-
Get involved.
We want your input!
Apply for Membership and join the conversations about everything related to broadcasting.
After we receive your registration, a moderator will review it. After your registration is approved, you will be permitted to post.
If you use a disposable or false email address, your registration will be rejected.
After your membership is approved, please take a minute to tell us a little bit about yourself.
https://www.radiodiscussions.com/forums/introduce-yourself.1088/
Thanks in advance and have fun!
RadioDiscussions Administrators
Optimod TV for FM?
- Thread starter NHRadio
- Start date
TV stereo is a different technology from FM stereo. Not compatible
The television version of the 8100 (without the stereo generator) has a different Card 5. I had heard that if you put an 8100's Card 5 in the TV version it's essentially the same, sans the composite stereo generator. Keep in mind the 8100 FM's stereo generator is where the magic happens as far as overshoot control.
If you use the TV version for simple audio processing it may be fine, but if you're looking for a competitive sound you'd be better served finding an 8100 FM.
If you use the TV version for simple audio processing it may be fine, but if you're looking for a competitive sound you'd be better served finding an 8100 FM.
Just build on this slightly more, TV processing has a different goal than most FM stations. TV is after peak control and some gentle AGC whereas FM tends to be far more aggressive, thus, the differences in the design of card5. I also seem to recall that Orban didn't use the patented distortion cancelling clipper in the TV box. Additionally, analog stereo TV uses a different form of composite audio with a lower frequency pilot and integrated DBX companding noise reduction. So, even if you could get the basic sound that you wanted from the TV box, it would have to be in mono. Probably, it's more trouble than it's worth, hence the price difference.
If you need a card 3/4 and a card 5, you can use these cards from the TV Optimod in an 8100. The ST chassis used these cards, usual procedure was to remove the cards from the 8100, and insert a couple of "dummy" cards in the 3 & 4 slots (they had buffer amps but none of the other circuitry).
Then years pass, and the the two boxes get separated--and you have an 8100 that is basically a stereo generator.
The TV 3 & 4 cards are identical, but the #5 card has an extra switch & IC which has some effect on processing. The switch has to go (unless you leave the interior front panel off--not recommended in high RF areas) but you can just hard wire the circuit in the position you like best.
Then years pass, and the the two boxes get separated--and you have an 8100 that is basically a stereo generator.
The TV 3 & 4 cards are identical, but the #5 card has an extra switch & IC which has some effect on processing. The switch has to go (unless you leave the interior front panel off--not recommended in high RF areas) but you can just hard wire the circuit in the position you like best.
Bill DeFelice said:
There is no overshoot control in the 8100a stereo generator card,this is all done in cards 8/9.
Regarding the 8182a tv optimod, it has the same cards 3/4/6/8/9 as the 8100a, but card 5 is different, and the 8182a additionally has the loudness controller card and Hilbert cards.
Both the hilbert cards and loudness controller cards are defeatable.
Paul.
BROADCAST said:
Thanks for the clarification.
I also thought the timing on the TV's card 5 was much different than the FM version?
The bass timing module is the same, except for threshold level, the master timing module is quite different though.
Besides the 8182a master log/linear release option, the timing circuitry is somewhat different so cannot give the exact same sound.
I have a 8182a here that has the 8100a card 5, as well as the 8100a stereo encoder card fitted.
I added a rear bnc mpx out and also did some extra motherboard wiring including making the function switch work all the original 8100a's positions.
As the hilbert and loudness controller cards can be bypassed on the other cards jumper options, you can then remove these (spare)cards, so making the occupied slots the same as a 8100a.
Paul.
Besides the 8182a master log/linear release option, the timing circuitry is somewhat different so cannot give the exact same sound.
I have a 8182a here that has the 8100a card 5, as well as the 8100a stereo encoder card fitted.
I added a rear bnc mpx out and also did some extra motherboard wiring including making the function switch work all the original 8100a's positions.
As the hilbert and loudness controller cards can be bypassed on the other cards jumper options, you can then remove these (spare)cards, so making the occupied slots the same as a 8100a.
Paul.
Bill981 said:
Nope.
100% modulation in FM = 75 kHz deviation
100% modulation in (analog) TV = 25 kHz deviation.
Bill981 said:
You say TV pre-emphasis is 25us? Then why did my 8282 Optimod-TV have only 50us and 75us settings available?
Just for fun, read this old thread. This was about my use of an 8282 for FM. KEEP IN MIND that in the end I only used it as a pre-processor, and did not bypass the processing in the existing 2200 as I had suggested in the original post.
This processing chain ran on the air for 3+ years and was just recently retired.
http://radiodiscussions.com/smf/index.php?topic=162668.0
A
alleo
Guest
three tv Optimods were selling at Alfa Electronics a month ago ,alfaelectronic.com. Ralph has info on them can I give out a number ?
- Status