The GM Voice

David Jackson · Joined: Oct 01, 2008 Posts: 4 Location: Ottawa

I built a GM Voice using Thomas' schematic and PCBs but I'm having trouble getting it working. The activity light flashes when I press a key on my keyboard, but I don't get any sound out of it except for some 60Hz buzz.

Also the LM7805 gets very hot after I leave it on for 20-30sec. However, I checked the voltages on all of the pins of the connector and are correct whether or not I connect the daughter board. The LM7805 only gets hot if I connect the daughter board.

I tried two of those NEC clone boards I bought on Ebay from the guy in Shanghai and the same thing happens. Does anybody have any suggestions?

Dan Lavin · Posted: Thu Oct 02, 2008 5:56 am Post subject:

David,

I know a number of people on this forum have bought daughterboards from the gent in Shanghai and have had good luck, including some of our "heavy hitters" , so it's unlikely 2 boards wouldn't work, but not impossible.

To give yourself confidence in the daughterboards, I'd suggest you breadboard up the circuit and get that working with each board. It's such a simple circuit, it should only take about 15 minutes.

The only other thing I can suggest to check is the orientation of the daughterboard. The ground side of the daughterboard connector is towards the card's edge. I think I've seen some boards with reversed pin numbering.

assuming none of that helps, pls get a voltage reading from input and output of the 7805....that might tell us something.

regards, Dan

David Jackson · Joined: Oct 01, 2008 Posts: 4 Location: Ottawa

Thanks for the suggestions Antman. I tried building the circuit on a breadboard but still had the same problem. I took things apart until I just had +5V and ground connected to the midi board and still had the same problem. 5V was connected to 6, 10 and 14, and ground connected to pins 1,3,5,7,9, and 11. I checked to make sure the pin numbers were right.

I actually bought one board, but they sent me five of them. I measured the current from the power supply for all five boards and it ranged from 182mA to 205mA. Thomas said in an earlier post that the draw on the 5V supply should be 40mA, but I'm getting 5x that much with only the midi board connected. Sad

Does this mean all of the boards are bad? I wonder if they sent me five boards because they know they have quality problems?

David Jackson · Joined: Oct 01, 2008 Posts: 4 Location: Ottawa

Also I checked the input and output of the LM7805. Input was 12V and output was 5V.

Dan Lavin · Posted: Fri Oct 10, 2008 5:35 pm Post subject:

David,

Well TH's 40mA was on a much smaller daughterboard...not a Yamaha compatible one. The Yamaha ones are much larger and it's not inconceivable that they could draw 5X the amount of current, although I think that's a little high because 200mA would make the regulator warm and I don't remember my Yamaha's regulator getting warm at all.

It seems really odd they would ship you 5 of these. I would offer to test one for you but I know US/Canada customs can be a hassle, (you wouldn't know we were friends based on those guys!)

I traded my Yamaha daughterboard off to someone on this forum so I can't help with measurements. Perhaps someone can help David with current measurements on their units? Fonik?

Regards, Dan

fonik · Posted: Fri Oct 10, 2008 5:45 pm Post subject:

fonik · Posted: Fri Oct 10, 2008 5:50 pm Post subject:

David Jackson · Joined: Oct 01, 2008 Posts: 4 Location: Ottawa

Thanks for the measurements fonik. Yes I connected the other pins to ground too, but when I did the current measurements I only had the digital ground pins connected. I fiddled around with it some more, assuming that the currents are ok, but still no luck.

antman: If you PM me your address, I'll send you a board. I don't need all 5 anyways. If I mark it as a "gift" I don't think they'll charge you duty on it.

Dan Lavin

To my friends in the UK that wish to do this project, please check out the following auction for a Yamaha DB50XG, probably the best daughterboard you can find.

http://cgi.ebay.com/Yamaha-DB50XG-Daughterboard_W0QQitemZ380074246690QQcmdZViewItem?hash=item380074246690&_trksid=p3286.m63.l1177

Dan Lavin · Posted: Fri Oct 24, 2008 11:32 am Post subject:

David,

OK, I PMed my address. If I get good results I can post photos of what I've done.

-Dan

THeff · Posted: Tue Oct 28, 2008 12:27 pm Post subject: Yamaha DB60XG audio inputs

The web says that the Yamaha DB60XG is the same as the DB50XG with additional audio inputs that pass through the on-board effects. Does anybody know which pins are these input pins? I have searched many web sites and cannot find any info on that.

Thanks,

Tim

THeff · Posted: Tue Oct 28, 2008 6:56 pm Post subject: External inputs on the DB60XG

After further investigation it looks like pins 12 & 14 are the inputs. On other daughter cards these pins are N.C., but on the DB60XG they go to the AK-4510-VS IC. This may be the mixer IC. I have tried inputting a signal on these pins but the signal is not passed to the output.

I'm thinking it probably requires a SYSEX command to open this path. This link http://www.studio4all.de/htmle/main96.html has a lot of SYSEX info.

If anyone has any ideas, I would welcome them.

I think adding the inputs to the DB60XG would be nice so that my synth modules could utilize the nice Yamaha processor effects.

