MATRIXSYNTH: Farfisa Syntorchestra demo and tech tips


Saturday, December 07, 2024

Farfisa Syntorchestra demo and tech tips


video upload by ohm_studi_ohm

"i've serviced several Syntorchestra and I found out that because of the age, build quality and design limitation of the synth, owners can sometimes wonder if their unit is working and sounding how it should.
So here you have an example of a properly working unit, with its strength and weakness. These instrument are quite unique. Before I laid my hands on one I was not really convinced by the demos I heard. Sure is sounded nice but nothing to rave about. But I must admit that when you have the chance to play with one you get quite quickly drowned in its sound. There is something very unique about that instrument, nothing I can really compare it too. Especially when you play both sections together, something magical happens.
First part of the video is a quick performance using a Welson S12 drum machine and Vermona VRS23 for reverb. Second part is recorded dry from the synth with no production. I go over every sound and parameter of the synth in that section so you can compare to your unit.

TECH TIPS: (check this page for full tech tips: https://gearspace.com/board/electroni...)

Among the issues often raised is the 'hanging note in the background', especially audible in the mono section. What happens is that in the mono section when no keys are played you will hear a quite audible note in the background. Pitch of the note is that of the last key pressed and is related to the footage of the preset (32/16/8/4). I demoed this very explicitely from 15:10 on. This is not an issue and is actually by design. All the syntorchestra I had at hands behaved the same, and level of the note was the same too (I currently have a second Syntorchestra that sounds exactly like that one). I think it is meant as a way to keep the VCA of that section open.
As far as floor noise is concerned, these are moderately noisy. Far less than most of the italian string synths, mainly because it does not include a BBD ensemble FX which are a notable cause of high floor noise. Normal signal to noise ratio is that you can hear at the end of the video, from 15:00 on. In case you have a doubt about your unit you can compare it to that one.
If one of the section has a noticeably higher noise floor than the other, especially if it's unconstant then you may want to check the preamp op amp of that section, SN76131N. These are obsolete but can still be found, and there are some equivalent (don't have the reference at hand). If you suspect that chip and don't want to source one without being sure you can simply invert the 2 chipsets of the 2 sections
recapping: like most of the italian stuff from late 60s/early 70s the electrolytic capacitors are of bad quality, probably the worst ever produced, Facon and Ducati. A full recapping is a must do on these instruments
wires: they are lots of wire in there and they can easily break. Usually they just break at the solder point and you don't necessarly see it. Check every wire by carefully pulling them. If for one reason of another you have to unscrew and move a pcb (like for recapping) you will have some wire they will cut, this is 90% sure. Before you do anything TAKE PICTURES of the wiring. Detailed pictures. You will thank me for that.
pcb cleaning: there seem to be some kind of green varnish Farfisa used to protect solder joint I guess that tends to deteriorated in some kind of gluish tar. If possible clean the PCB with isopropyl and check the wire and solder if there is a lot of that greenish sticky material. You may need to cut wires and redo the soldering in order to have a proper connection
tuning: the mono section takes a very long time to get at temperature, Something like 30 minutes at last. It's not a big deal since you have that dedicated pitch fader that will help compensate for the bad tuning while it warms (or acts as a detune of course). Warming only affects root note, not scaling, so if your synth is rightly calibrated and tuned it won't affect that.
If you need to calibrate the synth i strongly advice to let it warm AT LEAST 1 hour (that is for the mono section only). To do so just follow the procedure found in the service manual, it's well explained and easy to achieve. Poly section is based on Top Octave Oscilator so it won't be affected by warming time (providing you have a nice clean recapped power supply) and you simply tune the root note at the back of the synth with the dedicated screw type potentiometer. It's a set and forget one."

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