Pyra volume control

[picmaster]

Hello everyone,

Just wanted to share my opinion about small improvement on the Pyra volume control.

The current volume control on Pandora is really cool, I like that the knob is physical and you can touch it and manipulate it without any software slow-down, or even when the Pandora is off (if you want to prevent waking-up your wife at night just because you wanted to play some old DOS game ). I also like the fact that the volume control is an analog potentiometer (hard to explain why, maybe comes with the age).

Aside from these advantages there's also a small disadvantage - the left and right channels of the potentiometer doesn't have the same resistance while turning the volume up and down. There's a slight difference of about 1-2dB which changes the panning (balance), and this panning changes slightly with different volume levels.

I definitely understand that this is normal for stereo potentiometers (unless they cost a fortune) and I don't criticize. My suggestion to the Pyra Hadware Design Team is to look for similar volume knob that has better resistance tracking between the channels, or to think about the possibility of having voltage-controlled volume - this can be done with mono potentiometer, and usually has much better and repeatable resistance tracking across chips. Also usually circuits for electronic volume control has the feature to suppress pops/clicks in the output even if the potentiometer is old/dusty, which is better when the console ages with time. Unfortunately this approach with the electronic volume control will add additional cost for the volume control chip, and has big chance to degrade (at least a tiny bit) the sound quality.

Please share what you think.

Kind regards,

picmaster

 

[slaeshjag]

I think better quality pots will go a long way.

On mine, I get mono sound if I don't have it very quiet or very loud.

 

[FBnil]

Hmm... if you bring in the arguments in the thread "not all pandora's are created equally". I have, and only at the very first millimeters of sound, a difference in left-right, then it just is the same volume. Mine crackles latetely a bit too, but not much. As for direct delivery of electrons, I like analogue too. Maybe its bias, but I think it does not alter the sound that comes out of the DAC of the Pandora, i.e. it helps in delivering better sound. Also, for an open machine, where you can hack into it, I think it is easier to replace the current volume knob.

There was a discussion on another board, combining a digital stereo volume control chip with a single-gang linear pot (use the linear single pot to control the volume control chip). But you have to add cirquits in for volume state. (link below)

Consider a volatile digital potentiometer. There was an old discussion thread, too lazy to look it up. Basically, the volume resets each time to a default, or you need to upload the value each time to the potentiometer... It also is just a wheel that does not have a point it stops (because the max volume now, could be, after replacing the batteries (where the volume state might be lost), a medium volume). Of course, you can then add an additional cell battery to keep the state, but that would require a chip that can upload/download the value.

The idea met with quite some resistance (and a few that were all for it)

So... its cheaper analogue, less manipulation of the electrons (should mean better sound).

Sources:

http://www.beavishifi.com/articles/Volume_Control/

http://en.wikipedia.org/wiki/Potentiometer

http://sound.westhost.com/pots.htm

http://www.head-fi.org/t/77342/mono-pot-as-a-stereo-volume-control

@Slaeshjag. I was going to recommend wd40 on the potentiometer, but then I read this: http://www.electronicspoint.com/threads/safe-to-use-wd40-as-switch-or-potentiometer-cleaner.13537/

Dont be lazy, go and buy a contact cleaner spray can.

Oh, and there was this idea to have the volume wheel spectrum-coloured, so you could see visually if it was loud or not. (not sure what happend to that). edit: Putting lines of nailpaint is feasable.

 

[AFAIK]

So that's what it was on my Pandora! And I was already going to resolder my right headphone because of jarring balance issues on lower volume settings.

 

[levi]

I suppose what I should do is set the master volume a little lower in the mixer (or in my music player perhaps). That will limit how loud I can make it when on speakers (since there's no separate controls for headphone and speaker power) but will mean I can run my sensitive headphones on a higher part of the volume wheel where balance is better.

 

[comradekingu]

I also like that the knob is physical and that you can touch it and manipulate it, instead of waking up your wife.

http://www.alps.com/prod/info/E/HTML/Potentiometer/RotaryPotentiometers/RKJ1/RKJ1_list.html is there anything better than this?

