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Re: PhonoVision Mechanical video recorder Version 3

PostPosted: Sat Dec 12, 2020 12:36 pm
by smeezekitty
You want a transformer to change the impedance. A small mains voltage transformer might work in a pinch (i.e. 6-12v on one side and 120/240v on the other). Put the low voltage end to the amplifier and the high voltage end to the cartridge.

Re: PhonoVision Mechanical video recorder Version 3

PostPosted: Sat Dec 12, 2020 1:34 pm
by Harry Dalek
smeezekitty wrote:You want a transformer to change the impedance. A small mains voltage transformer might work in a pinch (i.e. 6-12v on one side and 120/240v on the other). Put the low voltage end to the amplifier and the high voltage end to the cartridge.


OK mmm step up used the idea on the passive NBTV modulation on my scope ...give it a go right now ..
post when i get back ...
OK it worked ; )
it was a 6v 0 6V so 12v used got the amplifier volume down to 40% with using 6v got it down to 30 % Yes this will make making an Amplifier a lot easier good thinking and thanks !

Re: PhonoVision Mechanical video recorder Version 3

PostPosted: Sun Dec 13, 2020 5:01 pm
by Harry Dalek
Spent the day working on an amplifier or one half of the stereo idea ,i happened to find a Lm1875 30 watt amplifier ic in my junk box running it with a dual 30 volt supply and it worked great,i just have to buy another for other channel now i know this works .
P1070529.JPG


So the amplifier side of it is worked out this now makes it a stand alone unit ,i will add PWM recording and AM now


Re: PhonoVision Mechanical video recorder Version 3

PostPosted: Sun Dec 13, 2020 5:50 pm
by Steve Anderson
Good progress Harry, looking forward to further updates...

Steve A.

Re: PhonoVision Mechanical video recorder Version 3

PostPosted: Sun Dec 13, 2020 8:14 pm
by Harry Dalek
Steve Anderson wrote:Good progress Harry, looking forward to further updates...

Steve A.


Thanks Steve i was pretty surprised how well this amplifier works ,nice to spend a day working on something and it does what you want .

Re: PhonoVision Mechanical video recorder Version 3

PostPosted: Thu Dec 17, 2020 6:37 pm
by Harry Dalek
Just finished the second amplifier
P1070534.JPG


Now that's out of the way apart from connecting mounting the lathe cartridge the recording part of it is all there for AM ,i will construct a PWM circuit similar to this old laser modulator i used last time around i'll improve the 741 side of it with a better opamp ...i found last time around PMW recorded well so it will do at least AM and PWM recording
LASER_COMM_simple.gif


Next i need to work on the play back side since this will be non record player RPM standard i need to play back with this turntable.
Figure 1 - Phono Preamplifier (RIAA Equalisation)
p06-f1.gif
p06-f1.gif (5.93 KiB) Viewed 9446 times


So that's where i am up to now and what's on my mind :roll:

Re: PhonoVision Mechanical video recorder Version 3

PostPosted: Tue Dec 22, 2020 7:27 pm
by Harry Dalek
Bad time of the year for project time but update 2nd amplifier tested works ,built the phono cartridge Ne5532 circuit ,need a 15v dual voltage for this which i will adjust via regulators from the stereo Amplifier's dual 30 volt DC supply ,work on that so that's next .
Bit slow but will work more on it next 2 days .
I have on my mind to later get it to play back to display on a CRT monitor might be a bit fussy for this signal wise ,but i think it would be nice to see it can record other nonstandard NBTV and display back on a CRT ,Bairds 30 line low frame rate would be possible to make now should be able to record it and play back via this beast ..but thinking ahead here for 2021.

Re: PhonoVision Mechanical video recorder Version 3

PostPosted: Sat Dec 26, 2020 7:49 pm
by Harry Dalek
Had some time to work on the record play back board .. being a touch more fussy on the video channel for record and play back this time ..
Still going to add a little amplifier for playback to a small speaker .
getting there ;)

Re: PhonoVision Mechanical video recorder Version 3

PostPosted: Mon Dec 28, 2020 2:55 pm
by Harry Dalek
Bit more work yesterday working on the lathe side of the circuit ,i can try PWM or AM either sound or video or a mix .
I tried the little 2 watt amplifier see if i can get away with just using it with the cartridge but level is a bit low so i will add its own preamp.
Everything else circuit wise seems to be fine for what i need so will not be to much longer before i scratch a few records out .
The 2 ics on the right are CA3040's

Re: PhonoVision Mechanical video recorder Version 3

PostPosted: Tue Jan 05, 2021 6:25 pm
by Harry Dalek
The electronics on the lathe part is finished, just have to test the cartridge L,R both at the same time just have to add another transformer to the stereo Amplifier ,i was just testing the sound side of it in the video ..I am going to have to be careful with levels i cranked it up to far and noticed sparking in the cartridge .


