Yamaha CS-70M

We are Brokering this instrument for and on behalf of our UK customer

Servicing Status: KSR have carried out a full service this CS-70M in July 2023.


This was one of those ‘time capsule’ moments when then owner of the CS-70M turns up with the instrument contained in its original retail packaging, and reveals the best condition example I have every seen in 22 years as a specialist vintage synth dealer. This CS-70M was purchased new by my Client on 25th February 1983. We have an image of the original sales invoice from 1983 (kept confidential but will be supplied to the new owner), along with all the original documentation, so Owners Manual, Service Manual and the colour printed Yamaha Sales Brochure for the CS070M (all pictured below).

The CS-70M has for many people been overlooked, overshadowed by its bigger brother – the CS80, but this instrument has ascended in popularity among aficionados, and we know this synth is highly sought after by those who truly appreciate it.

6 Voice, dual-channel (stereo), aftertouch, 30 memories, ring-mod, chorus & Leslie effects, lowpass, high-pass, and bandpass VCF, fully programmable and with a 4 channel polyphonic sequencer etc.

Those in the know will already tell you that this is one of the finest hybrid analogue polysynths ever made and a work of audio art in its own right.  It shares most of the same technology as the CS80 and many of the characteristics and tonal qualities as well. The big ‘plus’ over the CS-80 is the digital auto-tune facility that snaps the voice cards into tune upon powering up the synth.  These models do not suffer from any wayward tuning issues, so this was a step-change for Yamaha when this hybrid polysynth hit the market, of that over the CS-80 and its pure analogue foibles at least.

There are a few demos on YouTube of these but we like this rather ambient-noodling one from the Channel of MoreAnalog as it demonstrates nicely how the CS70M has that beautiful ambient CS80 vibe we love about this synth: 



As mentioned above, this is a remarkable single owner example that perfectly meets all the criteria to be a fine collectors item, as well as a usable music instrument. This is a completely factory stock survivor machine, so has not been retrofitted with MIDI, so no holes have been  drilled into its pristine case, so this lacks MIDI, but once you buy it then you can decide if that’s important to you to have implemented of if you prefer to retain its originality and collectable value by keeping it original.

The serial number for this CS-70M is: 1654


The cosmetic condition of this example is exemplary with no perceivable ageing to the control surfaces. The faux wood laminate cabinet is in outstanding condition, unmarked, We would grade this as in Excellent condition – 10 out of 10 cosmetically…really.

All the original controls, slider-caps, knobs are intact and everything still looks sharp and clean.  We have all the original manuals and other documentation as mentioned above. There is even the small rubber cover for the Keycode port on the rear-panel still in place.

Operational Condition:

Operationally, our trusted and world-renowned ‘Yamaha CS Series’ restoration expert – Kent Spong of KSR, has already carried out a full service on the CS70M, so it’s 100% perfectly working and ready for its new owner now.  Servicing included re-capping the PSU, full system-wide test and calibrations and cleaning of sliders and pots where needed as the synth has been sat unused for some time so it did need some light attention, but we wanted a very light touch with this instrument. 

The only item that we need to report that is non-functional is the magnetic strip reader as there is a custom Yamaha IC that has failed on the reader and that part is no longer available. This is a very common problem on the CS-70M and we don’t currently have any workaround for this, so we are declaring it here so you have full knowledge when considering to to purchase the instrument.

The CS-70M operates from 100V to 240V as there is a switchable PSU switch(s) on the back panel, and this Yamaha is supplied with its original & proprietary 2-pin power cable. The unit has been fully tested under UK 240V conditions at the KSR workshop.

Packing, Shipping, Insurance and Warranty: 

We can ship this CS-70M worldwide, although the packing, shipping & insurance costs are not included in the sale price below, so are subject to quotation.  As this is supplied in its original retail box, then we would have to order a custom sized export-grade cardboard carton that encompasses the OE box as well, so it will be a large and heavy.

There may be some short delays in getting the packaging materials produced for shipping as they are custom ordered for the specific dimensions of each instrument.  We are happy to discuss your requirements so please email us if you have any questions on the logistics and/or need a quote, but you are also welcome to collect it from us in person in Reading, UK.

As the instrument is being Brokered through RL Music, it will be sold with a full 3-month (return-to-dealer) warranty, covering all parts and labour.

Sales Price: 

£10,990 GBP

VAT is not applicable to UK buyers, however, the packing & shipping costs are subject to VAT @ 20%, should you need the goods shipped to you.  


This CS-70M is available for sale now.

Click on the thumbnail for a higher resolution photo of the actual CS-70M for sale.  If you require specific pictures not already featured of the instrument then please contact us so we can try and accommodate your request but there may be a short delay in getting this done for you as the instrument is currently in secure storage.