AG-7350 linear audio with high pitch noise?

[BartoloniDavy]

Ok
this is a small video piece without audio (vhs tape noise i think)
starting with dolby adctivated, and after without dolby

[timtape]

Thanks for the sample.

It's hard to judge if the noise level is normal without a reference signal to compare it to.

In a linear audio track there will always be much more noise than a good HiFi track, even with Dolby. This is not a fault in the linear audio.

[BartoloniDavy]

Tim, if i can ask, what is the purpouse to move the head to right ? this conical thing seems created for this, but there are no instructions on service manual.

[timtape]

I think on a reference tape we adjust it so picture and sound are in "lip sync" and when the tracking control is in the middle position the tracking meter reads maximum. It might need some adjustment after adjusting A/C head height with the other large nut. Normally neither nut needs adjusting.

[BartoloniDavy]

thank you very much Tim

[BartoloniDavy]

another question.. can i use the "anti-serial" method to replace some 1uF 50V NOT polarized caps?
(2 polarized 1uF 50V in serial mode with the two + connected)
i have found 2 of them with ESR of about 4 ohms and one with 7.4 ohms (c20 on servo board)

i will receive some 1uF 63V not polarized next month , but i want to make some tests to reduce this audio noise...

[timtape]

Yes but in series the capacitor value is reduced, so in this case each needs to be 2uF.

[BartoloniDavy]

thank you i will try

[big t]

BartoloniDavy, any updates/news?

[BartoloniDavy]

Caps replaced, but still noise on linear audio...
i will try on next days to change audio head to have audio signal only on 1 channel..
the strange thing is that i have audio on both channels ... but linear is mono right? and i'm not using HIFi switch..

can be that the AG7350 is generating a fake stereo audio from single linear audio track?

going crazy because this is a very nice unit with small amount of hours of use.

[big t]

For stereo sound you need HiFi mode enabled, Hi-Fi pictogram on display as in this picture attached.

[timtape]

Quote:

Originally Posted by BartoloniDavy

... but linear is mono right? and i'm not using HIFi switch..

can be that the AG7350 is generating a fake stereo audio from single linear audio track?

going crazy because this is a very nice unit with small amount of hours of use.

Yes and no. VHS linear was originally mono but later they split the mono track into two narrower tracks for stereo (just as the audio cassette did some years earlier). The 7350 was one of the decks with linear stereo, both record and playback, in addition to HiFi stereo. For some years commercial prerecorded movies on VHS had both HiFi stereo and linear stereo, but most consumer decks could only play mono linear audio.

[timtape]

It occurs to me we havent confirmed if there is actually a problem in the linear audio. You may be trying to fix a non existent problem.

Linear audio is much hissier/noisier than HiFi. Not as hissy with Dolby on. That's normal. Why not upload playback of a commercial prerecorded cassette, switching between linear and HiFi?