single ended connection. I don’t have any RCA interconnects at the moment but could probably get some xlr to rca adapters and try it out but I doubt it will help based on Ted explanation.

I think Ted explained it well as being the ultrasonic energy and how it can effect the output, if things weren’t designed the way it is supposed to be used.

Ted, maybe a blunt question but is the addition of 50KHz low pass filter needs to be a hardware change in the DS or DS Jr ? Cannot it be handled in the fpga itself ?


#30

Ted, your intervention here is very much appreciated indeed.

Just to illustrate my case in particular, DSJ officiates both as preamp / dac in my system. No separate preamp component and no extra “body” being added to the signal path.

I know you would not “name names” as in mention models for brands other than PS Audio. But in my case do you see maybe the MC-152 (or its interaction with the DSJ) being the “culprit” here?

Noise is not unbareable or anything. But you can sense it, it’s not really subtle and it’s present basically every instant the DSJ is on. F.i. when the power amp is on but the Junior is not I don’t get it. And it seems to emanate from the right speaker (!) more, or at a louder volume, than that of from the left.

Odd -very odd actually. It does not detract from how I love how the thing sounds, how Torreys’s been voiced etc. That I absolutely love. But this noise can get significantly annoying and I wish there was something I could do to at least mitigate it. Will try with the -20 db alternative, and with RCA interconnects instead of the balanced I am currently using. Who knows something might change…


#31

Ted, is the ultrasonic noise an ever present thing, irrespective of volume level? A coupe of them said it was present even with volume at zero. I haven’t had the problem these folks talk of, but then my hearing is not so great anymore. frown Sure seems odd how many different amps/preamps these folks have tried and they still have the noise.


#32
Dev said pmotz - no, its not a ground loop 60Hz hum. I know that sound very well since I have the problem with my HT setup. The noise is kind of loud hiss or similar to a noisy tube rush but louder in decibel. I use a Cary slp-05 preamp which has 3 pairs of 6SN7 and when connected to any of the Amps the hiss from the tweeter is normal (my tubes are quiet).
Dev, what is the rest of your system and which 6SN7 tubes are you using with the Cary SLP 05?

Thanks


#33
Dev said Ted, maybe a blunt question but is the addition of 50KHz low pass filter needs to be a hardware change in the DS or DS Jr ? Cannot it be handled in the fpga itself ?
The FPGA software can do a little lowering of the ultrasonic noise, I'll consider if it can be used to ameliorate this problem. But adding a relay and a filter to the output of the DS is the minimum required change in hardware and that isn't likely to happen in the near future.
EfeTe said I know you would not "name names" as in mention models for brands other than PS Audio. But in my case do you see maybe the MC-152 (or its interaction with the DSJ) being the "culprit" here?

Noise is not unbareable or anything. But you can sense it, it’s not really subtle and it’s present basically every instant the DSJ is on. F.i. when the power amp is on but the Junior is not I don’t get it. And it seems to emanate from the right speaker (!) more, or at a louder volume, than that of from the left.

Odd -very odd actually. It does not detract from how I love how the thing sounds, how Torreys’s been voiced etc. That I absolutely love. But this noise can get significantly annoying and I wish there was something I could do to at least mitigate it. Will try with the -20 db alternative, and with RCA interconnects instead of the balanced I am currently using. Who knows something might change…

One of the possibilities is certainly that the DS and the MC-152 don't play well together, but it also could be that the speakers in question can't deal with too much ultrasonic energy. Some active crossovers may have a problem and some tweeters may have a problem. Also some speakers are so sensitive that the non-ultrasonic noise of the DS may be audible. A third possibility is that with the DS (but not the DS Jr) very capacitive cables can raise the level of ultrasonic noise. I don't know of any specific cases of this, but it's possible.

My (very limited) personal experience with Mac amps is that the DS sounded very ragged bypassing the preamp section of an integrated Mac amp in a local store (We were using Martin Logan speakers.) Using the Mac’s preamp made a big positive difference (actually as I think about it I don’t remember for sure which was the best: thru the preamp or direct to the amp. But there was a huge difference, from not wanting to listen at all to a very enjoyable listening session.)

Does the louder noise change to the other speaker when you reverse the output of the DSJr?

