Mockingchick: An Apple II Mockingboard clone (hopefully!)

Well bu**er me sideways with a pitch-fork!

For the life of me I couldn't work out why my Mockingchick board wasn't working. As one last test before I went through another redesign, having re-re-re-checked my version against every other schematic I could find, I wrote Sweet Micro's test disc over the supposedly Mockingboard enabled copy of Zaxxon I had been using and...

...It works!!! Ooo, my ears. The last because I had it plugged in to the portable amp I use with the band with the volume right up in case there was any sign of life.

So there you go. I'm not (quite) as stupid as I thought. (Bl**dy Zaxxon!)

Things to check:
-why does the computer lock up after the first demo screen? (I think because my board has no speech support)
-Is it truly stereo, and are the channels the right way round?
-does the amplified out work, and as expected shut off with a jack in the line out?
-does the motherboard audio mixing work, without pushing it in to mono? (Already spotted a mistake here but I think I only need to change a couple of components to fix)
-have I got the motherboard / Mockingchick mixing levels about right? (I guessed this but now I can hopefully test it)

As a nice bonus it's working with a 7404 rather than the 7505 logic I feared it might need. Not a Biggie but the former is much cheaper and easier to get hold of than the latter. I'll probably try some WDC 6522's at some point to see if they work too - the new WDC IC's don't work quite the same as the good old R6522P's, something to watch out for when making devices using this chip.

Pretty darn pleased to say the least! :D

Grr, bl**dy Zaxxon, grumble
 
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well done!

asimov FTP has some test disks under hardwaresoundmockingboard, do you have all those?
 
well done!

asimov FTP has some test disks under hardwaresoundmockingboard, do you have all those?

Thank you, and thanks for the link I'll go have a nose about in a bit. The very good news is Prototype #4 seems to be fully functional!

20170914_145155.jpg20170914_145133.jpg:DMockingchick Prototype #4 Fully Functional:D

I'm most pleased to report everything works as expected. The only thing that needed adjustment was the mixing resistor to get motherboard sound coming through the sound card at a similar level to the card's own output. The photos above show the first working prototype which is pretty much as the intended production boards will be. The primary difference will be boards I intend to make won't have socketed ICs, but I will MUCH prefer to send either bare boards or kits rather than fully assembled. (There are a lot of potential configuration options) In case anyone's wondering the black thing in the photo is a pair of speakers I salvaged from an old laptop to test the amplified header.
I shall go update my draft manual in case anyone is interested shortly, but for now I hope nobody will mind if I post the final features list:


Mockingchick, a 100% Mockingboard compatible sound card for the Apple II line of computers

Stereo sound card with six voices thanks to two AY-3-8913s
Works in any slot, although much supported software expects slot four
Motherboard audio may be mixed through the card without effecting stereo output
Line out for external amplified speakers
Amplified (three Watt) stereo header*
Automatic switching between outputs
Stereo audio the right way round
Will gracefully stop on system reset / crash
Minimal size and component count
Should not physically interfere with other cards
Plenty of scope for modification
Function LED

*The header is provided primarily to allow for internal speakers.

The card does not support voice synthesis. I did consider it but the necessary IC's are very hard to find and stupidly expensive.

Draft Guide and Schematics
View attachment MockingChick Guide and Schematic.zip
Draft Guide and Schematics​
 
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Hey, I learned to do something new today. My very firstest video upload to YouTube to demonstrate my Apple II has a new trick up it's sleeve.

How many old computers can you spot, and can you name them?


I had a sneaking suspicion the laptop speakers I was using to test the amplified audio header were being driven a bit hard as they were actually getting too hot to touch so I went on a hunt for something more suitable. Happily I found an old iPod speaker dock that doesn't work with Apple's latest connector and so without a hint of irony butchered it to see if useful goodies lurked within:

20170915_174026.jpg20170915_174007.jpg
Post Butchery Session

Two 3w, 8ohm speakers, a plop load of wire, and some potentially reusable interconnect blocks. Hurrah! Close inspection of the photos will show my repurposing of these various bits 'n bobs to function as my new internal speakers, in action in the video above. The plan is to mount the whole thing, face up, under the Apple's keyboard using the screw posts from the remains of the shell as stand-offs. I'll probably go bananas with the old hot glue to fix it in place but if things line up nicely I wonder if the screws from said posts might line up with some of the grill slits on the base of the machine.
For those interested in keeping old machines faithful to their manufacturer I can happily report only Apple products (but for a bit of solder and hot glue) were used in this speaker upgrade... Even the wire was pulled out of an old Apple serial lead and then delightfully plaited by yours truly. Further photos of the install to follow.
 
