Freeing these Waveblaster Cards

[Cloudschatze]

Well, I was going for the Maxim MAX743.

Hmm. I wonder how much work would be involved.

I need to take some electronics courses...

[Cloudschatze]

I'm trying to order the remaining parts for this project (finally, right?), and have a question regarding the zener diodes.

The English component list simply specifies a "zener 12V" diode, while a Swedish(?) list specifies a "Zenerdiode 12V 400mW." No problems so far. I plan to substitute a 500mW diode, since the 400mW variety do not seem to be overly common in the US.

Here is the problem: There are several different current ratings to choose from (5mA, 10.5mA, and 20mA).

If figure that, since the WaveBlaster current-draw is going to be ~20mA, I should use the 20mA-rated diode. However, since I'd rather not assume anything, can anyone provide input?

[mace]

Take a look at mine btw:

clicky

It's not pretty, but it works!!
Still need to do the casework

Anyway, i'm not too familiar with the circuit design you're using, but usually zeners are used as reference and not as a direct supply, so any standard part will do.
Are you using the elektor circuit?

[Cloudschatze]

Take a look at mine btw:

clicky

It's not pretty, but it works!!
Still need to do the casework

That seems like a pretty good idea. I have a few tiny ATX supplies, come to think of it...

Anyway, i'm not too familiar with the circuit design you're using, but usually zeners are used as reference and not as a direct supply, so any standard part will do.

Ah, good to know. Since they were only $0.04 each, I ordered all three types.

Are you using the elektor circuit?

Yes, heaven help me. 



I haven't soldered anything yet, and I still need to buy the MIDI and RCA connectors. Thus far, I've not been able to locate a PCB-mount RCA jack that is compatible with the pin spacing - just one more piece of ridiculousness that is this project. 

[Edit: I just found some RCA jacks that will work. Time to try and get some "free samples." ]

[Cloudschatze]

 

Oh, poor, woe-begotten project...

I've stumbled into what I hope will be the final kink (there can't be any more...).

I'd planned to use a standard, 26-pin strip for the daughterboard connection, but, wouldn't you know it, the solder pads are on the "wrong" side of the board. I had the idea to buy a strip with longer pins, and, rather than mount it with the tail pins through the board, insert it so that the header pins go through from the component side. This will result is a mixed-metals issue...

The header pins come in tin or gold-plated varieties. Soldering a gold-plated pin to the PCB isn't a good idea (from what I've read), nor is having just tin pins, since the WaveBlaster sockets I've seen all have gold contacts.

So, I can either try removing around 2mm of gold-plating to make a slightly less-corrosive connection, or buy a surface-mount header (the pads look like they'll accomodate one), and risk misalignment. Another option might be to try mounting a through-hole header correctly, but using solder paste, which I would then hope to melt by heating the tail pins through the board (would this even work?).

What would YOU do? 

[mace]

I would cut pieces of thick-gauge solid core copper wire to equal length and solder them on the underside, the side with the pads.

I'd use some foam underneath, the component side,  to stick them in and hold them upright and parallel while soldering, then cut them flush with the board afterwards.

[Cloudschatze]

I would cut pieces of thick-gauge solid core copper wire to equal length and solder them on the underside, the side with the pads.

I'd use some foam underneath, the component side,  to stick them in and hold them upright and parallel while soldering, then cut them flush with the board afterwards.

It's funny that you should mention doing that, since the directions actually suggest something similar. However, the photograph of the completed project shows that they did something else entirely...

Thank-you for the response!

[Laust]

I wouldn't worry too much about the mixed metal corrosion issues myself... If you have to reseat the wavetable board once every 3(?) years, so what? 
You can also pull the plastic off the pinheader, ending up with a bunch of loose pins which can then be mounted entirely on the solder-side. It's tricky, but doable and extends the length a bit (it helps to fit the pins in something, like a female IDE connector before soldering).

It looks to me like the Elektor board is using extra long SIP sockets, like the ones pictured at the bottom here:

[Cloudschatze]

I wouldn't worry too much about the mixed metal corrosion issues myself... If you have to reseat the wavetable board once every 3(?) years, so what? 

