Видео

???? there is nothing digital about it. Do not understand you.... Problem with your proposal is the limitation by 'standard' recording with a bias. Limitation is the limited dynamic range. By using FM modulation etc ther is more room.

@@TheoFaber But it’s not the same as recording to magnetized tape. it doesn’t have the saturation characteristics. I am researching more. I do not completely understand this FM modulation to tape concept

@@johnviera3884 Your right, i's not the same. Magnetized tape??? the tape is magnetized by the recorder head. The old way or by a video-head. By ordinary longitudinal recording (open reel to reel) there is a very large (HF) bias current to overcome the problems in de record head. Without that bias, audio wil be distorted. By using the video heads, there is no bias current because there is no analogue audio but a FM modulated carrier(s).

Thank you! But 'audio dub' is not possible with HiFi recording on the video-heads, it will erase everything that was previously recorded. I never seen a (VHS) recorder with dub and switchable video, only on UMatic and above. But if you can, pls send a link to some info. And yes, those where the day's. But still a lot of people love analogue, so i still design new (old) equipment for HiFi recording on VHS tape. My next video will be a DIY VHS / schematic for the technicians. Build with ordinary components. But there is nothing wrong with digital!!!

You are partly wright, the recorder had no HiFi audio, only (low quality) video. I used (1982) a pcb from a scrab HiFi VCR, but only the audio part. Disconnected in my machine the original video part and used the rotating head to record audio. So the original video heads are used for audio. That was my idee, leave the video part out and use the entire bandwidth of the tape for audio. There is space for more channels. Also the audio will not be partly erased by the video, as in the original HiFi designs. And indeed, when I measured the RF (audio) output from tape, the level was enormous and turning the tracking control gives no effect. So a great improvement on the original HiFi recorders. But than (you wright again) there was the problem of tracking / synchronization. I know that from the start. So I started developing a stable (X tal) signal for the servo systems. In this machine, only the frame synchronization is compared with a pulse, deriving from the video drum. From my x-tal and divider a pulse is written - in rec - by a stationary head (original design) like the stationary audio head. And also in playback used to synchronize the servo’s. So in playback the pulse from tape is compared with the pulse from the video head. The problem of ‘buzzing’ is not there. By correctly adjusting the take over point from head A and B AND using the same video drum for record and playback, buzzing is not measurable or audible. But another reason is the absence of erasing by the video head, like in a original HiFi machine. In all the years I never heard anything disturbing like drop-out’s or so. Only with complete damaged tapes from defective machines. All this was done, because in 1982 going digital mend a lot of money. And designing / building something yourself - out of the question. Hope this story helps?

@@TheoFaber All understood! So in practice you have built a circuit to drive the fixed head (which normally manages mono audio track and sync track) to have a very precise synchronization between tape position and rotaring heads. Also not partly erasing audio with video heads like original design helps to have a strong and stable signal. All clear!! Uhmm I am very curious to the quartzed synchronization circuit :) I am sure a great difficulty is to integrate it with servomechanism of vcr, to let them work normally without a video input. But I also think that hi-fi audio tapes recorded will be playable with perfect quality only in the same machine: in another one maybe the distance between rotating drum and fixed head is different, so the synch has to be regulated...

@@PuccaLover83 No - I am not clear. The existing audio / ctl head (stationary) is used. Only it’s driven by an extra pcb (see film) of my own, how has a standard video proc IC (verry cheap) that produces a standard bl/w video sign. That is connected to the video in port - that’s all. I good have made special modifications to the servo systems, but I did not (verry buzzy in 1982). So synchronization of the servo systems, is reassembly standard. In rec and play back. Sorry but I do not remember the type number of the IC(s). Also the schematic’s I draw, are lost in time. But every stable 50 / 60 hz pulse can be used, by simply inserting the pulse on the wright point(s) in de servo circuitry. You are correct, by stating that every recorder you want to reform, will need it’s own solutions. So knowledge and schematic’s are necessary. Some measurement equipment will be helpful. A scoop will bring some light in the dark. The old audio track is also still in use and the quality is terrible. Wow and flutter (and noise) are going to the sealing, see film 1 at the end. But still, after all these years, the HiFi specifications are a dream.

@@TheoFaber yes I did understood that your special circuitry drove the fixed head of vcr! I have seen also first video. A question: why have you also transplanted the fm modulator of hifi audio from another vcr to this one? Did not was simpler to modify directly that vcr? Maybe its servo system was more complicated to work? Or maybe because you wanted a small, portable machine?

@@PuccaLover83 I used an existing pcb from a scrap recorder, because from audio to video head is a long way. First there is a low pass filter (30kc) then a measured level control (manual with meter) a noise reduction (like Dolby), then a pre emphasis, so the audio level has to be correct. I did not have the time to design all that in 1982 incl the play back with all the filtering. I did design the rec / playback amplifier for the video drum, see film. That was necessary, because the extra pcb did not have one. After the fact, it was stupid, because the rec/playback amp from the original rec is now unused. And was absolute useable for the purpose. Now I have time to spare, and maybe I built another one, with more channels, just for fun. And do the entire design. Maybe … because it serves no purpose, unless you are a audio analogue enthusiast. Which I am not.