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Electron, apple iie platinum, BBC, colocovision. Your office is as organised as mine...

... office :)


im planning a wedge under the keyboard too, I'll respond with pics if the cheapo speakers I ordered fit, there's a tiny gap, prob too small but I'll try.

Biggest issue is the slot as my z80 card is in 4. Will overcome somehow!

Cheers!
 
Electron, apple iie platinum, BBC, colocovision. Your office is as organised as mine...

... office :)


im planning a wedge under the keyboard too, I'll respond with pics if the cheapo speakers I ordered fit, there's a tiny gap, prob too small but I'll try.

Biggest issue is the slot as my z80 card is in 4. Will overcome somehow!

Cheers!

Good spotting on the computer front, but there's two more lurking... ;)

Soldering and instructions made sense?

FWIW: Mockingboards will work in any slot, it's just not all software that supports them either auto-detects or asks. The default assumption is slot 4.

Have fun!
 
Instructions look a-ok thanks!

And it arrived yesterday, I just hadn't noticed the post. Thanks again Charlie, I'll get to it in the next days and will report back
 
Time, I feel, for some installation photos.

First off lets's get those internal speakers sorted:

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Internal Amplified Speaker Set-up


In the end I decided to cut down the plastic from the set of speakers I butchered further up the thread to make a slightly neater installation. Also I used a fine old trick to make some damped stand-offs for mounting them to the chassis. Too many vibrations going trough the base plate of the computer might result in some rattling... Take a hot glue stick and cut it in to a number of appropriate lengths, then use some melted hot glue to attach said lengths to the plastic. In this case six pieces. Next stand the speaker board on it's feet in position and slide a hot knife between each leg and the base of the computer. This procedure:
Melts the end of the glue stick, so attaching it to the surface.
Allows one to adjust leg lengths as required.
Gives the speakers some vibration damping attachment.

I then ran the plaited left and right channel wires under the motherboard to poke up in the region of slot 4. The other end is attached to a stereo potentiometer for internal volume control. This was mounted through a drilled knock out on the back of the machine. There's a sticky label under the pot to reduce the chances of a short with the metal case. For info I'd say a 5k pot is more than enough, stereo, and preferably logarithmic.


20170919_142202.jpg
Close Up Wiring

The photo above shows how I wired the pot up: Pin header takes left and right audio from the amplified output on the board to the pot. The grounds are wired to the left most pins and to their respective outside headers on the output side. The left and right lines are each soldered to the middle pins of the pot, and the two middle pins of the output header soldered to the two rightmost pins on the potentiometer. Grounds are therefore wired straight through, but left and right go through the pot.

At this point I decided to make a production board of my own to stay in the computer. I'll keep the socked board for testing ICs.

20170919_161337.jpg20170919_161321.jpg
Look Ma' No Sockets

Here's my semi-built production board showing some hopefully useful suggestions: The motherboard audio in cable was taken from the Apple's now redundant speaker and soldered directly to the IC side of the board. The reason being for added security; once an IC is soldered over it it's unlikely to come free. Note: If this cable is attached the wrong way round audio pass-through won't work! No harm done, it's easiest to to swap the pins round on the motherboard header end.
It's really very important to solder in the Amplifier Module's pins before soldering in any ICs, BUT then solder in the ICs before soldering the Amplifier Module.
Also there's no harm in attaching the 3.5mm audio header to some short lengths of wire (twisted), so allowing it to be mounted to another knock-out rather than necessitate grovelling about inside the computer when you need it.


20170919_172512.jpg
Job Done

As it happens I've run out of PAM8403 Amplifier Modules... I bought loads but must have used more than I realised on my dud boards. So my production board has no internal out at the mo'. Never mind, it works fine plumbed via the line out to my monitor's speakers and I have more on order.

PS:
 
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Very neat. Inc lots of USB sockets... for the pi?

i will get to mine soon I promise! Need to receive my speakers and measure up. Thanks also for the new pics which are always useful.
 
