GOLT !

Synth Repair and Restoration Videos

One of the things I am really passionate about is saving old analogue synthesizers. In fact it's probably my most rewarding hobby. I spend hours and hours not just repairing synths but restoring them to "as new" condition. This can involve total disassembly and cleaning each part individually or searching the world to find an original replacement knob. Sometimes it takes much longer to clean a synth than it takes to repair it.

Another thing I am really passionate about is the transfer of knowledge. We are only the temporary guardians of these wonderful synths. It is our responsibility to pass them on in the best condition that we can. For this reason we all must share in the knowledge of how to keep them running and in good condition. We all must be aware of each synths strengths and common failure points. During each restoration I usually encounter a problem I have not seen before, or a mistake in the manual, or a better way to do something. Every piece of knowledge that I gain I will pass on through these video's.

If you are interested in synth repair, analogue circuit design, or electronics in general, please subscribe to my YouTube channel. I have not activated the monetary side of the account so there should be no ads. I plan to set up a Patreon account soon.

You can click the title of each video to open it at full scale in a new tab.

OBERHEIM

OBERHEIM OB-X

The OB-X is a notoriously unreliable synth until it is serviced well. Luckily the repair community has nearly 40 years of accumulated knowledge regarding the OB-X, which means today it is a relatively straightforward synth to repair. The most common failure points have been known for a long time, and the circuity is mostly discrete and still obtainable. I love this synth and have put a lot of time and effort into this series of videos.

YAMAHA

YAMAHA CS-60

All three synths from the early Yamaha CS series are very highly regarded; for their expressiveness and their characteristic "Vangelis" sound. But with careful programming they are much more than that. The CS-60 sits in the middle of the early CS range and is an excellent acquisition if you can fine one. These video's show a full restoration including repair, cleaning and calibration. Including an explanation of the power supply and voicing circuits.

YAMAHA CS-20m & CS-40m

The third (and last) group of synths in the Yamaha CS series had wood side panels and rudimentary patch memory (the M in the name stands for Memory). However, in this late CS series only CS-20M and CS-40M had two oscillators per voice. The CS-70M had a single oscillator per voice, but contained two voice layers (much like the CS-80). These late CS instruments have the best filter sound of all analogue Yamaha's in my opinion, but unfortunately only one filter per voice layer. There are more video's to come on these synths, I just haven't got around to filming them yet.

ROLAND

ROLAND Juno 6

The DCO synth that started it all! (well sort of... it at least kicked off the Juno family and DCO use in general). This is actually a really charming synth. The lack of patch memory has huge benefit, it's the only Juno that does not have digital stepping in the filter. At high resonance the filter sweep is silky smooth. It's still super limited, but so are all the Juno's in one way or another.

ROLAND SH-101

A great little monosynth (I mean "little" in vintage terms). I've never been a huge fan of the CEM3340 saw wave, but no one cares here as the pulse and square on this thing are awesome. Especially with the sub oscillator being able to go down two octaves. The filter is classic late Roland, very wet and powerful. The keyboard has serval weaknesses, one of which is shown in this video. The rubber key contact rubs directly on circuit board traces and can wear out tracks. Apart from that it's a relativity reliable synth with a simple design.

ROLAND TR-808

This is the one. The synth I can't be without. Many years ago I sold one only to buy it back again after all the Roland clones (of their own stuff, roll eyes) came out. In my opinion the 909 sound has been really well cloned for a while now, but there's something about an original 808 that is so much more organic than the clones. This is the only physical object that I have an unreasonable personal attachment to. I also know it's circuits like the back of my hand because I used to modify them in the late 90's.

AKAI

AKAI AX-60

So many things about this synth remind me of the Memorymoog, and it's not just that they share the same Panasonic keybed, or that both can make the VCO modulate the filter. Their standard electronics are not very reliable and both have power supply issues. So much so that I decided to redesign the power supply in both synths, but it's the AX-60 that benefits from it the most.

If you have the standard power supply please don't adjust it as I do at the end of the first video. Yes the voice chips will tune better (and that was my point) but the standard power supply has a lot of trouble holding that voltage for a long time (and may die). If your CEM3394's have drifted permanently, it's best to just upgrade the power supply. The synth tunes MUCH better after that and sounds a lot better. The new AX-60 power supply is now finished and the related files are in the Synth Resources section of this website.

MOOG

MOOG MEMORYMOOG

Probably the most notorious synth in the world of synth repair. The inside looks like spaghetti. But aside from the internal mess, it's really no different from any other analogue synth of the same era. The oscillators were common CEM3340's, the filters had been around for 15 years or so, even the VCA's were off-the-shelf. As far as problems go, they were all common too; connector issues, heat issues, tuning issues... nothing we haven't seen before. So I think the fear around this synth is misplaced. I will have a lot to say in this set of video's, which will be a comprehensive service and restoration guide.

MOOG PRODIGY

The mini version of the minimoog. Basically the same ciruits, and the closest to the mini in sound. Basically the third oscillator became a permanent LFO (reduced cost) and the mixer section was reduced (no noise, less options). But what you get in return is probably the best oscillator sync ever heard. Amazing. In this set of video's I show a full a restoration.

ARP

ARP AXXE

The 4072/4075 is my favourite 24dB low pass filter of all time. I think I like the 4075 better, but both are great. Even though at first glance the schematics for both filters look the same, they are actually quite different, especially in the feedback loop (the resonance) and the biasing. The ARP oscillator also is also quite remarkable, it sounds absolutely massive and tracks over nine octaves. Quite a remarkable feat. These video's show the restoration of the ARP Axxe and how to install LED sliders.

KAWAI

KAWAI SX-240

The split/layer capability of the SX-240 is really great. It really fattens up the synth and helps the DCO's come to life. I've never been a huge fan of the filter but the ensemble (chorus) effect on this synth is massive. This synth does much better strings than the Juno's in my opinion. The first video explains how the DCO's work and the second fixes a battery leak.