[charmerci]

First, with the output that has the Y-adapter you can compare the sound through the one speaker with the sub disconnected versus connected with the sub input level set to "0" and see if you can tell on this system if the combined imput impedance has any effect on either the frequency response or the output level.

Steve

Best advice above IMHO.

It's an Odyssey pre-amp and an AVA amp. I can't hear any difference.

Thanks for the responses/help!   

[James Romeyn]

Good for you! 

I've seen a lot of sub amps, and looked at the input impedance of many.  Most are low, 10k or so.  The sub amp parallel with the power amp yields a sum total impedance less than the lowest of the two, often requiring too much current from the preamp (similar to a speaker impedance being too low for a particular tube amp).   

IMO your setup is an exception to the rule.  One or more of the following must apply in your system (beware to retest as above if any of the following components change):

Your preamp output current is higher than average
Your sub amp input impedance is higher than average
Your hybrid amp input impedance is higher than average (usually tube input impedance exceeds SS)

[charmerci]

Good for you! 

I've seen a lot of sub amps, and looked at the input impedance of many.  Most are low, 10k or so.  The sub amp parallel with the power amp yields a sum total impedance less than the lowest of the two, often requiring too much current from the preamp (similar to a speaker impedance being too low for a particular tube amp).   

IMO your setup is an exception to the rule.  One or more of the following must apply in your system (beware to retest as above if any of the following components change):

Your preamp output current is higher than average
Your sub amp input impedance is higher than average
Your hybrid amp input impedance is higher than average (usually tube input impedance exceeds SS)

Well, I've just sent an e-mail asking the input impedance of the sub amp. Odyssey doesn't seem to receive/want to answer my e-mails and AVA stuff is pretty robust (designed to deal with non-optimal conditions) so I think I'm pretty safe.


Right now, I've got the sub's output level at about 1/6 so it's hardly straining in the least.

[James Romeyn]

Well, I've just sent an e-mail asking the input impedance of the sub amp. Odyssey doesn't seem to receive/want to answer my e-mails and AVA stuff is pretty robust (designed to deal with non-optimal conditions) so I think I'm pretty safe.


Right now, I've got the sub's output level at about 1/6 so it's hardly straining in the least.

Where a system (or sub in your case) operates in its power envelope is a function of overall gain, which includes volume control position and other parameters.  IOW, depending on parameters, your sub could be lower in its power envelope with volume set to maximum vs. different parameters with the volume set just above minimum. 

You can not judge where a system operates in its power envelope by looking at volume control setting alone.  It's funny how strong and long lasting is the myth of determining where a system operates in its power envelope by looking only at volume control setting.

Other items: the closer a system operates to it's dynamic limit the less is its dynamic range.  Also, the longer it operates near its limit, the less is its dynamic range over time.