Re: PhonoVision Mechanical video recorder Version 3

PostPosted: Sun Jan 10, 2021 4:18 pm
by Harry Dalek
Little more work today on how to mount the ceramic phono cartridges for record playback and balancing the tone arm with counter weight arm which is adjustable as i will need this when i get around to playing back .
As posted in the electronic section i am also looking into using the Devil A for Andrew monitor for play back ,i know i can adjust this monitor from past go's to different line frame rates which will come in handy for a non standard NBTV recordings with in its limits , know i can do 32 line and hope sound along with it but it would be nice to do a flashy Baird 30 line low frame rate record in honour of phonoVisions inventor in fact the inventor of the first video recorder ever :idea:

Re: PhonoVision Mechanical video recorder Version 3

PostPosted: Sun Jan 24, 2021 8:23 pm
by Harry Dalek
Sorry for any one following this apart from hooking up the cartridges and mounting the 2 audio out put transformers i should be right for tests ,i was also looking into fixing one of my crt monitors so i could test if 48 line was possible to record..., it would be more flexible if i had more than the software monitor where i am stuck with 30 32 and 60 line...60 line was a failure last time i tried bandwidth to wide i would think but there are so many factors to a good recording and playing back correctly i hope its just a mistake i made last time .

Something i had in mind if the stereo thing didn't work was this idea nothing new under the sun ! 2 audio tracks this case in the video.
I would think this would of been Baird's plan if he was more successful with PhonoVision 2 tacks on the same record half video on one end audio on the other half .


youtu.be/PgbO_OFVaQc

Re: PhonoVision Mechanical video recorder Version 3

PostPosted: Sun Jan 16, 2022 1:20 pm
by Harry Dalek
Time to get I started working on the remaining parts to this build but something has gone open circuit with the geared plater motor so unless its an easier fix the motor needs replacing looks like i will have to go looking in my motor junk box for a replacement fingers crossed .
i will look into that now .

Re: PhonoVision Mechanical video recorder Version 3

PostPosted: Sun Jan 16, 2022 2:58 pm
by Harry Dalek
OK i was lucky i had a spare gear duplicate of the small geared plater motor shown now mounted below
DSCN6913.JPG

DSCN6914.JPG


Testing it the idea is working fine again ,it has variable speed you want it around the RPM rates of a record player or record time is very limited if to fast ,here i really just want it to work and the geared motor does not seem to noisy i may place cork under the platter mount to case as any noise would be recorded .


Next week i will mount the cartridge's retest the amplifier's .
Also got to test the play back arm positioning can be delicate need some fine wire for cartridge arm to circuit so it does not effect movement both recording and play back have to work or either will effect results .
Have to also jog my memory what the hell i made bit of reviewing
If any thing i expect same results as my large version fingers crossed ....last time i could do 32 line NBTV i am pretty much limited to what the cartridge Bandwidth is.

Re: PhonoVision Mechanical video recorder Version 3

PostPosted: Mon Jan 17, 2022 7:16 pm
by Harry Dalek
Here a look at Baird's vision of a player viewer mock up concept i would think since he was never able to view any of he's recordings
The Sphere - Saturday 25 May 1929
I would like to get a little case for mine every thing is a bit easy to knock about as it is now .
I forgot to show how i move the plater ,a geared motor from an old video camera lens zoom adjustment connected to a pulley wheel.
Its got the torque when embossing the cds with out to much noise ,i tried a stepper motor on one of the other gos and they are way to loud vibrations and all so may have the speed nice and correct but the record would be a waste of time so this is the next best thing when i try a bit of a cork under the mount should be good enough ... nice and small to how how i originally was trying for on mark 1.