Budget passive preamp with stepped attenuator?

[Sokel]

According to someone on this thread, reducing only DAC volume reduces SINAD by 2dB, compared to turning down the volume pot. Turning down the volume pot also decreases SINAD.

You seem not reading the posts in your own threads.
That's a real world DAC in real world conditions when reducing it's levels:

Reducing DAC volume doesn't necessarily decrease bit-depth of audio data.

What you see is a line that goes down exactly with the volume, this means the absolute level of the noise/distortion remains constant. Let's see real world (attenuated at the DAC side not generator level,as a user would normally do) : -2db of attenuation 104.8 SINAD -30db of...

www.audiosciencereview.com

Reducing DAC volume doesn't necessarily decrease bit-depth of audio data.

Just for the fun of it I did a loopback of the E-MU to see,first with it's crappy analog pot from the headphone amp and then just attenuating it by windows mixer (all ASIO). at -4db at -30db crappy pot at -30 by windows mixer. Fell free to comment,suggest other measurements,etc...

www.audiosciencereview.com

So forget about the SINAD thing on either side,if noise is ok you're ok with a decent amp.

 

[Deleted member 58865]

You seem not reading the posts in your own threads.
That's a real world DAC in real world conditions when reducing it's levels:

I was referring to

Budget passive preamp with stepped attenuator?

You've gained 2 dB dynamic range at -20 dB volume position with a perfect analog volume control. Without a lower noise / lower gain amplifier you will not be gaining much from using a higher dynamic range DAC or an analog volume control. -20dB is just DAC volume. You need to also take...

www.audiosciencereview.com

 

[Sokel]

I was referring to

Budget passive preamp with stepped attenuator?

You've gained 2 dB dynamic range at -20 dB volume position with a perfect analog volume control. Without a lower noise / lower gain amplifier you will not be gaining much from using a higher dynamic range DAC or an analog volume control. -20dB is just DAC volume. You need to also take...

www.audiosciencereview.com

What he writes is absolutely correct,but you should understand that this is propotional to level,not a steady state.

 

[solderdude]

You have a balance control on your player. Use that. No more overall imbalance.
The channel imbalance on your Aiyima is because of a crappy cheap pot being used and is not representative for all volume controls.
It is more common with cheap gear (channel imbalance at lowest volume settings).

 

[JustJones]

Right, SINAD is dominated by attenuation. That's why I want to remove the damn gain. Can I connnect DAC directly with speakers without an amplifier between them?

Or, can I insert a stepped attenuator between DAC and speakers?

I'm still waiting to see the results of a DAC connected to speakers without an amplifier.

 

[Sokel]

I'm still waiting to see the results of a DAC connected to speakers without an amplifier.

Benchmark Dac3 maybe?
(18V output)

 

[JustJones]

I guess I'm just a plebian. Set DAC to DAC mode, set volume on AMP 75% since you have imbalance at lower level, put one of these between them since you want passive.. You're done. Or just buy a decent integrated amp and forget it.

 

[Deleted member 58865]

You have a balance control on your player. Use that. No more overall imbalance.
The channel imbalance on your Aiyima is because of a crappy cheap pot being used and is not representative for all volume controls.
It is more common with cheap gear (channel imbalance at lowest volume settings).

I swapped the left output and the right output from AIYIMA A07. And, the right speaker was still louder. This means if AIYIMA A07's volume pot is above 9'o clock, channel imbalance comes from asymmetry in space or my speakers or my head.

I removed most of channel imbalance by sliding the right speaker to the right a little bit. The problem is that even turning my head a little bit creates channel imbalance because my head is so close to speakers.

 

[solderdude]

Then use the balance control on your player. Problem solved. That's exactly what balance controls are for.
The channel imbalance that seemed to bother you is below 8'o clock.
Have you swapped the speakers themselves (in place) ?

 

[Deleted member 58865]

Have you swapped the speakers themselves (in place) ?

I will try that tomorrow. If swapping the speakers results in opposite channel imbalance, then it is channel imbalance in speakers.

If it doesn't, then it is asymmetry in my head or the room space.

