Quantcast Dist amp recommendations with TBC-1000? - digitalFAQ Forum
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01-04-2022, 01:14 PM
lightbulb1986 lightbulb1986 is offline
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Howdy folks,

TLDR: Can I put my TBC-1000 after proc amp and detailer in order to use the built in dist amp to capture to multiple cardsóand what are the issues (noise?) Iíll face? Whatís the best s-video dist amp to place as the final link before multiple capture cards? What is the importance of bandwidth and resolution measurements on DAs and why are some measures at -3db and others at -1db? The TBC-1000 is an 8bit digitizer, and I have the capability to capture 10bit uncompressed/~lossless. Is there any benefit of capturing 10bit after the TBC-1000 has digitized to 8bit? Disk space is not an issue. Are there any 10bit TBCís that come recommended with equivalent quality as the TBC-1000?

First a big thanks to LordSmurf, Sanlyn, JWillis and the myriad knowledgeable people on this forum as Iíve been lurking for years. My VHS capture journey has been a long one and interrupted by the pandemic and work for a couple years. Iíve got about 15 VHS tapes and maybe 40 Hi8 tapes to digitize and I initially used this setup:

Pan AG1980>TBC-1000>ATI 600 USB>WinXP VirtualDub on 2008 MacBook in Virtual Dub.

I had continual issues with frames sticking, dropped frames, etc. when capturing to HuffyUV. I thought this might be a driver issue with using WinXP in boot camp. I then let my workflow take a breath for about 2 years before finally getting back on the horse. I tried again on a Windows 10 machine and also had some issues that I couldnít resolveódropped frames, inserted frames, audio sync, frame sticking, etc. I donít think itís a problem with the hardware since the VCR and TBC were reconditioned by TGrantPhoto. Like a lot of us, I started out with a cheapo VCR off eBay and no TBC and the difference in playback is night and day. Iím considering heading over to Goodwill and picking up a respectable WinXP native PC.

After reading some JWillis posts on his Mac setups I took the plunge and bought a Vidbox NW07:

Pan AG1980>TBC-1000>Vidbox NW07>Videoglide on 2011 Mac Mini running OSX 10.12

I was absolutely blown away how EASILY I was able to capture uncompressed 4:2:2 video, trim losslessly in QT7pro, and compress to h.264. Those compressed vids and the uncompressed masters were included with our newly digitized family photos onto portable hard drives for each one of my family members. The process reminded me why Iíve been primarily using Macintosh for the past 20 years.

BUTóI consider the Vidbox caps a ďstop-gapĒ measure. I could only capture 640x480 and the NW07 and/or Videoglide did not allow me to capture deinterlaced videoóso like most things Macintosh, the convenience factor came at the cost of user controls. If JWillis or any other member could turn me on to a card that captures 720x480i in Videoglide please let me know!

The Vidbox reinvigorated me and the crazy resale values on my hardware have allowed my twisted brain to rationalize spending more money on this project. Iíve got a BVP-4+ on the way from TGrant which I know I can put to use on my tapes, and I bought a Vidimate VDM-300S on eBay which looks a little beat up but for the price Iím willing to take a gamble on it. I intend to use the BVP-4+ and/or Vidimate only if it adds value to the chain.

I also went a little overboard on capture cardsÖ.Iíve now got a selection of cards that work on Mac and PC, including AJA Io HD, AJA Io, Grass Valley ADVC Mini, Hauppage USB Live 2, and Diamond VC500. I intend to play around with these but Iíve got all the necessary hardware and software to make the AJA products work and enough old school Mac computers to have about 5 capture cards running at one time. Iím willing to put in a little time to get the learning curve down on the AJA software and Iím even willing to put the time in on a WinXP build.

Iíve also read and seen some good things about AVISynth median filter Success with Avisynth Median filter, it works wonders! and it leads me to consider recording each video 3 times to give it a shot. Luckily(?) the 100+ vhs tapes my mom had in storage that originally prompted my hardware purchases turned out to be mostly recorded soap operas and other ďgarbageĒ and only about 15 VHS tapes with about 20 hours of total footage are worth my time.

