Cassette interface

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Cassette interface

Postby vbriel » Jun Mon 11, 2012 4:17 pm

Well, after I read that Mike W. worked on the -12V questions and got the cassette interface working on his Mimeo I thought I would try it on my replica 1 cassette interface prototype. The good news is I can get the cassette interface to work on my machine using a Panasonic cassette recorder. I will see if I can load wav files from something more modern like my cell phone. Stay tuned. I may finally have this thing working properly.

Vince
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Re: Cassette interface

Postby vbriel » Jun Wed 13, 2012 2:45 pm

Ok, testing is coming along. I will try more replica 1's I have laying around to see if they work. One thing to note is the replica 1's with EEPROM's (28C64) onboard in place of EPROM's (27C64) have a noise issue. What I would do if I produce these is to ship an EPROM for the replica 1 to replace your EEPROM. I need to know how many people are interested in getting a cassette interface. Looks like kits would be $50-59 and assembled would be $79. This is not for the meek. Cassette interface storage is difficult to get right and I can not guarantee that your cassette or sound source will work with the replica 1's. I will however work with anybody who is having problems getting it to work for them.

My suggestion is to go out and find a Panasonic RQ-2102 like the apple 1 used, it works great for me using a 5V 1000mA power supply as the voltage source. Email me if you want one. We need 20 people wanting one to make this a go.

Vince
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Re: Cassette interface

Postby PaulB » Jun Tue 26, 2012 8:01 am

Hi Vince,

Great to hear that you have had some success with the ACI for the replica and sounds well priced too.
I think that although you can use EEPROMS/ CFFAI or just dump your programs from PC, you really do get the authentic feel of vintage computing when you load/write from tape.
My replica sits in the corner of my office and i often play a game of Chess throughout the day, having my turn whenever i walk past . I almost always load from Reel to Reel tape which never seems to stop amazing people who were born less than 30 years ago.
Although it takes a bit of tinkering to set them up properly i would recommend it to anyone wanting to recreate a true replica experience.

For those interested my machine can be viewed in the Creation Room Forum, "R1 Downunder with ACI".
All the best for now.
Paul.
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Re: Cassette interface

Postby tranter » Jul Thu 05, 2012 11:03 pm

Hi Vince:

Any update on whether a run of the boards will be happening?
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Re: Cassette interface

Postby vbriel » Jul Fri 06, 2012 12:04 am

Yes, I am doing the final layout now for a prototype board. I will be placing a board order just before I leave for Kansas and the boards will arrive shortly after I get back. I'll do a small run of 20 boards for people. I prefer people who are not "novice" users to help beta test these since ACI boards can be tricky. So, probably this weekend I'll start taking preorders!

Vince
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Re: Cassette interface

Postby vbriel » Jul Sun 08, 2012 1:33 pm

Final schematics for the cassette interface:

Image

The changes from the original design is very small. I replaced the PROM's with an EPROM and added a jumper for voltage select. The voltage select is very important as it will help you decide on the voltage you want use to read back the cassette at. The standard ACI used -12V for a voltage swing but using ground instead does appear to work. So, I decided to put a jumper select on the board so the user can find which one works best for them.

You can download the schematic in pdf format here: http://www.brielcomputers.com/files/cassette_rev1.pdf

I will do a BETA run of 20-30 units. Everybody is welcome to order one but I encourage those with experience working with cassette interfaces to be in the beta run and those with no experience to hold off until testing is complete. I've not produced these boards until now mostly because of the difficulty getting the data to load back onto the replica 1 was unreliable.

So, the kits will be $59 and assembled units $79. I will get a preorder page up shortly and the kits will ship shortly after I return from Kansas Fest. Please expect 4 weeks for the boards to be made and the kits to ship.

Vince
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Re: Cassette interface

Postby vbriel » Jul Thu 19, 2012 7:36 pm

Sorry for the delay guys, I'll have the order page up soon for the beta run of cassette boards. I've been at Kansas Fest and in my spare time I've been testing out the cassette interface more and more. Everything seems to work but I'd like to get my phone to play back since I hear iPhone's work with the cassette interface.
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Re: Cassette interface

Postby Corey986 » Jul Fri 20, 2012 4:51 am

vbriel wrote:Sorry for the delay guys, I'll have the order page up soon for the beta run of cassette boards. I've been at Kansas Fest and in my spare time I've been testing out the cassette interface more and more. Everything seems to work but I'd like to get my phone to play back since I hear iPhone's work with the cassette interface.



You may have a problem storing stuff with the iPhone, the compression can be an issue. However playback should be fine. If you have an old iPod Classic you can record in WAV format uncompressed. If you just want to test iPhone, try Wendell Sander's stuff it's all volume ready for iPhone. Remember unlike a tape player, the iPhone needs to be at almost max volume and you have to use the headphone jack. The dock cable adapters line level is too low.

Good luck, I can't wait to get my Replica-1 ACI to complete my exhibit ;)

Cheers,
Corey
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Re: Cassette interface

Postby Corey986 » Jul Fri 20, 2012 7:04 am

Forgot to add. Don't expect the LED to work with the iPod. Not enough volume.
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Re: Cassette interface

Postby tranter » Jul Sun 22, 2012 3:24 pm

Vince:

I see the design has the change to the input capacitor from .01 to .1 uF that Mike Willegal found improved reliability. He also found that using a 7474 rather than 74LS74 improved the performance, so you might also want to make that change. And don't forget that R1 through R4 should be 1% tolerance resistors.

There's some good info on using an iPod for recording at this link: http://www.apple1notes.com/old_apple/Notes.html

The original Apple 1 ran at 1.024 MHz but with DRAM refresh ran with an effective speed of 0.960 MHz.
The Replica 1 runs at 1 MHz. I'm wondering if that difference might affect being able to read tapes recorded on a real Apple 1.
There are audio files around for Apple 1 software that could be used to test this.

I'm looking forward to being able to order and build one of these.
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Re: Cassette interface

Postby Corey986 » Jul Mon 23, 2012 5:32 am

[quote="tranter"
He also found that using a 7474 rather than 74LS74 improved the performance, so you might also want to make that change.[/quote]

Actually Mike did more checking and the switching of the 74ls74 doesn't help. I have one ACI with each and the LS one is more reliable with the iPod. I think he even stopped shipping both in his kits.
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Re: Cassette interface

Postby tranter » Aug Mon 20, 2012 8:00 pm

Vince:

When do you expect the kits to be shipping out?
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Re: Cassette interface

Postby vbriel » Aug Mon 20, 2012 8:25 pm

I should be getting the boards in this week, so very soon. I'm still writing the manual for it. The manual will have the build instructions plus jumper settings for the voltage jumper. Other than that, the apple 1 ACI manual will be included to perform operations since it is nearly identical to the original ACI.
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Re: Cassette interface

Postby tranter » Sep Sat 08, 2012 4:38 pm

Any update on the cassette interface kits?
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Re: Cassette interface

Postby vbriel » Sep Sun 09, 2012 11:16 am

I'm starting to bag kits today. They will go before the assembled units. Boards came out nice. I'll try and get pictures up soon.
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