my “secret” (reading that as my piece of gear that probably not a lot of people doing similar stuff use) is also Yamaha FM, the tx81z.
Only 4-op FM synthesis, but real nitty gritty, so with the time taken to understand how to shape the sound, can make some very nice timbres.
I could tell you, but then I’d have to delete all your user accounts and nuke the thread… 
Hidden Gem: Casio VZ-10m
16 Voice DX style Phase Modulation synth with 8 Modules (their term for Operators) arranged into 4 cascading “Lines” (pair of modules) You could Mix, PM, or Ring Mod the two modules in a line then use that output as an external Modulator for the next Line in the series giving you a ton of FM synth possibilities.
Add in it’s multi-timbral and has 8 stage envelopes and it’s crazy.
Snagged mine a few years ago for a song they’re a little pricier now but well worth it.
came in here to say midiverb II. glad to see other people dig it! i use it as a send effect and have the 100% wet output going to it’s own stereo channel on my mixer. love sending tape loops and drum machines through it.
my roommate had a yamaha rx11 sitting in our front room throughout the entire length of our lease and i didn’t stumble upon it until the end. i cleaned it up real nice and have really come to love the sound of it. pretty corny sounding most of the time and not many ways to adjust the sounds, but when it works in a tune…it really works!
also long time lurker, first time poster. 
That’s not very open, Mike! 
Man, I’m so intrigued by tape (tape echo, studio reel-to-reel, and four tracks), but have always been held back my worries about maintaining the machines and the availability of tape.
Around 10-years ago I used to come across old Space Echo units all the time at Japanese music shops, and most had been overhauled and were in tip-top shape. I really wish I had taken the plunge, although I wonder if the reason I’m not seeing them anymore is that the music shops have stopped buying them due to the amount of effort it takes to get them in proper working order and limited parts.
Japan is facing a massive generational crisis at the moment. I hope we don’t lose a lot of the knowledge about older devices in the coming years when that generation passes away. I’ve read on other forums about how we’ve lost a lot of our knowledge about manufacturing tubes because much of the manufacturing know-how was basically lost when the big plants went under. That’s one of the reason people seek out NOS tunes from the 1950s.
I’m getting another one of these from a friend soon. I had one in the past and loved it, but ultimately sold it because I had no place to put it where I could comfortably access the front panel - necessary even when using a software editor. Nevertheless, I regretted selling it - the sound is like nothing else. It’s not a CZ, nor is it a DX, but offers some of the best qualities of both. I can’t wait to have one again.
There are still suppliers of pre-fab cartridges and loops if you don’t want to roll your own. I have a number of tape echoes, including a Fulltone Tube Tape Echo, a pair of Multivox tape echo/reverb units, and an ancient (and from what I have seen) unique Brenell tube unit from the late-50s/early 60s. I use that one mostly for grungy tape loops, though.
Cool. Do you do all your own maintenance and how often do you need to service them? Any worries about part availability?
I do all of my own gear maintenance when I can. And always on the tape echoes. I’m not going to pretend that regular maintenance isn’t necessary, but it’s not too bad. I’ve changed the tapes once on the Fulltone, and a couple of times on the Multivoxes in the past couple of years. I use them quite a lot, but not every day. Most maintenance is what you’d do with any tape machine: cleaning heads and demagnetising.
All vintage gear is a risk, so I rarely recommend going that direction without some knowledge of repair. But as for tape and tape cartridges, those can be found. I generally buy a bunch of ‘em at once. Funnily enough, I wish I’d never had to change the tapes on my Multivoxes - I really liked the deep, swirling wash of noise from the tapes that were on them when I got them. However, the tapes were shedding pretty badly - they were probably decades old, and I didn’t want to risk damaging the units.
Much respect man. I should see if I can seek out someone here in Japan to teach me some basic maintenance. I’d like to reorganize my life to have more time for projects like this. #goals
Korg ER-1 mk 1 or mk 2 ? Do you think it would complement a Machinedrum UW?
I totally agree. Having 2 drum machines working in time together is great for mixing it up. I’ve done this with My MD and Digitone before. Also a few times with my MD and my Korg EMX-1. I sold the Korg shortly after because I was broke from the MD purchase, thinking I didn’t need 2 drum machines.
Ironically enough, here I am thinking about pairing up my MD with another Electribe. 
Electribes popped up more than once. People seem to swear by these. I may have to see what all the fuss is about…
Love the 707, so playable with the faders too, I think it has a very nice punchy and fat sound and always seems to fit nice in a mix even with other drums, especially analog sounds.
I don’t have any secret weapons, but these are some hidden gems - which I classify as affordable overlooked older gear:
Yamaha SU-10 - super limited in memory, sample rate and polyphony, doesn’t have the prestige of a vintage akai or SP but always sounds nice in a crunchy punchy way, oh and it can send samples via sds into your MD or Rytm, and the file size is comparatively very small.
Yamaha TQ-5/YS-100/YS-200 - Yamaha’s foray into “easy FM” yet very capable and sufficiently deep for most stuff. Smooth (for FM) sound too, although Digitone can be smoother.
Roland MV-30 - Rompler with excellent digital filters, MC-500 derived (but expanded) sequencer, very nice 90’s Roland waveforms with pretty comprehensive editing, and a “compumixer” feature which allows you to realtime record your mix using the 8 onboard faders, a real sleeper unit IMHO.
http://www.muzines.co.uk/articles/roland-mv30-studio-m/790(http://www.muzines.co.uk/articles/roland-mv30-studio-m/790)
Electrix Repeater - In my opinion the best looper ever made - because it is so different from most others, super friendly to use, faders for each of the 4 tracks, excellent sound quality and tons of features. But for midi synced 4/4 loops it is hard to beat, it doesn’t fare well where a lot of other loopers excel and vice versa, an original take on the concept.
A secret only a few people know about, is reading the manual.
Is this delay similar to (or the same as) the FX Korg used in the EMX-1/ESX-1?
How would you say this compares to the EHX 2880 (and later variants)? That has faders per track too, and excellent midi sync.
edit: having looked up the spec online, the Repeater seems to offer some more advanced features such as different pitches per loop track, and up to 99 loops as well. Nice.
A free plugin I must mention:
TAL Reverb 3 (not the more popular 2 and 4)
Strange, lush, simple and elegant
Ha. Beat me to it. TAL Reverb III is weird little critter but I find myself using it all the time, even instead of Valhalla stuff.
I’d also like to mention Permut-8. Very versatile and surprising plugin. Maybe not a hidden gem, but a definite gem.
Spaceship Delay. Lovely free plugin with a ton of fun and handy features.