[Build Thread] Jasper, an EDP Wasp Clone

[jasonl]

25 January 2017 - 4th run PCBs - ready to ship

It's been too long. Anyway the 4th run PCBs are ready to be shipped.

Essentially the PCB is the same as the previous versions - but I wanted to update the silkscreen to match the current BOM.

A Mea Culpa - I was also tempted to adjust the 'phones out to enable the use of mono Cliff jack sockets as well as the stereo ones used. A very simple change to swap the speaker output to the centre pins on the socket. And I made a mistake here.

So when a stereo cable is plugged in, signal is only output on one channel, not both as intended. It still works, only affects the 'phones output.

A fix is easy, if you wish to do it. It's not obligatory as the amplified 'phones output is designed for older style high-impedance phones or equipment needing higher input levels. I've attached a note to this post describing the issue and fix. If you're not using the 3.5mm jacks then this is academic anyway.

It doesn't affect the operation of the rest of Jasper - which still sounds great. I built a PCB just using the silkscreen values, not referring to the BOM at all and everything works fine.


Update 31 August 2016

Finally an updated build guide attached below covering the second version PCBs!

Update 14 July 2016
For the second PCB run, an updated BOM taking in account the differences between the second version and Jasper from the first run.

Update 5 April 2016
Finally completed an initial version of a construction guide, and a FAQ document. The construction guide is quite large, and illustrates the construction of the PCB and panel set. Or at least it shows how I make up the PCB....

Here are some audio samples

Update 21 March 2016
PCBs have started shipping!

This is the build thread for the Jasper, EDP Wasp clone PCBs.

The original thread is here: viewtopic.php?t=151625

BOM, PCB and Panel measurements, Enhanced mode PCB construction guide are posted below.

Jasper Construction Guide, FAQs to follow.

[dalhasumai]

yay !

[LED-man]

how about a powersupply, any kind of 12V DC with 1000mA works ?

[jasonl]

how about a powersupply, any kind of 12V DC with 1000mA works ?

Should do. Jasper uses less than 40mA using the line out, or less than 200mA if driving a speaker. Basically anything between 6V and 12V will do.

The MCP1702 I specify has a low dropout voltage of less than 650mA, but has a maximum input voltage of 13.2V. The 386 amplifier runs at the unregulated voltage - again a max voltage of about 12V is sensible.

I've tested using a 9V PP3 battery, linear bench power supply, small wall wart, large 3A 12V power brick....

Noisy (cheap?) switching supplies could affect the keyboard sensing circuit, but I've not had any problems with the supplies I've tried so far.

[4floorsofwhores]

I'm assuming negative leg of electrolytics is the yellow side. Can anyone clarify?

[jasonl]

I'm assuming negative leg of electrolytics is the yellow side. Can anyone clarify?

Yep. Long positive leg goes through square pad.

[4floorsofwhores]

Thanks Jason. That was quick

[duff]

PR140 appears to be 50K in the BOM and 100K on the board. Is there a preferred value?

[jasonl]

PR140 appears to be 50K in the BOM and 100K on the board. Is there a preferred value?

It should be 100K. I'll correct the BOM. Thanks for pointing that out.
In the original Wasp service manual R140 is a sort of 'select on test' resistor for the keyboard sensitivity.

[duff]

Ok my first one is up and running.

I had an initially comedy issue of no power - prodded and poked for a while before looking at the schematic and seeing that there should be a switch but couldn't remember installing one. Went over the board looking for where the switch went and couldn't find it. Eventually remembered the switched pots! Switched it on and had power.

I also initially wondered why I could see a trigger on the link header but my envelopes and VCA would not fire but I had missed LK1 out.

Now I just need to work out why I have permanent pitch modulation, but that can wait for tomorrow.

Edit: Oh and the pink stuff Tayda uses to pack ICs is the perfect height for lifting the alpha pots up to meet the panel.

[jasonl]

Ok my first one is up and running.

I had an initially comedy issue of no power - prodded and poked for a while before looking at the schematic and seeing that there should be a switch but couldn't remember installing one. Went over the board looking for where the switch went and couldn't find it. Eventually remembered the switched pots! Switched it on and had power.

I also initially wondered why I could see a trigger on the link header but my envelopes and VCA would not fire but I had missed LK1 out.

Now I just need to work out why I have permanent pitch modulation, but that can wait for tomorrow.

Edit: Oh and the pink stuff Tayda uses to pack ICs is the perfect height for lifting the alpha pots up to meet the panel.

