Mist and an audio input... is it possible?

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slingshot
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Re: Mist and an audio input... is it possible?

Post by slingshot »

DrOG wrote:Hi!

I have built the V6Z80P tape input adapter and it works fine!
I wanted to build this for ages :) Nice little board. Also ZX81, Apple IIe and Amstrad cores support it. And would be good to try C64's serial port, too.
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Re: Mist and an audio input... is it possible?

Post by DrOG »

I forgot it almost as well, perhaps will try this method with the Amstrad core, but first I need to modify the built-in Datacorder of my Spectrum +2A, as I don't have any Amstrad cassettes... Found a nice tutorial, just need some time to realize it: https://spectrumforeveryone.com/technic ... -standard/
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Re: Mist and an audio input... is it possible?

Post by DrOG »

slingshot wrote:... And would be good to try C64's serial port, too.
Paradroyd forum member wrote a nice tutorial, needs a RPi to work:
https://www.google.com/amp/blog.paradro ... t-fpga/amp
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Re: Mist and an audio input... is it possible?

Post by slingshot »

DrOG wrote:
slingshot wrote:... And would be good to try C64's serial port, too.
Paradroyd forum member wrote a nice tutorial, needs a RPi to work:
https://www.google.com/amp/blog.paradro ... t-fpga/amp
I think a simple RS232-USB serial converter should work connecting to a normal PC.
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Re: Mist and an audio input... is it possible?

Post by slingshot »

DrOG wrote:I forgot it almost as well, perhaps will try this method with the Amstrad core, but first I need to modify the built-in Datacorder of my Spectrum +2A, as I don't have any Amstrad cassettes... Found a nice tutorial, just need some time to realize it: https://spectrumforeveryone.com/technic ... -standard/
It just about accepting an external tape input for the Speccy, how can this help here? (I did a similar mod already on my +2A, just with piggy-backing another jack on the existing one instead of this split stereo). I would try to connect some .cdt player to the MiST's new EAR input.
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Re: Mist and an audio input... is it possible?

Post by DrOG »

slingshot wrote:...
It just about accepting an external tape input for the Speccy, how can this help here? (I did a similar mod already on my +2A, just with piggy-backing another jack on the existing one instead of this split stereo). I would try to connect some .cdt player to the MiST's new EAR input.
Perhaps I simply misunderstood the essence of the project. My goal would be to make a 'line in' connector to reach the built-in tape unit of the Speccy, so I could record audio i.e. from a PC. I acquired this 2A+ recently, so I'm not an expert... Tried the new EAR input with a cellulal phone and downloaded .wav files from here: http://zx.zigg.net/zxsoftware/ , but did not work. I assume mobile phones' amplifier has not enough power to drive the signal through the circuit. Next attempt will be to burn these .wavs to audio CD, and use a standalone CD/DVD player, perhaps it will solve the problem.

Cheers: Gábor
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Re: Mist and an audio input... is it possible?

Post by slingshot »

DrOG wrote:
slingshot wrote:...
It just about accepting an external tape input for the Speccy, how can this help here? (I did a similar mod already on my +2A, just with piggy-backing another jack on the existing one instead of this split stereo). I would try to connect some .cdt player to the MiST's new EAR input.
Perhaps I simply misunderstood the essence of the project. My goal would be to make a 'line in' connector to reach the built-in tape unit of the Speccy, so I could record audio i.e. from a PC. I acquired this 2A+ recently, so I'm not an expert... Tried the new EAR input with a cellulal phone and downloaded .wav files from here: http://zx.zigg.net/zxsoftware/ , but did not work. I assume mobile phones' amplifier has not enough power to drive the signal through the circuit. Next attempt will be to burn these .wavs to audio CD, and use a standalone CD/DVD player, perhaps it will solve the problem.

Cheers: Gábor
Yes, it provides the EAR input, but I think the quality of the recording wouldn't be that good. I could load things via a phone set to the maximum volume (you should hear this on the Speccy's normal sound output, too). Just I didn't understand what's the connection of the Speccy's mod to MiST. You can play the same cdt/wav directly to MiST.
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Re: Mist and an audio input... is it possible?

Post by DrOG »

slingshot wrote: Yes, it provides the EAR input, but I think the quality of the recording wouldn't be that good. I could load things via a phone set to the maximum volume (you should hear this on the Speccy's normal sound output, too). Just I didn't understand what's the connection of the Speccy's mod to MiST. You can play the same cdt/wav directly to MiST.
My goal would be to use the Spectrum's built-in Datacorder to storage files on cassettes (sometimes I overcomplicate things). Phone didn't work in first turn, but after opening the .wavs in GoldWave, they are very silent (max. amplitudo circa 20%). Will try to maximize the sound files, and I give a second chance to my cell phone... If this works it's the most simple way!
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Re: Mist and an audio input... is it possible?

Post by DrOG »

Hi! The story continues...