Another possibility is to get some reasonable quality in-line attenuators, say 10 or 12 dB to sort of meet in the middle between using the 20dB attenuator and not. If you are handy with a soldering iron you can build your own with a resistor or two. See: http://www.psaudio.com/forum/directstream-all-about-it/directstream-dac-output-level/#p50640

pmotz said Ted, is the ultrasonic noise an ever present thing, irrespective of volume level? A coupe of them said it was present even with volume at zero. I haven't had the problem these folks talk of, but then my hearing is not so great anymore. frown Sure seems odd how many different amps/preamps these folks have tried and they still have the noise.
The ultrasonic noise is essentially constant no matter what the volume level. As I mention above instead of the amp or preamp it might be sensitive speakers (or speakers that really don't like too much ultrasonic noise.) Some preamps may actually make things better by simply filtering out some of the ultrasonic noise. With the DS (but not the DS Jr) very capacitive cables can raise the level of ultrasonic noise.

#34
yacheah said
Dev said pmotz - no, its not a ground loop 60Hz hum. I know that sound very well since I have the problem with my HT setup. The noise is kind of loud hiss or similar to a noisy tube rush but louder in decibel. I use a Cary slp-05 preamp which has 3 pairs of 6SN7 and when connected to any of the Amps the hiss from the tweeter is normal (my tubes are quiet).
Dev, what is the rest of your system and which 6SN7 tubes are you using with the Cary SLP 05?

Thanks

I am using Sofia electric. Have also used variety of NOS in the past but the tube rush isn’t bad as when the DS connected directly. My speakers are only at 90db.


#35

Thanks Ted and everyone for chiming in.

Will try a couple of things when I get back (I’ve got a trip for the duration of the month), what is clear is that if it’s the B&W’s it’s not because due to sensitivity issues (88 is not a whole lot), but maybe what you Ted said about them reacting to ultrasonic noise.

Just finished the acoustic treatment of my little room, everything looked really promising but then again with all the absorption, isolation and stuff it could well be that this hum has become so much more apparent for just that. :frowning:


#36
Dev said
I am using Sofia electric. Have also used variety of NOS in the past but the tube rush isn't bad as when the DS connected directly. My speakers are only at 90db.
What power amp and speakers are you using?

Thanks


#37
yacheah said
Dev said
I am using Sofia electric. Have also used variety of NOS in the past but the tube rush isn't bad as when the DS connected directly. My speakers are only at 90db.

What power amp and speakers are you using?

Thanks


power amps - Pass Labs, Nord One; Speaker - Acoustic Zen Crescendo MkII

#38
Dev said
power amps - Pass Labs, Nord One; Speaker - Acoustic Zen Crescendo MkII
That's such a coincidence. Which Pass?

I’m using a X 350.8 with a Cary SLP 05 too. Vienna Acoustics The Kiss speakers.

Overall, what sort of sound are you getting out of the DS with this pairing?


#39
yacheah said
Dev said
power amps - Pass Labs, Nord One; Speaker - Acoustic Zen Crescendo MkII

That’s such a coincidence. Which Pass?

I’m using a X 350.8 with a Cary SLP 05 too. Vienna Acoustics The Kiss speakers.

Overall, what sort of sound are you getting out of the DS with this pairing?


X 250.5. They sound very good to me :slight_smile:

#40

Ted Smith said
One of the possibilities is certainly that the DS and the MC-152 don’t play well together, but it also could be that the speakers in question can’t deal with too much ultrasonic energy. Some active crossovers may have a problem and some tweeters may have a problem. Also some speakers are so sensitive that the non-ultrasonic noise of the DS may be audible. A third possibility is that with the DS (but not the DS Jr) very capacitive cables can raise the level of ultrasonic noise. I don’t know of any specific cases of this, but it’s possible.

My (very limited) personal experience with Mac amps is that the DS sounded very ragged bypassing the preamp section of an integrated Mac amp in a local store (We were using Martin Logan speakers.) Using the Mac’s preamp made a big positive difference (actually as I think about it I don’t remember for sure which was the best: thru the preamp or direct to the amp. But there was a huge difference, from not wanting to listen at all to a very enjoyable listening session.)

The ultrasonic noise is essentially constant no matter what the volume level. As I mention above instead of the amp or preamp it might be sensitive speakers (or speakers that really don't like too much ultrasonic noise.) Some preamps may actually make things better by simply filtering out some of the ultrasonic noise. With the DS (but not the DS Jr) very capacitive cables can raise the level of ultrasonic noise.
Hi Ted, your experience with DS/integrated Mac amp is exactly what I am currently experiencing with my DSJ/integrated Luxman amp. The sound from bypassing the preamp section was not bad, the issues I think mostly came from raided background noise. The raised noise level can be clearly heard from the listening position, the needle on the dB meter jumped from -64 when the preamp was in to -60 to -48 when the preamp was bypassed, when DSJ attenuater was on, the needle was at around -55. The raised noise level will only go back down to -64 when the DSJ was totally turned off, not by putting it in standby or mute.Therefore, I am listening with the preamp in.

Fred