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  #1  
10-09-2021, 07:03 PM
Teefer Teefer is offline
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I purchased a deck (JVC SR-V101US) from Lordsmurf as part of a workflow and received it last week. I demoed it and discovered its RCA audio outputs are showing high-frequency noise through my television, my hi-fi systems, and my capture system, and with 8 different VHS tapes. The noise only appears when the audio output circuit is engaged by the deck.

I e-mailed Lordsmurf audio samples from the JVC SR-V101US and my Panasonic PV-8451 for comparison. My PV-8451 does not display this audio issue. Not only is there a noise issue with the JVC unit, but the general audio quality seems poor as the audio is missing a lot of high frequencies since my Panasonic unit sounds much better when playing the same media. Maybe both issues are related?

After listening to the two samples I quickly grabbed from the decks (links below), Lordsmurf replied by e-mail and indicated that "it's not the deck" and that I'll need to post on the forum.

Although the audio is lossy, the noise is so prominent in the JVC video I've linked that I'm not sure it even matters to have lossless audio captured. If I'm wrong about this, let me know and I'll capture lossless files for spectrum analysis.

JVC SR-V101US (noisy unit from Lordsmurf) Sample - https://youtu.be/5aLjuhX-JRU
Panasonic PV-8451 (my own unit with no noise) Sample - https://youtu.be/omoYduH6mW8

Here's what I've tried to solve this issue:

(1) Removing any potential ground loops by lifting the AC ground, trying different electrical circuits, running it off of an isolated power supply, and running it off of a DC-to-AC inverter UPS; no change.

(2) Moving the unit into different physically locations to check for potential RF interference; no change.

(3) Checking user manual for features/functions I may have missed; no change.

(4) Verifying RCA cable quality; no change.

-----

I'm not sure what's wrong, but I've run into issues like this in the past with some of my old audio gear. Replacing all PCB-mounted electrolytic capacitors has solved audio circuit noise issues in the past. Hoping that's not needed in this case.

Looking for input as to what the issue is believed to be. Maybe I'm missing something simple... ?

Thank you for your time.
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  #2  
10-09-2021, 08:50 PM
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I think this is an issue of your exact source tapes, VHS audio understandings, and VCR output expectations.

In the samples on Youtube, I hear two things:
- Panasonic is too loud, audio is being distorted.
- JVC has muffle and whine, an infamous issue with low-quality VHS linear (non-HiFi) tracks on JVC decks.

You need to re-test with cleaner sources. Something retail, and HiFi.

Which FYI, I did.
- Retail with HiFi, and mono.
- Homemade with HiFi, good mono, and not-great mono.
And it passes those tests, with expected results. In fact, that exact deck you have performed above average.

I wanted you to post about this here, as I know others in the forum have more detailed info on why this happens. Many here have experienced this exact issue, for decades. It's not the fault of VHS, or JVC, etc -- it's just a combination of factors that results in what you hear.

It's not uncommon to capture a tape twice, using different VCRs: once for best audio, once for best video, and the re-merge later in post-capture (anything from VirtualDub to Premiere, even Avisynth).

Youtube is also adding compression noise, so it's hard to make further comments.

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  #3  
10-10-2021, 03:01 AM
Teefer Teefer is offline
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Thank you for the reply, LS!

I found an article another user who reported the identical high-frequency audio issue with the JVC V101US. His post (below) contains a link to a WAV file whose high-frequency noise is identical to what is heard in my sample video posted above for the JVC V101US.

JVC SR-V101US buzzing audio issues?

I have confirmed on my end:

-retail media with hi-fi audio (with mono audio selected on OSD) exhibits high frequency buzzing on the V101US audio output.
-all of my non-hi-fi (mono) consumer media (with mono audio selected in OSD) exhibit an identical high frequency buzzing on the V101US audio output.
-retail media with hi-fi audio (with hi-fi audio selected on the OSD) does not exhibit high-frequency buzzing on the V101US audio output.

To confirm - selecting 'hi-fi' on the OSD when playing hi-fi-audio-containing media results in no observed high-frequency noise. Selecting 'mono' on the OSD when playing hi-fi-audio-containing media, or consumer mono media results in high-frequency audio noise.