Thanks for the advice, Laust. I went ahead and used a long, tin-plated header.



One down, one to go... 

[Rhizome]

One down, one to go... 

That looks so professionally done 

[mace]

One down, one to go... 

That looks so professionally done 

Unlike mine. 

A PCB goes a long way. 

[aleksej]

I'm use custom maded external DB adaptor too with AWE64 Gold on my second retro RIG
This one (description in russian)
Still available for order (here in Russia).

[Synthesized]

Hi All

I'd like to join the club   I've made my own waveblaster breakout board.  It runs off a standard 9v plug pack and uses a MAX743 to generate the required +/- 12v for the Waveblaster.  I designed the PCB up myself and had a shop etch it for me.  I soldered it up the other day and it's working pretty good now.  It's nice to be able to get some use out of the old waveblaster cards again   It's not perfect however, there's a few things that could be improved in the design.

Pics here for those that are interested: (about 1mb of pics)
http://users.tpg.com.au/gbtyson/wb/waveblaster.html

It seems to be working pretty well now, however the DB50XG is stupidly loud for some reason.

It's interesting to see the other solutions others have come up with.  I had looked at the Elektor board, but I didn't feel like using mains electricty (and i'm not sure of the legalities of such a thing either) when I decided to make my own and started investigating ways of getting the voltage for the onboard opamps.  I've also been writing a midi playing program, all in all it's been an interesting project and I've learnt a bit about midi and electronics.

Edit: updated to fix ambiguity.

[Salient]

Cool!

I just printed the circuitboard on film today and this or next week i'm gonna create the board itself. In the meantime I hope I can find all the parts for it.

[mace]

It seems to be working pretty well now, however the DB50XG is stupidly loud for some reason.

Probably because of the opamps, it really doesn't need them.

[Synthesized]

It seems to be working pretty well now, however the DB50XG is stupidly loud for some reason.

Probably because of the opamps, it really doesn't need them.

Yeah maybe, the gain could be all wacky.  I'll see if I can figure out what the DB50XG and the SCB-55 have the gain set to. maybe they'll be quite different.
It's kind of odd that it would be loud enough to cause clipping in some cases.   I'll have to fire up my old dos computer and compare the volume of the cards.

[mace]

Yeah maybe, the gain could be all wacky.  I'll see if I can figure out what the DB50XG and the SCB-55 have the gain set to. maybe they'll be quite different.
It's kind of odd that it would be loud enough to cause clipping in some cases.   I'll have to fire up my old dos computer and compare the volume of the cards.

Yes.

I use my DB50XG without extra amplification and it's fine without it really.
I don't have a SCB-55, else I'd test it for you.

[Synthesized]

I use my DB50XG without extra amplification and it's fine without it really.
I don't have a SCB-55, else I'd test it for you.

Thinking about what i said, I think we might have misunderstood each other.  When I said "+/-12v for the opamps", I meant the ones built onto the Synth card itself (IE: the waveblaster needs +/- 12v to work). I have no amplification built onto my circut. It's a direct connection between the Waveblaster and the line in port on my PC.

The SCB-55 sounds fine, but the DB50XG distorts quite a bit.

[mace]

Thinking about what i said, I think we might have misunderstood each other.  When I said "+/-12v for the opamps", I meant the ones built onto the Synth card itself (IE: the waveblaster needs +/- 12v to work). I have no amplification built onto my circut. It's a direct connection between the Waveblaster and the line in port on my PC.

The SCB-55 sounds fine, but the DB50XG distorts quite a bit.

Ah, I see.

Well maybe your SB50 is defective somehow, because mine does not distort at all.

[Synthesized]

Ah, I see.

Well maybe your SB50 is defective somehow, because mine does not distort at all.

No, I don't think so.  When it's connected to my AWE32 it behaves itself.
Some sequences are OK, others are clipping to the max.

I must have missed something in my breakout board design.

EDIT:
The roland clips heaps as well, but only on some sequences.  Interesting.

Mace: Does the line out on your DB50XG connect straight to the line in on your PC? Is there anything in between?