No, it's quit difficult because of the switchover at the and of a frame (head a and head b). And it's digital. Diff systems exist like DV and DVCam....

There is enough bandwidth to record MP3, MP4 that's not the problem. But at the end of a (video) frame there is a cap. In 'normal' VHS recorders there are 2 video heads. They switch over at the end of a frame (25or30Hz). So it's necessary to overcome that problem because the fault compensation can not handle that switch over distortion. Sony (but more marks) had a solution, in those day's. They time compressed the digital package and used only the visible part of the video track. The end of a frame was not used. By playback, they expand they package and the original stream became available. BUT tha's all digital, and there are so many good recording formats that can record digital. My design comes from the 80s. And is ALL ANALOUE. In those day's a perfect alternative for the costly digital solutions. (in fact, it costed next to nothing) But the idea is not so bad, i to wondered several times. Sorry for the bad English

Tech combined with real live is my way to go.....!!!

@@TheoFaber Stay dirty

$härp eyy mae id ßuit you well -: -

Dear Todd. Thanx for your reply. You can be very proud of your Grandfather. The AR-88 is a fine radio and still performing very well. Our interests as older technicians are the amazing designs and products, that came out of a period where electronics was in it’s infancy. They build things with components that where - to say the least - not high standard as now day’s. And still the product’s (kept with love operational) perform very well. I made this short docu with a friend (he’ s in the film) for a club of enthusiast that restore radio’s mostly from the period 40-50.

@@TheoFaber Another search yielded a page of patents in his name from his time with RCA. I was just a tyke when I would spend the day tinkering with him in the basement of the apartment complex they lived through retirement, with no idea how brilliant he was. It's no wonder I'm a Designer myself - strong genes I suppose!

@@toddfowler9863 Possibly your genes? - I have several designs on YT - maybe of interest for you???

and your voice are better than this AI. Not a problem if your english is not good

Bicause i am Dutch and my Engl is terrible...😪

He is talking throughout the video, you fool. AI voice is used only for the diagrams.

Although top quality that was digital not analogue.

Thank you... but it can be better!

No I am sorry, receive this request often. It will be to expensive, because it's an enormous amount of work.

Just get a PCM encoder

Although top quality that was digital not analogue.@@telesniper2

I have the 50th I dig it:)

I am dutch - what's thousand-hole base?

@@TheoFaber Mit tausend Löchern meine ich die gelbe Strecke, die im Video zu sehen ist. Wie wurde es hergestellt?

That's the picture of a oscilloscoop. With that we can see the quality of the signal. A measurement (apparatus) that we technicians use to look at the signals - in this case the audio quality. @@k333ization

No - not compared. But digital will be even more steady than analogue on a oscilloscoop. And yes; a digital system can have even better spec's. But the modification is from 1982 and meet even today wonderful spec's. The people how love analogue, will be in heaven with this. And when you use something that makes you happy, measurements do not matter, unless you own a studio.

I am Dutch, so it's not clear (English) what you mean by 'emulate'. If you have a HiFi, than use the video heads as active audio heads. Short the HiFi heads and recalibrate the (videoheads) record current. So the output of the HiFi recorder amp is connected to the video heads. BUT FIRST check if the hole recorder will work without video signal. Normally this is necessary by the mode rec!

@@TheoFaber I will like to do what you've done with your VCR: use only the hifi track, totally supressing the video sinal. My VCR is a hifi one already.

Than you have all the necessary things incl de compressor / de-compressor. Hope you can modify the audio volume, otherwise your stuck with the automatic, rather not! But it will work with the automatic. Hope you have the knowledge to modify the servo-systems. You can try to put comp video on the standard input, even if you dont record video. @@eudesfernandes4774

Most of the profit is the absence of video and the use of the video-heads as audio recording. Suc6 with your hobby!

Thanks... no ADAT was a digital system, and special on this modification - it's fully analogue!

We like to put energie in both...

There is more than electronics that keeps us buzzy... 🙂

Very nice thoughts ! for only it was possible. DCC used a special head with 8 (?) tracks, to record a digital stream in parallel. And the other answer is more technical. To deviate a carrier FM you need at least 5-10 times the highest audio frequentie. Mostly in use is 75 - 150kc. VHF walky tolky's (speech only) use about 25kc. To have a reasonable relation between the carrier and the deviation you need to go in to the hunderts of kc. Best is above 500kc. All this is not possible on a audio cassette. But the thought is beautiful and proofs that you have the fantasie and curiosity to go far in electronics!

Note: this machines are the only (proto) examples and are not for sale. With country are you in? You can give me your e-mail adres or a temp one, i wright back in my beste English :)

Worked for years with C format (Sony) technical and video-production. But never in my wildest dreams i had the nerve to modified it (it was the master machine). So my deepest respect for your modification. Never knew that the AFM frequency's where so low?