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Author Topic: SE-ONE music file player (Read 44542 times)

Offline geco

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Re: SE-ONE music file player
« Reply #45 on: 2018.May.17. 22:20:53 »
cool :)

Offline Zozosoft

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Re: SE-ONE music file player
« Reply #46 on: 2018.May.18. 07:04:53 »
I have made a MSX adapter prototype:
Wow! :smt038

Offline pear

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Re: SE-ONE music file player
« Reply #47 on: 2018.May.18. 07:35:37 »
What level (voltage) does the audio signal which come into EP ?

Offline gflorez

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Re: SE-ONE music file player
« Reply #48 on: 2018.May.18. 09:34:25 »
Directly.... It gives good sound without distortion.

And the Enterprise seems to mix it perfectly with the internal sound.
« Last Edit: 2018.May.18. 09:38:21 by gflorez »

Offline pear

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Re: SE-ONE music file player
« Reply #49 on: 2018.May.18. 10:07:49 »
This is not the point.
On my FlexiBridge I made a mini jack for audio input.
I predicted the possibility of its protection against applying too high voltage.
I need to know how much it is "too high voltage".

Offline Zozosoft

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Re: SE-ONE music file player
« Reply #50 on: 2018.May.18. 10:12:26 »

Offline pear

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Re: SE-ONE music file player
« Reply #51 on: 2018.May.18. 10:47:56 »
From the scheme we can deduce what is the level at the output.
At the input it should definitely be below 5V, but for audio it's still too much.
It's hard to say, does DAVE have any security inside ?
In general, the external audio input circuit in EP is strange because it does not cut off the fixed voltage.
I would be careful.

Offline gflorez

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Re: SE-ONE music file player
« Reply #52 on: 2018.May.18. 11:31:17 »
If you describe me the way to measure that level with a multimeter, I can do it.

Sometimes I  notice a small downing in the volume on some higher parts of the songs, the transitions are very smooth, so they don´t interfere with the listening. After that high point, the volume slowly returns to its initial state.

But probably in my specific case this correction is done on the TV amplifier input, not inside the Enterprise, because the mixed sound is very clear on all instances.

For me the effect is very similar to the auto-level that the tape recorders incorporated from mid 80's.

I have to try the same song section with other monitors or amplifiers.


-----

May be you can understand the inners of the Dave chip.
« Last Edit: 2018.May.18. 11:36:43 by gflorez »

Offline Zozosoft

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Re: SE-ONE music file player
« Reply #53 on: 2018.May.18. 11:36:38 »
Try with headphones/speakers at the tape out connector.

Offline pear

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Re: SE-ONE music file player
« Reply #54 on: 2018.May.18. 11:37:33 »
Set the multimeter to measure the AC voltage.
The MAX measurement function would be useful.
The input signal set at maximum, but no overdrive.

The effect you describe may ba a change in the signal's constant voltage.
The change will not be heard in the form of some sound, but it will change the parameters of the amplifier's operation (change of volume).

Offline gflorez

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Re: SE-ONE music file player
« Reply #55 on: 2018.May.18. 11:40:36 »
May be you can understand the inners of the Dave chip.

----
Ok, I will try.
 

Offline gflorez

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Re: SE-ONE music file player
« Reply #56 on: 2018.May.18. 12:17:34 »
On idle the voltage remains at 0,002v, and on the higher peaks of a song it rises max to 0,350v. It changes fast... but I have not seen a 0,4xx figure.

Offline pear

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Re: SE-ONE music file player
« Reply #57 on: 2018.May.18. 12:33:25 »
Usually, the audio signals have a level of 0,7..1,0 V.
That's what I expected, but I did not have any confirmation.
Thank you :)

Offline TMTLOGIC

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Re: SE-ONE music file player
« Reply #58 on: 2018.May.19. 00:49:31 »
What is an DAVE chip?
WWW.TMTLOGIC.COM

Offline gflorez

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Re: SE-ONE music file player
« Reply #59 on: 2018.May.19. 01:41:34 »
It is one of the custom chips of the Enterprise, the other is Nick. They have the name of each of their designers, Dave Woodfield and Nick Toop.

Nick manages the video output, and Dave the sound and memory pagination..
« Last Edit: 2018.May.19. 01:47:30 by gflorez »