View Full Version : L65A hard left sound stage problem...?

07-27-2008, 07:41 AM
I recently installed my re-roamed 122a woofers from Morgan Sound & re-placed all resistors w/ Mill mra12's, reason for the resistor replacement was 1 of the coffin types had gone open through corrosion, & not do to moisture, just some green crud that started on all of them internally. So out they went. all other N65A XO components are stock & test to spec. Problem is with any source or the 2 differant tube amps I have tried the sound stage is hard left..I switched the speakers around this mourning to see if it went to the right, it did not, still hard left,..... on any cd, radio, album, does not matter. So it is not in the recordings. Can not get a center image for nothing, all hard left. I have a schematic of the N65A XO & it shows for 122a that green is to to + on woofer & green/black is to neg. except these XO's only have a pure black wire, so I hooked black to neg. Is this a phase issue, since this problem does not follow the speakers..? I am stumped & bummed as these L65A really speacial sounding w/ my DIY tube amps. much better than I would have ever thought & they are not even running correctly, well just the stage issue..
Thanks J & G

07-27-2008, 08:00 AM
If it doesn't follow the speakers it could be the preamp, an amplifier or the source component. I would power it all down and make sure all your cable connections are good. Remote chance it could be a cable. Check your balance control if you have kids.


07-27-2008, 10:42 AM
I suppose I should try a 3rd amp. Both the 2 amps tried could have slight issues. I reversed phase on the OT's of my DIY tuber & that did not fix it eaither. I suspect it is a slight spl differance in one of the channels, I know through experience it does not take much to swing it one way or another. When I used to build DHT amps I could straighten out a stage with pin piont accuracy by just ever so slightly adjust the filament voltage & or current & this was minute amouts of adjustments.I could swing it L or R at will. Glorified balance control it was. I will switch tubes around next in the SE amp. It is a simple 2 stage amp so shouldn't be hard to see if that is the culprit. If it is not, a seriouse challage awaits me..
Thanks J & G

07-27-2008, 11:20 AM
... another amp. I would go so far as using an integrated amp or receiver, just to remove ALL your usual components from the loop. I would also try swapping the L and R outputs of your source and see what happens.

I have had a similar experience as you, when tuning up a speaker with better parts, bringing it back to spec one would think, I found that any and all the problems in the system jumped out at me all the more. Actually, rather an obvious result... Duh!

I also have had a similar problem for years, a moderate pull to the left channel, regardless of what I do. Then I read that people are left or right "eared", as in handed, we tend to use one ear more than the other. Same thing with our legs/feet and our eyes :blink: . Supposedly we go with the opposite of our hands, so if you are right handed, you will be left eared. Whether or not this is actually a factor, I do not know :(

Good luck, in my experience the image always is dominant in the left channel, as if things are mixed that way on purpose. I do get a good center image, given a good source, so I would think you may have an equipment problem.

I recall a famous solid state designer, when asked why he did not use tubes, say they don't measure the same from day to day. So borrow a solid state receiver from a friend, slap in on those speakers, and see... er, hear what happens. You won't have to put up with the sound for long, think of it like an annoying medical examination... like for colon cancer... ;)

07-27-2008, 12:07 PM
Just abit ago I wipped out my tester & flipped the 27/6l6g SE amp & tested every part, all were perfect, or very close to it. then I had a brain storm,............. what if it is the freakin tubes....? duh,,,, so I switched the 27's around & fired it up, instantly straightend up the center image. My tester does not support 70-80 year old tubes *s*, so I depended on them bieng NOS or just hopefull thinking. dang,, I can't believe I did not try this 1st.. I got a good sunday workout trying everything else before the obviouse stuff...dang tubes......love em though, except on these occasions. The other amp a 300B PP amp I am sure is way off on bias by now & is on last leg with the tubes in it, so I am sure that amp was off too. Thanks for all the help.
J & G