Questions:

Iíd like to record about 20 hours of vhs footage at least 3 times in hopes of using the avisynth median filter. I also want to experiment with multiple capture devices. I donít want to tax my equipment or my time unnecessarily. I know Iíll have to make 3 separate passes for use with median filter but Iíd like to capture to multiple cards and save that data just in case so I can put this project behind me once and for all. Harddrive space or file size is NOT an issue. My workflow will be all S-video as follows:

Ag1980>TBC-1000>VDM-300s(detailing)>BVP-4+(color)>???>MULTIPLE CAPTURE CARDS AND COMPUTERS

What effect would a dist amp have on the signal if it is the last link in the chain above? Will it introduce noise or potentially affect the signal generated by the detailer or enhancer? What is the best dist amp available? I emailed SignVideo about their DAS-5 model but who knows if theyíll respond.

Is there any known quality issues with Extron or Kramer models? Those seem to be the s-video dist amps Iím seeing online for sale.

My TBC-1000 has a four output dist amp, but it is upstream of the detailer and enhancer so if I use the dist amp on my TBC, then only one capture card will be able to hook into my detailer and enhancer. Would it be possible to shift my TBC up the chain so itís the last link before the capture cards?

I think the AJA products prefer broadcast quality so the TBC should be upstream. If I use, say a Panasonic ES-10 after the VCR and moved the TBC-1000 to the last link for dist amp use, would the TBC features of the TBC-1000 be negated?

Last Question:

The AJA products can capture 10bit uncompressed. There seems to be some hot talk on the forums as to whether 10 bit is overkill since the color on VHS is equivalent to 6bit dithered. Is that still the case even if the picture is enhanced with a BVP-4+? Also the TBC-1000 (and the AG1980?) digitizes to 8bit with their respective TBC functions, so is it the case that the analog signal coming out of the TBC-1000 wonít have any detail that canít be captured with 8bit encoding? IF file size is not an issue, is there any benefit AT ALL to 10bit encoding? If I had a 10bit external TBC to replace the TBC-1000, would that change the equation?

If you have read all the way down to this point, congratulationsóyouíve already accomplished your New Years resolution to read more for the year! Any help would be appreciated thanks!
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  #2  
01-04-2022, 01:32 PM
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Proc amp and detailer won't like pre-TBC (frame, not line) workflow. Proc amp is always at or after, and detailer last in chain.

For optimum results, it'd be separate distro amp after TBC-1000.

And it needs to be a non-crap distro amp. There's some options from Cypress (AVT), DataVideo, Extron, few others.

I skimmed this, getting tired. Did I miss anything?

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01-04-2022, 04:15 PM
lightbulb1986 lightbulb1986 is offline
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Thanks Smurf. So vcr>tbc>proc amp>detailer>dist amp? Or you rec detailer last in chain even after dist amp? That would kinda spoil my intentions to feed the best signal to all cards simultaneously.

What do you think about Kramer? https://www.ebay.com/itm/20357067678...0AAOSwLnRhHtFg

Extron MDA-3sv? https://www.ebay.com/itm/29370909072...EAAOSwkEVXGiO3

This amp has adjustment knobs for y gain and c gain—what’s the purpose/benefit there? https://www.bhphotovideo.com/c/produ...tribution.html
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01-05-2022, 05:52 AM
RobustReviews RobustReviews is offline
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Quote:
Originally Posted by lightbulb1986 View Post
Howdy folks,
What is the importance of bandwidth and resolution measurements on DAs and why are some measures at -3db and others at -1db?
Can't help with much here, but possibly this bit.

Can you share the specifications so we can take a look? I'm sure you're aware -3dB is the half power point and is useful for discussion of amplifier/filter response in the frequency domain. -1dB could be used to fudge stats or maybe used for another purpose (or different unit) but without seeing the data it's difficult to determine. It's worth remembering (and this is a trap for everybody) that 'dB' is simply a ratiometric representation of two values, 'dB' itself doesn't mean anything and is dimensionless.

