The Mystery of the Modified Blonder-Tongue Audio Baton. Can you solve it?

[bryansw]

I realize this is a very old thread and I apologize for bumping it up. I had a couple of these units back about 1997, purchased from eBay. When I received them (and I knew this) they were in a very bad state. Parts, of course, had decayed, but someone had made modifications similar to what was shown in the first picture. Mine had some of the pots for the upper bands punched out and a tube socket in it's place, as well as several modifications. I ended up removing all of the parts save the original sockets, as many of the potentiometers as I could save, and some of the other hardware (transformer, light bulb sockets, etc.) They were completely rebuilt with modern components, and the messed up pots were fixed by soldering washers with the correct diameters into the extra tube socket holes. The second unit was just a chassis, so it went into a SES-COM rack case. I think I still have a few of the barber poles for it.

I was never able to figure out what was going on with these things, or what the modifier had intended. I now assume, since the ones here had similar modifications, that there was some sort of article or publication somewhere that detailed making modifications to these units.

If you want to see the results (sorry, no digital camera back in 1997 so all I have is film prints) and a schematic, I made a small post about that on a small personal site:

https://pygg.xyz/projects/index.php/2022/04/14/1959-blonder-tongue-audio-baton-graphic-eq-rebuild/

and the Sams folder, 600DPI scans:

https://pygg.xyz/projects/index.php/2022/08/31/blonder-tongue-audio-baton-bt-b-9-schematics/

I don't think the sites are rate limited, but if posting another URL like this isn't good, I can upload the schematics and images as files. I'm actually trying to locate them (the units,) I'd like to see if they're still in operation.

 

[EL504]

Attached is the "BBC AM1/11 Octave-Band Response Amplifier", which is clearly a modified version of the Blonder Tongue Audio Batton (or was the Audio Batton perhaps the modified version of the BBC AM1/11?). Main differences: It has an input transformer and an output transformer driven by an 8D3 (= 6AM6 = 6064 = EF91).

The schematic contains a mistake: C14 and C21 should be 0.00161 uF instead of 0.0161 uF.

 

[bryansw]

Interesting, thank you for that. I suspect that's what mine had (at least someone attempted a similar modification) done to them. That's a 20-year mystery solved!

 

[bryansw]

The URLs for my links have changed, replace pygg.xyz with wereboar.com - the schematic link should automagically redirect you but just in case...

The other link for the pictures is still there, just poke around a bit in the April 2022 section.

I found out that .xyz domains aren't well liked for email, so it's just a placeholder until the name expires in 5 or so years.