Condenser Coupling or Direct coupling on Hitachi HMA amp?

[fazman]

I have a Hitachi HMA-8500 MKII Mosfet amp and matching HCA preamp...
On the back of each unit there is an option of either hooking them together via Condenser coupling or Direct coupling...
Can anyone tell me the difference between the two? and which one is the preferred hook up option?

Thanks

 

[ryuuoh]

What does your owner's manual say about the switch?

 

[bowtie427ss]

Direct is preferred if it plays ok with your other components that way. The capacitor/condenser blocks DC voltage. Some amplifiers are able to pass/amplify DC, just a small amount is enough to engage the protection circuit in some amplifiers making them unable to be used with a preamp that has DC leakage to any degree even tho it may be "normal" for the unit.

 

[wualta]

bowtie and inductor are correct.
Since the amp itself (a gem, IMHO) is DC coupled, you don't want any DC voltage at its input, for the reasons given. Since Hitachi had no control over what cockamamie bit of electronic flotsam you might take it into your head to connect to their wonderful amp, they gave you the safety option of sticking a nice DC-blocking capacitor into the audio stream right at the input.
If your preamp is up to AK standards, it doesn't put out any DC voltage along with its signal, thus there's nothing to worry about, and you can flip the switch to Direct and forget about it.
You might want to contact-clean that switch, if you haven't already done so. Failing that, turn off the amp and exercise the switch several times to make sure 30 years of atmospheric exposure hasn't affected it.