Question about the DYNACO QUADAPTOR

Hi,
I have been luckey enough to obtain some dynaco stuff at a yard sale on sat. Namely an st70 amp+PAS Preamp and a DYNACO QUADAPTOR. The preamp is not working at this time however the power amp works fine with my Ipod.

So I was hoping the resident experts here could help me with some info.

The DYNACO QUADAPTOR instructions indicate the it can be hooked up and will adjust the ouput level of the rear speakers. Will any harm be done by not hooking up front speakers? I want to run my CD player directly to the ST70 hook the amps output to the quadapter and connect the rear speaker outputs to my two speakers and the use the level control on the quadrapter as a volume control. then I will spend time rebuilding the preamp. Can anyone tell me if this is safe to do? Im not sure if it was designed to be used without all four speakers! I really just dont want to damage my speakers or my new (vintage) amp.

Thanks in advance!

The Dynaco Quadaptor depends on the impedances of all the speakers to "create" the pseudo-surround signals to the rear speakers. You can substitute appropriate resistors for the front loudspeakers.

Unfortunately, that won't work. The Quadaptor circuit wires the rear speakers to reproduce the difference signal between the left and right channels. All you will hear is the "ambience", not the main left/right outputs. These are only available from the front channels which have no level control. I would recommend ordering an attenuator from Bob Latino. That will allow you to use any source directly connected to your ST70.

Best Regards,
Charlie

As said above, the quadaptor will not work in the manner you describe. The pot on the quadaptor unit does not pan the volume back and forth between front and rear speakers. The pot will adjust the volume of the ambient sound in a rear set of speakers in relation to a front stereo pair. It will not pan the volume down in the front pair of speakers. Try hooking the quadaptor up as it was intended to be used and you might find it pleasently extends the sound stage of a stero pair of speakers - but don't expect it to create a four channel or surround sound system as it was never intended to do so.

Thanks everyone for your replies. I was just looking for an interim solution and rather than buying things like attenuators Id rather put the money into repairing the preamp. To that end I have ordered the parts to replace the zenier diode and caps and have found a "Ham Guy" with a tube tester that will help me verify the tubes. Thanks again!!!