kevco Posted October 5, 2009 Share Posted October 5, 2009 I have just added an A/B switch box to my system that for the first time will allow me to play my Marantz 2275 receiver through my new Forte II's. The speakers have been pushed by my modded Dynaco ST70 for about a month with great success. The 2275 is a pretty old girl and has served me well since an extensive recapping about a year ago. It has never seen high efficiency speakers though. I noticed pretty quickly that it's available power will drive the Fortes to unbearable levels with only a moderate spin of the volume knob. It's pretty obvious to me that the soundstage is balanced to the right side a bit. Lead vocals seem to eminate from the right of the soundstage on pieces where I know it to be centered. The sound, while not as smooth and detailed as the tube amp is good for rock music, and the extra power delivers tighter bass response than the Dynaco. When I switched back to the ST70 the sound was once again centered as it should be. The Marantz is obviously the culprit. Even a slide of the balance knob did not equalise the sound. The volume seems to be equal between the channels, yet placement of vocals and some instruments in the soundstage is skewed to the right. I never noticed this effect before with this unit, but then again it was never coupled to such fine speakers. Anybody have any thoughts as to what may need to be addressed? I tinker a bit with the simpler circuits of tube gear, but solid state repair is probably out of my scope. I am capable of changing capacitors however if I know which ones I'm after. A $300 bench test and repair bill is not yet in my budget, but if that's what it takes...All ideas greatly welcomed. Quote Link to comment Share on other sites More sharing options...
Don Richard Posted October 5, 2009 Share Posted October 5, 2009 Try shaking the speaker wires where they connect to the receiver one at a time, and see if there is any change. there may be a bad connection inside the receiver. If no change, try swapping the speaker wires left to right and see if the problem moves to the left side. If the imbalance stays on the right side, there may be a channel balance issue inside the receiver. Could be switch contacts - operate all of the switches several times with the volume low. If that has no effect it sounds like a shop job. Quote Link to comment Share on other sites More sharing options...
kevco Posted October 8, 2009 Author Share Posted October 8, 2009 Try shaking the speaker wires where they connect to the receiver one at a time, and see if there is any change. there may be a bad connection inside the receiver. If no change, try swapping the speaker wires left to right and see if the problem moves to the left side. If the imbalance stays on the right side, there may be a channel balance issue inside the receiver. Could be switch contacts - operate all of the switches several times with the volume low. If that has no effect it sounds like a shop job. Thanks! There's always something I haven't checked....One of the old spring bindings had bit right through the copper of my speaker wire to the center plastic tubing causing a diminished contact. A new pair of pin post plugs on the wire and all is balanced! I tip my hat, sir! Quote Link to comment Share on other sites More sharing options...
WMcD Posted October 8, 2009 Share Posted October 8, 2009 I'm glad to hear you've experience the excellent performance of the F2s. As far as the problem: I would check the polarity of the wiring to the speaker to see if one is reversed. Sometimes, but not always there is a reduction of bass, and that is a tell -tale. But with a given room, wide placement and the magnificent bass of the F2, I wouldn't be certain. Only if the speaker boxes are very close to each other you will hear the bass go down in some circumstances. I've experienced some odd imaging with out-of-polarity speaker feed. The center image is sort of okay but not quite correct and solid. Then you move your head a bit left and it gets different and maybe better in some ways; then you move your head to the right and again it is different and better in some other ways. So you go back and forth through the center of your listening sweet spot and something is wrong in all cases. OTOH, maybe you do have a technical issue with the amps. I'd suggest listening to them with headphones (they need not be of very high quality) and see if that shows up an issue. Best, Wm McD Quote Link to comment Share on other sites More sharing options...
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