Even people who work with the decibel all day occasionally fall in to this trap, trust me!
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01-05-2022, 10:24 AM
latreche34 latreche34 is offline
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Why would you want to capture to multiple cards the same source? By now you should know what is the best card and just proceed with using it primarily.

On the analog equipment part I can't help since I don't use them at all, Anything analog in the chain reduces quality in my opinion, The only analog part in my setup is from the VCR to the ADC chip, everything else is all in the digital domain, TBC, proc amp ...etc.

https://www.youtube.com/user/latoak34/videos
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01-05-2022, 11:51 AM
lightbulb1986 lightbulb1986 is offline
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Quote:
Originally Posted by RobustReviews View Post
Can't help with much here, but possibly this bit.

Can you share the specifications so we can take a look? I'm sure you're aware -3dB is the half power point and is useful for discussion of amplifier/filter response in the frequency domain. -1dB could be used to fudge stats or maybe used for another purpose (or different unit) but without seeing the data it's difficult to determine. It's worth remembering (and this is a trap for everybody) that 'dB' is simply a ratiometric representation of two values, 'dB' itself doesn't mean anything and is dimensionless.

Even people who work with the decibel all day occasionally fall in to this trap, trust me!
Thanks Robust. Could you look at this product: https://www.bhphotovideo.com/c/product/159613-REG/Kramer_105S_105S_Distribution_Amplifier.html/specs

Vs the Das5 by signvideo (canít find it for sale but using it as a baseline comparison since itís a reputable brand). http://www.signvideo.com/das5_das15_s-video_distribution_amplifier.htm
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01-05-2022, 12:02 PM
lightbulb1986 lightbulb1986 is offline
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Originally Posted by latreche34 View Post
Why would you want to capture to multiple cards the same source? By now you should know what is the best card and just proceed with using it primarily.

On the analog equipment part I can't help since I don't use them at all, Anything analog in the chain reduces quality in my opinion, The only analog part in my setup is from the VCR to the ADC chip, everything else is all in the digital domain, TBC, proc amp ...etc.
You do have a point there. Thing is I bought various different capture devices and while I could review each one, the results may vary from tape to tape. Meaning I would have to test each tape among at least five capture devices. I also would like to make three captures on whichever card is best so that I can try the avisynth median filter. My hope was that a dist amp would be 100% transparent so that I could just capture to all cards simultaneously. I have 100s of TB storage so file size is not an issue. My concern is quality of capture and capturing as much of the analog info as possible for archival and potential tech advancements that allow better restoration.

Can you tell me about your digital workflow? Sounds very interesting. What does your chain look like? I think I had read your prior posts suggesting that the switch from a/d to d/a back and forth can degrade quality. Hopefully not a misquote. What are your thoughts there?

I had asked above if the TBC-1000 that digitizes at 8bit would negate any benefit of capturing at 10bitówhat do you think?
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01-05-2022, 03:02 PM
RobustReviews RobustReviews is offline
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Here, -1dB is a curious point to measure in my opinion. If anybody has any suggestions beyond mine please chip-in.

Firstly, the stats are planer on the Kramer unit.

Essentially, these stats don't mean a tremendous amount, the bandwidth for both is perfectly cromulent for the Y-bandwidth for both units, wider bandwidth isn't better, a tightly controlled passband is more useful here, but without seeing plots or full datasheets it's difficult to determine. Essentially these numbers can be put on a website, most people won't pay them the blindest bit of attention.

Without wandering in to dull maths, the convention is to measure at -3dB (half-power) whereby the response should become broadly linear rising/decaying at Ī20dB/decade. This isn't especially useful here and requires deeper mathematics and electronics theory to understand: -3dB is a useful convention, it's almost universal.

-1dB will give better headline figures for sure (≈0.8x). Either way, I would just wait for a user of these units to have an input, as there's more to this than video bandwith, although it's interesting to look up.