Here are links to audio samples. Noise at the beginning, audio at the end:

Audio captured when 'hi-fi' selected on OSD displaying minor and acceptable noise: https://www.mediafire.com/file/yj0kp...Hi-Fi.wav/file

Audio captured when 'mono' selected on OSD, showing high-frequency and unacceptable noise: https://www.mediafire.com/file/sfoix.../Mono.wav/file

--

Based on the hours of testing on my end, and the fact that another user has the exact same issue with the identical high-frequency noise documented in their audio sample -- the most likely explanation to me is that this is a hardware issue -- either inherent to the design itself, or related to some sort of component aging. Absent other evidence, it's hard for me to conclude otherwise. This doesn't happen on my other two decks when playing the same hi-fi or mono media (consumer or retail).

Since I will never be processing VHS media with hi-fi audio tracks, this deck's audio output performs far too poorly for my digital conversion workflow purposes. Yes, you can pull audio and video from two different decks, but it was not my intention to double the workload when I can just buy a deck that doesn't have an issue that renders the audio unlistenable. Really too bad, since the video quality is great on this deck!!

If there are any suggestions on how to fix this, or maybe some other things that I and the other user documenting the same issue may have simply overlooked, please let me know. Thank you.

Last edited by Teefer; 10-10-2021 at 03:55 AM. Reason: Added audio samples; clarified wording
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  #4  
10-10-2021, 06:32 AM
hodgey hodgey is online now
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Interesting, I also have similar issues with linear audio on two related late-model JVCs. Both on the XVS20 as noted and the exact same on a DR-MX1. Both use the same mech and a similar all-in-one video/audio ic (XVS20 a slightly older revision of it, MX1 exact same ic name). In my case it's not quite as bad though, so I don't know for sure it's the same issue, could also be down to PAL vs NTSC and different deck setup (since mine are both combos).

Another separate thing I have encountered the previous generation JVCs, like my HR-S8600 is that you can get a high-frequency whine if the ground connection to the vcr mechanism is a bit bad. That issue very easy to test though, just use a screwdriver or some other metal thing to connect between chassis and tuner and see if it goes away. In that case there was whine on all hi-fi too though from what I remember.

As for audio quality otherwise being a bit poor on JVCs vs other decks, it can come down to audio head alignment, at least on the previous generation models, as documented here, though adjusting it is very finicky so it's something to be careful about if trying. Misalignment on it's own shouldn't cause buzzing on linear audio though, just muffled/weak audio.
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10-10-2021, 09:46 AM
timtape timtape is offline
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The original is a linear audio recording so HiFi is irrelevent here. There are two issues here as Hodgey alluded to.

1. The audio control head in the JVC is obviously misaligned to the camera tape's recorded pattern. This doesnt necessarily mean the JVC head is misaligned to standard. A skilled transfer technician would custom align the JVC's audio head to the pattern on the camera tape, restoring all that lost treble. Since your Pana seems already fairly well aligned to this tape, there seems no problem transferring this tape.

It may be your original camera tape is itself misaligned, and your Pana VCR just happens to be misaligned in exactly the same way. Or perhaps the JVC is misaligned from standard. But to expect all linear audio tracks to play perfectly aligned is unrealistic. Ideally audio azimuth would be checked and adjusted on each and every tape played, just like people used to adjust picture tracking. But for most people this is too technical.

2. The JVC is outputting what I consider unacceptable electronic noise which is not part of the original recording. The Pana seems much quieter, emitting only a moderate hiss, which is normal. It's hard to be definitive though as your camera recording is quite loud and would be masking other noise only audible on a quieter recording. Unfortunately some later decks, even quite sophisticated ones, did have noisy linear audio, which is a shame. I dont know if this is normal for that JVC model or if there is a fault in your particular unit.
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10-10-2021, 01:01 PM
latreche34 latreche34 is offline
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It could well possibly be some filter capacitors in the linear audio pre-amp, I will look up your model's service manual and tel you where they are if you are handy in replacing electronic components.

https://www.youtube.com/user/latoak34/videos
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10-10-2021, 02:03 PM
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Quote:
Originally Posted by latreche34 View Post
It could well possibly be some filter capacitors in the linear audio pre-amp, I will look up your model's service manual and tel you where they are if you are handy in replacing electronic components.
I worked as an electronics repair tech for 3 years and have a full rework setup at home, so please send them over! Should Lordsmurf agree that I should take a crack at swapping the caps, I will. Thanks for the offer.

