TDX Laptop Stereo Card - Progressing..

 ***Update***
11/12/2009
Well finally hit some good headway with this tonight and have a fully working circuit with dual channels and volume control and works happily with headphones.
This uses the base of the original circuit (as per the FAQ) but removes the 2nd stage op amp and introduces 2 x LM386 power aps and 2 x DS1669 Digital Pot ICs. There are 2 push buttons that control up and down volume.
Massive thanks to Michael Mahon who has been very patient with me over the last couple of weeks :).
Still have quite a bit of work to do as I also plan to look at other ICs that might be able to simplify the design..as currently the power amp section requires 4 ICS....

7/11/2009

Well I plan to do a small run of the version 1.0 card (15 cards or so and will be offered to the CSA2 community first). The output is designed to go via power speakers. My website will get updated at some point to reflect availability :)(www.drew2gs.com).


I have stopped working on getting input functionality working, but rather have decided to focus on making a card that can fit in the portable GS that is being made by www.a2gs.com.

The portable GS will need to be able to run via headphones or un-powered internal speakers. This means I need to redesign the existing card to contain power amps. This has also made me think that once I get input working I can make a version 2.0 stereo card that has Line-out, headphone-out with vol control and Line-in/Mic-in. There is potential here to obvious make a completely slotless design.


**It was pointed out that I can get rid of the line-out and just use headphone out to connect to powered speakers**



Well tonight have had 100% success getting headphone output to work with volume control and zero distortion :). This happily worked along side the line out with no obvious issues. Was only able to test one channel as currently only have 1 potentiometer. To get it to work successfully I bypassed the 2nd OPAMP.



There is still hiss/white noise which I am not happy with until I have eliminated the bread board, but am going to continue with the current design. I  will use a version 1.0 board along with a hand made board to see what it all sounds like before i start looking at layout and how to get it to a size the portable GS guys are after :).

Schematic with the output from the low pass filter opamp going into a LM386

 

Working breadboard (one channel powered) utilising bother lineout and headphone out.

TDX Stereo Card - Prototype Complete

25th November **Update**

It seems the white noise wasn't helped by using headphones to do my testing. As soon as I used a set of powered speakers the sound seemed much much better. There is still some white noise over the right speaker but much less so than my Audio Animator. Therefore I would say card is all good for production, once i decide if i want to add input capability or not :).

24th November **Update**

Prototype was completed tonight. Didn't take long to solder together and all worked (kinda). The only issue is hiss coming from right speaker, similar to the bread board. Will investigate. Anyway some pictures are below.

 

 

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The prototype boards have turned up. Will try to get something built over the next couple of days to see if all works and how it sounds.

The card has 4 mounting holes and also a space for a connector for +5 and -5 volts to power the board without a slot. How this will get housed has not yet been decided, but at least base design can potentially be used for slotless application.


My current thoughts are now to encompass a digitiser, using info from CSA2 and also the hyperstudio audio card as an example circuit...so will be back to the drawing board once I have a working board.

TDX Stereo Sound Card - Update

6/11/09
**Update**

I have decided to wing it ;-) and have sent the latest PCB layout to have a prototype made. I should be a in a position within the next 10 days to actually make my first card.

Still awaiting quotes for back plate fabrication...:(





3/11/09

I am planning on making an audio cable similar to the Sonic Blaster one, but with only one 3.5mm jack:-

I am also looking to include a stereo phono cable similar to :-

These cost less than a £1 each , so it will depend on what the total cost comes to for the card.

2/11/09

Today I have been thinking about what I can really achieve in this project as a lot of things are new to me. At this point I have decided to go with a slot based design with connectors for J25 connection and audio out. This will allow the Stereo out connector to be screwed to one of the plates at the back.


One thing I don't like with the stereo card is mono sound only comes out one speaker (same as my Audio Animator, so nothing specific to the TDX), so I am planning to now put a switch to allow the mono sound to come out of both speakers giving a stereo effect if desired. This switch will be mounted on the back plate.


Work has now started on getting quotes together for PCB boards and plate manufacture while I work on the prototype card. I have had some initial quotes back. They look very promising and now just waiting for back plate fabrication quotes.



I fully plan to investigate slotless design and ADC after the initial run is completed.

TDX Stereo Sound Card - Breadboard Complete

30/10/2009


Bread Board is complete. Surprisingly all worked (well had an initial issue where i wasn't providing +5 and -5 volts properly to the board), bit of hiss in the background, but suspect this is because its on a breadboard.