Yes, USB , RJ45, and HDMI ports from the Pi. ;)
 
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Oo, oo...
Don't hold your breath because I tried this before and failed, but I never could work out why the Mockingboard used two 6522s when the only important difference in their wiring was which 6522 and AY chips were active: one 6522 to each AY... why not use one 6522 and activate the AY chips directly?

So in the interests of neatness (maybe OCD) I've come up with a design that uses one fewer 6522s. If it actually works there's a few pennies saved, a bit less soldering, and a slightly less cramped layout. I've also noted my version of this board is bl**dy picky as to what type of 7404 IC is used, I guess there's some timing right on the edge... I may trial using a 7400 (NAND) as an inverter in the hope of achieving some extra robustness and a few more pennies off the cost. I guess I could generate my own clock instead of stealing one from the computer but that's more components. If a 7400 proves a better choice that will probably see the end of the activity LED... tbh I only included that because the 7404 had a couple of spare gates.

Anyway, the .zip below contains the Eagle files for this version. If it looks like it will work I might order a few boards as I'm very nearly out of Mk4 boards. Feel free to make comments.
 

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Awesome work my friend, my only concern is the volume control being on the speaker outs...
this will upset and change the loading on the Amp module and 5v supply.
Volume pot needs to be inline with the inputs going to the Amp module.

:)
 
Thanks for the feedback, I shall do a bit of jiggling and post an update...

If there's a frustration it's one can't rely on where the slot cut-outs will be. I'd like to give the option to mount stuff on the board that lines up with the back of the computer, but I think it's going to have to continue to be wires.
 
Another update:
This time a proper header for volume control on the internal header, placed in circuit before the amplifier. I feel another order to Seeed coming on... 'nervous that I haven't understood the implications of removing a 6522 properly and I get another batch of coasters. Fingers crossed.
 

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MockingBird

MockingBird

Yet another update:

Primary board has grown a little bigger to allow easier placing / soldering of components, hence name change.
Addition of buffering IC to help stabilise Apple bus.
3.5mm socket and volume adjustment now on separate (snappable) board for easier mounting.
System and MockingBird audio mixing now adjustable via a trim pot.
Holes added near audio in/out headers for cable management / strain relief.

Thoughts / suggestions most welcome. If anyone feels like doing a sanity check to help ensure I've not made any stupid mistakes I'd be grateful. :)

PS
I've neatened up the schematics and boards a bit since posting this link. Primarily thicker GND and VCC lines and some slightly neater routing in places. Also added option for further decoupling cap on the 7404, but otherwise no functional changes. Did I set up the buffer IC properly? Should be A to B pins and no blocking...
 

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...maybe.

I guess there's something I don't understand, or at least I'm aware that I don't understand something from among the vast array of things I'm entirely unaware of...

I'd swear the Mockingboard design could get away with just one 6522 rather than two by offloading chip select duties on to the two AY 8913s, I'm always keen to make things as efficient as possible. Sadly, while I can get it to work, I can't get it to work reliably in all situations. Bum!

So two 6522s and two AYs it is then. On advise I've added a 74LS245 to buffer the bus, a trim pot to allow adjustment of system and sound card mixing, and given the components a bit more room. I've made extensive use of GND and VCC fills, not apparent in the photos. Also 3.5mm audio connector and volume control devolved to a daughter card for a more professional result... oh, and I put the volume control in the right place this time. As a result the card's grown a bit so I think MockingBird and Egg would be more appropriate names:

MockingBird2V2b.jpg
MockingBird

MockingEggV1.png
Egg

The two are to be joined by a 10 way ribbon cable. It could have been smaller but some duplication of signals was needed as the Egg itself can be cracked in two should separate mounting of audio port and volume control be desired.

I'll probably order some PCBs to test in a bit. Comments / suggestions are most welcome.
 

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Just beautiful my friend, Someone is writing a .mid to mockingbird Convertor ;)

:)
 
Just beautiful my friend, Someone is writing a .mid to mockingbird Convertor ;)

:)

blush: Thank you, and both excellent and intriguing news.

I need to go though the audio lines one last time to be sure I haven't gotten any of my wires crossed, and reread the 245's data sheet to be absolutely sure I set it up right, but do you feel time I sent off the Gerbers for a test run?

Thanks again for the kind comments / helpful advice.

