My DIY Audio Scope so far (will update)

[Wurly1]

Here's a tricolor meter project i made some 3 years ago for a jukebox.
red is for bass, green for mid and blue for high.
I'm thinking about using the same technique and use color to separate front from rear instead of bass vs treeble.
What do you think?

 

[Jim the Oldbie]

Wow, is that an NSM jukebox? My first real job in high school was working for a local guy, fixing pinball machines and his fleet of NSMs scattered around the county. Haven't seen one of those carriages in over 40 years...

 

[Wurly1]

Wow, is that an NSM jukebox? My first real job in high school was working for a local guy, fixing pinball machines and his fleet of NSMs scattered around the county. Haven't seen one of those carriages in over 40 years...

Yes i bought NSM carriage parts and my goal is to design new control circuits from ground up using TTL logic, transistors and relays and put all this in the smallest coolest cabinet.
I managed to make it work and select correctly few times but i had to put this project aside. Since retirement is just around the corner I intend to resume work on it in 2021 and maybe use a raspberry pi to provide touch screen control. I still have to learn to code with python do.

 

[Jim the Oldbie]

That sounds like a fun project! If I may stray from the topic just awhile longer: Does your carriage have the core memory or the motorized pin selector underneath?

(Your LED meters look bitchin' by the way.)

 

[Wurly1]

That sounds like a fun project! If I may stray from the topic just awhile longer: Does your carriage have the core memory or the motorized pin selector underneath?

(Your LED meters look bitchin' by the way.)

Thank you for the LED meter comment.

The record tray does not have any selection pins, when the carriage is moving, two opto-couplers fed through a comparator and counter tell the record positions of the carriage. The position is then compared to the memory containing the selection information (1 = play, 0 = continue). the mechanism in the carriage have a selenoid which when energized, toggle into "load and play the record" at the end of the record, the mechanism return to scan mode. At the left end of the record tray there is a pin than physically toggle a switch on the carriage thus reversing the carriage from left to right. The same thing happen on the right "Home" position.

 

[Jim the Oldbie]

Thanks for the additional video, that really takes me back.

That rack & carriage looks very similar to the ones I used to service, but also a bit different. The optical seek system must be a newer development, or did you DIY that part?

As you may know (and if I remember correctly), back in the late '60s/ early '70s, NSM used a real magnetic core memory for record selection, using tiny ferrite cores & wiring just like the computers of the day. But after a court loss to Seeburg, who was using the same type of system, NSM had to revert to a motorized sliding pin arrangement under the rack, which was a step backward technologically.

That's the reason I asked about yours - the mag core setup relied on a faint 1 uS pulse from the cores to detect the selected positions in the rack, and might have been more of a challenge to DIY, heh.

As for the topic: I've been wanting to throw together a simple analog quad "vector-steering" circuit to use on the front end of an old dual-channel CRT scope I no longer use at work. But awhile back it occurred to me that I no longer have an easy way to connect something like that to my system! Everything is digital right up to the power amps, with separate analog outputs for each woofer, tweeter & midrange coming out of a pair of miniDSP nanoAVR-HDAs (see avatar).

I'll have to keep any visualizations in the digital realm, since that's where the audio lives for the most part. Not that I'm complaining - I absolutely love the sound - but things sure ain't as simple as they used to be!

Oh well - another reason to get back into coding, which I've missed.

 

[Wurly1]

As you may know (and if I remember correctly), back in the late '60s/ early '70s, NSM used a real magnetic core memory for record selection, using tiny ferrite cores & wiring just like the computers of the day. But after a court loss to Seeburg, who was using the same type of system, NSM had to revert to a motorized sliding pin arrangement under the rack, which was a step backward technologically.

That's the reason I asked about yours - the mag core setup relied on a faint 1 uS pulse from the cores to detect the selected positions in the rack, and might have been more of a challenge to DIY, heh.

This is from one of their last models using ortofon cartridge.
I removed the front tone-arm protective harness, that make it look much different.
The sensor module was part of the carriage. There's two sensors close to each other and a rotating disc making one turn every time the carriage advance one position. when the carriage goes in one direction, sensor 1 pick up the pulse signal before sensor 2 and if sensor 2 pick up de pulse signal before sensor 1 it means the carriage goes in the other direction. All i had to do was to normalize these pulses using NE555 and then decode these pulses with logic gates to generate pulse on the up or on the down pin of a counter.
Simple in theory but a bit challenging.
I like using older technologies like TTL logic and static memory.
That's what i studied back in early 80's at college.
A lot of fun finally! lol

 

[doity]

Well I thought I was done, and I should had been done, but I couldn’t leave well enough alone. I got the bright idea that if I added some clear holographic vinyl with rainbow color that it might allow the LED’s to throw off extra light. I guess I was hoping that like in Matrix mode there would be some hidden music just waiting to come out. Or in my case hidden light. Well in a nutshell it didn’t and the vinyl was real thin and was not only hard to apply right but it also looked like crap when on.