(56k Resistors still arn't here but put some in series to get the resistence needed)

29/10/2009 - RS Stuff has all turned up, but I had forgotten to add the 56K resistors to the order...3.5mm Stereo PCB jacks also turned up...but suspect they are too close to the board to accept a jack unless at end of the card..Will be fine for breadboard and prototype, but will most likely look at some that are slightly raised to allow cable to not impact back of case. (ideally i want to use a cable from the board to the the back of the case to fit in one of the ports...but finding parts seems difficult)

Connector seems to work well with the ribbon cable and though its a bit of a tight fit on the motherboard it does fit, and didn't need any crimps. Also started the bread board...not sure its big enough, but its what i had available :).

28/10/2009
I have been busy getting parts together for this new project and have just ordered the following parts from RS.

• 517-3181 - TL084I quad 3MHz 13V/uS op amp, DIP14
• 197-2669 - 16 way turned pin DIL socket,0.3in pitch
• 519-0316 - Dual 4-1line mux/demux,MC14052BCP DIP16
• 135-910P - RES HYSTAB 0.25W/10K
• 135-932P - CFR16 carbon film resistor,15K 0.25W
• 365-4234 - NHG min Al electrolytic cap,4.7uF 50V
• 365-4240 - NHG min Al electrolytic cap,10uF 50V
• 122-4235 - FKS2 Polyester Cap,100Vdc,1.5nF
• 622-4397 - Plastic film capacitor,100nF 63V 5%
• 157-547  - MBA0204 M/F Res, 0.4W 50PPM 1% 56K
• 289-9846 - Speedbloc(R) 10 way IDC ribbon cable,5m
• 189-9592 - HE14 AUTOCOM cable socket 26/28awg 7W
  

I have also ordered a selection of connectors/headers to see what will be best for connecting to the mainboard.

Andy at work likes his circuit diagrams and has kindly drawn up a schematic and a PCB layout based on the TDX diagram and Polymorphs use of the Quad Amp. He still has to add the connector layout for the GS slots, but I am well on my way to having a bread board ready for some testing.


Version 1 Schematic and PCB Layout

I am just going to be using a single sided copper board for the prototyping stage (once breadboard testing is done) this will mean that I will not have the +5V, so will plan to add a L7805 Reg to bring the +12V down to +5V. This will mean only pins 34 and 50 will be used on the connector.

TDX Stereo Sound Card

Right on to my next project.... I am now going to attempt to make the TDX sound card i have seen in the FAQ and on Polymorph's site.

I don't actually need one as I already have an AE Audio Animator, but again things get older and i could also do with the external box not being on my desk. More importantly more electronics fun :-)














I have several goals with this project

1. Re-Produce the above using the information available and assistance from the A2 Community.
2. Do a more complex electronic's project
3. Possibly look at mass production....
   

I will start ordering kit and getting people at work geared up to help :-)

Things to think about....

• Cable to GS ?
  
• Audio Output ?
  
• Making more than one...
  

 















J-25 Connector
  1  Analog to digital in 
     (end nearest front of computer)
  2  Analog ground
  3  Waveform out
  4  Channel address zero
  5  Channel address one
  6  Channel address strobe
  7  Channel address two

 

Replacement GS PowerSupply - Complete :-)

Well today I completed my first electronics project :). I initially was going to just mount the regulator to the case, but someone at work suggested i use a bit of strip board as well as use relevant connector (floppy type in this case). All works. Apart from the 240Volts I got yesterday lol, it was a pretty successful little project. Photos below.


After old power supply was stripped out

New Power supply mounted including Regulator
Used existing mount point to provide a secure fixing then plastic mounts for the rest.

Used existing mounting point to mount the strip board with L7905CV regulator

Circuit diagram for the negative regulator (make sure Capacitor + is to ground)

Circuit Diagram for the MeanWell PT65B PSU

L7905CV -5 Regulator

TECHNIKA 15.4" HD Ready LCD TV (Tesco) - Model 15.4-310

Bought this from Tesco today on a bit of a whim. I have tested lots of LCDs with the GS and this is the best one yet and only £99 (is HD Ready, with VGA, component as well). I will say that the colours aren't as vibrant as real monitor or compared to my Samsung 24inch next to it (when using Carte Blanche via VGA).

Some quick screen shots of GS/OS below.

Some screen shots of 40 column text

80 Column Text

Meanwell PT-65B

The new PSU has turned up. Need to look at getting connectors sorted out....

