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Optimod TV vs 8100A
- Thread starter Studio1
- Start date
The TV Optimod does have a stereo generator in it. It also has a reference video input so that the stereo pilot is locked to horizontal sync.
The TV Optimod uses DBX noise reduction in the L-R channel. Otherwise, they're pretty much the same.
The TV Optimod uses DBX noise reduction in the L-R channel. Otherwise, they're pretty much the same.
Previous thread on this:
http://boards.radio-info.com/smf/index.php?topic=162668.0
http://boards.radio-info.com/smf/index.php?topic=162668.0
boiseengineer said:
Thanks for the heads-up. My bad for not searching for a previous thread on this, however I didn't think anyone would be as mad as me
to even think of the idea that popped up in my head! [no disrespect to the poster of the other thread]
It's just I see quite a few TV Optimods on Ebay at the moment and no 8100A's and I wondered if it was possible to use, by modification, a TV unit for FM processing.
The other thread answers *some* questions, but got me totally lost with the rest of it as I don't know one end of a TV unit from the other, so I don't understand what they are talking about with respect to MTS stereo and SAP generators etc.
eBay has been flooded with Orban TV equipment for quite a while now. TV stations are junking their obsolete analog gear left and right, and some people think they can make money off of it. I haven't even seen any of the actual Optimod TV processor up for bid. All you usually find are the "Optimod"-branded MTS stereo generators, SAP generators, and PRO channel generators -- none of which are applicable to FM radio broadcasting. So be very careful of what you bid on, because they all come in the same brown 8100/9100-style rack unit.
The 8182 have a different card 5 adding a release shape control. There's 3 more cards, slots 0 and 1 for the Hilbert Clipper (left and right) and a loudness controller on the slot 2. You can easily find a 8182 for less that $500. Actually, I have installed a unit for my satellite TV audio system at home...
hypwr said:
AAAAHHHHHHH!!!
If they are actual processors (and not the stereo gen or SAP units) that's insane! Those units still seem to bring a few hundred a piece on ebay!
They could still be used to get '8100 sound' out of the unbalanced test jacks. This would be ideal in-store music systems or maybe drive-in movie theaters that are using cheaper part 15 transmitters.
It would be a nice way for some of the campus-limited broadcasters I deal with to get that Optimod signature without going totally broke trying to find an 8100.
A couple of question though: from what I remember there was the 8182a, which was a stereo processor meant to feed the external TV stereo generator? Was there a combo unit with the processor and stereo generator as one in the 81xx TV series?
Secondly, I know the Optimod TV's card 5 is different, but are the time constants so different that it's harder to get acceptable "FM-like" audio processing from the box? I would think the timing wouldn't be all that different.
BTW: If anybody has a lead on one I'd love to help a school replace it's aging 411 stereo Volumax.
A couple of question though: from what I remember there was the 8182a, which was a stereo processor meant to feed the external TV stereo generator? Was there a combo unit with the processor and stereo generator as one in the 81xx TV series?
Secondly, I know the Optimod TV's card 5 is different, but are the time constants so different that it's harder to get acceptable "FM-like" audio processing from the box? I would think the timing wouldn't be all that different.
BTW: If anybody has a lead on one I'd love to help a school replace it's aging 411 stereo Volumax.
If you can make heads or tails out of the following, it's an e-mail from 2007 from Bob responding to my questions about Optimod TV units...
At 05:19 PM 10/29/2007, you wrote:
> Hey, Bob...
>
> I have a question. I've been seeing a few of the old 8180As (Optimod TV) units on ebay lately. The controls seem identical to the 8100A.
>
> While I understand that the desired characteristics of TV processing would be GREATLY different than FM, is it still possible to get the 'classic' 8100A sound out of this box? I would want it for production purposes only and not for broadcast, but it would need to be able to handle music as well as an 8100A.
The 8180 is essentially an 8100 with a line driver output in place of the 8100's stereo generator. You can get a very similar sound to the 8100. It still uses the 8100-style clipping system. Note that the 8182 has a differently different clipping system, so you should make sure that your acquisition is an 8180 and not an 8182.
>
> Did you guys scale back the relative effects of each control on this unit, or simply rely on the intelligence of a TV engineering staff to set it less aggressively?
The latter.
> Also, is the frequency response similar?
Yes.
>
> Also, do the 'test' RCA jacks on 8100As or 8180s deliver a flat or pre-emphasized output?
The test jacks are preemphasized. The 8180's main line driver output is capable of emitting a flat or preemphasized signal.
At 05:19 PM 10/29/2007, you wrote:
> Hey, Bob...
>
> I have a question. I've been seeing a few of the old 8180As (Optimod TV) units on ebay lately. The controls seem identical to the 8100A.
>
> While I understand that the desired characteristics of TV processing would be GREATLY different than FM, is it still possible to get the 'classic' 8100A sound out of this box? I would want it for production purposes only and not for broadcast, but it would need to be able to handle music as well as an 8100A.
The 8180 is essentially an 8100 with a line driver output in place of the 8100's stereo generator. You can get a very similar sound to the 8100. It still uses the 8100-style clipping system. Note that the 8182 has a differently different clipping system, so you should make sure that your acquisition is an 8180 and not an 8182.
>
> Did you guys scale back the relative effects of each control on this unit, or simply rely on the intelligence of a TV engineering staff to set it less aggressively?
The latter.
> Also, is the frequency response similar?
Yes.
>
> Also, do the 'test' RCA jacks on 8100As or 8180s deliver a flat or pre-emphasized output?
The test jacks are preemphasized. The 8180's main line driver output is capable of emitting a flat or preemphasized signal.
Of course, the Optimod-TV units also have the built-in "idle-gain" setting, where the gain reduction comes to rest at 10dB of gain reduction (labeled at '0' on the Optimod-TV, which is graduated from +10 to -15 instead of 0 to -25) I believe Bob also told me that this can be defeated internally.
This would make sense for TV applications in addition to gain-freeze gating due to long periods of near silence in some TV programs or movies.
This would make sense for TV applications in addition to gain-freeze gating due to long periods of near silence in some TV programs or movies.
IIRC,
Except for card 5,the loudness controller card and the hillbert clippers can be bypassed so allowing for cards 8/9 to be used the same as an 8100a,check out the manual's diagrams.
The main difference to card 5 is the master band,the control module is different as well as some threshold values.
I have still got my modified 8182a,i added a stereo gen card and did some motherboard rewiring and fitted a bnc mpx socket on the back.
As the ribbon cable from functiion switch to m/board is the same as the 8100a,it is possible to wire the m/board for the "missing" function sw positions,like 19k osc and 38k agc positions.
Except for card 5,the loudness controller card and the hillbert clippers can be bypassed so allowing for cards 8/9 to be used the same as an 8100a,check out the manual's diagrams.
The main difference to card 5 is the master band,the control module is different as well as some threshold values.
I have still got my modified 8182a,i added a stereo gen card and did some motherboard rewiring and fitted a bnc mpx socket on the back.
As the ribbon cable from functiion switch to m/board is the same as the 8100a,it is possible to wire the m/board for the "missing" function sw positions,like 19k osc and 38k agc positions.
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