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Orban 8100A > Composite Audio Out > No Output!

K

kj6eo

I acquired a nice 8100A from a Friend. I hooked up the INPUT audio and turned it on. Gee ... meters move and lights flash just like the 8100A videos I've seen on YouTube. I hooked the COMPOSITE OUTPUT of the 8100A to a spare BW Broadcast TX-300 I have hooked up to a dummy load. I turned the transmitter on but got nothing but silence. Is the COMPOSITE BASEBAND OUTPUT of the 8100A incompatible with the MPX/BASEBAND INPUT of my TX-300? Maybe I need an adaptor of some kind. Any comments you might have would be appreciated.

Regards,

Bill - KJ6EO
 
It sounds as if you should be getting something on the exciter. If you're sure the exciter is OK, and you're also sure the composite level control wasn't turned down all the way, I have heard of the composite output chip on the 8100A going south. It's an AD518N, but the more common NE5534 works perfectly and is, IIRC, a pin-for-pin substitute. The LF357 or MA332 should work as well.
 
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I agree with Dumber, the output Opamp for the composite output may be toast. You can stick a paperclip in the center pin of the BNC connector and a couple clip leads to one side of a headphone plug. The level will be low, but you should hear audio on one side of the headphone. If not, replace the AD518 Opamp with a NE5534.
 
Thanks for your replies. I presume the Opamps your referring to are located on Card #7 (Stereo Generator)? I found 2 of the Opamps you mentioned located near the front of the card behind the pots. One is the original AD518, and one has been replaced with an NE5534. Interestingly enough the NE5534 thats on the top side of the card has Pin 1 facing the front of the card. The other one the AD518 has Pin 1 facing the back of the card. It caught my attention, but this could have just been the way the layout was designed. Although I didn't mention it, I have another 8100A. The second one doesn't have a Card #7 in it. Were the 8100A's designed to work with or without Card #7 ... i.e Mono/Stereo? To answer your question, I know the exciter is good. I put it on the air to test it ... works great! After I didn't get anything out of the Composite Out of the first 8100A, I put my scope on the BNC Connector. There was nothing there of course. Any additional comments you might have would be appreciated.
 
Ok ... I've got one of them working. I downloaded a set of schematics from Orban. The first thing I noticed was that the model number of my 8100A was 8100A/1 which was factory configured for use with the XT Chassis. After resetting all the jumpers on the cards for "Normal Operation", I had composite output at the BNC Jack. As I previously mentioned, I'm missing "Card 7" on my second one. I'm not sure if the second one will work without "Card 7". If someone has a YES/NO answer to this question, please let me know. Thanks again for your suggestions. I'm gonna take the working one to the Hill tomorrow and put it on the air. I have a pair of prisims I can put in front of it if necessary.
 
It's been a while since dealing with 8100's regularly, but I'm pretty sure there are unbalanced output jacks for L and R non-pre-emphasized audio on the 8100's backplane. If that's where the user wants to take audio outputs from the box, then card 7 is unnecessary. Also, if it's set up in a split studio-transmitter configuration, then card 7 will live in the transmitter box (the ST chassis) and not in the 8100 chassis.

The Prism/Optimod setup was so widely used that a retrofit kit consisting of replacements for Optimod cards 3 and 4 (the audio input cards) was sold and made the setup sound even better.
 
Thanks for your reply. Yes, there are unbalanced output jacks for L and R non-pre-emphasized audio on the 8100's backplane. I just ignored them because I'm balanced everything. The only exception is unbalanced audio from my automation computer's sound card. I run that in to a Henry Stereo Mixer which does an excellent job of converting it to balanced. My automation computer and EAS are in my garage here at home. I'm sending my audio up to the Hilltop via a pair of Bric Link II's over a Ubiquity M5 Nanobridge. I started out running FLAC but the link is so good I'm running 1.6Mb uncompressed now. At the Hilltop I've got an Omnia 3FMT into a BW Broadcast TX300. The antenna is a Scala 5-element CP Yagi on top of a cell tower. I'm eager to see what the 8100a sounds like on the air.
 
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That reminds me, I have two 8100A Orbans in storage. Worked fine when I removed them. Replaced due to lack of rack spare.
 
Bill, you can probably get pretty good money (maybe $500?) for those on the eBay machine. For some reason there's a bunch of broadcasters and hobbyists who still think the 8100 is the best thing ever.
 
