CPLD/FPGA
It is highly unusual to use this in hobby projects but since I started programming hardware devices in 90's, when Arduino and Raspberry did not exist, I am able to program these devices most in VHDL language.
I am used in using the Altera devices from classic to new devices. I do even own a Pentium4 PC 600Mhz with the latest version of Maxplus2 for programming classic devices as EP900 (25 years old platform). Currently Altera is owned by Intel and does provide Intel Quartus Prime software suite and most devices are programmed via JTAG.
The big advantage is the very high speeds these devices run and can run loads of parallel tasks on different clock busses.
And it is hardware that runs (fuses get programmed in logical blocks), not a processor running software.
In the old days I designed hardware were we controlled the grid (electricity) of South Hollland with these kind of devices.
My early hobby nixie clocks and CD-player were running on FPGAs.
You can contact me with the contact form to discuss the possibilities.
Arduino
I am able to write programs (in C) for most of the Arduino processors.
It can be as simple as a delayed output or complete cd-player interfacing with (touch) LCD panels and IR remote control.
Do you have an idea but like to have it physically in your hands ? You can contact me with the contact form to discuss the possibilities.
3D Printing
HMR-audio is able to print your 3D designs and can design 3D parts for you based on your requirements.
You can contact me with the contact form for the possibilities.
Some examples
Fusion360 design: Fan tunnel
Printed part
Fusion360 design: Rimlock Tube Socket
Simulation
Sometimes it is quite useful to simulate your analog design, for example an active opamp filter.
If you are not familiar with simulation and would like to know if your designs is doing what it is suppose to do, let me know !
I can also do digital simulations.
Tube Tests
HMR-audio can test a lot of tube types and can do matching (max anode voltage 450Vdc).
You can contact me with the contact form.
matching curves (different measuring on top of each other)
quicktest report