 

[Zek]

It turns out that either my room is asymmetric, or my speakers are asymmetric.
I had to keep the right speaker a little bit farther from me than the left speaker is.
In my listening position, the left speaker is closer to the left wall than the right speaker is to the right wall.

If you had stated this at the beginning, people would not have spent so much energy to find you a suitable solution.

 

[Zek]

then it is asymmetry in my head

Bingo !!!!

 

[JeffGB]

I'm glad you are finding a solution to your problem. I think the main problem is the Aiyima A07, which has a much higher gain than many of the specs for the amp would have you believe. The gain when Amir tested it was just over 29db. I have an A07 as well as several other amps that have various different gains. The Topping PA5, for instance is 20db gain and sounds much quieter in my system than the A07 (mentioned only because the gain spec for the Aiyima is often wrong). The JLE Sylph D200 tpa3255 amp has a gain of only 14db (due to post filter feedback having been added).

I also found the imbalance in the Aiyima at very low volumes because that is the way I listen to my system as well. Just adding a level control to a power amp doesn't necessarily change the gain, even if the manufacturer refers to it as a "gain control". Unless the amplifier's feedback is increased to decrease the volume, it is just an attenuator. Sometimes they are a combination where the feedback is minimally affected along with attenuation, such as with the Crown XLS amplifiers. BTW, if you add another physical unit with volume control between the DAC and amp, you are increasing the possibility of ground loops and RF interference. In my location it is AWEFUL . I ended up going to all balanced to get rid of the noise, but I didn't have a problem before I added a single ended headphone amp/preamp between the DAC and amp. In other words, it is quite possible to actually cause much higher noise in an attempt to lessen an inaudible "problem".

Good luck with your decisions but I think a few db reduction in the digital volume control of your DAC to put the Aiyima's volume control into a less problematic area is the best compromise without changing many components.

 

[sarumbear]

Anyway, upon further research, I found out that attenuating the output of an amplifier is impractical because it wastes a lot of energy.

You are in for shock then as almost every volume control works by attenuating

 

[antcollinet]

You are in for shock then as almost every volume control works by attenuating

But not by doing it on the power output from the speaker output terminals.

 

[sarumbear]

But not by doing it on the power output from the speaker output terminals.

Who in their right mind will do that?

 

[Deleted member 58865]

BTW, if you add another physical unit with volume control between the DAC and amp, you are increasing the possibility of ground loops and RF interference. In my location it is AWEFUL . I ended up going to all balanced to get rid of the noise, but I didn't have a problem before I added a single ended headphone amp/preamp between the DAC and amp. In other words, it is quite possible to actually cause much higher noise in an attempt to lessen an inaudible "problem".

A passive stepped attenuator isn't going to add a ground loop to the audio system.

 

[Deleted member 58865]

Then use the balance control on your player. Problem solved. That's exactly what balance controls are for.

I'd rather fix channel imbalance at the root cause. The universe is a machine actuated by cause and effect. You have to remove the cause if possible.

Only if you can't remove the cause, you address the symptoms at the level of effect.

Cause and effect, bro. Fixing problems at the root cause is the best solution. Anything else will perpetuate the problems for eternity.

I dread the idea of addressing the symptoms instead of removing the root cause.

 

[Deleted member 58865]

I swapped the left speaker and the right speaker. The channel imbalance was reversed.
I swapped the left speaker output and the right speaker output. The channel imbalance was not affected. There is no significant channel imbalance from amplifier outputs.
I swapped the speaker cables, and there was no change in channel imbalance. There is no asymmetry in speaker cables.

It seems one speaker is more sensitive than the other.

Good news is I don't have to change my room or replace my current head with a new one.

I should either change speaker placement or buy a new pair of speakers. Because I'm 50 centimeters away from speakers, a slight channel imbalance can be felt.

Is it common for one speaker to be more sensitive than the other?

 

[solderdude]

It shouldn't but is possible.
Not all drivers are created equal. When it is only the tweeter (so treble that is louder) then padding down the tweeter is a 'source' solution.
Requires opening up the speaker and put an L-pad before the tweeter.
When it is the woofer the only option is to buy another speaker or use the balance slider on your player. That's exactly what its there for. To compensate for level differences whatever the root cause.
Another option is to use 2 RCA attenuators with the required difference in them and use that between DAC and amp.