Are digital/stepped attenuators far more balanced than potentiometers?

CowCat

Member
2019-04-05 12:12 am
With a cheap potentiometer, when the volume is low, one side is perceptibly louder than the other.

It seems stepped attenuators have perfect channel balance.
I don't know much about channel balance of digital volume knobs(digital attenuators?) that come with amplifiers like Topping MX3 and SMSL AD18.
 
Do the following amplifiers come with digital attenuators?

  • FX-Audio D802C Pro : STA326 (FDA) Yes
  • SMSL AD18 : TAS5508C front-end; TAS5342A power stage Yes
  • Topping MX3 : NJW1194 stepped attenuator No
  • SMSL SA100 : TPA3116 amp; probably stepped attenuator No
  • SMSL Q5 Pro : TAS5508C front-end; TAS5342A power stage Yes
 

CowCat

Member
2019-04-05 12:12 am
  • FX-Audio D802C Pro : STA326 (FDA) Yes
  • SMSL AD18 : TAS5508C front-end; TAS5342A power stage Yes
  • Topping MX3 : NJW1194 stepped attenuator No
  • SMSL SA100 : TPA3116 amp; probably stepped attenuator No
  • SMSL Q5 Pro : TAS5508C front-end; TAS5342A power stage Yes

Do you think D802C Pro and SMSL SA100 are ok?

  • SMSL SA100 is comparable to Allo Volt+ With Stepped Attenuator although the digital volume knob on SMSL SA100 sometimes skips numbers. The stepped attenuator on Allo Volt+ is going to be more reliable. Other than that, they would be similar in sound quality.
  • D802C Pro is substantially more powerful than SMSL SA100.
 
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rayma

Member
2011-04-29 8:37 pm
Do potentiometers develop substantially more channel imbalance as they age? If they don't, they might still be useable except at very low volumes where they exhibit channel imbalance.

That can happen for some poorly made pots. The ones in Dynaco's old preamps were known for tracking problems at lower settings. There was an adjustment on the back of some of those pots that you could use to try to tweak them back into balance. Even if an old pot does track acceptably, there are often other reasons to change it out.
 
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CowCat

Member
2019-04-05 12:12 am
That can happen for some poorly made pots. The ones in Dynaco's old preamps were known for tracking problems at lower settings. There was an adjustment on the back of some of those pots that you could use to try to tweak them back into balance. Even if an old pot does track acceptably, there are often other reasons to change it out.

It seems stepped attenuators and digital attenuators are clearly the better options. How do you think of SMSL SA100?
 
Do you think D802C Pro and SMSL SA100 are ok?

OK in a general sense to listen to or OK for channel balance? I'd not myself bother with any TPA3116-based amp as I've heard and played with that chip and moved on from it many years ago. There are plenty of options - more modern classD chips - which sound better than that one. STA326 is an open-loop FDA and so is very sensitive to PSU quality - particularly bass suffers if the power supply isn't optimized. Its much better than TPA3116 in the mid and HF with a reasonably low impedance PSU.
 

CowCat

Member
2019-04-05 12:12 am
OK in a general sense to listen to or OK for channel balance? I'd not myself bother with any TPA3116-based amp as I've heard and played with that chip and moved on from it many years ago. There are plenty of options - more modern classD chips - which sound better than that one. STA326 is an open-loop FDA and so is very sensitive to PSU quality - particularly bass suffers if the power supply isn't optimized. Its much better than TPA3116 in the mid and HF with a reasonably low impedance PSU.

What kinds of class-D amps do you recommend? I currently own a TPA3251 amp and a TPA3255 amp. Both are cheap chinese implementations. Other than channel imbalance at very low volumes, they sound fine.
So, I reduce the amplifier volume to the point where there is no perceptible channel imbalance and reduce DAC or software volume.
I read that Allo Volt+ D is a fine amplifier despite being a dual TPA3118 amplifier.
 
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CowCat

Member
2019-04-05 12:12 am
I've yet to find a classD amp I would recommend in stock form. This is after all DIY audio. But yeah TPA3251 and TPA3255 are much better starting points for an amp than TPA3116. Channel imbalance has never bothered me, I'm so lazy I pretty much always use software volume control.

In my case, a lot of channel imbalance comes from computer fan noise.
Beucase my computer case is placed to the left of my speakers, fan noise affects the left speaker a lot.

I've felt a veil in front of the left speaker. I didn't know what the veil was until I realized it was my computer's fan noise.

Fan noise is problematic if you listen to music quietly.