2. amps-preamps
  3. 127576-91582

connecting mono amps to pre amp

Newbie here. I'm 56 and this past year and a half, I've  gotten back into 2 channel. Various amps/pre amps and receivers. I would like to know how to properly connect (2) Mcintosh 2120's to a Mcintosh MA 6100. Have several mac pieces as well as others. But seems Mac is kind of like BMW/Mercedes -European cars with the fact of over engineering or over features, for a lack of better words. Can someone shed some light here with regards to the MONO bloc connection on these? Thank You in advance!!

2channeladdicted
2channeladdicted OP
14 posts
 
the two 2120's can be run as mono i believe as stated in the owners manual with using the right channel only and then bridging the common?  last question when bridging the common on the amp you are using for the left channel speaker you would also bridge the common on the right channel amp you are using for the right speaker? In the 2120 manual it shows using 2 speakers with only one amp in MONO.  Sorry to sound so confusing but just want to make sure nothing gets FRIED!!!


tls49's avatar
tls49
1,351 posts
 
"then you would bridge the common/negative on the speaker terminals"

No, use "COM" terminal on left channel output to speaker negative, then if your speaker is 8 ohms, connect "16" terminal on left channel to speaker positive. Also, connect a jumper from "16" terminal on the left channel to the "16" terminal on the right channel.

Not sure why manual shows 2 speakers connected in mono operation, however I’m reading the instructions for my comment.
almarg's avatar
Ag insider logo xs@2x
almarg
9,670 posts
 
Thanks, Tony (Tls49). As you realize, my comment and the one by Mb1audio02 did not address the connections between the amps and the speakers, since they were not asked about by the OP. The manual you linked to indicates that for mono use the two channels on each of the amplifiers are paralleled, so what you stated in the last paragraph of your first post is correct with respect to the speaker connections. It should also be noted, though, that the tap which should generally be used (assuming the speaker’s nominal impedance rating is reasonably accurate, which of course is not always the case) corresponds to the nominal speaker impedance multiplied by two. In other words the paralleling of the channels results in what is designated as the 16 ohm tap becoming an 8 ohm tap, and what is designated as the 8 ohm tap becoming a 4 ohm tap, etc.

I would expect, though, that connecting the speaker to the appropriate right channel terminals and jumpering the right channel tap that is used to the corresponding left channel tap would work equally well.

Best regards,
-- Al

2channeladdicted OP
14 posts
 
Thank you all!!! You guys are a plethora of knowledge!  never have had the opportunity to utilize mono application in my younger years,,,,LOL. have a couple of tube amps that I'm using with a mac c26, but using those to bi -amp a set of paradigms so  a little different than trying to do the MONO thing. Thanks again!

almarg's avatar
Ag insider logo xs@2x
almarg
9,670 posts
 
You're welcome, 2channeladdicted.  Just be sure to keep in mind the following statement in the 2120's manual:
Should the MODE SWITCH be left in the STEREO position and the output transformers be strapped for a monophonic load, one channel will attempt to drive the other and cause circulating currents and overheating. Be certain that the MC 2120 is never operated in the stereo mode with the outputs connected for monophonic operations.
Regards,
-- Al
 
More to discover