I had to rip it all off which also ripped off the dimming film I had on there to hide the innards. Once I got it all of I noticed that it looked better off because then you could see the LED strips which you couldn’t see before, just the lighted segments when on. I had to mask off the areas that showed the wiring and the glue that I used but I think it actually looks better now. It doesn’t look so blank as before as there seemed to be too much empty space on the screen whereas now it looks more whole if you will.

Actually the whole point should be moot as I am getting a receiver with a fake scope thingy real soon but now I think I will run this also. Never enough flashing and blinking lights that’s what I have always said . Let me know how you think it looks now. I promise I am DONE messing with this stupid thing.

 

[Wurly1]

Hi all!
Since last january i've been working hard on a solution for a 4.0 visualizer and soon i'll be able to post a video of it.
i've made 4 versions of my display and decoder design and the final one will be finish soon. Here is a picture of the 440 led screen forming a kind of radar view of the sound panning from left to right and front to back.
I'm currently in the assembling of the decoder pcbs which i received today.
The learning curve was tuff as i had to learn, understand and use the Kikad pcb design software suite. Then i dared to send my 1st decoder pcbs files to manufacturing company to have my pcbs professionally made. I was so amazed by the result, it gave me a big push to go ahead and design the hole display. The decoder (V1) was used to make some test to rectify, add, subtract and compare different analog signals to drive the display. V2 and V3 were not manufactured as they were derivatives from V1. But V4 will be fully functional. I'm still waiting for some parts i need to assemble it. Next weekend i will be working on a convenient cabinet.
1st picture: display
2nd picture: actual V1 decoder
3rd picture: 3D representation of the V4 decoder.

 

[Soundfield]

Hi all!
Since last january i've been working hard on a solution for a 4.0 visualizer and soon i'll be able to post a video of it.
i've made 4 versions of my display and decoder design and the final one will be finish soon. Here is a picture of the 440 led screen forming a kind of radar view of the sound panning from left to right and front to back.
I'm currently in the assembling of the decoder pcbs which i received today.
The learning curve was tuff as i had to learn, understand and use the Kikad pcb design software suite. Then i dared to send my 1st decoder pcbs files to manufacturing company to have my pcbs professionally made. I was so amazed by the result, it gave me a big push to go ahead and design the hole display. The decoder (V1) was used to make some test to rectify, add, subtract and compare different analog signals to drive the display. V2 and V3 were not manufactured as they were derivatives from V1. But V4 will be fully functional. I'm still waiting for some parts i need to assemble it. Next weekend i will be working on a convenient cabinet.
1st picture: display
2nd picture: actual V1 decoder
3rd picture: 3D representation of the V4 decoder.

Very impressive! Would love to learn more about your circuit design, any attempts I've come up with have been far too complicated! Do you plan to make the boards available in any form?

 

[malcolmlear]

Now that does look great!! Clearly a lot of time spent working on the layout. Looking forward to seeing it in action ))

 

[Sonik Wiz]

Hi all!
Since last january i've been working hard on a solution for a 4.0 visualizer and soon i'll be able to post a video of it.
i've made 4 versions of my display and decoder design and the final one will be finish soon. Here is a picture of the 440 led screen forming a kind of radar view of the sound panning from left to right and front to back.
I'm currently in the assembling of the decoder pcbs which i received today.
The learning curve was tuff as i had to learn, understand and use the Kikad pcb design software suite. Then i dared to send my 1st decoder pcbs files to manufacturing company to have my pcbs professionally made. I was so amazed by the result, it gave me a big push to go ahead and design the hole display. The decoder (V1) was used to make some test to rectify, add, subtract and compare different analog signals to drive the display. V2 and V3 were not manufactured as they were derivatives from V1. But V4 will be fully functional. I'm still waiting for some parts i need to assemble it. Next weekend i will be working on a convenient cabinet.
1st picture: display
2nd picture: actual V1 decoder
3rd picture: 3D representation of the V4 decoder.

I am impressed! I have attempted to learn some schematic design apps (not too bad) & PCB design apps (my brain smoked). So congrats on such great progress.

A few ???'s:
Did you make the Quad Display board yourself?
I see the obvious purpose of the diagnol/corner LED bargraphs but what is the purpose of the many, many surrounding LED's?
When you refer to the decoder board, is this for the input to the display? Or an actual quad type decoder?

Edit: I just read so fast & got so excited to reply... re-reading I see most of my questions answered.

 

[Wurly1]

Very impressive! Would love to learn more about your circuit design, any attempts I've come up with have been far too complicated! Do you plan to make the boards available in any form?

