Mismatched preamp and CD player?

georgelofi has the best low cost solution.

" What is likely causing too much system gain?  This gear has been used together before (not the MMGs but other Maggies) and I don't recall the problem."

Its not that any one component has too much gain as a design flaw, you just have to be careful when you match components. In your case, the 3.6's are a much more difficult load to drive than the MMG's. Your line level amps needed to deliver a lot more power to your power amp to get the same volume out of the 3.6's than your MMG's. This makes the volume control much more sensitive.

It's also worth noting that there is more than one way to fix this issue. If you know what you're doing, swapping out any one component can fix it. For you, that's not a practical solution, so that's why a passive volume control was recommended. In your case, this can also lead to a substantial increase in sound quality by eliminating your active line stage (the GTP-500). Doing this should help with whatever brightness issue you have, that still remains after the speaker are broken in.

The Denon DCM-280 has a variable output. Just turn it's volume down to allow the Adcom preamp's volume control to go higher and not be extremely loud.

Thanks to all of you for your patience and knowledge.

So let's see if I have this right.

Onix XCD-88 goes into one of the two inputs on the SYS.  The tape out on the Adcom preamp goes into the other input on the SYS.  The output of the SYS goes to the Adcom amp?  Can the SYS sit on top of the amp as the preamp was originally designed to do?

If I decide to add a turntable, the turntable goes into the phono section of the preamp.  Will selecting tape out on the preamp send the phono output to the SYS and then onto the amp?

" Onix XCD-88 goes into one of the two inputs on the SYS.  The tape out on the Adcom preamp goes into the other input on the SYS.  The output of the SYS goes to the Adcom amp?  Can the SYS sit on top of the amp as the preamp was originally designed to do?"

Yes. Just think of the SYS as a 2 input preamp. Its just passive and doesn't process or amplify the signal in any way.

" If I decide to add a turntable, the turntable goes into the phono section of the preamp.  Will selecting tape out on the preamp send the phono output to the SYS and then onto the amp? "

Yes again. But as a future upgrade, you may want to get an external phono preamp and connect it directly to the sys.