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Author Topic: How to mono an amplified stereo signal Richard May Phenomenal Film Handler Posts: 1057 From: Floral Park, NY USA Registered: Aug 2004 posted 08-26-2007 01:20 PM                     This is actually for music outside of a building. I have 2 speakers that are fairly far apart. How can I mono the left and right amplified signals to these speakers to eliminate the stereo effect. I'm using an amplified tuner with left and right outputs. There are no controls to mono the signal internally.  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 08-26-2007 01:32 PM                     It is odd that there is no "mono" button on the tuner as that often is a way to improve the quality of a weak signal. Anyway...there are several way to mono up a signal. You can try to use a simple "Y" cable but since the tuner's outputs are bound to be low impedence, it is possible that it won't want to see the "other channel's" low impedence output. The way around that is to use resistors. Odds are that anything over 1K will work (I'd start with 4.7K). Alternately, you can go the active route and use a summing amplifier available from many different sources like RDL. Steve  |  IP: Logged John Hawkinson Film God Posts: 2273 From: Cambridge, MA, USA Registered: Feb 2002 posted 08-26-2007 04:42 PM                     See Rane's technote, Why Not Wye?. It provides some simple schematics. --jhawk  |  IP: Logged Bruce Hansen Jedi Master Film Handler Posts: 847 From: Stone Mountain, GA, USA Registered: Dec 1999 posted 08-27-2007 11:41 AM                     DO NOT ever connect two speaker outputs together. They WILL blow each other up. You may be able to sum the two speaker outs with 8 ohm (or 10 ohm) resitors. This will cut the output level a little though. Use power resistors that are about the same power as the output of the amp.  |  IP: Logged Larry Zuverink Film Handler Posts: 98 From: Caledonia, MI, USA Registered: Nov 2002 posted 08-27-2007 01:26 PM                     Richard, I'v used Speco(not the platter guys)TSM-30's for years. They work great. You can get them online for less than $15.00  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 08-28-2007 06:12 AM                     Wait a minute...I might have missed a key element in this problem that Bruce hit upon...are you saying that you do not have access to the tuner signals directly as they come off the tuner stage and only the amplified outputs? If so, Bruce is dead on in that a resistive/inductive solution is your best bet. The problem with pure resistive is that you will affect the damping factor significantly and will likely have exaggerated bass as a result. Steve  |  IP: Logged Larry Zuverink Film Handler Posts: 98 From: Caledonia, MI, USA Registered: Nov 2002 posted 08-28-2007 06:57 AM                     Steve, I also missed that it was speaker level. The TSM-30 is for line level.  |  IP: Logged Louis Bornwasser Film God Posts: 4441 From: prospect ky usa Registered: Mar 2005 posted 08-28-2007 02:03 PM                        At one time you could buy a 3 winding transformer. 2 primaries for the amp outputs and one secondary to feed mono to any number of speakers. Don't know if this is still made, but 2 individual transformers may work also. Louis  |  IP: Logged Phil Hill I love my cootie bug Posts: 7595 From: Hollywood, CA USA Registered: Mar 2000 posted 08-28-2007 03:44 PM                  The TSM-30 is speaker level.  |  IP: Logged Larry Zuverink Film Handler Posts: 98 From: Caledonia, MI, USA Registered: Nov 2002 posted 09-04-2007 12:24 PM                     Your right Phil, I get more confused every day.  |  IP: Logged

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