When I am guilty of the one thing I chastise others the most on, gain staging.

[Gazdatronik]

I have been battling a odd problem with my system. Strange distortion behavior on certain high bandwidth tracks.

I also run mixing boards for bands and churches, and nothing gets my goat as much as improper gain staging, seeing the trims set randomly and the sliders having unequal control.

However, upon swapping my amplifier with one more powerful and better suited to my speakers with very aggressive impedance curves, I found my problem still existed. I should have known the signal going into my preamp was too hot as one volume click was generally more than enough for quiet listening off of my computer, dramatically louder than the phono input.

My olde soundcards were easy to stage. With the volume set to max, it was true 0db. But the computer I use the most now is not like that at all. I finally plugged the soundcard output into the hardware mixer to use the meters to see what it was doing, and sure enough, an A440 0db test tone at full soundcard volume comes out of the computer at +10db gain. I set it to 50%, like some new computers require you do, and it dropped dead on to 0db.

The APT preamp is good to 2.0V input headroom (i think), so it never really complained too much, but when that headroom is exceeded the mains start snapping and popping like the amp is going into DC. This effect was most pronounced in the imho badly recorded Bladerunner 2049 soundtrack, which has so much digital distortion on some of the tracks that stuff sounded like a bowl of rice krispies. The hard limiter was working overtime on that production for sure.

So for those of you who use the on board cards on your stuff, if you haven't done so, you owe it to yourself to see how hot the output is. Its not a standard. Now the sound is clean and I get to use more of my volume knob, which is nice too.

 

[xero-D-hero]

My NAD 106 preamp is rated to handle a max input signal of >10V so it usually does'nt complain what's feeding it.
Beside the PC's SB Zx soundcard is actually feeding into a Parasound D/AC-1000 anyways.
That DAC only throws out 2V nominal to the NAD 106 so everything is very happy in that rig.
Volume for the PC is set to 100%.

But yeah I'm sure there are plenty of other rigs that run into trouble with that sorta thing.

My other rigs seem ok at the moment.but I'm sure the inputs on those rigs are'nt quite as forgiving as that NAD 106 preamp's inputs are.
Though I have a second NAD 106 just in case I ever need it...

Good tip for folks to keep in mind though.

FWIW

Bret P.

 

[Gazdatronik]

My NAD 106 preamp is rated to handle a max input signal of >10V so it usually does'nt complain what's feeding it.
Beside the PC's SB Zx soundcard is actually feeding into a Parasound D/AC-1000 anyways.
That DAC only throws out 2V nominal to the NAD 106 so everything is very happy in that rig.
Volume for the PC is set to 100%.

But yeah I'm sure there are plenty of other rigs that run into trouble with that sorta thing.

My other rigs seem ok at the moment.but I'm sure the inputs on those rigs are'nt quite as forgiving as that NAD 106 preamp's inputs are.
Though I have a second NAD 106 just in case I ever need it...

Good tip for folks to keep in mind though.

FWIW

Bret P.

Now that you mention it, it did sound a little off. I had to re-read the spec sheet, its not 2 but 7 volts, with a 7 volt maximum on the output.
Not sure what the input buffer on the amp itself is rated for but something along the path sure hated it. Now, this would only happen listening to extreme music at higher volumes. Most of the time it was all good.

Yes, with a dedicated DAC its not as much of an issue. With computer soundcards, they are designed to easily drive a pair of 32 ohm headphones, which might be too much.

Another thing, the fletcher munson curve would be more extreme at the beginning of the volume knob. Meaning bass and treble has been artificially boosted more than it should have been all this time.

 

[xero-D-hero]

Funny thing,the analog outs on my SB Zx wound up falling short once I really started leaning on it harder.

That came around when I was going thru my "high impedance headphone phase" (I discovered AKG's to be precise).
The SB Zx soundcard can drive the 600 ohm AKG's via it's ACM,but the volume needed to be near max to get useable listening levels outta those cans.
So I began to explore my options with that situation,,,that of course led to a short voyage down one of many audio "rabbit-holes"...

