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Jen SX1000 (Synthetone) [Midi-fied]

My 1st Jen SX1000 at one stage...

My 1st Jen now....



Jen SX1000 and C Y

bulletI got my 1st Jen after i went to a gig and saw a group using it on stage.
bulletThe Jen was the 1st synth that i really got into modding... didn't do a good job the 1st time round, but learnt a great deal. Thing about the Jen is, it's broken down into 4 PCBs and it's like 4 modular pieces stuck together.

bulletLove it because it's simple, and it can do some wicked PWM soundz.
bulletHate it because it's expensive to get proper CV - have to get a Kenton CV retrofit, it's not just sockets, it comes with a daughter board which Kenton has built to compensate the weakness in the Jen in taking up proper external controls - it's very well built i must say, but just a bit pricey....
bulletThis 1st Jen, there were many noisy/scratchy pots, ad i think i replaced 5 - 7 of them!
bulletI have also installed a Synhouse Midi Jack on this Jen - it's all right, but what i hate about midi jack is it doesn't do pitchbend or portamento, and the Kenton CV in doesn't do portamento either, so it's have to rely on the midi-CV to get pitchbend and portamento.
bulletLots of the Jen SX1000s are missing the colour knob caps.... it looks bad. I am lucky that this Jen has 95% of the caps there, only missing like 3.... and they always tend to fall off...

Some caps have fallen off... where are they.....

bulletA little later, i got a 2nd Jen, This Jen was believed to be faulty - indeed it was, the audio was very very low and seemed like the VCA out had problems - so it was sold relatively cheap to me. In the end i found that it was just a faulty jack socket that was causing the problem! Took me 15mns to find the fault and fix !! (LUCKY!!!)
bulletThe 2nd Jen is slightly different. It's a later model, the PCBs are slightly different because they were now using different Pots - the pots on the 2nd Jen are chunky big pots! It somehow also seemed to me that the components of the 2nd Jen are slightly better... 
bulletAlso, the knobs on the 2nd Jen all have screws. The 1st Jen only has the selector knobs that had screwed nuts. On this Jen, all knobs are screw securely....

Jen with chunky pots and also the Kenton CV board

bulletOnly a couple of little/minor issues with this 2nd Jen - the front panel is a little rustier than the 1st.... also, the rotary selectors are a bit noisy, otherwise it's quite good!
bulletAfter fixing the 2nd Jen, i already planned what to do - exchange the boards to the 1st Jen, and then use the boards from the 1st Jen to make a Jen Rack !!!

bulletThe 1st Jen keyboard is now revived. Currently (as of Christmas 2003) I'm still working on the rackmount..... [project halted at the moment...due to.. hmmm... complaints from neighbours about the drilling noises!! ]...



C Y 's Mods on the Jen SX1000

Most of the mods i've done are combinations of mods from Bluebear, Håkan Eriksson and Neil Johnson's sites.
I didn't do all the mods, as i planned to do some more on the Jen Rack.
bullet Jen Kbd Mods:
IEC Socket, Sub-Osc, External Audio Input, Amplitude Boost, Filter Cap Bypass, Saw Multiplier, Kenton CV & Synhouse MidiJack
bullet Jen Rack planning....
bulletAdditional Jen Rack Mods: 2nd LFO, 2nd White Noise, Swell Pedal/CV In




What's what on my Jen SX1000 keyboard

Originally I had 4 switches for the Sub-Osc and so on... Since i had to change the rotary switches on the 2nd Jen, i moved the sub-osc and external audio input to the noise selector knob. So now I have put the switch and pots for the sawtooth multiplier here.

On the right, there's the Midi Jack Config switch and Cal hole, also a switch for selecting internal keyboard and external CV/midi. The switch next to the filter on the top right is just for bypassing a cap in the filter input thus resulting lesser HPF.

on the rear:
IEC Mains Socket, Audio In/Out, Midi Jack Footswitch Input, Kenton CV/Gate/Filter Sockets and Midi In. 



The 2nd Jen Keyboard, wood-ends and panel...
This is now sold to some nice gentleman (Hi, Paul!) who needs them to revive his Jen.



Some Jen SX-1000 Soundz

Here're some of Jen's soundz - basically the "famous" PWM....
bulletJen PWM 1
With PWM, playing Octave Bassline, slowly turning the filter slightly up.
Then added the Sub-Osc (-1 octave)...
bulletJen PWM 2
PWM Lead sound, changing the LFO speed - then adding the Sub-Osc (-1 octave).
bulletJen PWM 3
Another PWM Lead sound, with a little Portamento, again changing the LFO speed - you can hear it syncing and de-syncing....
 -> Play ALL



Other Links on the Jen SX1000...

bullet Neil Johnson's excellent Jen Restoration site with full detailed documentation on modding the Jen...
bullet Bluebear's Jen SX site
bullet Håkan Eriksson's site with Jen SX1000



C Y 's files on the Jen SX1000

Jen SX1000 Schematics1 Coloured
bulletThe Jen SX1000 Schematics that you could download are splitted into 4 pages. I found it a bit hard flipping thru them, so i glued them together into 2 big images, and put little colour codings on them for easier read/trace. 
This is the 1st part - PSU, VCO & LFO

bulletNote: Somehow, the gif (strangely) might not open in Internet Explorer (dunno why), but it is downloadable (ie, do a "Save as...")

Jen SX1000 Schematics1 Coloured

bulletThis is the 2nd coloured schematics for the Jen SX1000, mainly the VCF section and also the VCA.
bulletNote: Somehow, the gif (strangely) might not open in Internet Explorer (dunno why), but it is downloadable (ie, do a "Save as...")




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