ESTECHO

National is a brand name belonging to Matsushita electronics, who are better known outside Japan under another brand name, Panasonic. I’m not aware of other musical instruments sold under the National name, so I was surprised to see this drum machine show up for sale. Until 2009, Matsushita used the National name almost exclusively for home appliances (washing machines, microwaves etc.), keeping the Panasonic name for audio & video, so a National drum machine was unexpected…

This drum machine is pretty standard for the era, similar to a Rhythm Ace. It does have three cancel switches (snare, clave, cymbal), which provides a little extra versatility, and a somewhat different set of preset rhythms (eg. Teen Beat, African Beat and Kwela). The sounds are standard for the time: tuned bass drum, toms, percussion and snare “bottom”, noise burst for cymbal, maracas and snare. As usual for this kind of device, multiple preset buttons can be pressed at the same time, creating variations I’m sure even the designers didn’t really expect…

Following is a scan of the original Japanese spec sheet. The list price was 56,000 yen, which amounts to more than 600 US dollars… Ouch! But that’s OK because it had a fantastic “touch start” feature!

Another selling point was the tempo pilot light, which flashes brighter on the first beat of the measure. As the manual puts it: “The tempo Lamp illuminates brightly for the first beat and weakly for the other beats. This is very convenient because the tempo can be regulated correctly just by watching the lamp.”

Below is a scan of the owner’s manual. Interestingly, page three mentions a “voltage adjuster” at the back of the unit, which isn’t present on mine. There’s a hole made for it in the chassis, though, that has been covered by the serial number plate. I guess units destined for export has the voltage adjuster added.

Owner’s Manual. Click to download.

Technical Info / Service Notes

One of the big selling points of this unit was the “touch start” feature: at the top of the unit, and also as a remote switch, only a brush of the finger could start or stop the unit. A similar kind of switch can also be found on some Ace Tone units, such as the Rhythm 77, albeit a much better designed one. The National’s switch, 30+ years later, has become completely useless, while the one on my Rhythm 77 still works flawlessly.

I don’t know exactly what weird chemical reaction has been taking place over the years, and why this particular kind of metal reacted in such a way, but when I received my SY-50, both switches looked like leaking batteries, and were completely useless (probably shorted). Fortunately, it was easy to get the drum machine going, by simply plugging a cable in the footswitch jack and touching its tip, thereby providing the static “pulse” needed to start/stop it.

An engineer’s nightmare… The cabinet switch, removed from the unit (front), and the remote switch (back)

When servicing the SY-50, the first thing I did was to remove the touch start switch from the top of the cabinet, and proceed to clean up the mess. The corrosion didn’t affect other parts of the drum machine, although the PCB right under the cabinet switch received a good dose of precipitation over the years. Fortunately, it was pretty easy to clean and didn’t cause any serious problems…

Corrosion residue has accumulated on this board

Multiple outs & start/stop switch modifications

When I began modifying the SY-50, I’d just bought a “step bit” allowing me to drill holes in cabinets with relative ease, so I decided to split up the sounds extensively by adding jacks to the back panel. I split up the signals this way:

1 – Bass drum
2 – Snare drum
3 – Low conga
4 – Low bongo
5 – High Bongo
6 – Cowbell / Claves
7 – Cymbal / Maracas
8 – mix signal

Finding the individual voices wasn’t very difficult, although the tuned sounds and noise bursts were on two different boards. Also, for some strange reason, the cowbell sound is actually made from two different voice sources, combined at the output. They are always firing at the same time in all of the drum’s presets, so I just combined them.

Top voice board

“noise burst” voice taps

Bottom voice board

Remaining voice taps

I also found a lot of small pots inside the unit, allowing for control over a range of things such as tuning, feedback (eg. for extending the bass drum sustain), and also two pots controlling the amount of noise mixed in the cymbals, maracas and snare. I decided it would be convenient to have these available as outside controls, since I often have trouble with too much noise when comes time to mix a track using that kind of drum machine; the noise burst is so loud it’s hard to keep the cymbals mixed in without them taking over the whole mix!

So I unsoldered the two pots in question (on the upper right of the top voice board, see pic above), put some wires instead and connected them to two pots I installed on the back panel, next to the extra outputs. In total I had to drill seven holes, two for the pots and five for the outputs.

Back panel modification to accommodate multiple outs

After installing all the new jacks and pots, and wiring everything, I got all the individual outs I wanted, with extra noise mix control. I’d kept the signal path for the “full mix” sound that was originally available, but I found that my mod kind of messed it up: the bass drum and snare sounds have almost disappeared from it. With a slightly more elaborate wiring scheme, for example disabling the BD output when no jack in inserted, I know I could have kept the mix full signal strong, but I don’t really plan to use it anyway so I didn’t bother.

* * *

All I had left was to find a way to replace the “touch start” switching. I’d removed the switch early on, because of the aforementioned corrosion issue, but was left with a problem: no way to start the unit! So I decided to reroute the wire that had been going to the touch start switch, and send it to one of the cancel buttons at the front. I chose the “snare drum” switch, because the other two are still a little useful (I’ve paired some sounds in my output configuration: Cowbell/Claves and Cymbal/Maracas, so it’s still useful to be able to disable the Claves and Cymbal)

I unsoldered the snare drum wiring from the switch, then soldered both wires together. After that I soldered the start/stop wire in the same position, with the shielding conductor also connected to ground. Now the snare drum switch is used to start/stop the unit, although one of the quirks of this method is that I need to press the button twice every time!

Specifications

Manufacturer	Matsushita Electric Industrial Co., Ltd. (Japan)
Date	Probably early-mid 70s
List price	56,000 yen
Sounds	9 (BD, SD, Cy, low conga, low bongo, high bongo, cowbell, claves, maracas)
Presets	16 (rock, slow rock, fox trot, swing, rhumba, cha-cha, bossa nova, waltz, tango, teen beat, african beat, kwela, beguine, mambo, samba, jazz waltz)
Programmable	No
Controls	- Cancel switches for snare drum, cymbal and claves - No tone control
Outputs	2 (same signal)
Trigger out	No
Footswitch	Yes, "touch start" switch (see below)
Related models	Ace Tone Rhythm Ace series