Optical Rotary Encoder Volume Control unit using the Grayhill 62P

[DJ Exprice]

...with a LS7804 4-bit decoder with some DS1666 logarithmic digital potentiometers.

PSEUDO JOSHUA TREE ATTENUATOR!

Has NOT been build or tested yet. In fact, I would really appriciate it if someone (or even plural) could give me some pointers or the thumbs-up on this design.


Possible names?

OREViC (pseudo-acronym).



Enjoy these files!

EAGLE Files - Includes both the .BRD and .SCH file.
EAGLE Library for the 62P series encoder - Includes the file needed for the schematic and footprint of the 62P encoder from Grayhill. On the schematic, it is noted as 62P22-H-0. Look at the 62P series encoder Datasheet for more information.



Screenshots:



PCB Layout:

Click here for full resolution.


Schematic:

Click here for full resolution.

[I_Forgot]

A PIC uC and a PGA2310 or 11 would have made for a simpler circuit. The PIC can even be put to sleep when not actually changing volume. The pushbutton on the encoder could be used to set balance between channels and switch muting on/off.

I_F

[DJ Exprice]

There is a MAX5440 which does what you are talking about, but I was aiming for something simpler and that was more understandable. I think my design is clean, so I want to see what I can do to improve it.

Sketch of design:


Click here for full resolution.

Enjoy

[DJ Exprice]

Hah! Just noticed that the files had the name "AD5220". That is fixed now, no changes to the URL or any of the file's actual data. Just renamed the files on the inside of the ZIP file from:

"AD5220.brd"
and
"AD522.sch"

to

"orevc.brd"
and
"orevc.sch"

Saves some confusion.

(PS: They were named "AD5220" because of my original digital potentiometer, however, they were linear, making them obsolete to me. The DS1666 is made by Maxim (as well as the MAX5440 that I mentioned earlier) and is logarithmic - well, pseudologarithmic at least.)

(PPS: Why is everything PSEUDO this… PSEUDO that! Why can't we have the real McCoy? I'll tell you why. Maxim's just lame and won't make anything simple unless it's crumby - and they are the only company that makes a digital potentiometer anywhere NEAR usable for an application like this one.)

</rant> All good now!

[DJ Exprice]

I'll try to make a spinoff of this idea by using Maxim's MAX5440 if I can figure out what the datasheet is trying to tell my about itself. It's currently confusing me to the point of going crazy!

[DJ Exprice]

Hello all! I fixed one of the channel's outputs. (The left output).

Also, minor fixes. Links did not change. If you have this for your screenshot:


Click here for full resolution.

Then you need to update your file to the new one so that it looks like this:


Click here for full resolution.


Schematic did not visually change.

Remember: URLs are the same. Bad files are now renamed to "*filename*.bad.*extension*" Is teh hax0rStyl3

[cd-i]

I used a TDA7313 and a PIC uC to build a volume+ tone controller.

It works quite nice I might say



Regards

Daniel

[I_Forgot]

Originally posted by cd-i
I used a TDA7313 and a PIC uC to build a volume+ tone controller.

Tone controls?
I thought people only bought expensive cables for that!

I_F

[cd-i]

Originally posted by I_Forgot


I thought people only bought expensive cables for that!

I_F

I'm afraid I don't understand . My english is not so good... But what does cables have to do with tone control???

Maybe I didn't put it right. When I said about tone control I was thinking about treble and bass control.

[I_Forgot]

Your English is great! I was being sarcastic.

These days, audiophiles tend to frown on tone controls because they typically use op-amps, and to them, every stage of active circuitry, especially op-amps, makes the sound worse. Nevermind that there are probably hundreds of them in the recording console that was used to mix the disc. On the other hand, the "everything has to be modified to sound decent" crowd loves op-amps because it gives them endless forums posting opportunities to inquire about which op-amps to swap with which for better sound.

It is sort of like the selectivity of thinking exhibited by people who buy expensive power cords ignoring the fact that there are miles of cable in the walls and running back to the power generation facility. "I can't control the hundreds of op-amps in the recording console or the miles of cable between me and the power generator, but I can control the number of op-amps in my stereo and the last 2 meters of power cable."

Many of the same people will go out and spend vast sums of money to buy audio cables that provide the same function but without the adjustability that tone controls provide. You can see many posts in these forums by people looking for cables that will mellow out the harsh sound of some particular CD player, etc. When you read descriptions of the sounds of different audio cables (sometimes even power cables!) they sound just like descriptions of tone controls.

I've always like parametric equalizers...

I_F