Thursday 7 November 2019

Jasper-Wasp build pics - part 1


Jasper Build notes. I'm building this for a friend.
These aren't official notes and I'm not a professional Synth Technician..
Just my personal thoughts to help me trouble shoot if I encounter any probs.

The official website where you can buy a kit is here:
jaspersynth.co.uk

There are lots and lots of CMOS ICs. This is almost a Lunetta synth. Here is my page on CMOS &  Lunetta synths


Anyway, the integrated circuits used in this build are mostly CMOS (with a smattering of the occasional op-amp). I've got a few old vintage WASPs and I love how they sound .esp considering the simple components.
This is the main Jasper PCB. The keyboard is attached.
I like how the colour of the keys is reversed.

 iT should be a fun build. This is a rev 2.2 , July 2017 PCB.


Here is a list of the ICs used.
LM386 or NJM386D
555
CMOS 555 like TLC555CP recommended
LM3900

CD4006 - shift register
CD4013 - dual flip flop
CD4016 -- analog bilateral switch
CD4019
CD4024 - shift register
CD4028
CD4040-- counter .. binary,ripple
CD4046 .. PLL phased locked loop... probably the VCO
CD4052 .... multiplexer.. dual 4 channel
CD4069UBE... its an inverter ... I think this is part of the wasp filter ???
CD4070... XOR gate
CD4071....quad two input OR gate
CD4081... quad 2 input AND gate
CD4503
LM13700
CD40103
CD40174

There are many ways to build this but I like to put the IC sockets on first.

Then caps, resistors, etc. All the simple non polarized stuff.

* R9 and R15 may need changing to adjust master oscillator tuning (4K7 on original).
** R56, R99, R163, R171 changed to 68K to adjust level of pulse/square when using osc vol pots. (150K on original)

For the moment, I'm using what's in the BOM.
R9 & R15 = 3K9
R56, R99, R163, R171 = 68K



Electro caps are polarized. Insert thus: Long lead in square hole.


The link port cable on the underside of the main board.
 The switched pots.


Fix everything into place then solder.

The rotary switches. You need 6 of these.
These are 2 pole, single level.

two alternatives
LorinCK1060
Alpha SR2612F

I went with the Lorin... more expensive.

 You need to cut the shaft to the right length.


You can set the number of positions with the key washer:
In the pic below, it's set to 4.

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The original vintage circuit also uses the CA3080 ... a OTA...Operational Transconductance Amplifier instead of your standard Op-amp
An OP-AMP is a Voltage to Voltage amplifier.
The OTA is like a op-amp but the output is a current source instead of a voltage source.
Also the OTA has 3 inputs (unlike a op-amp with 2) . The 3rd input sets the gain with a current.

To be continued................. Part 2 of this build is here:
https://djjondent.blogspot.com/2020/02/jasper-build-notes-part-2.html

Links:
+ Jaspersynth
+ BOM
+ Build notes
+ DSL man.de
+ Knobs
+ Elby Knobs
+ Muffs 
+ Muffs - 1 
+ Muffs - Build thread 
+ Buying Jasper
Mouser cart
 

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