JVC SR-V101US non-HiFi audio issue

[MBK]

Hello, this is my first post on this forum. I have learned a lot on this forum in the last few years.

I recently got a JVC SR-V101US to convert my VHS tapes to digital. It works perfectly with tapes that have a HiFi audio track. I have never had any problems with the video quality. The only problem with it is with tapes that do not have HiFi audio. The audio I get with said tapes has a constant "hum/buzz/hiss". It is constant and it there on all non-HiFi tracks. With HiFi tapes I can switch between audio tracks, but the "normal" audio track has the same "hiss"


I cleaned the audio heads with standard isopropyl alcohol when I got it to get rid of some pops and cracks in the audio and have not had any pops or cracks since. Just the same constant "hum/buzz/hiss" on all tapes with no HiFi.

I have read about interference and checked in different locations in my house. The hum is always there.

I uploaded an audio sample of the constant "hum/buzz/hiss".


Any help in fixing this issue is greatly appreciated. Thank you in advance!

[JVRaines]

The linear track will always have some amount of hiss. This is endemic to linear magnetic recording. The hum is complex with a series of overtones and could be coming from poorly shielded components in the VCR, or maybe picked up from other devices such as your computer. It looks like something gets turned on or activated 15 seconds into the sample. Does the picture get a lot brighter at that point?


[Attachment 47615 - Click to enlarge]

[KarMa]

Linear audio is going to be bad, and gets worse with EP tapes. That being said I don't know that I've heard it that bad. Are you capturing this through the LINE on your audio card? Are you amplifying this at all? Be sure to have both your computer and your VCR on the same leg coming out of your power pole transformer, which can simply be confirmed by having all your equipment on one wall outlet. If your VCR comes with a Coax output then it has a RF modulator, which is known to sometimes go bad and dump noise into the rest of the VCR. I had to take mine out on a Sony Hi-Fi VCR for this reason.

Now that I think about it, this noise sounds like the noise my other desktop makes (a Dell). The front audio jack is just the worst and not sure why it is, while the back jack is fine I believe. Might be a bad audio chip on the motherboard or might be a cheap PSU put in by Dell. But that's what your audio reminds me of.

[MBK]

I believe the buzzing is coming from the 5-12khz range. I'm not sure what happens at the 15-sec mark, but the picture is unaffected at that mark.

I typically use a "Behringer U-Phono UFO202" preamp for audio. I've had no problems with it in the past with Vinyl, LaserDiscs or any VHS tapes until now. But all my VHSs in the past have been HiFi. But this buzz is present with or without the amp. I use audacity or Audition to record the sound directly from the amp to .wav then sync it to the video.

I also tried using the front s-video and audio jacks on the JVC, but couldn't get any video or audio from them at all. I do have all the equipment for this on the same wall outlet. I have also tried this on my Mac, my Windows 7 PC and my Windows 10 PC. I'm starting to think it has to be hardware related since the HiFi works fine.

I read on another forum that changing from SP to EP could make a difference but when playing this VHS it will not change. It stays in SP no matter what. I can stop the video and manually switch to EP but as soon as I hit PLAY it goes back to SP. Does anyone know how to force the JVC SR-V101US to play continuously in EP mode?

The VHS is about 70 mins long. I attached a screenshot from Spek that shows the buzzing at various frequencies for the entire recording. The buzzing continues even after the VHS is done playing, which makes me think the problem is with the JVC and not the VHS. Maybe this will help diagnose the problem.


Thanks for the help so far!

[lordsmurf]

I've not listened to the sample, but audio heads buzz when failing.
If for sure not the tape, not outside interference, then that's probably next most likely.

SR-V101 decks were cheaply made. Lots of ratty condition units out there. If from eBay, I'm not surprised.

[johnmeyer]

First, anything over a few thousand kHz is usually not classified as a "buzz." It's a nit, but until I saw your spectrum chart of the WAV, I thought you had different problems.

The frequency shown by that horizontal line is almost certainly the 15.734 kHz horizontal scan frequency. I understand the signal theory behind NTSC TV, but not the details of the electronics, so someone else will have to tell you what is the likely cause of frequency getting through. However, in my own experience, virtually every VHS capture I've made, using over a dozen different VHS decks, all have this frequency present. It is usually inaudible to all but the best, youngest ears. I used to be able to hear it easily, but in my dotage, that is gone.

I doubt you'll be able to modify your equipment to eliminate it, so the easiest thing to do is get a good sound restoration tool and simply notch it out. You should be able to do that without introducing any new artifacts. I use iZotope RX, but that is expensive. I think Audacity (free) may have a good notch filter, but someone else will have to confirm that.

[JVRaines]

I read on another forum that changing from SP to EP could make a difference but when playing this VHS it will not change. It stays in SP no matter what. I can stop the video and manually switch to EP but as soon as I hit PLAY it goes back to SP. Does anyone know how to force the JVC SR-V101US to play continuously in EP mode?!

It is not possible to switch the speed mode in playback. The deck will revert to whatever mode is recorded on the tape.

I doubt you'll be able to modify your equipment to eliminate it, so the easiest thing to do is get a good sound restoration tool and simply notch it out.

That will be quite laborious as there are many harmonic components of this hum. It's not just around 15 kHz.

[johnmeyer]

I doubt you'll be able to modify your equipment to eliminate it, so the easiest thing to do is get a good sound restoration tool and simply notch it out.

That will be quite laborious as there are many harmonic components of this hum. It's not just around 15 kHz.

That will depend on the tool used. With iZotope RX, I can specify up to eight harmonics. Once the preset is created, it will remove all of them in one pass.



This stock image shows all harmonics getting the same treatment, but you can change many of the parameters for each one.

Of course once you get into removing harmonics of a 15 kHz tone which is so high that most people can't hear it, you get pretty close to the point where only your dog will notice. I'm still wondering what the OP was actually hearing because this frequency is so high that no one would mistake it for a buzz. Perhaps there was some other noise that is not showing up on the spectrum display posted.

[JVRaines]

In the spectral display I posted, there are more than a dozen noise components below 15 kHz.

[jagabo]

That noise is at -45 dB -- that's about the noise floor of VHS's linear track anyway. There's a reason it's not called HiFi.

And yes, there are many peaks in the spectrogram below the 15 KHz one. Many at 30 Hz and harmonics, and 24 Hz and harmonics. The most annoying ones are between ~6K and ~12K, many harmonics of 59.94 Hz.