Quote:
Originally Posted by timtape View Post
The original is a linear audio recording so HiFi is irrelevent here. There are two issues here as Hodgey alluded to.

1. The audio control head in the JVC is obviously misaligned to the camera tape's recorded pattern. This doesnt necessarily mean the JVC head is misaligned to standard. A skilled transfer technician would custom align the JVC's audio head to the pattern on the camera tape, restoring all that lost treble. Since your Pana seems already fairly well aligned to this tape, there seems no problem transferring this tape.

It may be your original camera tape is itself misaligned, and your Pana VCR just happens to be misaligned in exactly the same way. Or perhaps the JVC is misaligned from standard. But to expect all linear audio tracks to play perfectly aligned is unrealistic. Ideally audio azimuth would be checked and adjusted on each and every tape played, just like people used to adjust picture tracking. But for most people this is too technical.

2. The JVC is outputting what I consider unacceptable electronic noise which is not part of the original recording. The Pana seems much quieter, emitting only a moderate hiss, which is normal. It's hard to be definitive though as your camera recording is quite loud and would be masking other noise only audible on a quieter recording. Unfortunately some later decks, even quite sophisticated ones, did have noisy linear audio, which is a shame. I dont know if this is normal for that JVC model or if there is a fault in your particular unit.
Thanks for the reply!

I have a couple questions and comments for you:

The reason I mention hi-fi in my reply to Lordsmurf is that it seems that when 'hi-fi' is selected on the OSD when playing hi-fi-audio-containing media, the high-frequency noise goes away. It's only when 'norm' is selected that it appears. This is what leads me to believe it's the linear audio circuit that's causing the issue. Since pretty much all of the tapes that I will be digitizing only have linear audio, the hi-fi mode will never be used, and thus the noise will always be present. If my understanding is incorrect, please correct me.

1. How can you confirm the audio head is misaligned to the tape's recorded pattern? I'm wondering if the audio artifact that you're hearing could be the result of the same issue that might be causing the buzzing, rather than a result of some misalignment? For example, poor circuit design, or perhaps aging circuit components? I should also say that all of my tapes (multiple manufacturers over the course of many years) all exhibit this same issue on the JVC with the high-frequency buzzing, and the missing audio high frequencies. This issue does not exist with any of my tapes on my Panasonic unit. The missing high frequencies is something that I can understand and accept as a quirk of the JVC. The high-frequency noise, however.. no good!

2. If you check my second post in this thread, I added some audio clips showing the output when 'hi-fi' and 'norm' are selected on the JVC unit's OSD. Another user reported the same issue, and with the same noise pattern recorded. I linked to that post as well. Take a peek at those if you're interested! I also do not know if this is a fault of my particular unit, or if it's common in the design. If it's common in the design, it is my opinion that this unit is not suitable for a digitizing workflow if the user intends to capture the linear audio with this same unit. There is just too much noise.

Quote:
Originally Posted by hodgey View Post
Interesting, I also have similar issues with linear audio on two related late-model JVCs. Both on the XVS20 as noted and the exact same on a DR-MX1. Both use the same mech and a similar all-in-one video/audio ic (XVS20 a slightly older revision of it, MX1 exact same ic name). In my case it's not quite as bad though, so I don't know for sure it's the same issue, could also be down to PAL vs NTSC and different deck setup (since mine are both combos).

Another separate thing I have encountered the previous generation JVCs, like my HR-S8600 is that you can get a high-frequency whine if the ground connection to the vcr mechanism is a bit bad. That issue very easy to test though, just use a screwdriver or some other metal thing to connect between chassis and tuner and see if it goes away. In that case there was whine on all hi-fi too though from what I remember.

