george a

2002-05-06 1:12 pm
Hi All

I've been running a diy Pass A5 for a couple of years now, (with great joy)

Recently I completed my home made ribbon speakers and had connected them to the A5 via a 4 ohm resistor in series with the ribbon rather than use a matching transformer.
The ribbon is 26" long x 1" wide and operates above 650hz with a 48dB/oct crossover via a dcx2496 crossover.

The problem is this :
the amplifier output offset is abt 40mV- which when direct coupled via the resistor causes some ribbon deflection at no signal- but not enough to be a problem....other than a wobble.... music is played and the ribbon starts to move more or less randomly -but not in time with the music .-ie: it is not a regular or constant wobble.
I would guess its frequency is random and well below 1hz and even then its not constant - deflection woves with louder transients yes - but is still more of a wobble than anything.

Is the Aleph A5 prone to a "wobbly" or varying offset???

I have resorted to using a matching transformer to avoid the problem as the ribbon will deflect outside the magnetic gap when direct coupled.

oh and the wobble is still there if the dcx2496 active is turned off....

Sound wise though....:D:D:eek::)

Any comments or opinoions ?