8100A against Omnia 3FMT

PT .... I think you'd be surprised as to what you'd get for them on Ebay. There's an 8100A on Ebay right now (without cards) buy it now $599 (Starting Bid $399). A set of cards would probably cost $300. I've seen a couple over the last 6 months that fetched close to $1K. I didn't pay attention but those might have had the XT Chassis to go with it. Anyway, It might not have been a fair test, but I put my 8100A (unmodified) up against my Omnia 3FMT. I put the 8100A in the rack because I need to do a little work on my 3FMT. The 8100A will take the place of the 3FMT while I'm working on it. So here's the results: The 8100A was easy to set up. The presets that Orban gives are actually meaningful. The 3FMT on the other hand required allot of cranking to get the sound I wanted. IMHO the 8100A has a warmth to it that the 3FMT doesn't. However, the 8100A is far from being a 3FMT. On the 8100A, I was able to duplicate the sound of the 3FMT until I got down to 200hz. The 8100A seemed to attenuate everything from 200hz all the way down to 60hz. I put an equalizer in front of the 8100A in an attempt to boost 60hz to 200hz. It worked somewhat, but trying anything over 6db got messy. Regarding BASS, the 3FMT has got big shoes. Utilizing the DEEP and PHAT bass settings you can really get some thunder. All things considered though the 8100A sounded really nice. I instantly connected with it's sound, that nice smooth warm sound of 80's Classic Rock. The settings that seemed to work the best for me on the 8100A for Modern Country were: Clip (+.5), HF Limit (10), Release (0), Bass (0), Gate (0). So, that was my little experiment for today. I need to have a look at my second 8100A to see if it's got any mods or replacement 3/4 cards.
 
The 8100A with the XT2 is still one of the best processors around. I recapped and aligned our set, and we sound just as good as the big guys in the larger market.
 
I came off a little negative.

I also like the sound of the 8100A, but I do consider modern processors (like an Omnia ONE) to be superior.
 
I spent some more time with the 8100A. As I previously said, I put an equalizer in front of it to boost the bass frequencies. Here's what I added:

25hz 40hz 63hz 100hz 160hz
3db 3db 3db 6db 3db

I came very close to duplicating the sound of the 3FMT. The noticeable difference of course was the 3FMT's BASS handling capabilities (punch, loudness). Regarding Classic Country, the 8100A had a beautiful WARM sound that I couldn't get out of the 3FMT. However the 3FMT handled the new modern stuff better. I put my Prisim's in front of the 8100A and the sound was way out of range. I had to turn the HIGH, PRES, MID pots all the way down. I guess I'd need the Texar Card for the 8100A to allow the PRISIMS to work well with it.
 
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Back in the early 90's (so long ago), I installed an 8200 on my FM replacing the long-standing 8100XT. One night when we were down for maintenance, I did an abbreviated audio proof as part of the work. I switched between the original 8100XT and the new (at the time) 8200. I was floored at the difference of s/n between the two. I couldn't even measure a noise floor with the 8200 (infinity), where the 8100XT was roughly -55db. Analog or digital, aggregate noise floor is destructive to your FM signal. Modern digital processing are miles ahead of 1970's technology, when it comes to providing a low noise, low distortion product to your listeners. Remember folks, we now compete with portable music players and streaming too. Don't get caught up in the trap of assuming your listeners think loudness wars or heavily processed audio sounds good, as you may. Your audience isn't a bunch of radio-technical people, who have been around since the 1960's. Clean and natural sounding nets higher TSL, where distortion drives it away.
 
sallut ,as tu reussi aujourd'hui à avoir du son ,sur ton processeur ,moi je vient d'en acheter un et je suis très deçu ,il y a la lumière les aiguilles bougent ,mais pas de son en sortie,aurais-tu une idée?

Translation:
Hello, did you manage to have sound today, on your processor, I just bought one and I am very disappointed, there is light the needles move, but no sound at the output, would you have an idea?
 
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neptunium....
It sounds like you may have an 8100 that has the XT2 output engaged......
There are internal jumpers to set the output to "default"....
I had this problem with one of the 2 8100s I own,,,,the techs at Orban legacy in AZ corrected the issue when they did their overhaul.
(Is someone able to translate if needed? Thanks!)
 
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