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A-136 full- and half-wave rectification

2006-11-01 by Tim Stinchcombe

Hi list,

I only just discovered all this chat about full-wave rectifying etc., 
and what the A-136 can/can't do, so I'm arriving to the party a 
little late I'm afraid!

Yes, the A-136 can do this, but as Jari pointed out previously, it 
requires some very careful knob twiddling. Here is what I did:

1. Fed a sine wave into the input - the amplitude is deliberately 
kept below about +/-2V, as otherwise the first stage in the A-136 
will clip it.
2. Inserted patch cords into the 'ext level' sockets: the other ends 
are not plugged in anywhere else, and simply act to keep the '+L' 
and '-L' levels from interacting at all.
3. Adjusted all three 'A' controls to get the minimum out - this is 
to get the 'A' gain at the (electrical) centre-spot (care must be 
taken not to touch this again!).
4. Adjusted '+A' and '-A' in opposite directions to get full-wave 
rectification: half-wave is obtained by setting each of these to 
zero, in turn.

If this was going to be a regular occurence, it would probably be a 
simple matter to modify the module with a few switches to 
connect/disconnect stuff, and to put gains at precise settings.

I've posted some scope traces in the 'files' section, folder 'A-136 
rectification'

Tim

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