I've had a very long and tiring day, apologies if this doesn't make much sense.
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  #9  
01-06-2022, 06:19 PM
lollo2 lollo2 is online now
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Quote:
Iíve also read and seen some good things about AVISynth median filter Success with Avisynth Median filter, it works wonders! and it leads me to consider recording each video 3 times to give it a shot.
captures.jpg

It is always a good idea, but if your tapes and captures are good do not expect a major improvement. Here you can find a comparison for one of my tape where I compare the first capture with the median obtained using this first plus 2 additional captures. Marginal improvement.

differences and parameters capture1 versus median:
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A image comparison: https://imgsli.com/ODkwMDI
A video comparison: stats_median_frame109.jpg

On the other hand running a denoise filter like TemporalDegrain2, even at its lower temporal radius (=1 in following example) is more effective. Here the comparison between the "median" and the "denoise" clip.

differences and parameters capture1 versus denoise:
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differences and parameters median versus denoise:
cfr_median.mp4

A image comparison between median and denoise: https://imgsli.com/ODkwMDM
A video comparison between median and denoise:stats_denoise_1_frame109.jpg

The advantage of running multiple captures is when the tape has defects that do not appear identical at every capture, so they can be reduced through the median operation, or if large amount of noise is randomly distributed through the different captures because the hardware. Is is also useful if you see a bad field or a frame in one of your capture, because hopefully it will not be present in the next capture (but in this case you replace it, do not perform a median).
In theory it can also allow to use a filtering with a denoiser in AviSynth with a less aggressive setting, reducing then potential artifacts.

In practice, if you plan a restoration activity, denoise filters in AviSynth or VapourSynth are excellent, and the prior noise reduction with the median is hidden and not very effective.
Judge yourself on your material if multiple captures (and multiple stress) of your tapes (and hardware) is worth the effort. Also remember that the captures must be exactely aligned frame be frame, not a single "drop" or "inserted" is allowed: if they happen you should manually remove frames!


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01-06-2022, 06:44 PM
msgohan msgohan is offline
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Quote:
Originally Posted by lollo2 View Post
Also remember that the captures must be exactely aligned frame be frame, not a single "drop" or "inserted" is allowed: if they happen you should manually remove frames!
The Median filter has a frame-matching feature to account for this. In my experience it works well (no frame drops/inserts on the PC side for my captures, but frame dupes caused by the DVD recorder passthrough).

Post by the plugin author regarding this.
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01-07-2022, 03:46 AM
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Quote:
The Median filter has a frame-matching feature to account for this. In my experience it works well (no frame drops/inserts on the PC side for my captures, but frame dupes caused by the DVD recorder passthrough).
Yes, you are right. I know the sync parameters in the plugin, and I know by experience how difficult a frame matching is (I was helped recently to build a "bad field detector" for AviSynth https://forum.doom9.org/showthread.php?t=183582).

In this contest the author proved that a single frame misalignement is not that critical, but in general I tend to be wary of "automatic" detection, and do a visual check and manually align the videos as much as I can, just because I am a bit paranoid about it. :-)

A channel on S-VHS / VHS capture and AviSynth restoration https://bit.ly/3mHWbkN
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  #12  
05-24-2022, 07:59 PM
lightbulb1986 lightbulb1986 is offline
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Originally Posted by lordsmurf View Post
Proc amp and detailer won't like pre-TBC (frame, not line) workflow. Proc amp is always at or after, and detailer last in chain.

For optimum results, it'd be separate distro amp after TBC-1000.

And it needs to be a non-crap distro amp. There's some options from Cypress (AVT), DataVideo, Extron, few others.

I skimmed this, getting tired. Did I miss anything?
Wanted to follow up on this Smurf: do you mean to say that a separate distro amp after the TBC-1000 is preferable to using the four outputs/splitter on the TBC-1000 itself? Seems like less gear between vcr and capture card would be better, no?
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  #13  
05-24-2022, 08:58 PM
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Quote:
Originally Posted by lightbulb1986 View Post
Wanted to follow up on this Smurf: do you mean to say that a separate distro amp after the TBC-1000 is preferable to using the four outputs/splitter on the TBC-1000 itself? Seems like less gear between vcr and capture card would be better, no?
If multiple connections are a concern, then you need to modify the TBC-1000, remove the VP-299. That tends to add more problems than any external s-video connection will.

