DIY Project Show & Tell

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Jim the Oldbie

My right elbow hurts.
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Hi Kids,

Sonik Wiz's recent DIY post made me think this might be a good general-purpose topic. What are you all building out there? Here's one to kick it off:

I love music, and I love electronics. I also have a fondness for electronic music for some reason. :) As a nerdy teenager in the mid-'70s, I spent hours & hours at the local music store (where I later wound up working for 32 years), messing with one of the synthesizers they had on display, an ARP 2600. This now-classic synth was used by Edgar Winter, Joe Zawinul, and many many others, and it's the one that taught me how synthesizers work.

Unfortunately for me, the price has always been a non-starter. The 2600 sold for about $3400 USD back in the day; and if you want a nicely restored one now, it'll set you back around $10,000-15,000. Sorry, but nope.

BUT! Now you can buy a reasonably-priced replica of the original 2600, called the TTSH (Two Thousand Six Hundred). It's available in various configurations: as a completely assembled & tested unit, a complete kit of parts, or just individual bits like the front panel & PC boards. I work as an electronics tech, and I used to love building Heathkits as a kid, so of course the complete kit version was a no-brainer. It arrived last week:

TTSH_FP_and_Boards_resize.jpg TTSH_parts_resize.jpg

Here's a pic of the finished version, and a great one of Edgar in the studio with his 2600:
KITHCTTSHFULL01-800x800-800x800.jpg ARPedgarwinter_zzhi43.jpg
I haven't been this excited about a project since I was a kid! Not only do I finally get to own a 2600, but I get to build it from a box of loose parts!! Somebody pinch me! :LB

Okay, I showed you mine, now show me yours! :D What do you guys have splayed out across the dining room table??
 

Sonik Wiz

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Hi Kids,

Sonik Wiz's recent DIY post made me think this might be a good general-purpose topic. What are you all building out there? Here's one to kick it off:

I love music, and I love electronics. I also have a fondness for electronic music for some reason. :) As a nerdy teenager in the mid-'70s, I spent hours & hours at the local music store (where I later wound up working for 32 years), messing with one of the synthesizers they had on display, an ARP 2600. This now-classic synth was used by Edgar Winter, Joe Zawinul, and many many others, and it's the one that taught me how synthesizers work.

Unfortunately for me, the price has always been a non-starter. The 2600 sold for about $3400 USD back in the day; and if you want a nicely restored one now, it'll set you back around $10,000-15,000. Sorry, but nope.

BUT! Now you can buy a reasonably-priced replica of the original 2600, called the TTSH (Two Thousand Six Hundred). It's available in various configurations: as a completely assembled & tested unit, a complete kit of parts, or just individual bits like the front panel & PC boards. I work as an electronics tech, and I used to love building Heathkits as a kid, so of course the complete kit version was a no-brainer. It arrived last week:

View attachment 45334 View attachment 45335

Here's a pic of the finished version, and a great one of Edgar in the studio with his 2600:
View attachment 45336 View attachment 45337
I haven't been this excited about a project since I was a kid! Not only do I finally get to own a 2600, but I get to build it from a box of loose parts!! Somebody pinch me! :LB

Okay, I showed you mine, now show me yours! :D What do you guys have splayed out across the dining room table??
I think DIY, like HAM radio, is just not as popular as it once was because most everyone can do on the PC what used to be done with hardware. Besides you Par4ken is the only other DIY'er I know on the forum. But I am happy to say at one time every pice of gear that I had (except fot the VCR) was modified in some way or repaired . I even slogged my way through the Pioneer DVL-700 LD service manual & figured out how to defeat the always on video noise reduction (you pull a LSI chip out of it's socket, bend a pin up & connect it to ground).

I have posted about other projects I've dome here: the Quadraflange, Chase RLC-1, mods to the Space Matrix deecoder, etc. But man-o-man never built anything like the 2600 synthesizer! That is incredibly cool! Now I'm not a musician at so I wouldn't build that anyway. But I have built quite a few PAIA/SWTP stuff. Always read Craig Anderton's articles & I always learned something.
 

quadsearcher

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I repaired a 2600 years ago. It was "just" a shorted tantalum cap on the output, allowing it to pass DC. Fell in love with the thing. With normalled patches, it practically plays the opening to Weather Report Birdland by itself. And more. Well not really, but I'm not a keyboard player and it was easy to pick out, because the notes sounded just like the record (with some playing with settings). I didn't have the cash to buy it. Yes I would enjoy the kit.
My favorite of projects from the 80s (maybe that was 70s?) was just the effects module from PAIA Stringz n Thingz. Bought the board and stuffed it with stock parts and Radio Shack, put it and controls in an old radio case. Kind of like multiple Leslies except done by voltage controlled delays driven by separate LFOs.
 

Sonik Wiz

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Here's something I don't think I've posted previously. Not quite the usual DIY project but fun, pretty easy, & impressive.

Like others here I have a good 'ol Panasonic quad scope at the top of my gear rack. Works perfect, bright trace. It does take up a bit of space & I needed that top shelf to put in something else. So I pulled the Q Scope.