As for audio quality otherwise being a bit poor on JVCs vs other decks, it can come down to audio head alignment, at least on the previous generation models, as documented here, though adjusting it is very finicky so it's something to be careful about if trying. Misalignment on it's own shouldn't cause buzzing on linear audio though, just muffled/weak audio.
Thanks for the reply.

Interesting to hear this same issue is exhibited on other JVC units. I wonder if this truly is a design issue, or if it's a design issue coupled with some sort of aging component issue like latreche34 has alluded to as a possibility.

Unfortunately, it doesn't seem to be a simple grounding issue - too bad

Since this unit came from Lordsmurf, I'm going to assume there isn't a head alignment issue so I won't mess with that unless he recommends otherwise.


------------------------------------------


I appreciate the replies everyone. Keep em coming!
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10-10-2021, 05:26 PM
latreche34 latreche34 is offline
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Do this test to rule out electronic component issue, Clean the stationary audio head, Record a one minute clean audio signal freferably dialog followed by a minute of silence and play it back with the option normal only for linear audio, capture it and post a sample here. If the file came out clean with a little bit of hiss then it is going to be an alignement issue, if it plays with the same symtoms then it's an electronic components issue.

https://www.youtube.com/user/latoak34/videos
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  #9  
10-10-2021, 06:55 PM
timtape timtape is offline
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Quote:
Originally Posted by Teefer View Post
1. How can you confirm the audio head is misaligned to the tape's recorded pattern?
If I had your tape with me I could confirm it by aligning the JVC's A/C head to the tape. But we have your sample. Below are screenshots of the spectrums of the JVC and then the Pana playback.

In the JVC shot (12) notice the dark band between 4 and 5 kHz. That is a classic comb filtering null due in this case to azimuth error. The audio is lost and cant be recovered in post.
Notice too how after the vertical blue line, the camera tape's pause point, the band briefly heads downward, the error becoming momentarily worse, and another null briefly appears at about double the lower null's frequency. The dip represents the azimuth error becoming even worse until the tape angle stabilises. Then the band briefly rises, meaning a less severe error, then it settles down to the error angle before the tape was paused.

But also, notice that in the JVC shot, horizontal orange bands extend right up to almost 15 kHz. VHS linear audio wasnt capable of recording frequencies that high. Around 10 kHz would be max. So those higher noise bands cant have been in your camera recording. They have to be from the JVC playback.

Your Pana spectrum (13) contains no nulls (blue bands of silence). Notice the Pana playback is strong up to about 8 kHz, not too bad for linear playback, although with a little azimuth fine tuning, maybe a little more could be extracted from the camera audio. Notice there is no visible noise above about 8 kHz meaning the Pana linear audio playback is a lot quieter than the JVC in those bands, regardless of azimuth.

Again perhaps this noise in the JVC is typical of that model. Perhaps manufacturers of later HiFi VCR's assumed most consumers would be recording and playing programs with HiFi audio and so cut a few corners in the linear audio playback design. That doesnt help people like yourself with older or camcorder recordings with only linear audio. I've transferred many camcorder tapes, both VHS and Beta, with only linear audio. I would never tolerate such a poor, noisy playback such as your JVC example.


Attached Images
File Type: jpg Screenshot (12).jpg (71.8 KB, 12 downloads)
File Type: jpg Screenshot (13).jpg (69.2 KB, 8 downloads)

Last edited by timtape; 10-10-2021 at 07:44 PM.
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10-10-2021, 08:18 PM
hodgey hodgey is online now
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That's interesting, the extra noise bands and "null" band on the spectrum looks suspiciously similar to what you see in the spectrum I posted in the thread I linked about my XVS20. Maybe there is something that's prone to failing on these models?

