TSL Off-board wiring

[eljay]

Hi Tony, I'm just completing the off-board wiring for my 3U wide Transistor Superladder (yes at last I've got to it) and I just wanted to clarify one thing. In the guidance at the bottom of page 12 (Issue 3.13 BG) you refer to the use of the pads in the I/O box, specifically you mention the use of pads 5 and 7 which connect to module ground, am I correct in thinking that these connect to the NC lug of the Resonance CV socket and the other to one of the NC lugs of the other 4 CV input sockets? If so which one?

[Synthbuilder]

If so which one?

All the NC lugs of the input sockets, both CV and audio, should be connected to module ground (0V). Given that you only have two pads to solder all these wires, this will usually involve some daisy chaining of wires. Now how you do this is up to you, but if you have used standard 112A sockets and not the PC mounted version it's pretty straightforward. If you have used the PC mounted version then you can build a solid core wire frame much like I do for the panel ground connection. Just make sure any inserted tip doesn't short into the wire frame.

Tony

[eljay]

Thank-you for the clarification Tony, I think I was led astray by the table on page 12 of the BG describing the I/O pads for the 1U version which on inspection differs from Schematic page 3 and I think has a couple of incorrect descriptions. I think Pin 3 in the table should say Connect to Resonance NC, giving (Pin 3 - GND - Connect to RESONANCE - NC Lug) and Pin 7 should say connect to Input NC giving ( Pin 7 - GND - Connect to INPUT - NC Lug).

[Synthbuilder]

I think Pin 3 in the table should say Connect to Resonance NC, giving (Pin 3 - GND - Connect to RESONANCE - NC Lug) and Pin 7 should say connect to Input NC giving ( Pin 7 - GND - Connect to INPUT - NC Lug).

Yes, you can do that way. The method shown for the 1U build in the Builder's Guide just saves you a wire. My thinking behind this is that if you only have one audio input, there is no need to have that input's NC lug tied to 0V as you wouldn't be using the module without an input lead connected. I guess there is a possibility of using the TSL as a oscillator but the amount of crosstalk picked up by the floating audio input would likely not be heard over a self-oscillating filter.

However, I will make a change to the BG to mention that you can use pin 3 as 0V point as well as 5 and 7.

Tony

[Synthbuilder]

Actually, I was just checking this and it sparked a distant memory of why pin 3 is unused. This goes back to the original Diode Superladder many years ago. Pin 3 is not used on the DSL, it floats and, even though this was changed on the TSL, the wiring for each of the 3U modules was made to be the same.

[eljay]

3U TSL Rear left

3U TSL Rear right

3U TSL Front Panel

Assembly complete, initial testing shows all is working, pots and sockets correctly wired, sounds great already! Just remains to be calibrated, a task for tomorrow.

As you can see I used a couple of Sock4 boards to help wire the pots, both links (L1 and L2) were made to ensure all NC lugs could be connected to ground which I did by using some stiff single core wire to make a small wire frame to link the connections. I used the three GND connections on the I/O socket (pins 3, 5 and 7) one for each Sock4 and the third for the standalone RES CV socket.

I've used thin strips of stripboard to wire the pots and also stop the pots from twisting if they become loose.

I've used Molex connectors to connect all external wiring to the topside of the board, I could have attached the input pots header to the underside of the board which I guess might have made the wiring a bit neater but my preference was to put all the connections on the top. Overall, given the amount of external wiring I don't think it looks too bad.

It seems such a shame that the Oakley 5U range has come to the end of its commercial life, these modules IMHO look and sound superb. I bought quite a large number of 5U DIY modules earlier this year when the first hints of demise were mooted so I have all the Oakley PCBs I need to complete my 99U case that I've just built to re-house and extend my 5U system but there is a definite feeling of sadness that these products will not be available for DIY in the future.

Many thanks to Tony for introducing me to the world of DIY modular synth, I look forward to anything new you may develop in the coming years.

[terjewinther]

Nice build! You need to show us the 99U case when finished.

[waldenpotato]

Nice looking build.