So I got that NAD preamp and hooked it up directly to the SB Zx analog outs.
And all of a sudden I was hearing all sorts of digital hash I was'nt hearing before (a real WTF moment...).
The inputs on that NAD were obviously more sensitive,and the headphone amp significantly more powerful (> 8V into 600ohms IIRC).
It must've been amplifying what I could'nt hear before with the lesser output from just the SB Zx soundcard.

So that lead to a DAC experiment.
First tried a Fiio D3 just to see if the optical out would isolate the digital hash confirming it was likely USB or PSU noise.
And just like that it was GONE,well that was fortunate enough,but a weird thing also happened,it actually sounded better as well.
Well,that lead me to the "Hey maybe there IS something about all that DAC non-sense all those other folks talk about" realization.
So that was followed by MUCH studying,and of course some further experimentation.

Next was a Schiit Modi optical.
When I got that it was already a bit dated,but funtional enough for my needs.
The "test" was to see if it sounded noticably better than the Fiio D3 did.
Wll it did,but it was'nt as night & day as the Fiio D3 vs. the analog outs of the SB Zx.

But knowing that it was'nt "al that" as far as DACs go it still made it clear that there were indeed gains to be found in terms of SQ.

So then that Parasound D/AC-1000 was obtained and I put that DAC into the chain.
And that was the end of the whole process,audio nirvana was found,search over.

The Modi optical was moved to my BR 2.1 system where it's hanging in the nicely to this day.
I dont really need/want a highly revealing DAC in that rig anyways.
But the headphone/nearfield rig is pretty much my reference system at this point.
So it only stands to reason that it should be my best sounding rig.

And it IS my best souding rig at the moment.

It's also why I currently have 2x of each of those pieces (NAD 106 & Parasound D/AC-1000).
And anytime I have the money and I run across more of 'em I'll likely buy 'em w/o giving it a second thought.
For the money they typically go for they're absolute bargains in terms of the SQ they achieve.

Problem is if I keep making posts like this I'm gonna be letting the cat outta the bag on that deal.

So I digress.

Bret P.

 

[Gazdatronik]

Funny thing,the analog outs on my SB Zx wound up falling short once I really started leaning on it harder.

That came around when I was going thru my "high impedance headphone phase" (I discovered AKG's to be precise).
The SB Zx soundcard can drive the 600 ohm AKG's via it's ACM,but the volume needed to be near max to get useable listening levels outta those cans.
So I began to explore my options with that situation,,,that of course led to a short voyage down one of many audio "rabbit-holes"...

So I got that NAD preamp and hooked it up directly to the SB Zx analog outs.
And all of a sudden I was hearing all sorts of digital hash I was'nt hearing before (a real WTF moment...).
The inputs on that NAD were obviously more sensitive,and the headphone amp significantly more powerful (> 8V into 600ohms IIRC).
It must've been amplifying what I could'nt hear before with the lesser output from just the SB Zx soundcard.

So that lead to a DAC experiment.
First tried a Fiio D3 just to see if the optical out would isolate the digital hash confirming it was likely USB or PSU noise.
And just like that it was GONE,well that was fortunate enough,but a weird thing also happened,it actually sounded better as well.
Well,that lead me to the "Hey maybe there IS something about all that DAC non-sense all those other folks talk about" realization.
So that was followed by MUCH studying,and of course some further experimentation.

Next was a Schiit Modi optical.
When I got that it was already a bit dated,but funtional enough for my needs.
The "test" was to see if it sounded noticably better than the Fiio D3 did.
Wll it did,but it was'nt as night & day as the Fiio D3 vs. the analog outs of the SB Zx.

But knowing that it was'nt "al that" as far as DACs go it still made it clear that there were indeed gains to be found in terms of SQ.

So then that Parasound D/AC-1000 was obtained and I put that DAC into the chain.
And that was the end of the whole process,audio nirvana was found,search over.

The Modi optical was moved to my BR 2.1 system where it's hanging in the nicely to this day.
I dont really need/want a highly revealing DAC in that rig anyways.
But the headphone/nearfield rig is pretty much my reference system at this point.
So it only stands to reason that it should be my best sounding rig.

And it IS my best souding rig at the moment.