PS
Yamaha do some interesting AY compatible ICs:
https://en.wikipedia.org/wiki/General_Instrument_AY-3-8910
I was going to base the card on the YMZ284 but couldn't find any at a sensible price... The YMZ285 could be very interesting indeed with regard to MIDI and other stuff, assuming it can be found at a sensible price and I find the datasheet. ;)

PS
I have to say this PCB designing lark can make one very paranoid, and a tad frustrated...
Last night I thought I'd have one more run through both boards before generating the Gerbers for manufacture of prototypes. I couldn't help but fiddle with the daughter card to make it nicer but judged the MockingBird itself "good" but for the addition of a logo... but I though I'd take one more look at the schematic: Blast! I'd forgotten to hook up one of the data lines between the left 6522 and AY ic's...
...much paranoid checking didn't throw up any other errors so I went back to the board to insert the missing line, but d*mn me if I couldn't see a way to route it in!
So, back down to the power line level, reroute the whole bl**dy thing again and now I've got some hopefully good designs to send to Seeed.

FWIW:
I'm a self taught rank amuter when it comes to using Eagle but I'll quickly run through the process I use in case it helps others.
1) Design the schematic in Eagle trying hard to keep things neat and use the absolute minimum of wired connections. Much better to label all the pins with something sensible and use those labels to make connections. That way the schematic has some chance of being legible and is much, much easier to alter.
2) Open a board for said schematic and place the ICs in something approaching a logical arrangement while attempting to keep the "rats nest" of connections looking as "nice" as possible. Place passive components with attention to making positioning neat and logical while also trying to ensure you're not adding too much complication to said "rats nest". Attention here will make routing much easier later.
3) I find Eagle does a pretty good job auto-routing but tends to make power lines unnecessarily complex. As it's nice to have extensive power and ground planes I tend to route these myself, power on the front and GND on the back. Again attention to neatness, while balancing the shortest runs but trying to keep to the edges of the board. The latter will help routing the rest of the lines. I also tend to at least double the default line width using the change icon when routing power lines. I tend to add / route power rail smoothing caps and any IC decoupling caps myself as Eagle seems only to put them in electrically sensible positions rather than on the power inputs / next to the desired ICs.
4) I then usually get Eagle to auto-route the rest using "maximum" effort settings. It's then a case of picking the neatest result from the presented options that make it to 100%. Once selected it's worth looking at the result in detail, where there's room I try to give more room to any lines where Eagle has jammed them a bit close and neaten up any stupid / ugly routing.
5) At this point I use the draw, polygon function to draw two boxes tightly round the whole PCB. Assuming the gnd is routed on the back and power on the front I select each box in turn (right click, properties) to put one on the top and one on the bottom, and fill 0.016 in to the spacing box to be sure the fill doesn't get too close to the traces. Right click on the bottom polygon, choose name, and type gnd... Eagle will ask if you want it connecting to GND, say yes. Do the same with the top poly but call it vcc. If you then select tools, ratsnest Eagle will fill you two nice power and gnd planes covering most of the board.
6) I usually go through step 5) again, but this time not renaming the 3rd and 4th polygons to fill any remaining gaps... pointless but neater.

Eagle can be set to auto select trace width via the schematic but as I do the power/gnd lines myself I don't find it useful. Also you can do the power/gnd polygons before routing so, in theory, these are done automagicaly. Having said that I find Eagle tends to make a right Horlicks of this and takes an absolute age to route... even with 8 cores going at 4.5Ghz.

Right, time to go knocking on Seeed's door and see what other mistakes I've made.
 
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I realise I'm probably the only one interested in this but while waiting on Seeed to send me my V2 boards I couldn't help but fiddle a little more with the design:

MockingBird2V2test.jpg
MockingBird V2 test

Basically the same as before but with added separate headers for each of the AY's three voices, a 5v header, and a 12v header. Why? Because I could, but also because I came across another elcheapo mini amplifier stereo module that will give about 15w per channel at 12v (OEP30W). This gave me the idea for an add on board, and that would need the extra headers...

MockingBird2x6Amp.jpg
Six Channel Sound at 15w Each, Baby!

Will anyone but me want this? Probably not, but I'm looking forward to six channels of Line Out or a thoroughly amplified six speaker set up inside my Apple II, assuming the PSU doesn't give up entirely. :blink:
 
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