Sonofcastille has published a set of videos demonstrating beautiful steampunk-style synths and noise generators.
Here are a few of the coolest:
WSG

This is Ray Wilson’s Weird Sound Generator circuit off of musicfromouterspace.com, plus audio amp scavenged out of a Radio Shack amp. The case was an old telephone from the 70s.

Over at The Steampunk Workshop,  Jake von Slatt has a nice write up on a Jules Verne inspired analog synthesizer with etched brass control panels.
While we’ve seen hundreds of nice modular synths, you have to admit the etched brass panels on this are pretty sextacular.
Here’s what the synth’s creator has to say about [...]

Not sure what to make of this - pask present has created a sort of steampunk electrochemical synthesizer:
Pressing a key causes salt solution to flow over a copper and aluminium connection, generating a low signal which is filtered by a capacitor and then amplified, creating a complex white noise, with amazing fluctuating oscillations.
The device demonstrates [...]

This is one of the stranger bent instruments I’ve seen - a sort of steampunk Furby sequencer by nervoussquirrel.
Here’s what nervoussquirrel has to say about the Furby sequencer:
Each furby has 4 controls: mute, crash, loop and reset. The handle turns 8 cams which operate corresponding microswitches to create interesting rhythmic patterns. Part of the [...]

Remember the steampunk music sequencer? Here’s something even more lo-fi.
The Bubblegum Sequencer is a physical step sequencer that lets you create drumloops by arranging colored balls on a tangible surface. It generates MIDI events and can be used as an input device to control audio hardware and software.
The Bubblegum Sequencer senses the position of the [...]

PhD student and cybernetics guru Peter Bennet has created a new tangible interface, Beat Bearing, which is a sort of steampunk-style music sequencer.
Creatively, Bennet uses ball bearings on washer as a way of completing a circuit to make a switch. Sequences are created by moving ball bearings from the tray to one of the rows [...]