Roland D-70 Synthesizer - Possible upgrades
Firmware
It is possible to change the Eproms of the D-70 (latest system 1.19). Note that most of these system versions only have bug fixes or hardware change support for later production models. Updating the firmware does most of the time not give you new functions. See the D-70 Firmware list here to see the changes (not complete, if someone has information about 1.16 or 1.18 changes, let me know, thanks).
WARNING
I've seen some D70 becoming broken when people trying to upgrade to the latest firmware. Be sure to put both the Eproms in the right direction. I hesitated a long time before doing the upgrade, but it was quite easy to do.
Only motherboards version 0.3 seem to be able to go to the latest firmware. See more info on the D-70 Firmware page.
Firmware mods
How great it would be if some rather simple things could be added as the other modules of the family can do things the D-70 doesn't.
- All characters available for text input (by the dial button)
- Additional LFO shapes: like Saw down (the U-20 has)
- The auto pan function of the U-220
As it is already available in other firmware of the Roland family (U-220 and MV-30) it seems to me that it can be done but it would be hard work probably. It is not just a copy and paste thing.
I looked into the firmware myself. There is room for some additional content on the roms. Biggest issue is that the info of the firmware should be converted to some programming language will it be possible to add things. Adding a thing will make addresses change for example and that will result in errors or break the system totally.
The only thing which seams to work without much problems is adding some of the characters the D-70 can use for text input. These can only be added by using an editor (see the info about the special characters). Adding these to the dial button is ideal but can’t be easily added to the firmware. What did work, is using the Caps button to add some of the characters. Because buttons 2-8 have the same info with or without caps there is room to give these buttons other characters when using Caps for example. So it is possible to add maximum 14 additional characters to the set (of the 23 missing). Because some other characters can be accessed by using the dial when an additional character is put on the screen, it could be possible to acces them all without the need of a computer.
Update
The modified Firmware loads and displays banks fine. Test with input of characters with and without caps, loaded without problems in the new firmware. Older firmware could load the bank with the new special characters.
There are only 4 different character set groups that can be accessed by the dial after selecting one, and there is one character “ that had no acces with the dial to other new characters. So I only replace the special characters of buttons 2-8 (/ + * # . , ! ) and access these with Caps. See the working in this youtube video.
This 2nd beta is working great. The characters are handful for a programmer, and compatible with older firmware (tested 1.14)

Processor upgrade
There is also an upgrade method by installing a slightly faster processor. I was going to try this, but this may also be risky. For the moment I just keep it the way it is.
While the processor in the D70 was limited by regulations at that time, I don't know if the faster processor will give some benefit. For example fixing the famous slowing down LFO on the D70 would be a great thing...
Interesting remark of Mr. Noriyasu (Roland) in Sound of Sound April 1990, about regulations limiting the processor and memory capacity of the Roland synths at the time the D70 was to be previewed in Frankfurt:
"It seems like a strange place to raise this issue, but even if we had faster processors, we couldn't export them due to a regulation set by COCOM (Coordinating Committee for Export Control). We are already facing the COCOM limitation with our fastest processor speeds and largest memory capacities. We must receive government approval before being allowed to export, due to the COCOM rules. These obstacles are quite a burden to deal with, so we must sell large quantities to justify the trouble. It's unfortunate that regulations such as these, which have nothing to do with music, force us to place limitations on the level of musical instruments we can develop. The concern of COCOM is that the CPUs and memory devices of high-end musical instruments could be easily removed and used in Soviet submarines. Although I think this would be unlikely, we must comply with the law."
Polyphony upgrade
The designers of the D-70 made it possible to link more D-70's in one chain. This is a way to double the polyphony by buying a second D-70. The performances/patches need to be reprogrammed to reallocate the tones on the 2 synths.
Effects upgrade
The effects are an important factor of the sound of the D-70. It is easy to alter the sound to the synth and make it sounding more like todays standards with using the dry outputs and use effects from your DAW for example. Or you can connect an effect module to the synth, if the module has midi you can switch the sounds automatically with the Performance (by sending an program change). I used an Yamaha REV500 module (1996 sound) with the basic factory for example, see this simple youtube audio demo.
Circuit Bending
Circuitbenders have a device, the “ROLAND AUDIO DESTRUCTION PATCH BOX’ that could work with the D-70 as it works on the U-110 and U-220. Intended for the R-8, this patch box which acces the instrument by using a PCM card slot, gives like it seems the possibility to add DLM to these machines: link to the Circuitbenders site.
I must say I hesitated with getting this expansion. Price wise this Destruction Box seams reasonable, but with the conversion form GBP to Euro and the added VAT because of the Brexit and shipping there is about 50% to add to the amount. Still, couldn’t resist to get my hands on this cute red box and supporting those who took the time and effort to create new things for our beloved classic synth.
Shipping went smoothly, and with no waiting time at the customs it took 5 days to arrive.
Quality
The build quality (handmade!) is good. The box looks great, with a nice design and the cable attached to the card makes it easy to pull the card out of the synth again. No worries of damaging the circuit board.
The package is well taken care off, with 9 patch cables included also. Everything is in the box to get you going.