But aside from that, the question doesn't make any sense.
- distro amp = fancy quality splitter
- proc amp = multi axis color/brightness adjuster

The distro amp is best not even used, unless you require such live signal splitting. On some TBC-1000 it can be modded for bypass, others not.

But the biggest issue these days is bad caps on a TBC-1000, if you're worried about loss.

No, less gear isn't better. What matters is the integrity of the signal being passed. The best TBCs have a high transparency, you don't even know it's there. (Unless you A/B to see it with/without, to understand what it's doing. Being transparent doesn't mean it doesn't do anything.) Same for the best proc amps, such as SignVideo PA-100/200 units in excellent condition (meaning almost never eBay finds).

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05-24-2022, 11:04 PM
lightbulb1986 lightbulb1986 is offline
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Great thanks. If I was unclear, I intend to use a dist amp to split the signal from the tbc-1000 into several capture cards. I was wondering if using the splitter from the tbc-1000 would diminish its tbc function (i.e., better to output from tbc on one s video cable into a separate dist amp that then splits the signal to capture cards). I don’t expect my tbc to have bad caps since it’s a tgrant refurb but I’ll A/B it with the dist amps I have.

Just doing some mental gymnastics beforehand!
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05-26-2022, 02:35 PM
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Quote:
Originally Posted by lordsmurf View Post
The distro amp is best not even used, unless you require such live signal splitting. On some TBC-1000 it can be modded for bypass, others not.

But the biggest issue these days is bad caps on a TBC-1000, if you're worried about loss.

No, less gear isn't better. What matters is the integrity of the signal being passed. The best TBCs have a high transparency, you don't even know it's there. (Unless you A/B to see it with/without, to understand what it's doing. Being transparent doesn't mean it doesn't do anything.)
What is the difference between the TBC-1000's that are and aren't moddable?

On the TBC-1000s I've recapped, between 1/5 - 1/3 of the caps were bad/ the ESR was multiples higher than it should be.

Quote:
Originally Posted by lightbulb1986 View Post
I don’t expect my tbc to have bad caps since it’s a tgrant refurb but I’ll A/B it with the dist amps I have.
They may have checked the caps instead of replacing all of them. I don't have experience w/ their work, but I would check them myself. Even though some caps may still be within tolerance, they will eventually go bad, and preventing future damage for the finite number of these units, is essential... So the entire VP-301 board should get recapped, the dist amp is optional since some of us bypass it anyway. An easy way to know if they are originals is to check the brand of the caps.

Just FYI, when I do refurbs for others it includes full video and power board recapping for this very reason.

Spending time and money on a bygone era
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05-26-2022, 05:16 PM
lightbulb1986 lightbulb1986 is offline
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What would the original caps be labeled? You got a link to more info? Would be helpful thanks!
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  #17  
05-26-2022, 05:55 PM
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Originally Posted by Diopter_Doctor View Post
What is the difference between the TBC-1000's that are and aren't moddable?
All are probably moddable, but some units will require vastly more parts and soldering, risking the units. Some of the earliest units have actual TBC-100 cards, but the 1000s became further and further removed over time.

Quote:
On the TBC-1000s I've recapped, between 1/5 - 1/3 of the caps were bad/ the ESR was multiples higher than it should be.
That was actually a good unit, too. Most are needing far more caps work, and it's really degraded overall since 2019. All the caps seem to be aging on the middle productions especially. The only takeaway is that supply chain was full of bad caps then, probably even the infamous counterfeit caps. The oldest, and youngest, seem to be better. But those are much rarer to find. TBC-1000 has at least a dozen iterations. DataVideo seems to have prescribed to just-in-time supply, with production supply changes resulting in modification to the base design.

Quote:
They may have checked the caps instead of replacing all of them. I don't have experience w/ their work, but I would check them myself. Even though some caps may still be within tolerance, they will eventually go bad, and preventing future damage for the finite number of these units, is essential...
TGrant does this. It's pissed many of us off, as we didn't realize this at the time. Rather than replace all the caps, he does a minimal job, then wants more more to repair it again within a few years time. Nevermind that issues may cascade, cause further damage, as you rightly mention. The experiences to date were all related to AG-1980, but I wouldn't at all trust him with a TBC-1000. When the TBC-1000 reaches the point of needing recap (or the AG-1980, for that matter), all caps need replacing. Not just the ones bad, as the others will fail in due time, be it days, or a few years at most.

