My DIY Audio Scope so far (will update)

[Wurly1]

RE: @audiomaster


As you say"an instant view with no lagging" but still it has an easy to follow pattern that didn't exist in what I mentioned above. I don't know if you put a calculated amount of decay in your unit, but it looks excellent. As I said the best solid state rendition of a CRT quadscope I've ever seen.

There is a 10pf capacitor to slow it down and it's almost unnoticeable as the signal fed to the LM3915 can reach up to 40khz! (unfiltered rectified 20khz) A switchable .1uf really slow down the signal and is good to avoid epilepsy crisis.
It is also slowed down for the differential mode. I did some frequency tests and the "decoder board" have a linear frequency response from 1hz up to 200khz and above. (i have no means to test above 200khz) So limiting the speed (even a little) is essential to have a pleasant experience.

 

[doity]

This really is very clever. The bar-graphs along the four cardinal axes show the instantaneous signal fed to each speaker. The LEDs in between effectively show the resulting phantom image locations arising in each quadrant. Thus, for example, when fed with a mono signal the FL and FR bar-graphs show the same signal level and a centre image location is indicated on a round LED in the front quadrant equidistant between them. I think this is particularly clear when the bar-graph and quadrant LEDs are different colours (See Wurly1’s previous videos).

I know. I really started thinking about it after my post last night when I was explaining to Wurly my initial reaction. Not only is this clever, this is on a whole nother’ level of clever. This is BAD ASS clever

 

[quadsearcher]

If there is to be another run of PCBs (with parts list and diagram, maybe suggested vendors) I'd be interested in one. As a kid, I built a simple voltage modulated mono three-channel color organ out of electroluminescent panels. Round shape, lows in middle, mids at a midpoint, highs on outside. I knew frequency modulated would've been more dramatic with EL, but that was beyond my skills.

 

[doity]

On my Japanese Technics receiver the scope display works very similiar except that it uses tricks of light to accomplish what the green LED’s do on yours. But for yours to be so accurate as you can plainly see in the videos is nothing short of genius. No wonder it uses 700 components.

 

[Wurly1]

If there is to be another run of PCBs (with parts list and diagram, maybe suggested vendors) I'd be interested in one. As a kid, I built a simple voltage modulated mono three-channel color organ out of electroluminescent panels. Round shape, lows in middle, mids at a midpoint, highs on outside. I knew frequency modulated would've been more dramatic with EL, but that was beyond my skills.

Selling you a 700 parts + kit would be a bit complicated to prepare and so many things can go wrong. For now i prefer fully tested complete unit. Also some LEDs colour configurations cannot be used as their forward voltages may prevent some LEDs to light properly. An example of this is if you put a blue and a red led in parallel the red will light but it will prevent the blue from lighting because the forward voltage will drop to about 1.3 volt, not enough to light the blue one which need 3 volts.
A bad led will also cause some weird problems and is hard to pinpoint.
Finally anyone who had fiddle with the LM3915 in dot mode know how frustrating it can be when oscillations occurs.

 

[quadsearcher]

Selling you a 700 parts + kit would be a bit complicated to prepare and so many things can go wrong. For now i prefer fully tested complete unit. Also some LEDs colour configurations cannot be used as their forward voltages may prevent some LEDs to light properly. An example of this is if you put a blue and a red led in parallel the red will light but it will prevent the blue from lighting because the forward voltage will drop to about 1.3 volt, not enough to light the blue one which need 3 volts.
A bad led will also cause some weird problems and is hard to pinpoint.
Finally anyone who had fiddle with the LM3915 in dot mode know how frustrating it can be when oscillations occurs.

Yup. OK. Though what I meant was parts list. I actually like choosing parts but it takes me a long time to avoid pitfalls. I know what you mean about voltage drops, matching is basic requirement in LED TV or document camera etc. There are many electrical, physical, and optical variations.
That's why I was hoping you might want to sell a PC board, to help justify a new run of them. Of course a schematic and part numbers/location would be essential, similar to Popular Electronics magazine in the 70's selling a kit, and/or a bare PCB with parts list/schematic and suggested sources.
I suppose one-off PC boards are easier now. I'm kinda fooling myself to think I have time to build one, even if instructions were provided. I have lots of things that need service more than I need a super cool visual sound display.

I don't know the LM3915 but I'll look it up. It is really cool that you are fiddling with this stuff, I miss reading about project design, building, and tweaking.

Do you really want to sell a fully tested unit?

 

[Wurly1]

Some pictures of the blue prototype, this cabinet is only a test. The final one will have de same dimensions but the front panel will have a very different aspect. The front and back panel will be transparent plexiglass with a back drop brushed aluminium looking showing the buttons descriptions along with some graphic designs. I want the wood to be a semi-gloss black finish. I will keep the handles as it make it look like a pro unit.
I can dream! lol

 

[Sonik Wiz]

Some pictures of the blue prototype, this cabinet is only a test. The final one will have de same dimensions but the front panel will have a very different aspect. The front and back panel will be transparent plexiglass with a back drop brushed aluminium looking showing the buttons descriptions along with some graphic designs. I want the wood to be a semi-gloss black finish. I will keep the handles as it make it look like a pro unit.
I can dream! lol

Dang, even the case is shaping up to look nice. And I like those handles too. A couple of ???'s:
What is Quadra X-Stereo?