I can try to adjust the head on My XVS20 or MX1 and see, may help with frequency response, though I don't think that's the root cause of the extra high-frequency noise.
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10-10-2021, 08:30 PM
latreche34 latreche34 is offline
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That's why I suspected bad capacitors, it sounds like a pulse leakage from neighboring chips that should have been filtered out but it didn't. If the OP can record an audio sample and play it back as I requested above we can confirm this. We can also confirm if it's a missalignement problem since miss algned VCR's playabck their own recordings without any problem.

https://www.youtube.com/user/latoak34/videos
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10-10-2021, 09:35 PM
timtape timtape is offline
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Quote:
Originally Posted by latreche34 View Post
...We can also confirm if it's a missalignement problem since miss algned VCR's playabck their own recordings without any problem.
I didnt bother to request a fresh recording to the linear track as I feel there is proof enough in the JVC playback null that the cause is azimuth error. Listen to the playback and correlate it to the spectral screenshot. Right after the camera tape is unpaused, the null's frequency wanders (audibly and visually). I strongly suspect the cause is tape wander (and therefore azimuth wander baked into the tape at that point) before the tape stabilises in the guides. If the other noise added by the JVC was not there, the effect would be even more noticeable. I've heard the "baked in" drift effect many times in VHS and Beta camcorders at pause points, as well as on countless audio cassettes. I cant think of any other cause. Can you?


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File Type: jpg JVC azimuth error null plus noise.jpg (71.8 KB, 10 downloads)

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10-10-2021, 10:21 PM
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I'm not convinced any caps are at fault here.

However, just to cover all our bases:

An unfortunate reality of shipping older hardware, that has capacitors, is that temperature and elevation changes can affect the caps. You're about 2000 miles (3000 km) from me, in a far colder and higher area. If it truly is caps related, it may be changing the behavior of the caps. Even more damning, there's also a chance it'd behave perfectly if I had it here again. Some caps can be "bad", yet still not bad.

Again, none of this is likely. Just covering all possibilities.

JVC is a mostly caps-free unit, and didn't use the cheapy Chinese caps that caused issues in Panasonics.

The more likely issue is power related. Are you on a UPS?

Then again, let's discuss alignment. Yes, I realign all decks. That's probably one of the most time-consuming PITA aspects of refurb'ing decks. Everything from usage to gravity weighs on alignment, and causes misalignment. It's about 15-25 years since any of these decks were new, and all of them need alignment tweaks.

Shippers suck. Although I label everything as FRAGILE and DO NOT DROP, then truth is they toss packages around. The guides are held by here springs, and tossing the box around too much can cause re-misalignment issues. To date, this has only happened once. Maybe you're the second? I have a JVC realignment post somewhere in this forum, from about 2-3 years ago, look for it. Take photos before starting. Dremel yourself a flathead screwdriver. Then carefully tweak the posts. But after you've tried other things suggested in the thread, before replacing caps.

We know the deck works, that's the good part.

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10-11-2021, 09:52 AM
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Quote:
Originally Posted by timtape View Post
I didnt bother to request a fresh recording to the linear track as I feel there is proof enough in the JVC playback null that the cause is azimuth error. Listen to the playback and correlate it to the spectral screenshot. Right after the camera tape is unpaused, the null's frequency wanders (audibly and visually). I strongly suspect the cause is tape wander (and therefore azimuth wander baked into the tape at that point) before the tape stabilises in the guides. If the other noise added by the JVC was not there, the effect would be even more noticeable. I've heard the "baked in" drift effect many times in VHS and Beta camcorders at pause points, as well as on countless audio cassettes. I cant think of any other cause. Can you?
A tape recorded on a misaligned VCR can exhibit the same behavior, Just because it played okay on a Panasonic doesn't make it a perfect tape, A recording test is part of a proper troubleshooting and cannot be skipped.
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10-11-2021, 03:32 PM
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Quote:
Originally Posted by latreche34 View Post
A tape recorded on a misaligned VCR can exhibit the same behavior, Just because it played okay on a Panasonic doesn't make it a perfect tape, A recording test is part of a proper troubleshooting and cannot be skipped.
. I agree that the main issue for the OP here is the noises the JVC unit appears to be adding to the playback. To test or measure that properly I would ideally use a blank tape. But in the absence of a video signal the VCR will probably mute the audio output. Yes a new recording could be made but I would use a section of audio silence at the beginning or end of a commercially prerecorded tape. If the same bands of audio noise remain regardless of the tape played, the noise has to be from the VCR playback. Unfortunately the audio on the OP's upload is quite loud. This probably masks a lot of any noise added by the JVC VCR. In recordings with truly quiet sections any noise contribution from the VCR will be much more of a problem to the listener.

