Can I buy some of your instruments or FX devices?

Can I buy something similar?

Yes. I have given permission to Synthesis Technology to use some of my circuits for their MOTM modular synthesizer. Also, a few of MAM's FX boxes were inspired by some of my projects.
 

May I build some of the circuits you've published on your homepage?

Yes. That's why I have put them there. It's part of a worldwide "synth-diy" community which has shared ideas for music electronics circuits over many years. However, this information is given for strictly personal, non-commercial use. If you like some of the circuits and build them for yourself, I am happy that you share my enthusiasm. I don't allow commercial use, though.

If you want to build some of my circuits and sell them to others, I invite you to buy my PCBs (see below) - you can then re-sell the devices you've built with them. 

How can I build the circuits? Is there any additional information available? PCB layouts?

Normally what I have put on the web site is exactly what I have. In other words, PCB layouts don't exist, because I have built on Veroboard.
Also, the schematics are by no means a "construction manual" (as you know them from diy kits). In general, I only recommend to build any of these if you are sure you have understood each function and circuit detail. This includes your ability to find errors. Yes, the schematics may contain errors, and I'm taking no responsibility whatsoever for their functions or for your safety. They are provided "as is" - to share some ideas and to document some of my own projects.
I am willing to answer technical questions about specific circuit details. For general questions I recommend to join the synth-diy mailing list, which is one of the best resources on the web for building your own synthesizers.
 

I do offer PCBs now :)

Where can I get these strange BC550C transistors?

These are quite common in Europe. I buy them from Reichelt. They are unexpensive low noise, high beta, small signal npn transistors. I'm sure there's a handfull of 2N.... equivalents, but I never checked. Sometimes I use them when high beta or low noise is required, but more often they are used as my general purpose type for practically everything. You can easily see it from the circuit context. The same applies to BC560C (pnp type) and BF245 (n-JFET). For the FETs, sometimes the threshold voltage is important. BF245 comes in A/B/C versions, indicating different threshold voltage (and maximum current). If you're looking for replacements, take care about my use of A, B, or C type.
 

How do you make your front panels?

I have them manufactured by Schaeffer Apparatebau in Berlin. You can download their free software "Frontplattendesigner", create the panel on your PC, have the manufacturing costs calculated by the software beforehand, send them the *.pcb file and get the aluminium panel by mail. They offer an excellent service, and they ship worldwide as far as I know.
 

Can I get schematics of Roland, Korg, EMS, ..., synthesizers from you?

Many of these schematics are available on the web, or directly from the manufacturer. Roland and Korg, and many others are selling schemos for a small fee (which will just cover their own expenses). Some of these are on large sheets which are hard to copy, so even if a friend has the manual you need, it may be more sensible to simply buy a copy from the manufacturer, than to spend an hour at the copier and to stick A4 sheets together.
Some schematics are difficult to find, and for a good reason. For instance, I'm often asked about EMS schematics because of the SynthiClone I've built. EMS is a company that is still in business and still sells analogue instruments, so out of respect towards EMS, I will not pass on any EMS circuits anymore. (Unlike Moog, who has patented his famous ladder filter, and who effectively has given it to public after the patent expired, EMS have not disclosed their circuits for the public, and I will respect this.)