Tim

Dan Lavin · Posted: Wed Oct 29, 2008 5:42 am Post subject:

Tim,

Thanks for the heads up on the analog inputs! I've been meaning to look into that for some time, but never had the chance. I used to own a Yamaha MU80 which is basically a db60xg with a user interface and I loved the effects. They're geared for both voice and guitar. The idea was a one-man-band would use the XG for backing parts and one AD channel for microphone and the other for his/her guitar. Obviously synths can use any of these effects. They're all very good, low noise and tweakable.

I think you're right about the SYSEX opening the channels. I recall I had to do something with the user interface before the analog ins got mixed with the MU80's output.

Keep us posted with any progress. I think the majority of people that took this project on are using the db60xg clones and this is opening up a whole new chapter to the story.

regards, Dan

fonik · Posted: Wed Oct 29, 2008 5:51 am Post subject:

as i read it, there are only two additional sysex commands for the db60xg: A/D 1/2 PART ON/OFF and KARAOKE LOCK (ON/OFF ). so there are at most 4 logical cases to try.
the Mixing Block commands seem to apply to the SW60XG only?

Dan Lavin · Posted: Wed Oct 29, 2008 7:12 am Post subject:

Matthias,

As far as I could research, the SW60XG is an ISA bus version of the db60xg, so the SYSEX commands for SW60XG should pertain to the db60xg as well......or maybe it is wishful thinking on my part?

I thought that Yamaha's MU50 also had analog ins but it would only mix to the output without use of the internal effects unit. That's why I bought the MU80 instead of the MU50. This could be the same with the db60xg.

Perhaps Tim can experiment and let us know.

-Dan

Dan Lavin · Posted: Wed Oct 29, 2008 7:22 am Post subject:

Tim,

Can you check those pin numbers again? Pin 14 is normally tied to +5V. I'm guessing Pin 12 and Pin 16 are the correct analog inputs. This would follow the precedent set with the outputs (pins 20 and 24).

regards, Dan

THeff · Posted: Wed Oct 29, 2008 7:29 am Post subject: DB60XG external inputs...

Hey Dan & Matthias,

I did connect a constant signal source to one of these inputs and tried sending the two DB60XG specific SYSEX commands with not luck. Since I have seen several references to the analog input capabilities of the DB60XG, I feel confident that there must be a way to use these.

If you follow the traces to pins 12 & 14 they go to a 47K shunt resistor, through some 0 ohm jumpers and then through some caps to the AK IC. This would make sense that they are 50K inputs.

If someone had the driver SW that came with a new DB60XG maybe they could monitor the MIDI data stream as the ext. inputs are enabled...I know that is asking a lot!

A copy of the owners manual would be helpful also, I could only find the DB50XG manual.

Do you guys know if the MU-50 had external inputs?

Tim

THeff · Posted: Wed Oct 29, 2008 7:38 am Post subject: MU-50 Inputs

I just did a quick web search on the MU-50 and it does have inputs on the front panel. Maybe the MU-50 SYSEX commands would be the same for the external input features?

Tim

fonik · Posted: Wed Oct 29, 2008 7:41 am Post subject:

i found some information of the (missing!) mixer on the db50xg at this g00gle group: comp.sys.ibm.pc.soundcard.music

THeff · Posted: Wed Oct 29, 2008 10:59 am Post subject: Ext DB60XG inputs

Dan,

I believe your are right about the pin numbering being 12 & 16. I was multitasking last night and had a brain lapse that the skipped pin was 13 instead of 14. I was also wondering if these inputs are mic/line with adjustable gain, or just line inputs and rely on a mic preamp on the main soundcard?

Tim

THeff · Posted: Wed Oct 29, 2008 2:24 pm Post subject:

Hi Dan,

I totally missed your comments about the MU-50 audio inputs...Doh! The manual states that you just plug in the external device and adjust the volume with the control on the front. It shows a guitar plugged in so I guess it is a low level high gain input.

Matthias,

From the quote you mentioned in your post it would seem that a SYSEX is not needed, but no audio is heard on these inputs on power-up. It's amazing how little information is available on the web for the DB60XG!

One DB60XG reference said it was only sold in Japan.

Tim

fonik · Posted: Wed Oct 29, 2008 2:53 pm Post subject:

THeff · Posted: Wed Oct 29, 2008 3:43 pm Post subject:

Hi Matthias,

I did try sending both of those SYSEX messages and there was no response at all from the DB. I had the card setup and played a MIDI song using Cakewalk just before sending the messages, so I know everything was working at the time. I'm still puzzled Sad

Tim

Dan Lavin · Posted: Wed Oct 29, 2008 7:19 pm Post subject:

Hmmmm. I wonder if one of the other pins could be a VCA control for the analog inputs? Can you see any traces from the other "unused" pins?

I could understand how that would work for the MU50, 80, etc. with a front panel knob, but on an internal soundcard? I think I'm getting desperate!

-Dan

THeff · Posted: Wed Oct 29, 2008 8:10 pm Post subject: Analog audio inputs on the DB60XG

Hey Dan,

I thought maybe you were on to something. I found that pin #8 goes to the H8 uC and is pulled high to +5v. I tried grounding this through a 1k resistor to see if it would enable the inputs...no luck!

I don't see any other connections to the unused pins 2 & 13.

I'm not giving up!

Tim