After a few weeks I started to miss it. I had an inspiration to use it located out of the way but put the trace on my 8' big screen. I have a closet just to the left of the rear of my audio rack with shelves so I put it there. It was too wide so I turned it vertically & the CRT was now on the "bottom". I have multiple generations of video cameras & I chose an old VHS-C unit for it's size & good close up capability. It was roughly put in position on top of some old Pop Electronics mags & supported laterally with a couple of bricks each side. It was a little clumsy but it didn't take long to get zoom/focus positiend & tweaked for no perspective didtortion. A composite video cable RG6 went from the camera to an input on the projector.

Since the Panasonic display is square (that is the bezel with the corner lights) & the vid cam format was square, and my screen is 4' x 7' the image filled top to bottom. I had a 4 ' Quad scope image.

It was as I said pretty impressive but fun. I got a blast out of it at first but eventually found it too distracting when listening to music. It's one thing to glance over at a 4" display but to have your attentionn riveted on a big display is straight ahead is too much. In audio vs video audio always takes the priority so eventually I quit using it. The Panny scope is now back home, sitting just above the Surround Master v2.
 

Soundfield

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I think DIY, like HAM radio, is just not as popular as it once was because most everyone can do on the PC what used to be done with hardware. Besides you Par4ken is the only other DIY'er I know on the forum.
Some others of us still dabble in the dark arts Sonik !.....

I previously posted about my little Hafler line level decoder:
HAFLER DECODER BOX
Experiment over, I gave it to a friend of mine recently who wanted to add Hafler surround speakers to his system – but could not do so conventionally by simply sticking the speakers across the hot terminals of the power amps as, like me, has valve amps with no common reference (being transformer coupled). It works really well and he’s delighted with the results – so much so that I might build him another with a delay circuit which improves on the effect, and a rear level control.

I was also in the process of building a three band full logic SQ decoder using the Motorola chipset. I designed a PCB for a single channel decoder and etched a set of three of them old style using ferric chloride (difficult to get these days)! One of the decoder boards and my hand drawn artwork is shown below:

Decoder PCB artwork and board.jpg


The intention is / was to feed them from a three band filter and to have different logic attack and decay characteristics in the decoders in each band. I’ve got all of the components sitting in a box, but the urge to complete the project was rather undermined by the arrival of the Surround Master! I may finish it one day, but as we all know, the path to Hell is paved with good intentions!
 

Sonik Wiz

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Some others of us still dabble in the dark arts Sonik !.....

I previously posted about my little Hafler line level decoder:
HAFLER DECODER BOX
Experiment over, I gave it to a friend of mine recently who wanted to add Hafler surround speakers to his system – but could not do so conventionally by simply sticking the speakers across the hot terminals of the power amps as, like me, has valve amps with no common reference (being transformer coupled). It works really well and he’s delighted with the results – so much so that I might build him another with a delay circuit which improves on the effect, and a rear level control.

I was also in the process of building a three band full logic SQ decoder using the Motorola chipset. I designed a PCB for a single channel decoder and etched a set of three of them old style using ferric chloride (difficult to get these days)! One of the decoder boards and my hand drawn artwork is shown below:

View attachment 45404

The intention is / was to feed them from a three band filter and to have different logic attack and decay characteristics in the decoders in each band. I’ve got all of the components sitting in a box, but the urge to complete the project was rather undermined by the arrival of the Surround Master! I may finish it one day, but as we all know, the path to Hell is paved with good intentions!
Hey Soundfield
I just wanted to say what a great looking board layout that is. IIRC the Vista/Photolume SQ decoder kit in Pop Electronics (?) didn't look near as clean. I have designed & etched more than a few PCB's myself so I understand the efforts. Like you I also have some etched & drilled & never used. At least I worked in the photographic field most of my career so I always had easy access to shooting the liths.

And I thnk that's very clever to use tri-band decoding with the Motorola 3 chip design. Even more clever if you could design the phase shift components to be more accurate for those pass bands. Since the chips use DC control coltages for balance/level/dimension you would now have to use ganged controls. Tri-band decoding would certainly reduce SQ Fool Logic side effects. Better than chasing down the Paramatrix rabbit hole.
 

Soundfield

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Essex, UK
Hey Soundfield
I just wanted to say what a great looking board layout that is. IIRC the Vista/Photolume SQ decoder kit in Pop Electronics (?) didn't look near as clean. I have designed & etched more than a few PCB's myself so I understand the efforts. Like you I also have some etched & drilled & never used. At least I worked in the photographic field most of my career so I always had easy access to shooting the liths.

And I thnk that's very clever to use tri-band decoding with the Motorola 3 chip design. Even more clever if you could design the phase shift components to be more accurate for those pass bands. Since the chips use DC control coltages for balance/level/dimension you would now have to use ganged controls. Tri-band decoding would certainly reduce SQ Fool Logic side effects. Better than chasing down the Paramatrix rabbit hole.
Thanks Sonik, yes, the PCBs were something of a labour of love - I even had to build my own UV light box to expose the photo-resist. If the project ever gets to fruition I will be trying different phase shift networks. The ganging of the control voltages across the three parallel decoders offers opportunities but is a bit fiddly. I wonder why no one has ever tried this arrangement before?!!
 
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