Matching preamp to amp

Hi Dave,

A preamp SHOULD have the ability to swing far more voltage at its output than the full power sensitivity of the power amp. The output voltage that the preamp WILL swing is not dependent on what it CAN swing.

Your volume control setting will be dependent on the gain of the preamp, the output voltage of the source component, the gain of the power amp, the sensitivity of the speakers, your listening distance, the dynamic range of the source material, and your preferred listening volume. The maximum output voltage swing that the preamp is spec'd for is not normally a factor in any of that.

If you are saying that the CAT is spec'd as having a MAXIMUM output voltage swing of 7 volts, that is probably near the low end of typical and is most likely not a concern. It is the gain of the preamp that might be a concern, if it is high and you are using a source component that has a high output level, such as most cdp's.

If that is the case, and you find yourself using the volume control at very low settings, you could use a Rothwell attenuator in series between the preamp and power amp.

Regards,
-- Al

Hi Al,
Thanks, that is what I think I need.
DaveyF

CAT rules! It could work either with SS or tubes almost all brands you can ever imagine. The key trick is its low output impedance. Yet it doesn't have the best possible maximum output voltage as it could reach in certain units upto 20V.
If the pre's output impedance is too high compared to the input impedance of poweramp than the output impedance becomes a part of circuit and divides voltage(i.e. eats a portion of such) passed onto the next stage.
Example: if your output pre impedance is 1kOhm and input impedance of amp is 10kOhm than 1/10th part of passed voltage is lost 'without reaching' the input of amplifier.

You shouldn't have any problems driving the D-70 with the CAT. Maximum output on your CAT is more like 50 volts which is the same as preamps from Audio Research.

Rrog, I am not worried about the fact that the CAT has enough output to
drive the ARC, instead I am concerned that it has way too much output.
The ARC is rated at 0.95 volts to drive it to full power... Since the CAT has the ability to drive 50 volts, I am concerned that even the slightest turn of the
volume control on the preamp will overdrive the amp /or the amp will be at full power. BUT, looking at the other responses, I suspect that it will be ok, once the amp is up and running we shall see and if not, then i think Almarg's suggestion should work.