Quote:
So the entire VP-301 board should get recapped, the dist amp is optional since some of us bypass it anyway.
The bypass must vary, due to board configs. For example, the brown power board is a PITA, when you want to use the native IO on cards that have it. You can either move it back onto the board (like a real TBC-100), or you must play musical chairs within the case. Assuming you don't plan to just gut, parts splayed everywhere, though you'll either need extension cables or re-solder longer cables. The fun part is when your attempt to modify results in bad caps making themselves known.

Repairing, or modding, a TBC-1000 can be a can or worm, a rabbit hole, a time-suck vortex. But at least it's not a money pit like the 1980, one-time proper fix tends to stick.

Quote:
Just FYI, when I do refurbs for others it includes full video and power board recapping for this very reason.
So are you recapping TBC-1000s for others?

Quote:
Originally Posted by lightbulb1986 View Post
What would the original caps be labeled? You got a link to more info? Would be helpful thanks!
There's no link. This is info that each of us has discovered. I probably have the most TBC-1000 info of anybody out there, but I just have a lack of time to share it all, nor present it in a way that makes sense to others. At least not now, hopefully eventually. But even I don't have a 100% complete and coherent picture over time, nor even does DataVideo. Stuff was lost to time, so us users, the ones still here decades later, have to reverse engineer, and collage the history through observation, sometimes using extant documentation (some non-public), etc.

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05-27-2022, 04:25 AM
RobustReviews RobustReviews is offline
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The distribution amp is a 'jelly bean' circuit, it's a real building block thing.

Unless this has something really remarkable in it (which I doubt) it should be very simple to bypass. It's unlikely to need many components. Like I have said before if it's suspect terminating unused outputs often solves problems with amplifiers with multiple outputs. That may or not be the case here, but it's good practice and just about free to try.

By best practice, unused outputs from amplifier circuits should be terminated correctly. Does it mention this in the manual?

Leaving outputs 'open' without proper termination is about the most surefire way to introduce noise in to an RF circuit; recall we're working with the vagaries of AC power here, and many still insist on applying DC circuit theory to this stuff. This is the same theory they learned in GCSE Physics and really isn't applicable when we start wandering in to RF circuits.

Also, remember unterminated outputs stress circuits, which I think may be the root cause of the problems that arise with a lot of these over time, they've probably been run for years with unterminated outputs which have eventually caused component damage. The maths bear this out, as does practice.

You're unlikely to walk into a studio environment and find machines with improperly terminated outputs.

I'm convinced a lot of the problems encountered on here with noise encroachment could be countered with basic but proper cable technique and correct termination. RF is a lot more nuanced than many who do not work with it to any serious degree (in the electronic sense) appreciate.
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05-31-2022, 01:30 PM
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Quote:
Originally Posted by lordsmurf View Post
The bypass must vary, due to board configs. For example, the brown power board is a PITA, when you want to use the native IO on cards that have it. You can either move it back onto the board (like a real TBC-100), or you must play musical chairs within the case.
Yes, all the units I've seen still have the composite "out" and unpopulated solder pads for the s-video interface on the VP-301 adjacent to the power board.

Quote:
Originally Posted by lordsmurf View Post
Repairing, or modding, a TBC-1000 can be a can or worm, a rabbit hole, a time-suck vortex. But at least it's not a money pit like the 1980, one-time proper fix tends to stick.
You could remove the dist amp, make a new/smaller PCB. One half with pre-power board caps and the other with your I/O fitting the holes that are already there, if you want a nice factory look.

Quote:
Originally Posted by lordsmurf View Post
So are you recapping TBC-1000s for others?
I have/am. The last one I did was a couple of months ago for ninlive, a newer member on here. I have been a little busy with other projects lately but am happy to make time if someone needs a re-cap.

Spending time and money on a bygone era
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