AM and SW audio processor units and info wanted

[W1DAN]

Hi!

Just on a distant chance.....

Looking for an Orban 9105A HF processor. Also a CRL MBL-100. Maybe an Optimod 9100A or B. All for ham radio hobby use and experimenting.

I have a Gregg 2530 and could use a copy of the manual. Have a 2540 with partial info and could use more complete docs.

I'm holding my breath....Just thought I'd ask!

73
Dan
W1DAN

 

[RadioMan203]

I know I've seen other hams with 9100's, whether they're the HF model or not is another question. I had been looking for a 9100 for use with a school's campus AM station and I was totally floored with this 30 year old box goes for in the wild, price wise that is. Considering you'd have to recap the beast you'll end up spending quite a bit more than it's likely worth.

There are probably other boxes that would work well and probably cost a fraction of the cost of a used 9100.

 

[kenglish]

Can't remember if I saw anything like that in the BBC World Service auction, or not.....I did see some, somewhere.
Keep an eye on E-Bay.

 

[VelvetR]

Hi!

Just on a distant chance.....

Looking for an Orban 9105A HF processor. Also a CRL MBL-100. Maybe an Optimod 9100A or B. All for ham radio hobby use and experimenting.

I have a Gregg 2530 and could use a copy of the manual. Have a 2540 with partial info and could use more complete docs.

I'm holding my breath....Just thought I'd ask!

73
Dan
W1DAN

MBL-100 was most recently sold as "Amigo". The bandwidth selections were a little different but setting them was the same. Problem is the packaged power supply. They're operating right at the edge of their capacity and are prone to failure. There was a "last call" on replacements over 5 years ago, at which time I bought two. Since then I've used one and the other is taped to the MBL-100 in the rack so whoever follows me will find it when needed. At that particular station I have an MBL-100 and an Amigo wired in parallel with a relay arrangement so only one can be powered at a time. Makes for quick (OK, dirty, but efficient) changeover when one fails. I run the MBL-100 as primary; the Amigo as secondary 'cause I subjectively like the sound of the older unit best. I do run them with the most constrained bandwidth they'll do - not for any digital reason, rather for the "reach" that gives the signal. In the situation audio quality is NOT important; it's a matter of putting service where there otherwise would be none. We run a kilowatt FM for the quality-conscious listeners who live in close.

If you're searching the various used equipment lists look for both MBL-100 and Amigo; they're essentially the same and I think your chances of finding the latter might be better as the MBL is much older with fewer likely to have survived. DO NOT buy one with a bad power supply unless you plan to invent a replacement that likely would have to be external to the original chassis.

 

[W1DAN]

Hi VelvetR and all:

Yes I am surprised at the prices of the Orban processors have stayed up there as everyone now is using digital, but there is some reason for it as it was the ultimate analog processing of the day. Yes today's digital boxes are cleaner and louder, which should have dropped the prices of the older gear drastically. My main interest is HF SW processing where the 9105A and the MBL-100 (designed specifically for HF BC) go for that extra inch of loudness in exchange for cleanliness.

I quickly compared the Amigo and the MBL-100 manuals. The Amigo AM has a stereo path and HF boost defined around the NRSC emphasis, versus the MBL-100 is a mono unit with more aggressive HF boost for more limited bandwidths (i.e. 4.5kc). The MBL-100 was designed specifically for HF SW broadcasting (the first contract was RFE/RL), whereas the Amigo seems to have been designed for domestic AM broadcasting, with the ability to do SW BC if needed.

The Orban 9105A (a derivation of the 9100A) is a louder box with a little more "finesse" of the audio. More careful audio curve design, clipping and more bands of limiting. Yeah, I'd go for an MBL-100 with dead power supply if cheap enough. Maybe I can clear it off someone's shelf. I would also do dead Optimods.

Fun to search for and study these units.

Thanks for everyone's input!

Dan

 

[VelvetR]

The Amigo I bought...and that was many years ago when they first were sold...was almost exactly like the MBL except for a very few tweaks. Definitely a mono unit. It's possible that the manual for the as-built version somehow hadn't caught up with reality or that perhaps the sales literature hadn't quite captured the reality. Something along that line could explain the (small) subjective difference I perceived between the units which led me to prefer the MBL and use it as the primary with the Amigo as a backup. So far as coverage went the two proved pretty close to identical. Again, subjective. For people looking for "reach" over audio quality I still believe the two are interchangeable.

In any case, there's almost 1,000 miles between me and the units (the manuals, too) and it's not worth what it would take to get at either to make any further comparisons.

 

[speakerman]

Here is likely the least expensive choice. I was able to get it to work on the bench with my SSB exciter however the computer picked up my full-power RF field when running the 1kW amp and it immediately crashed.

I use other analog stuff in the audio chain and have not played with it since the initial test.

RF speech clippers work very good at raising the average RMS without any time constants involved. A lot of folks roll their own
using old Collins mechanical filters and a few ICs.

http://www.dxatlas.com/VShaper/