126mhz Posted April 1, 2005 Share Posted April 1, 2005 I've been able to get all my dumb questions answered so I thought I'd run this one by the group. I have two Carver M400 "Cube" amplifiers that I have had completely redone by Rita at Carver/Sunfire not too long ago. For those who are familar with these amps they have both Stereo and mono modes that can be changed with the flip of a switch. Sooo, if I want to run them as monoblocks I can switch them to "Mono" and run only one channel of each into my Preamplifier? (This is a question not a statement) Since these amplifiers have both Mono and Stereo modes I should be able to run both the right and left channels into a RCA 2 into 1 adapter to the preamp right? (again a question not a statement) Please let me know what you guys think. Thanks again all, Bill Woodward Quote Link to comment Share on other sites More sharing options...
artto Posted April 1, 2005 Share Posted April 1, 2005 The answer to your first question is yes. It's usually the left channel that becomes the active input/output for the amp. Regarding your second question, some power amps are different. From my experience, when a stereo power amp is strapped for mono operation, usually a 2 to 1 interconnect cable/adaptor is not required. However you should observe the manufacturers recommendations. Usually in this type of setup, you simply run a standard interconnect from each preamp out to ONE input on each power amp, usually the left channel. The speaker outputs are usually derived from the left channel also. However some power amps may derive their speaker output from, say, both of the hot outputs from each channel when run in mono mode. In either case, if you dont really need the power output, then you should be aware that boot-strapping a power amp to monaural mode usually results in the combined noise and distortion of each channel, basically doubling both. So sometimes its just better to run one channel from each amp if you want true dual mono operation. Quote Link to comment Share on other sites More sharing options...
126mhz Posted April 1, 2005 Author Share Posted April 1, 2005 First thank you for the information. As I do this there's no chance of doing damage to the amps is there? Thanks, Bill Woodward Quote Link to comment Share on other sites More sharing options...
artto Posted April 1, 2005 Share Posted April 1, 2005 Well, with Carver there may be, which is why I recommend reviewing the owner's manual or contacting the company service dept/rep. Bob Carver's designs are not exactly known for their reliability or ability to be "user-proof" like say, Crown amps. Most of my solid state amps are Crown. The "D" series amps for instance use the left channel input and output in mono mode. The SA/PSA series use the left channel for input and the the "hot" outputs of both channels for the speaker, specifically the positive (+) lead from the load (speaker) going to the left channel hot, and the negative to the right channel positive on the amp. So as you can see, not all amps are the same, even from the same manufacturer. Quote Link to comment Share on other sites More sharing options...
scriven Posted April 2, 2005 Share Posted April 2, 2005 The M400 requires the source signal to be feed to both sides in mono mode. (At least the two I have require it!) Quote Link to comment Share on other sites More sharing options...
126mhz Posted April 2, 2005 Author Share Posted April 2, 2005 Hi Mark: I appreciate your reply but I'm not quite sure I understand. I believe you are saying that the M400 will need me to feed BOTH channels into my preamp,....Then at the preamp have them going into the pre with a RCA jack that feeds all four channels via a RCA 2 into 1 adapter? Thanks again, Bill Woodward Quote Link to comment Share on other sites More sharing options...
scriven Posted April 3, 2005 Share Posted April 3, 2005 Bill, Sorry I wasn't clear. The M400 runs the right channel inverting and the left channel non-inverting. In normal stereo mode the right speakers + terminal is connected to the amps ground and the speakers - terminal is connected to the inverting output. In other words the right speaker is connected out of phase. Since the right channel of the amp is inverting this reverse hookup causes the right speaker to be in phase with the left channel. The left channel works like you would expect, no inversions or backward connections. When you want to run it as a 400-watt amp you need to send the input signal to both the right and left channels of the power amp. E.g. for the left channel run the left channel preamp output through a Y connecter to both the left and right channel inputs of the M400 that is acting as the left power amp. Make similar connections with the right channel and the right channel M400. The speaker is then wired with the - terminal connected to the right (inverting) speaker connection and the + terminal is connected to the left (non-inverting) channel output. Note: in this configuration the speaker is NOT connected to the M400 chassis ground! I hope that is clear. If not please send me an email. I will see that quicker than a forum post. Quote Link to comment Share on other sites More sharing options...
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