Wanted: TBC
7 messages in this thread
Looking for TBC to use with Hi8/S-VHS and toaster. thanks, Brian
Also looking for same thing…I have tried several but none seem to do
what I need. I have Sony EVO 9700 and toaster BTW…anyone know
anything about Drop out compensatators….
Perry,<BTW…anyone know anything about Drop out compensatators….>
I'm no rocket scientist, but here goes. Drop out Compensator circuits
essentially take a portion of the RF signal from the playback VTR to "fill
in" horizontal luminance streaks that show up in the picture. A simple way
to think of it would be to look at a still frame that has a large amount of
brownish color, when a white streak of a certain luminance level is
detected, it is "filled in with an amalgam of the RF color signal of the
adjacent horizontal scan lines (in this case mostly brown) to "cover up"
the white streak. Since the drop out only appears on the screen for a brief
instant, the untrained eye usually misses the occourance. This "combining"
process is carried out inside the delay circuits of the TBC before it is
displayed at the output. The range as well as the intensity of the dropout
compensation can usually be adjusted. BTW, I have two TBCs that have DOC,
and now would not purchase a TBC that doesn't have one.
Frank
Thanks for the DOC explanation, Frank. Rocket scientist or not, sounded
good to me.
Now for the obvious follow-up: I have been reading the specs of the
various low end (under $1K) TBC's that are coming out – looking for DOC –
and none mention it. The I.Den IVT-7 advertises it has DOC, however, at
around $3K list. What unit(s) are you using and do you think there's a
qualitative difference in the effectiveness of DOC as offered by different
manufacturers? Also, what format are you editing in?
Thanks,
John
John, before you leap into the DOC issue you should understand that the
playback vtr has to have a DOC output in order for the DOC circuit to do
any good. Most contemporary industrial and all broadcast decks will have
it, consumer machines won't. The units I use are as follows; IDEN IVT-7
(which you should be able to get mail order for around 2k) but the new
"In-Board" unit that is selling for around $900 may not have DOC, you might
want to check. My other "Toasterfied" TBC is the FOR.A FA-300, also
marketed under JVC's name, it retails for aprox 4k, $3200 is going price
mail order for the FOR.A version, JVC won't discount the sucker. I also
have an older unit made by FORTEL (Y-688 model) that is not a full frame
unit but has DOC, primarily in use for duplication at this time. The only
real difference I can determine in the effectiveness of DOC circuits seems
to be in the available adjustment controls, for example; the IDEN's DOC
adjustments are inaccessable without taking the circuit board out of the
case, the FOR.A has the width and level controls right up front with all
the other controls. It's possible that the DOC circuits may be tied in with
comb filter technology. My edit setup is 3/4SP (two sources, one
portable),S-VHS (one source, one camcorder), and MII edit VTR, all
controlled by the Paltex Abner II edit controller (with time code) using
the Toaster as the switcher. Works real nice, no complaints except that
Toaster's CG still doesn't do the things that I need it to do, so I mostly
use my second Amiga downstream from the Toaster to run BT2 which gives me
typewriter reveals, coin flips, and different text colors on scrolling
titles.
Frank
Frank,
You have quite an assortment of hi end equipment. Could you recommend a
place where used equipment that falls out of favor can be had? I am getting
no where in my search for a Sony 6850.
Thanks again 🙂
–Paul
Whappin' from the Wine Country
Thanks Frank,
I didn't realize the VTR had to be "DOC compatible." Guess I thought that
since the TBC stores (temporarily) each frame before it sends it back out
(storing in the sense that it regulates the VTR output) that the TBC had
the opportunity to clean up the VTR output while it had it's "hands" on the
frame – regardless of the VTR's role in the process. Thanks for setting me
straight.
John