Last edited by timtape; 10-11-2021 at 03:45 PM.
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10-11-2021, 03:49 PM
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Quote:
Originally Posted by timtape View Post
. I agree that the main issue for the OP here is the noises the JVC unit appears to be adding to the playback. To test or measure that properly I would ideally use a blank tape. But in the absence of a video signal the VCR will probably mute the audio output. Yes a new recording could be made but I would use a section of audio silence at the beginning or end of a commercially prerecorded tape. If the same bands of audio noise remain regardless of the tape played, the noise has to be from the VCR playback.
Take a look at this post where I link two sample audio files:

High frequency noise from JVC SR-V101US audio output?

I recorded silence at the start of a retail tape, followed by some audio. Hope this works in the meantime until I can capture a new file following your instructions.

I'm also surprised people haven't commented on the fact that another user reported the exact same issue and linked a WAV file with the exact same noise. I linked to that user's post in the one above as well.

--------------

Thank you everyone for your replies. I am reviewing them and I'll try determine the path forward shortly.

Last edited by Teefer; 10-11-2021 at 03:55 PM. Reason: Additional clarification
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10-11-2021, 04:29 PM
latreche34 latreche34 is offline
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The silent sample sounds about right to me for non Dolby linear audio, Again without new recording and recapture we don't know exactly the performance of the linear audio of that VCR, It comes down to this, If capturing linear audio is very importnat you should get one of those VCR's that has Dolby decoder, Most comercial pre-recorded tapes used Dolby on the linear track, playing back without Dolby decoding results in a high pitched hiss (this is part of Dolby specifications to boost the highs during encoding).

You can miss-align the VCR to get better output for this tape but trust me you will be doing it for each tape if perfection is what you are after, there isn't one size fits all for linear audio, I've been there before.

Here is the suspect components I was talking about earlier if it is an electronic issue, The caps are C2008, C2011 and C2012, they are all 4.7uF/50V:



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https://www.youtube.com/user/latoak34/videos

Last edited by latreche34; 10-11-2021 at 05:19 PM.
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10-11-2021, 05:10 PM
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Teefer, comparing the noise performance of the JVC's HiFi playback to its linear is not really a fair test. The linear should normally be much noisier. Your Pana seems to have reasonable linear playback so why not use that as your reference playback as you did with the camcorder tape? I mean using the retail tape's silence and then music as your source tape, all linear of course.
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10-11-2021, 05:17 PM
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Quote:
Originally Posted by timtape View Post
Teefer, comparing the noise performance of the JVC's HiFi playback to its linear is not really a fair test. The linear should normally be much noisier. Your Pana seems to have reasonable linear playback so why not use that as your reference playback as you did with the camcorder tape? I mean using the retail tape's silence and then music as your source tape, all linear of course.
Will do! Just out and about but will report back shortly!

Quote:
Originally Posted by latreche34 View Post
Do this test to rule out electronic component issue, Clean the stationary audio head, Record a one minute clean audio signal freferably dialog followed by a minute of silence and play it back with the option normal only for linear audio, capture it and post a sample here. If the file came out clean with a little bit of hiss then it is going to be an alignement issue, if it plays with the same symtoms then it's an electronic components issue.
Hello again. Here is the link to the file I have recorded, as requested:

https://www.mediafire.com/file/vfz5j...pture.wav/file

Mono source recorded to new VHS tape in EP mode using the JVC SR-V101US.

Captured as mono-to-stereo (mono channel recorded on L and R channel) by playing back through the JVC SR-V101US using the 'mono' mode as selected on deck OSD (linear audio).

I used a dynamic dialogue sample for the source material and set the level to prevent clipping and also get a reasonable signal level.

First 1.5 sec: capture prior to pressing play on deck
Next 10 sec: VHS playing prior to the audio recording beginning
Next 68 sec: VHS playing recorded dialogue
Next 60 sec: VHS playing after the audio recording ended

Quote:
Originally Posted by lordsmurf View Post
I'm not convinced any caps are at fault here.