It's also why I currently have 2x of each of those pieces (NAD 106 & Parasound D/AC-1000).
And anytime I have the money and I run across more of 'em I'll likely buy 'em w/o giving it a second thought.
For the money they typically go for they're absolute bargains in terms of the SQ they achieve.

Problem is if I keep making posts like this I'm gonna be letting the cat outta the bag on that deal.

So I digress.

Bret P.

When you have an outboard DAC you have the option for much nicer power supplies than the ones in the computer, course there is no fast rule there, some computers I have had are silent. Other cheapies, with the nasty Realtek integrated cards were so bad that you couldn't even move the mouse.

The coaxial inputs on your DACs should work ok, good ones will have the Coax signal pass through an optoisolator before its processed, and even if it isn't, the digitial ground of the DAC should be separate from the analog ground of the audio outputs.

I have heard that the coax is the better way to pass signal, not sure I remember why, either timing or dropout issues, but you might stand to gain a bit if you have that option to try coax out.

 

[xero-D-hero]

Ask me and I'll say that people debate the whole coax vs. optical deal waaayyy more than it deserves to be. JMO ~ YMMV
I've had ZERO problems with optical,and it's been absolutely dead quiet in my system.

With redbook (16/44.1) I have'nt noticed any issues using optical,and I ONLY listen to redbook.
Now for those into high res material,yeah sure that deal may be another situation entirely.

I've often stated that this rig is "A bottomless pit of blackness" and I stand by that statement 100%.
That's this rigs greatest success.

The intent for this system was for low level critical listening,and it excels at that task largely due to that dead quiet background.
The speakers no doubt help there,they are Canton GL-260 supported by a Canton AS85-SC subwoofer.
And IMHO using the XLR outs from the NAD to the EV 7100 amp helps that situation as well.

And if there is any jitter / glare / yadda ~ yadda ~ yadda it's well outta the audible spectrum in this rig.
So why would I try to "fix" what is'nt even noticably broken ???

And no doubt the power supply scheme in the DAC is far superior to the PC & SB Zx.
The D/AC-1000 has three power supplies,one for the digital side,and one each for the analog L/R outputs (so yeah 3x PS).
Not to mention a whole slew of black gate caps to boot.

I had considered using some active monitors for this rig,hence the NAD preamp having both SE and XLR outs.
But I dismissed that idea as a lot of active monitors will have a very faint low level hiss when not passing a signal.
And I did'nt want that hiss.

So I researched power amps looking for those that excelled in a studio type environment.
Hence why I landed on that EV 7100 power amp,it's a great little (1ru) amp,it's built like a tank that's for sure.

I'm sure there are areas that I could "improve" this rig,but to be completely honest I see no need to do so at this time.
Maybe someday if something needs attention I'll consider doing so,but I'd so with caution as I'd hate to make a backward step.

FWIW

Bret P.

 

[Gazdatronik]

Ask me and I'll say that people debate the whole coax vs. optical deal waaayyy more than it deserves to be. JMO ~ YMMV
I've had ZERO problems with optical,and it's been absolutely dead quiet in my system.

With redbook (16/44.1) I have'nt noticed any issues using optical,and I ONLY listen to redbook.
Now for those into high res material,yeah sure that deal may be another situation entirely.

I've often stated that this rig is "A bottomless pit of blackness" and I stand by that statement 100%.
That's this rigs greatest success.

The intent for this system was for low level critical listening,and it excels at that task largely due to that dead quiet background.
The speakers no doubt help there,they are Canton GL-260 supported by a Canton AS85-SC subwoofer.
And IMHO using the XLR outs from the NAD to the EV 7100 amp helps that situation as well.

And if there is any jitter / glare / yadda ~ yadda ~ yadda it's well outta the audible spectrum in this rig.
So why would I try to "fix" what is'nt even noticably broken ???

And no doubt the power supply scheme in the DAC is far superior to the PC & SB Zx.
The D/AC-1000 has three power supplies,one for the digital side,and one each for the analog L/R outputs (so yeah 3x PS).
Not to mention a whole slew of black gate caps to boot.

I had considered using some active monitors for this rig,hence the NAD preamp having both SE and XLR outs.
But I dismissed that idea as a lot of active monitors will have a very faint low level hiss when not passing a signal.
And I did'nt want that hiss.

