Ace Electronics, the company behind the Ace Tone brand, was founded in the sixties by Ikutaro Kakehashi, the same man who founded the Roland corporation in the early seventies. Ace Tone products are often early versions Roland products.
Ace Tone only released a small amount of tape delays while they were active, the EC-10 and EC-20 being the ones I’m aware of. The EC-10 can be found in Ace Tone’s 1972 catalog, but not the EC-20, which implies that the latter was probably released a bit later, in the mid-seventies, a few years before Ace Tone folded.
The EC-20 is the smaller of the two, but is very interesting in its own right, and is still packed with features. The EC-20, just like the EC-10, uses a short tension loop, but while the latter uses a standard “pinch roller/capstan” combination to drive the tape, the former doesn’t have a capstan, the pinch roller being connected directly to the motor. It has four playback heads, a great amount of inputs and outputs, variable speed and a limited tone control in the form of a treble on/off switch. In doesn’t have a VU meter, but an overload indicator light is on the front panel, allowing some visual feedback on input signal strength. There’s also an input voltage selector at the back, which makes the unit perfectly suitable for any part of the globe.
The amount of tension on the tape can be varied by adjusting the tension roller from inside the unit; I had to adjust this to maximum tension on my unit in order to get steady echoes. This adjustment is closely related to the length of the tape loop, so it might need to be readjusted if you splice your own tape loop and the length isn’t exactly the same as the previous loop:
When I first turned on my EC-20 and played a few guitar chords through it, it output the most incredible, totally wild wobble I’d ever heard, like the machine was hopelessly drunk and was struggling to stay afoot… It was pretty interesting! I was curious to know what was happening, so I opened up the unit, and found the cause of the tape’s wild behavior: an elastic band instead of a drive belt!

The elastic band found in the unit, and its replacement. The rubber belt is longer to compensate for the elastic’s stretch.
It’s the second time I’ve found an elastic band in a tape delay, which was probably put there in the vain hope to replace a broken drive belt (by the way, if you ever need a drive belt for a tape delay, look up ‘turntable belts’ on Google and you’re on your way). Elastic bands do work, actually, because they have lots of grip and can really turn that flywheel… but they do so by constantly stretching and contracting, which give the ‘drunk’ effect. I’ve replaced the elastic band on my EC-20 with a proper rubber drive belt, but I kept the elastic, because I really liked the effect, it messes up the signal in a really organic way I can definitely use for sound morphing…
The other issue I had with the EC-20 was a very, very dirty tape path. When I removed the old tape loop, it was actually stuck to the heads, and the pinch roller was in a sorry state. I cleaned the heads with head cleaner a cotton swabs (with dense, hard cotton, not the ‘Q-tips” fluffy type), and the pinch roller with ‘rubber renue’, a product from MG chemicals (hard to find outside North America, but I’m sure there are other similar products available), and that improved tape steadiness some more.
Once I had done a good cleaning of the tape path, replaced the drive belt and adjusted the tension roller, I had no further issues with the EC-20. It works fine now and it sounds great.
Specifications
Manufacturer | Ace Electronic Industries (Japan) |
Date | mid seventies approx. |
List price | 85,000 Yen |
Transport type | Tension tape loop |
Motor speed | Variable (limited range) |
Playback heads | 4 |
Head selection | Mode selector buttons: 1 / 2 / 3 / 4 / 1+2+3 (multiple buttons can be engaged) |
Delay time | Mid-range |
Inputs | 5 (mic x 2, instrument x 2, vocal amp) |
Outputs | 3 (low, high, vocal amp.) |
Wet output only | Yes, through 'vocal amp' input |
Pinch roller | No capstan, so no pressure on pinch roller |
Tone control | Treble on/off switch |
Remote Control | Foot switch input |
Operating Voltage | 100v-220v (Switch at back of unit) |
Related models | Ace Tone EC-10 |
Do you remember the length of the belt you bought for this unit? I am getting this unit soon and want to refurb it. Thank you.
Great article and demo video on the Ace Tone EC-20. Thanks for sharing! My EC-20 makes a whine sound whose pitch corresponds to the speed of the tape movement. It is audible both as a mechanical noise (I hear it when i’m close to the unit), and an electrical sound that is audible in the audio signal. Any idea what’s causing it, and how to fix it?
Bonsoir je possède cette chambre EC20 et je recherche son schéma d’avance merci pour toute information.
Hello, I own an EC20 which needs to be repared… so I need the diagram of the circuitry.
thanks…