 

[Fzero]

I also like that the knob is physical and that you can touch it and manipulate it, instead of waking up your wife.

Ooh err missus

 

[Null]

I also like that the knob is physical and that you can touch it and manipulate it, instead of waking up your wife.

Post of the day. B)

 

[vandyswa]

The frequency knob on my ham rig (Elecraft K3) is based on some sort of optical sensor.  This lets the knob behave as if it had any arbitrary resolution, and avoids noise problems.  Of course, you then have to take the single knob value and apply it to two channels, but that inherently rids us of the balance problem.

 

[levi]

I quite like that type of knob in a lot of uses, but it is still a digital controller. It can have a lot more steps than you normally get via a push-button interface, but it's still discrete steps, and it doesn't stop when you hit 0 which is also a disadvantage. But yeah, they're still cool ever since they were the Tempest controller.

 

[comradekingu]

Se 2-11 here http://nwavguy.blogspot.no/2011/07/o2-design-process.html  There are other articles that touch on the subject too on that site.

And its really a matter of everything works together. Games and low latency also plays a factor. The good old analog pot does work extremely well for the purposes we use it for.

The drawbacks are cost and quality issues, but more cost can take care of that.  On the other side of the question i think the best quality components carry with them a value in that people are willing to pay more for them.

Something that far exceeds the cost of the materials. So more expensive can add value if done right.

 

[klapse]

my CD Player and Musical Fidelity DAC are just gathering dust. The Pandora audio with the Burr-Brown DACs are good enough for my high-end speakers.

 

[vandyswa]

my CD Player and Musical Fidelity DAC are just gathering dust. The Pandora audio with the Burr-Brown DACs are good enough for my high-end speakers.

This is really the biggest reason that the volume control bugs me--great, great audio, and then lopsided output and scritch-scratch-scrunch whenever I want to adjust level.  The volume control is not up to the quality of the rest of the audio chain on the Pandora.

 

[levi]

Whenever I'm using my better headphones, the Pandora's background amp hiss tends to distract me between tracks, but I just tried yesterday, and line-out via the TV out cable is much less noisy (tested going into my Rotel amp then out to the same headphones)

 

[TrashyMG]

Whenever I'm using my better headphones, the Pandora's background amp hiss tends to distract me between tracks, but I just tried yesterday, and line-out via the TV out cable is much less noisy (tested going into my Rotel amp then out to the same headphones)

The hiss doesn't bug me too much, but on occasion I use the TV out cable and my home made headphone amplifier as it can drive my high end headphones just a tad bit better.. 

 

[Granitehead]

Whenever I'm using my better headphones, the Pandora's background amp hiss tends to distract me between tracks, but I just tried yesterday, and line-out via the TV out cable is much less noisy (tested going into my Rotel amp then out to the same headphones)

The hiss doesn't bug me too much, but on occasion I use the TV out cable and my home made headphone amplifier as it can drive my high end headphones just a tad bit better..

That background hiss always bothered me quite a lot about mine. Annoying for films and for any kind of music with a large loudness range.

 

[TrashyMG]

Honestly the only time I really hear it loudly is in between tracks of music, right before the amps go idle and shuts off. When music is playing I don't hear it, even if there are a silent parts in the music/movie it's not totally hear-able to me, But I suspect many have better hearing then I do.

 

[levi]

Yes, I should clarify that I slightly overegged the pudding above. I can hear it between tracks if I listen for it, but it's quieter than the fuzz you get on a LP between tracks, so I don't find it very distracting. The main time I really notice it is after the music stops and your ears adapt to the level of the hiss, then the amp goes to sleep and the hiss stops.


But the fact it has that hiss means I don't consider the Pandora a perfect replacement for decent separates, although I still think that when I retire my Pandora it'll be plugged into my amp for the fact it can store gigabytes of music in any format I choose and play it back in pretty damn good quality.

 

[Bosbeetle]

thumbs up for the mono potentiometer idea