So I researched power amps looking for those that excelled in a studio type environment.
Hence why I landed on that EV 7100 power amp,it's a great little (1ru) amp,it's built like a tank that's for sure.

I'm sure there are areas that I could "improve" this rig,but to be completely honest I see no need to do so at this time.
Maybe someday if something needs attention I'll consider doing so,but I'd so with caution as I'd hate to make a backward step.

FWIW

Bret P.

I had a 7100! My first pro amp, I bought one at a local music store when I had to power an 18" Peavey Black widow in a cabinet the size of a refrigerator I found at a yard sale. It worked great in bridge mode to push it.

I later used it in stereo to run JBL controls when I was trying to do music, but as a broke high schooler it would be a few years before I figured out what I was doing.

I ended up trading the 7100 for a champange Marantz 2xxx, so It all worked out.

Hissy powered monitors are not good monitors, simple as that. I can expect powered DJ mains to be hissy since their internal gain is set to the stratosphere, but monitors shouldn't make a peep.

You probably made out better anyway, since a few powered monitors have gone D class.

 

[twiiii]

What really frustrating about computers is I have to have an extra amplification stage just to drive a decent pair of regular old Sennheiser headphones. You would think with the popularity of headphones now days they could spend a few extra bucks and improve the audio outputs or better yet have dedicated headphone out puts.

 

[RTally]

What really frustrating about computers is I have to have an extra amplification stage just to drive a decent pair of regular old Sennheiser headphones. You would think with the popularity of headphones now days they could spend a few extra bucks and improve the audio outputs or better yet have dedicated headphone out puts.

You are much better off using a headphone amp than relying upon any PC or player's output. Size and voltage levels are working against you for most PCs and portable players. Better yet, get a portable DAC and headphone amp.

 

[Gazdatronik]

What really frustrating about computers is I have to have an extra amplification stage just to drive a decent pair of regular old Sennheiser headphones. You would think with the popularity of headphones now days they could spend a few extra bucks and improve the audio outputs or better yet have dedicated headphone out puts.

The headphone outs on a computer work fine for common low impedance headphones. If the Sennheisers are high impedance units, which I am guessing they might be, that's probably your issue.

Computer parts are designed at a laughably low price point for what they are expected to do, and unfortunately for those of us with 600 ohm headphones, we probably represent less than 1 tenth of 1 percent of total computer users with these headphones. Their rationale is that anybody with headphones that nice probably will buy a better headphone amp than the rest, whether its out of desire, or in your case, out of necessity.

 

[xero-D-hero]

I typically use Sony MDR-7506 if running them directly from the 'puter (via the SB Zx ACM).
Easy to drive phones that are pretty much the industry standard for that sorta useage.

I could've easily been happy with just those Sony's were it not for a random foray into matching some cans to my Kenwood KA-7300/KT-7300 rig.
I wanted some "period looking" cans for that silverface rig,and I found some AKG K140 (closed back) for cheap,figured WTH they'd look nice with that rig.
Then I made the mistake of actually listening to them,and it was like WOW they sound pretty dang good,who'da thunk it ???
And I REALLY dont even care for "on-ear" style headphones @ all...
Thus that started the trip down the AKG high impedance headphone rabbit hole.

So now in addition to those K140 I have K140 (open back),K141,K141 Monitor,K240 Monitor,K240 Sextett (3x),K 240 DF (3x),K250 ~ Pro50 (2x),K260.
Honestly the search more-or-less ended with the K240DF as those "tick all the boxes" for me,but I still felt compelled to fill out my collection for kicks.
And FWIW the K240 Sextett and Realistic Pro50 (K-250) are now that Kenwood rigs headphones as they both have that crazy cool silver look to 'em.
And they sound absolutely amazing to boot.

But yeah the 600 ohm AKG need a stout headphone amp to drive them properly,otherwise they just wont sound as good as they can sound.
Some modern 'phones can be tough to drive in their own right,but it's often opposite what the old cans need (amps vs. volts IIRC).
But both the Sony MDR-7506 and my new AKG K52 are pretty easy to drive cans.

FWIW

Bret P.