Normalizing the .wavs resulted increasing their amplitude from 20% to 95%, I still needed the active PC speaker to load the games using my noname (Honor) Chinese phone (Attachment #1, #2 & #3), despite the max. volume.

During the next attempt I was using my old, jailbroken iPhone 4, and this time setting the volume to the max loading worked without external amplifier (Attachment #4 & #5)! I used AVPlayer app to avoid converting the .wavs to .m4a.

Next step is to modify the circuit to accept lower volume, perhaps line-level signals as well...
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Re: Mist and an audio input... is it possible?

Post by Lroby74 »

sorry DrOG, but you have near to this LCD monitor an awesome CRT 14" monitor (maybe a CM8833?) and really using LCD with Mist??? :O
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Re: Mist and an audio input... is it possible?

Post by slingshot »

After a while you'll get tired of that flickering 50-60 Hz CRT screen :)
@DrOG I wonder after the increased shunt resistor, it still doesn't accept lower levels.
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Re: Mist and an audio input... is it possible?

Post by DrOG »

Lroby74 wrote:sorry DrOG, but you have near to this LCD monitor an awesome CRT 14" monitor (maybe a CM8833?) and really using LCD with Mist??? :O
Sometimes yes, but this time I was just lazy to take apart my experimental setup. I use mostly my BenQ BL912 with the MiST (I have a rotatable monitor stand which is necessary for some arcade cores), and the Philips CM8833 with my real retro machines (Amiga, Speccy 2A+ and Enterprise 128). It supports the C128's 80-column video as well. It's only drawback is the lack of S-Video input, but this can be added following this tutorial: https://www.lemon64.com/forum/viewtopic ... 74c8c55d46
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Re: Mist and an audio input... is it possible?

Post by DrOG »

slingshot wrote:...
@DrOG I wonder after the increased shunt resistor, it still doesn't accept lower levels.
Tried to increase the shunt resistor's value to 2,4k, but the result was the same. After doing some math and several try-and-error tests I assume further progress is impossible without completely redesigning the circuit. It think it's related to biasing, but perhaps I'm wrong as I'm not an expert, but a hobbyist with a soldering iron ;-). After all, I think it's already acceptable result, as cheap active PC speaker can be used if necessary to amplify the signal level.
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Re: Mist and an audio input... is it possible?

Post by DrOG »

Hi!

Still playing around with the EAR connector, this time tested the Amstrad core, works flawless with my current setup (iPhone4 connected directly to 3,5"jack)! I found dozens of CDTs floating around the net, but finding a software which runs on recent Win OS that converts them to WAV was not so easy... I tested two of them with success, the CDT2WAV: https://cpcrulez.fr/emulateurs_UTIL-CDT-CDT2WAV.htm (see Boulder Dash) and the WinTZX0.9a: http://www.worldofspectrum.org/pub/sinc ... ZX0.9a.exe (see Super Pipeline 2). Both concerters run properly on Win10 64bit, the .wav file can be loaded immediately, no need to normalize it.
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Re: Mist and an audio input... is it possible?

Post by Lroby74 »

DrOG wrote:Hi!

Still playing around with the EAR connector, this time tested the Amstrad core, works flawless with my current setup (iPhone4 connected directly to 3,5"jack)! I found dozens of CDTs floating around the net, but finding a software which runs on recent Win OS that converts them to WAV was not so easy... I tested two of them with success, the CDT2WAV: https://cpcrulez.fr/emulateurs_UTIL-CDT-CDT2WAV.htm (see Boulder Dash) and the WinTZX0.9a: http://www.worldofspectrum.org/pub/sinc ... ZX0.9a.exe (see Super Pipeline 2). Both concerters run properly on Win10 64bit, the .wav file can be loaded immediately, no need to normalize it.
It's wonderfull! I think that same thing will be possible on Mistica (that has already EAR input)
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Re: Mist and an audio input... is it possible?

Post by slingshot »

Well, if you have MIDI input, you don't have to destroy it for tape loading:
tape-midi.jpg
The connection to the MIDI IN:
pin 4 - jack GND
pin 5 - jack signal (left or right)

It needs fairly high volume (but the VZ interface need it, too). I think a simple one-transistor common collector amplifier powered from the MIDI OUT port can be used if even the maximum volume is not enough, maybe I'll experiment with that.
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Re: Mist and an audio input... is it possible?

Post by vebxenon »

slingshot wrote: Sat Aug 29, 2020 1:43 pm Well, if you have MIDI input, you don't have to destroy it for tape loading:
tape-midi.jpg

The connection to the MIDI IN:
pin 4 - jack GND
pin 5 - jack signal (left or right)

It needs fairly high volume (but the VZ interface need it, too). I think a simple one-transistor common collector amplifier powered from the MIDI OUT port can be used if even the maximum volume is not enough, maybe I'll experiment with that.
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