Neither of these pages show a "click to start" message for me, but they should. In TFA I had to hover over the "silent gif" to see a volume control, and in the acid banger I had written half of this comment before I figured out you could just click anywhere to unmute.

That's a browser thing. Thank the advertising industry with their auto-playing audio ads. To get rid of that browsers now require you to engage with a page before audio can be played.

"To get rid of that browsers now require you to engage with a page before audio can be played."

Where "engage" just means any UI event, so also a simple mousemove over the area.

This is a wonderful little toy. As an aside is it difficult to pick up and use a 303 with no prior synth experience?

If you're transcribing written music then it's fairly straight forward - you program the pitches in one round, press a button and input the note length values. If however you want to jam around like you might with any other seqencer driven synth I find it's too much to keep in your head so a pencil and paper with a 303 sequencer grid on it is pretty essential.

The Behringer lets you connect to an app via USB so you can program it that way too.

The sound engine is easy to use and the knobs encourage experimentation - the interaction of the filter, the envelope and the accent is where the fun is. And of course the slide!

I think the issue will be more the cost, they go for about 2500 to 3000 euros

But yes arguably synth experience won't even help, the 303 sequencer is very weird and unlike any other sequencer

Behringer does really nice clones of these old synths, much more affordable (~120 EUR for this one): https://www.behringer.com/product.html?modelCode=P0DTD

Yeah, I have a TD-3. It's by no means trivial to use for a novice, but there are some nice guides such as the one linked below. You have to get used to holding the internal state of the sequencer in your head during programming, as there is no display showing which step you are on etc.

And the time mode must be programmed separately, which on several occasions has left me scratching my head at why the thing makes no sound at all.

https://airainfo.org/files/TD-3-Programming.pdf

A new TB-03 from Roland, which is a digital clone but quite nice sounding, is only $400.

Sounds really unlike the real thing

I love the key change button. What would make this a truly awesome DJ tool is if you could go BACK to some arbitrary pattern, rather than only going forward. Am I missing a button/option for that?

The beauty of synthesizers like this (and especially modular synth setups) is everything is ephemeral. It's like a sand mandala.

I don't think it would necessarily ruin the vibe to have maybe four snapshot buttons that let you record current state, which you can jump back to. Would let you do some cool builds that pay off by returning to a known state or perhaps jumping to a new preset.

What I would do on MacOS is send the browser audio to blackhole and then run it thru ableton before sending it to the speakers so you could record and playback any sections you like