Wow, that was quick!

Excellent idea to use the foam as spacers for the pots. I'm just completing the build I'll use to illustrate the builders guide so might suggest that as an alternative to the way I've been doing it.

Re the pitch mod - check that R62 is 470ohms - this sets the minimum gain for the LFO/pitch voltage when VR4 is counter-clockwise.

Again, well done for getting Jasper built so quickly!

[jasonl]

PR140 appears to be 50K in the BOM and 100K on the board. Is there a preferred value?

It should be 100K. I'll correct the BOM. Thanks for pointing that out.
In the original Wasp service manual R140 is a sort of 'select on test' resistor for the keyboard sensitivity.

I bought a 50k. Can I transform it into 100k? Thx

A 50K might work if you replace R140 with a larger value - try 68K to start with. PR140 is used to centre the point of the sensitivity pot at which the keyboard self-triggers.

[duff]

Re the pitch mod - check that R62 is 470ohms - this sets the minimum gain for the LFO/pitch voltage when VR4 is counter-clockwise.

Again, well done for getting Jasper built so quickly!

Turns out my pitch mod issue was a stray component lead offcut, so that was easily solved.

Thanks for the great project it was a nice straight forward build - although soldering 626 IC pins in one go was a bit of a slog! To be fair, I am not quite finished; My hold switch is a jumper, I am short a 9mm A50K pot for Osc 2 level (currently also a jumper), and I need to replace the sensitivity and tune trimmers - I used pots with standard length shafts as I had some to hand, but they are way too short. I also need to decide if this one is getting a speaker and/or batteries....

But for now

[Paradigm X]

Amazing work duff. and jason of course, looks like an easy and satisfying build. def in on round two!

[SmartBits]

I would like to order most components from Mouser (and TME.eu) in order to avoid nooby mistakes, but the
Hold switch (hold mod SPST) from the BOM has no stock at Mouser. What alternatives can I use from either Mouser or TME?

[LED-man]

I would like to order most components from Mouser (and TME.eu) in order to avoid nooby mistakes, but the
Hold switch (hold mod SPST) from the BOM has no stock at Mouser. What alternatives can I use from either Mouser or TME?

TME: 25346N

[jasonl]

I would like to order most components from Mouser (and TME.eu) in order to avoid nooby mistakes, but the
Hold switch (hold mod SPST) from the BOM has no stock at Mouser. What alternatives can I use from either Mouser or TME?

TME: 25346N

That's for the power over Link switch (which could be left out if you're not using the 8pin link sockets, or replaced with 0.1" 3 pin jumper.

The hold switch is a sub-miniature toggle switch (either SPST or SPDT) - On-Off or On-On.

From TME, try: TSSM1022A1 or TSSM1022A2 - the latter may be better as it uses PCB pins that can be cropped closer to the switch. There's not a lot of room underneath the panel.

[jasonl]

Double-post

[SmartBits]

Great, thanks!

[SoundPool]

nevermind. I apparently can't open a package correctly.

[jasonl]

got mine today- board and panel look great! While I can get most of my basics from Tayda and it looks like almost all the rest from Musikding anyone have any other sources for the switched pots from Farnell? Looks like international shipping might be a real pain for them. Preferably somewhere that offers fair international shipping (to Norway), or ships in Germany since I'll be there and can pick stuff up in a month.

You should have got a set of switched pots with your PCBs. PM sent.

[Grumskiz]

Just sent out an order for most components, but forgot to add the LM386
Is there a good substitution that I could already have in my part stash or does it have to be this part exactly?

[4floorsofwhores]

Noobie question again sorry. Can i leave out the link sockets? do i need to link anything? cheers

[jasonl]

Just sent out an order for most components, but forgot to add the LM386
Is there a good substitution that I could already have in my part stash or does it have to be this part exactly?

Any Lm386 or NJM386 should work - I tested with various -1 -3 and -4 variants and they all seemed to work OK. It's an audio amplifier, not a conventional single opamp, so a 741 or TL071 won't work.

However, if you just use the line output jack, you don't need the LM386 at all.

[jasonl]

Noobie question again sorry. Can i leave out the link sockets? do i need to link anything? cheers

They're not obligatory... But in my opinion Link is part of the fun things with Wasp/Jasper, as it lets you connect more than one together, or use a sequencer like the Spider, or an external Midi-Wasp adapter. Whether you want to use the on-pcb sockets is up to you, and depends a bit on how you wish to enclose the PCB.