However, just to cover all our bases:

An unfortunate reality of shipping older hardware, that has capacitors, is that temperature and elevation changes can affect the caps. You're about 2000 miles (3000 km) from me, in a far colder and higher area. If it truly is caps related, it may be changing the behavior of the caps. Even more damning, there's also a chance it'd behave perfectly if I had it here again. Some caps can be "bad", yet still not bad.

Again, none of this is likely. Just covering all possibilities.

JVC is a mostly caps-free unit, and didn't use the cheapy Chinese caps that caused issues in Panasonics.

The more likely issue is power related. Are you on a UPS?

Then again, let's discuss alignment. Yes, I realign all decks. That's probably one of the most time-consuming PITA aspects of refurb'ing decks. Everything from usage to gravity weighs on alignment, and causes misalignment. It's about 15-25 years since any of these decks were new, and all of them need alignment tweaks.

Shippers suck. Although I label everything as FRAGILE and DO NOT DROP, then truth is they toss packages around. The guides are held by here springs, and tossing the box around too much can cause re-misalignment issues. To date, this has only happened once. Maybe you're the second? I have a JVC realignment post somewhere in this forum, from about 2-3 years ago, look for it. Take photos before starting. Dremel yourself a flathead screwdriver. Then carefully tweak the posts. But after you've tried other things suggested in the thread, before replacing caps.

We know the deck works, that's the good part.
I've powered the unit using different circuits, behind an isolation transformer and using a DC-to-AC inverted UPS. I've tried to move the unit to check for RF interference - nothing changes it.

Do you have any comments on the extreme similarity to another user's issue that I linked in my first reply to you? His audio sample contains noise that is essentially identical to what I'm experiencing.

Quote:
Originally Posted by latreche34 View Post
The silent sample sounds about right to me for non Dolby linear audio, Again without new recording and recapture we don't know exactly the performance of the linear audio of that VCR, It comes down to this, If capturing linear audio is very importnat you should get one of those VCR's that has Dolby decoder, Most comercial pre-recorded tapes used Dolby on the linear track, playing back without Dolby decoding results in a high pitched hiss (this is part of Dolby specifications to boost the highs during encoding).

You can miss-align the VCR to get better output for this tape but trust me you will be doing it for each tape if perfection is what you are after, there isn't one size fits all for linear audio, I've been there before.

Here is the suspect components I was talking about earlier if it is an electronic issue, The caps are C2008, C2011 and C2012, they are all 4.7uF/50V:
Thanks for this information. I just posted the audio sample a couple of posts back so have a peek at that.

To play back linear audio on consumer-recorded tapes (the majority of what I'll be doing), does it still make sense to seek out a VCR with a Dolby encoder? I wouldn't think so..?

Appreciate the schematic and the component info. I'll see where I go with this issue and let you know if I do end up replacing the caps.
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10-12-2021, 07:26 PM
timtape timtape is offline
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Quote:
Originally Posted by Teefer View Post
Hello again. Here is the link to the file I have recorded, as requested:

https://www.mediafire.com/file/vfz5j...pture.wav/file

Mono source recorded to new VHS tape in EP mode using the JVC SR-V101US.
Thanks for the new audio sample. Are you sure this is linear audio recorded in EP? The high frequency response is way too good for LP or EP, and almost too good for SP. But whatever the format, the humming/ buzzing noises are unacceptable. If linear audio, we should hear the tape hiss but not those many tones/harmonics (I counted 27). You might try recording the same sample voice onto your Pana VCR as a comparison. Or even just a playback of this JVC recording on the Pana, event though there will be an azimuth error.

Screenshot attached of the spectral display. The white specks representing tape hiss are to be expected. The many horizontal lines shouldnt be there and on a camcorder recorded tape (linear audio) they would represent a very unusual fault.


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File Type: jpg Teefer speech example.jpg (69.1 KB, 7 downloads)

Last edited by timtape; 10-12-2021 at 07:38 PM.
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