Stereo maXX ® MYB-2


User Manual

Model MYB-2
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Due the none or little detailed info on the web about this old “work horse” stereo enhance unit (now seems to be discontinued after about 24 successfully years on the analogue broadcast media) I decide to present you my Stereo Maxx unit for those who still interesting for this first dedicated unit only for broadcast media without “thief” the mono information as others similar studio units of old time. As you already now this method of spatial enhance with some modifications and additions is on all big brand processing boxes as software of curse, they call it simply “maxx” or “diffuse” or SX or something similar.


I hope to find this presentation helpfully especially for those who by the unit from a econd hand market as this unit now is discontinued? belongs to history as one of thrilling units together with Optimod 8100A1.



The story began long time ago at about 1975 when the founder of Modsci Mr. Eric Small cooperates with Mr. Bob Orban on design of Optimod 8000 until the early of 8100 on 1981 (then come Mr. Greg Ogonowski). Eric also help on design of the AFC Fm filter Card or Card #0 for 8100A1, this extra filter protect the subcarriers i.e. SCA or RDS from the “splatter” of safety hard final clipper, it also reduces any residual overshoot by about 6%. Actually this Card # 0 has the same effect as an Composite Clipper.


Here what Bob Orban says about this cooperation trough the history of Optimod 8000.

A strange coincidence? : Stereo Maxx of Eric's and Bob’s 222A Stereo Spatial Enhancer have “very similar” topologies except the digitally delayed L-R audio on Stereo Maxx. The Stereo Maxx for first time introduced on broadcast media at 1985, the Orban 222A at 1988.


What’s all about?

Want to know what is that? With details? Here the User Manual but only the document which explains everything directly from the manufacturer of Stereo Maxx. Unfortunately I do not have permission to publish schematics or diagrams (it’s a company policy) but you can downloaded it from Modsci website Here.
You must be a registered user to have a password.

To reading this manual is a must not only for owners of “maxx” but and for all who want to learn about the stereo spatial enhancement principles. Always a detailed service manual of any processing unit is the best way to learn, except if the designer is some how secretive :-) opposite, just for example everything I learn about processing issues is from the manuals of Bob Orban, which gives plenty of his (knowledge) genius mind is more open and helping than others modern radio audio gurus which currently use his ideas & inventions. Probably without his and others great passionate purists contribution (cornerstone) the sound of broadcast media will be suffer from Low Fi? results.


I really need this or other brand Spatial Enhancer?

Actually Yes & Not. The Stereo Maxx by himself did not solving you any separation problems. Like other similar units simply add an effect an illusion that the stereo image is larger than life :-) "is more noticeable on cars and not on headphones" with its “pro and con” so it’s a matter of taste to use this or other brands stereo spatial effect.  


If you thing that your overall on air stereo image Is not so wide & solid as others on air radio stations, first thing to do is to make a detailed separation test, from console trough exciter including STL & Processing Box. Or you must need to upgrade all your audio side chain (if it’s old) including the Tx path i.e. STL fm exciter etc.

My results & opinions

I use this unit for about 7 months; it was ahead of my upgraded Optimod 8100A1/XT2 (XT2 is back on its original first XT version with split band 5 from 6) Soon I discover that actually I don’t need such effect on my audio side chain, never I like to use the “depth” control which it was always close because I notice some strange audible side effects especially on solo recordings i.e. piano, at the end of each note I hear some noise which is added from digital delay effect of the unit.

Else is an very durable constructed unit with excellent parts on audio path i.e. Silver Mica capacitors, Tantalum by pass capacitors, precision metal resistors, bulk mains transformers, split power supply for Digital’s, all the pots are sealed type high quality BOURNS, excellent way of metering, for enhance & limit of L-R VCA a fine 2151 type from DBX, in digital domain use excellent A/D converters from Analog Devices & Siliconix.

As a line buffer the unit sounds pretty good did not alter the quality of in / out audio, is much better with an optionally electronically balance out circuit rather than good Jensen audio transformers, for any isolation problems is the best solution.

Stereo Maxx is co operate harmonically with every kind of known processing on air audio. But beware do not overdoing it. With too high L-R enhancement will suffer the mono compatibility of your station.
As any gear on processing world I must remind you the golden rule “Less is More”. Good luck.



MYB-2 On The Bench.


MYB-2 Inside Look.

MYB-2 Front Close Up.

A close up photo of the in level status Led's & bypass switch which has a warning flickering led when the process is out.

Myb-2 Inside

An overall look of the face plate & internal PCB, on the left the two different main's transformers one big for analogue path & small for Digital’s. In the right chassis bottom the line out Jensen’s audio transformers.

MYB-2 Pots

This is the recommended position for the best enhance in all stereo programs material.

MYB-2 Led

The perfect & genius accurate meters, at this time shows that the stereo program which feed the MYB-2 has already contents very wide music (super wide recordings) the automatic width limit circuit detects it and immediately defeat all the enhancements.
If one channel is on air L or R you must expect the same display activity. Else (this not shown in photos) when the input is Mono i.e. presenters mic no enhance is occur the meters show this activity, with "no one led lit" except that the centered led is "on" to show this and all the enhancements processing immediately are defeated again.

MYB-2 Inside

A close up of internal PCB, in the front panel is the sealed high quality pots by BOURNS. No one manufacturer in now days use so high grade parts any more. All use cheap Japan type, this unit come from the golden analogue era when the "men's is really men & women's really women”

MYB-2 Back