You can get close with modern clones of the TB-303 bassline synthesizer and the TR-909 drum machine, but Roland made the originals, and it's making them again. They're not identical—being smaller, for starters—but they're taking the job seriously and response seems very positive: users say the new models are faithful and improved. The lineup is being sold as "Roland Boutique" and I doubt I'll be able to resist for long.
But here's where I'll say something blasphemous:
I think insisting on using the original 303 and 909, at their current used prices, is absurd. And not only that, but it cuts anyone who doesn't have large chunks of disposal income out of the joy of using these instruments. That's ironic for instrument whose legacy was built on being essentially undesirable – an unwanted machine that got into the hands artists who abused them in creative ways.
Don't get me wrong: if you've got an original TB-303 or a TR-909, good for you, and enjoy! But with reliability failing and prices continuing to clime, this simply isn't an option for a lot of people. (Ironically, it's easier to make a 17th century viola da gamba last than electronic instruments, so we're always going to have to deal with making new gear.)
What's special about the TB-303 and TR-909 remakes is that they actually give you what you want. They give you the sound and the design. But they also do the other things you'd wish for – they're convenient, they're not expensive, and they have some modern additions that make them more usable and fun to play. (Hey, we deserve this. We've been waiting a while.)
In any case, there's a spell you can cast on sufficiently-accurate replica technology to ensure the phenomena produced is interpreted perfectly by the consumer. But it's not for me to share.
