[sdiy] Synthi A repair and modifications by Robin Wood at EMS?

[beschaving at gmail.com]

Hello everyone,

Okay, not really DIY, but concerning the modification of an exisiting  
instrument...
I'm considering sending in my Synthi A MkII for calibration,  
maintenance and a number of modifications to EMS.

Any comments about servicing and modifications to the Synthi by Robin  
at EMS would be greatly appreciated. Which mods seem useful, how long  
did it take to be done? It would be great to hear some recent  
comments and experiences of others...

Most important to me would be the question of how long it would  
take... I use my Synthi almost every day so I wouldn't want to be  
without for a long time. The other question would of course be how  
much Robin at EMS charges for servicing and possible repairs...

I've had this Synthi for a little over a year. A number of the  
potentiometers crackle and don't turn smoothly, and the dials for osc  
1 frequency and reverb mix don't work properly.

I'm considering the following modifications:


> Oscillator Sync - variable via potentiometer(per osc)              
> 20.00
>
On oscillator 2 only.


> Voltage Controlled Shape                    (per osc)              
> 20.00
>
On all oscillators. Does this work with a patch cable going anywhere  
into the matrix?


> Hi/Lo frequency range - switchable          (per osc)              
> 25.00
>
On all oscillators. This extends the range of all oscillators from  
ultrasonic to slow LFO range, thereby making oscillators 2 and 3  
identical in functionality, right?


> Attack time extension - increased to 5 seconds                     
> 15.00
>
Probably...


> Voltage Controlled Filter Response ('Q')                           
> 40.00
>
Probably... Does this work with a patch cable going anywhere into the  
matrix?


> Centre-zero trapezoid - gives inverted bipolar output              
> 30.00
>
Probably...


> Patchable Voltage Inverter                                         
> 35.00
>
Probably...


> Extra Input Channel                                                
> 30.00
>
Not sure about this one. Would this be a third, independent line/mic  
input channel? Where would it be on the matrix? Would there be a  
separate socket for it on the control panel?


> Switchable 18/24 db per octave filter                              
> 15.00
>
Probably...


> Filter 'unslew' switchable on filter's CV input                    
> 15.00
>
Probably...


> External gate input using Control Output socket                     
> 6.00
>
Could this also be done using a separate input socket on the panel,  
so that two control output sockets remain available? This is actually  
already available on the Jones socket, right? I suppose I could just  
run a cable into there if I want to send gate signals into the Synthi  
from the outside world...

This list I have from an e-mail of Robin Wood from a few years ago.  
I'm assuming all these mods are still available, and that no new ones  
have been developed in the mean time (if this is the case I'd be  
curious to hear about it). I'm also assuming the prices haven't changed.



Thank you very much

Alex