Connecting C28 to power amp...

[bystander]

The C28 preamp as two sets of main outputs labeled left, center, right.

It also has one set of line outputs labeled left, right.

Which outputs (two channel, I only need left and right) should I use to connect to the power amp? Or does it make any difference?

thanks in advance...

 

[kcollins4]

Owners and serice manuals here, which should help. I have a C28 also, but I've never had a chance to play with it (yet):thmbsp:

 

[bystander]

Excellent, thanks Kevin! Per page six of the owner's manual, I will use the main outputs, left and right.

Hope you enjoy your C28 too!

 

[dshoaf]

Yes, there is a big difference between the Main Outputs and the Line Outputs - but not sonically if the preamp is up to spec.

Main Output jacks, L/C/R: These are the ones you'll normally want to connect to when using most power amps. The output levels of these jacks are controlled by the Volume Control on the front panel and by the Trim controls on top of the preamp. The Center output jack is just a sum of the L/R channels.

Line Output jack, L/R: These are driven by the internal headphone amplifier, which also presents it signal at the Headphone jack on the front of the preamp. What makes this headphone amp unique is that it is a ~2.5wpc Single Ended Power amp built into the C28! This means you can hook up a set of very high efficiency speakers directly to the Line Output jacks and expect to get some decent sound out of it. When you read the Owner's Manual, however, you will learn that Mac recommends the use of the Line Outputs when driving long runs of cable to a power amp located elsewhere in the room. Also note that the Line Outputs have Trim controls on the top of the preamp that are called, Headphone Level.

Lastly, these two Output paths are driven by separate power supplies inside the C28. This means that you can have used the standard Main Outputs for years and never know that there might be a problem with the other Headphone/Line Output path unless you tried to use the headphones!

See the block diagram that's on the top of the preamp to follow the above description.

Cheers,

David

 

[jameslrock]

Yes, there is a big difference between the Main Outputs and the Line Outputs - but not sonically if the preamp is up to spec.

Main Output jacks, L/C/R: These are the ones you'll normally want to connect to when using most power amps. The output levels of these jacks are controlled by the Volume Control on the front panel and by the Trim controls on top of the preamp. The Center output jack is just a sum of the L/R channels.

Line Output jack, L/R: These are driven by the internal headphone amplifier, which also presents it signal at the Headphone jack on the front of the preamp. What makes this headphone amp unique is that it is a ~2.5wpc Single Ended Power amp built into the C28! This means you can hook up a set of very high efficiency speakers directly to the Line Output jacks and expect to get some decent sound out of it. When you read the Owner's Manual, however, you will learn that Mac recommends the use of the Line Outputs when driving long runs of cable to a power amp located elsewhere in the room. Also note that the Line Outputs have Trim controls on the top of the preamp that are called, Headphone Level.

Lastly, these two Output paths are driven by separate power supplies inside the C28. This means that you can have used the standard Main Outputs for years and never know that there might be a problem with the other Headphone/Line Output path unless you tried to use the headphones!

See the block diagram that's on the top of the preamp to follow the above description.

Cheers,

David

I have wanted to use my B&O 4002 to play albums from the office system since it is an automatic turntable and then use SONOS to stream to the porch system. I used the line outputs from the C28 to the SONOS. I could not get the volume to work efficiently until I read your post. Many thanks. I turned up the headphone level all the way and now all is working at reasonable volume levels. Thanks.