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Mystery Audible Illusions MX2B Head Amp

Z

Ziconceo

New Member
Hello! I recently acquired this interesting piece of gear and can find absolutely nothing on it! No specs, instructions, history, anything. I contacted the company about a month ago but never got any response.

I replaced and upgraded everything inside (the last pic was mid upgrade) but have no idea how to set any of the switches for proper function and I'd rather not break something by messing with them.

Appreciate any info on this in advance :)

IMG_20250124_122624663_1.jpgIMG_20250124_122642593_1.jpgIMG_20250124_141913457.jpg
 
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The four pot of switches are probably loading resistors to adjust for different cartridges.
You can see the traces go to those resistors. This can be adjusted to correct value by listening.

The other switch on each channel might be gain as it is close to the transistor but IDK about that.

Are those two transistors the only active parts? Are they just single transistors? Do they have numbers/labels?

Orion says 1977-1982, $250.
 
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1977-1982 may have been before Art Ferris took over the company ( I seem to recall he was a rep for them before that)
If you do manage to get through to AI those days that’s gonna be Art.
 
Blue Shadow said:
The four pot of switches are probably loading resistors to adjust for different cartridges.
You can see the traces go to those resistors. This can be adjusted to correct value by listening.

The other switch on each channel might be gain as it is close to the transistor but IDK about that.

Are those two transistors the only active parts? Are they just single transistors? Do they have numbers/labels?

Orion says 1977-1982, $250.
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Amazing!!!!! Thank you!!!!!
 
Ziconceo said:
Amazing!!!!! Thank you!!!!!
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I will go and open the Head amp and get those numbers for ya. Think they are op-amps if I recall (they were marked). Edit: I was wrong, opened it up and they are : LM394BH super matched pairs of NPN transistors.
 
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Ziconceo said:
How on earth did you get that so quickly
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It is easy with the proper resources.

1) a copy of the orion blue book of used audio gear got the dates book can be found on the bay at times. Annual till late 90s-early 00s when they went digital. I have a 95 or so edition.

2) WRH has searchable on their site pdfs of a number of hifi related magazines and with knowledge of their names, Audio, High Fidelity and such and which issue is the buyers guide, I just opened the 1980 Audio magazine buyers guide issue and looked at the preamps section. Later searched and I got lucky as it didn’t show up in other places.
 
Blue Shadow said:
Someone that understands circuits could probably tell you if the voltage controlled variable amp application is used in this application and if that other switch might be gain control.

datasheet from Digikey

LM194, LM394 Datasheet by Texas Instruments | Digi-Key Electronics

View datasheets for LM194, LM394 by Texas Instruments and other related components here.
www.digikey.com
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I could probably hook up my function generator with a 0.5mv signal to the inputs and see what my scope says on the other while I flip the switches (turning the power off in between switching) to see what happens I suppose :)
 
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