Some additional details about this display.
Yes it uses the venerable LM3915 but the outputs are driving a 4 quadrant matrix of my design.
The decoder is using a total of 24 operational amplifiers to perform the special functions i designed such as: Quad/Stereo mode, Normal/Differential mode and finally Fast/Slow reaction speed.
Each time i ordered some pcbs i had to have a minimum of 5 board made. The first version of my decoder (V1) is pure loss as it's useless now. (At that time i also had pcbs made for the control switches which will not be used because of all the cables necessary to hook it to the decoder ) The V4 decoder has all the controls and switches built in as well as the power supply. For the final version i ordered 10 display pcbs and 10 decoder pcbs. Then i discovered it was much harder to get all the parts to assemble 10 complete units then it is for only one. For example: 3 x 4PDT switches is easy to come by but 30 identical in every way is another story and another price! lol
Next weekend work will begin on the design of a cabinet that would either fit on a shelf of stacked on top of standard 17inch wide components.
So in the end i will have built 10 complete units.
Maybe i'll build some more after these but not sure as the logistic of the whole project is very costly and time consuming.

 

[Sonik Wiz]

Some additional details about this display.
Yes it uses the venerable LM3915 but the outputs are driving a 4 quadrant matrix of my design.
The decoder is using a total of 24 operational amplifiers to perform the special functions i designed such as: Quad/Stereo mode, Normal/Differential mode and finally Fast/Slow reaction speed.
Each time i ordered some pcbs i had to have a minimum of 5 board made. The first version of my decoder (V1) is pure loss as it's useless now. (At that time i also had pcbs made for the control switches which will not be used because of all the cables necessary to hook it to the decoder ) The V4 decoder has all the controls and switches built in as well as the power supply. For the final version i ordered 10 display pcbs and 10 decoder pcbs. Then i discovered it was much harder to get all the parts to assemble 10 complete units then it is for only one. For example: 3 x 4PDT switches is easy to come by but 30 identical in every way is another story and another price! lol
Next weekend work will begin on the design of a cabinet that would either fit on a shelf of stacked on top of standard 17inch wide components.
So in the end i will have built 10 complete units.
Maybe i'll build some more after these but not sure as the logistic of the whole project is very costly and time consuming.

Ah, perhaps offer PCB's & parts, maybe enclosure, as a kit a la Heathkit. Let dedicated DIY'ers do the hard work.

 

[Soundfield]

Some additional details about this display.
Yes it uses the venerable LM3915 but the outputs are driving a 4 quadrant matrix of my design.
The decoder is using a total of 24 operational amplifiers to perform the special functions i designed such as: Quad/Stereo mode, Normal/Differential mode and finally Fast/Slow reaction speed.
Each time i ordered some pcbs i had to have a minimum of 5 board made. The first version of my decoder (V1) is pure loss as it's useless now. (At that time i also had pcbs made for the control switches which will not be used because of all the cables necessary to hook it to the decoder ) The V4 decoder has all the controls and switches built in as well as the power supply. For the final version i ordered 10 display pcbs and 10 decoder pcbs. Then i discovered it was much harder to get all the parts to assemble 10 complete units then it is for only one. For example: 3 x 4PDT switches is easy to come by but 30 identical in every way is another story and another price! lol
Next weekend work will begin on the design of a cabinet that would either fit on a shelf of stacked on top of standard 17inch wide components.
So in the end i will have built 10 complete units.
Maybe i'll build some more after these but not sure as the logistic of the whole project is very costly and time consuming.

Interesting, I was going to use bar graph drivers but combing them into an adressable true X-Y matrix proved to be too impractical for four input channels (at least given my level of patience!). So, are the green LEDs part of the active display or serve only as a "background" ?
No reason why you should want the hassle of going into production, but you could sell the blank PCBs I guess, or even just the Gerber Files so people could get their own made.

 

[Wurly1]

Ah, perhaps offer PCB's & parts, maybe enclosure, as a kit a la Heathkit. Let dedicated DIY'ers do the hard work.

That is a possibility

 

[Wurly1]

I see there's a "speed" control. Does this mean that the bargrap

Interesting, I was going to use bar graph drivers but combing them into a adressable matrix proved to be too impractical for four input channels (at least given my level of patience!). So, are the green LEDs part of the active display or serve only as a "background" ?
No reason why you should want the hassle of going into production, but you could sell the blank PCBs I guess, or even just the Gerber Files so people could get their own made.

The green leds are definitely part of the active display.

 

[Soundfield]

The green leds are definitely part of the active display.

Well, in that case you've certainly come up with a circuit far simpler than anything I'd been thinking about! Well done - look forward to seeing it in action!

 

[audiomaster]

That is a possibility

When will the 11.1 version for Atmos be ready? )

 

[surround.sound.enthusiast]

When will the 11.1 version for Atmos be ready? )

Hmm, it'd have to be three dimensional, or better yet, spherical to show the height speakers...

Got it! Just wire light bulbs to your speaker terminals and you'd have a full scale Atmos audio scope and blinking disco room Kidding... !