Another common configuration is 5.1 chs. The LFE would not need to be displayed as it has little impact on the sound localization. But anyone with this unit might also use center front and for that to be displayed. Me thinks that could be done by mixing equally at .707 into front Left/Right ? Any chance to include this or would it be for after purchase DIY?

You need a cool logo to match this. Or it will be known forever on the web in legend as simply the Wurly1 Quadscope. Actually I kind of like that.

 

[Wurly1]

You need a cool logo to match this. Or it will be known forever on the web in legend as simply the Wurly1 Quadscope. Actually I kind of like that.

That is a very nice taught!

As a matter of fact, i do have a logo to put on, i like Wurly1 but then nobody will know who Wurly1 is...
I could use it as the model number.

 

[Wurly1]

Dang, even the case is shaping up to look nice. And I like those handles too. A couple of ???'s:
What is Quadra X-Stereo?

This button switch between discrete 4 channels and 2 channels (X-Stereo).
X-Stereo explanations:

It could also be called Cross-Stereo but i think X-Stereo is more catchy.

I discovered feeding stereo signal thru the 4 discrete channels was not really appealing as it would only display straight horizontal lines on each sides and produce a pattern only on the upper and lower quadrant that is not really informative.
Something had to be done, the answer is X-Stereo! lol

By reversing the left and right channels of a stereo signal and feeding them thru the rear channels produce a more pleasant and informative display.
The result is the left channel being displayed at -45 degree and the right at +45 degree, thus X-Stereo. (right signal fed to the front left display and back right display and the right signal fed to the front right display and the back left display)

The X pattern allow for a more comprehensible view of what's going on.
The visual demonstration of this can be clearly seen in one of my previous clip of Billy Idol's Flesh For Fantasy.

 

[Soundfield]

Some pictures of the blue prototype, this cabinet is only a test. The final one will have de same dimensions but the front panel will have a very different aspect. The front and back panel will be transparent plexiglass with a back drop brushed aluminium looking showing the buttons descriptions along with some graphic designs. I want the wood to be a semi-gloss black finish. I will keep the handles as it make it look like a pro unit.
I can dream! lol

Great looking prototype! Just a thought - Is it too late to add a set of paralleled output sockets so that you can loop signals through it without having to use "Y" adaptors?

 

[Sonik Wiz]

Great looking prototype! Just a thought - Is it too late to add a set of paralleled output sockets so that you can loop signals through it without having to use "Y" adaptors?

Yup I thought about that as well. I second the motion!

 

[doity]

Some pictures of the blue prototype, this cabinet is only a test. The final one will have de same dimensions but the front panel will have a very different aspect. The front and back panel will be transparent plexiglass with a back drop brushed aluminium looking showing the buttons descriptions along with some graphic designs. I want the wood to be a semi-gloss black finish. I will keep the handles as it make it look like a pro unit.
I can dream! lol

Just beautiful. It even looks like a pro job with the case and all. And yes, a black finish would be the icing on the cake. You could even do something like calling it the “Limited Edition” to give it a air of exclusivity. If there is a waiting list I want to be number one for one of the blue LED models .

 

[furui_suterioo]

Now need to have triple-decoder for rgb LEDs ..jk!

 

[Wurly1]

Great looking prototype! Just a thought - Is it too late to add a set of paralleled output sockets so that you can loop signals through it without having to use "Y" adaptors?

it can easily be done as i originally ordered 20 sets of RCA inputs by mistake instead of 10.

 

[Wurly1]

Now need to have triple-decoder for rgb LEDs ..jk!

Maybe for another design because my design cannot use rgb LEDs as its working principle depend on the relationship between each LEDs forward voltage characteristics. The problem with rgb LEDs is the common anode or common cathode.

 

[doity]

I tried doing this yesterday but posted it in the wrong thread. Oops. Anyway, I made a different video that is much better. Here is my Technics ‘pseudo-scope’ and I picked a selection that shows off both it’s capabilities and it’s limitations. I was starting to think that the display was backlit because there is a white plastic square there and it got so bright at higher volume. Looking at it when it was working I realized that it seems to be there to throw the light back out as to appear that there is more going on than there really is.

Still, it does a reasonable job of simulating a real scope and at the very least it is cool to look at. My only complaint is the wavy plastic tends to throw light in a manner that is not in consistent with how a real scope works. Oh well.....I guess I am stuck with it until I can get my “Wurlyscope”

 

[Wurly1]

little update on my Quadscope.
I've completed 2 control amplifiers so far and one of them and a blue display are already installed in the prototype cabinet.
i started the assembly of the remaining 8 control amplifier pcbs and finished 5 out the 10 LED displays. The all-white one is very bright, too bright. I also spent more time working on it as the white leds i used were quite sensitive to the heat of my solder pen and simply burn.
There are additional delays for the cabinet i'm afraid but it's worth the wait.

 

[Wurly1]

assembly update:
all capacitors soldered in place.

 

[Sonik Wiz]

assembly update:
all capacitors soldered in place.

That is impressive! I can't quite tell from the pic but are you dealing with SMD stuff also? So tightly packed & so professional looking. May I ask what circuit /layout CAD you used?