New Power connectors (KK series in the 3.96mm pitch) have now turned up from RS, just waiting on the Crimps (now here).

• 6 way locking housing stock no. 173-3105
• 3 way locking housing stock no. 173-3076
  
• Crimp terminals - 22-28 Awg Stock no. 245-4718

More? GS Replacement PSU

As you can tell I have just started "blogging" today. The main reason i put this together was to have a place people might be able to get information on projects I am working on and if it helps them then it was worth it. It also gives me a record and something more to do that is Apple IIGS related yippie :-)

My latest project is to replace the insides of ageing GS PSUs with a modern equivalent. Why you might ask? Well it all goes back to having things original. My main GS happily works with a Mini ATX and external power pack. Its great as all the heat generated by the PSU is not internal to the GS. This is perfect for day to day use...well once a week use :P.

I have a couple of older GS machines (and also my newly acquired ROM03...but it has a 110v psu another reason for this project) that have PSUs that struggle when under load..so i wanted to use them as my guinea pig.

After some posting on the comp.sys.apple2 i was pointed into the direction of a Meanwell PT-65B open frame switching PSU (It has been used to replace a Vulcan PSU with some minor modification to component placement). Though this should fit inside an existing PSU casing it only outputs +5/+12/-12 the -5 is missing and you need to use a negative regulator to produce a -5 for the GS.

The GS connector has :-

• Pin 7 -5 Volts 0.25 Amps
• Pin 6 -12 Volts 0.25 Amps
• Pin 5 +12 Volts 1.0 Amps
• Pin 4 +5 Volts 4.0 Amps
• Pin 3 Not Used
• Pin 2 GND
• Pin 1 GND

I am hoping to have this completed over the next month or so but suspect there will be some challanges around actual placement and fixing inside the old PSU case etc and also that i will need help from friends who are more clued up around electronics as well as the Apple II community :)

Today I ordered my PT-65B and also picked up the following from Maplins

• Negative L7905CV Regulator to provide -5V from -12v
  
• Radial-lead style tantalum Capacitor 35v 2.2uF to be used with the Regulator
• TO220 Insulator and Bush so i can isolate the Regulator from the PSU case which i will attach it too.

New IIGS!

One thing i fondly remember was opening my GS (ROM01 model in coloured packaging) in late 1989 and the excitement of getting my first computer. Over the years i have collected a number of used GSs all of various ages, models and shades of yellow. I have a couple which are not too badly discoloured, but i really liked the original platinum colour of the GS and have wanted to get one in original colour.

A boxed unused ROM03 GS was listed on ebay recently and i was lucky enought to win it :). I was actually surprised i won it as its the first one i have seen on ebay since i have started looking and was expecting it to go for lots more. The box isn't great (though its complete and still sturdy) and inside its missing the mouse (shame) and one of the system disks, but apart from that the manuals are sealed with a Tour disk, and System tools disk as well as new keyboard and ADB cable all bagged up.

The GS is as new and there is not a mark on it, with totally original colour and shiny and new inside as well as outside. It was like christmas :-). I did power it up and all self tests worked.:-)

New Transwarp GS

Over the years i have replaced bits in my main GS (yes i have many lol) to bring it up to date...well as best you can a 20+ year old computer. I have replaced the PSU with modern mini ATX (using LittlePower GS) and used CFFA cards to use a CF as an HDD. I still enjoy the feeling of something original and one item i have been looking for over the last 15 years is a boxed Transwarp GS card (as well as a new GS in a box...more of that in a bit)

I was lucky enough recently to get the opportunity to buy a brand new unopened one :). It wasn't cheap and I have yet to open it as I have also acquired a used Transwarp GS card which i am currently using. I don't plan to keep it sealed and will be opening it shortly once other retro projects get completed.

First Post...

I didn't have a IIGS for very long when i was younger, and sold it around 1992 and used the money to buy my first PC. Since about late 90's have been collecting IIGS computers and tinkering with them ever since. Nothing major i am not a electronics engineer or programmer just a user :). I have enjoyed building up the system i used to have and collecting the rarer items as they come available. I am fascinated by the machine, probably because it was an underdog at the time and the end of the Apple II line, whatever the reason its a great retro hobby to have :).

After many years of being a PC person (in fact my work is all Windows lol) I am now an owner of a modern MacBook Pro....only taken me 20years+ to forgive Apple for killing of the Apple II ;)