How to fix 4343 speaker unbalance?

[pyonc]

Hi,

For the past several months I've been wondering about this issue:
why is the left speaker weaker than the right one? I couldn't find out why as I'm a beginner in this audioland.
I didn't notice this 'unbalance' problem initially because I played a CD or LP somewhat loud. Only recently did I feel the unbalance problem.
I asked our forum members for advice on this, and some suggested adjusting the L-pads levels and wiggling the crossover switch on the rear.
I tried as advised, yet the problem remained the same, fundamentally. Today, however, I think I found what's the problem after playing an audio test CD.
Initially I checked the volume adjustments of the L-pads, rasing the left speaker's UH, H, Mid levels at their highest. Initially it seemed better, but closer hearing, the problem remained the same. Finally, I decided to play the audio test CD (BINK AUDIO TEST CD), and I could feel clearly where was the problem: UH, H, Mid as a whole.
When I set the volume level of my preamp (Mcintosh C29) at its lowest and checked PINK NOISE, I still could hear from the right speaker the peculiar PINK NOISE loud, but a very, very weak one from the left, actually overshadowed by the right speaker sound. I switched the mode selector from STEREO to STEREO REV or to MONO, it's the same. So, is there any way I can fix it by myself or do I need a technican's help? Thanks for your kind guidance in advance.

[hjames]

I don't know that amp specifically, but did you actually swap the far ends
of the speaker wires from the left and right speaker?
Just to be triply sure that its the speaker at fault for the lower volume
and not some other issue like the amp or the wires or something else ...

Just trying to be thorough ...

Otherwise, I'd suspect bad contacts in the crossover switch -
seems to me I've heard of that being a known problems with the big 4-ways that have them.

Its one reason folks physically bypass that switch and biamp those speakers

Hi,

For the past several months I've been wondering about this issue:
why is the left speaker weaker than the right one? I couldn't find out why as I'm a beginner in this audioland.
I didn't notice this 'unbalance' problem initially because I played a CD or LP somewhat loud. Only recently did I feel the unbalance problem.
I asked our forum members for advice on this, and some suggested adjusting the L-pads levels and wiggling the crossover switch on the rear.
I tried as advised, yet the problem remained the same, fundamentally. Today, however, I think I found what's the problem after playing an audio test CD.
Initially I checked the volume adjustments of the L-pads, rasing the left speaker's UH, H, Mid levels at their highest. Initially it seemed better, but closer hearing, the problem remained the same. Finally, I decided to play the audio test CD (BINK AUDIO TEST CD), and I could feel clearly where was the problem: UH, H, Mid as a whole.
When I set the volume level of my preamp (Mcintosh C29) at its lowest and checked PINK NOISE, I still could hear from the right speaker the peculiar PINK NOISE loud, but a very, very weak one from the left, actually overshadowed by the right speaker sound. I switched the mode selector from STEREO to STEREO REV or to MONO, it's the same. So, is there any way I can fix it by myself or do I need a technican's help? Thanks for your kind guidance in advance.

[pyonc]

I don't know that amp specifically, but did you actually swap the far ends
of the speaker wires from the left and right speaker?
Just to be triply sure that its the speaker at fault for the lower volume
and not some other issue like the amp or the wires or something else ...

Just trying to be thorough ...

Otherwise, I'd suspect bad contacts in the crossover switch -
seems to me I've heard of that being a known problems with the big 4-ways that have them.

Its one reason folks physically bypass that switch and biamp those speakers

Thanks so much for your observation and advice.

As advised, I swapped the far ends of the speaker wires to the terminals, and surprisingly, the outcome was different.
With this swap, this time the loud, clear PINK NOISE came from the left speaker in question, not from the right.
The curret power amp is Adcom GFA-555, with preamp Mcintosh C29.
I did test this initially with Marantz amp, instead of GFA, with C29.

Another result from GFA-555, this time with GTF-400 preamp:

When in STEREO mode of GTF, the result was about the same with the GFA/C29.
In MONO mode, however, I heard about the same level of PINK NOISE from both speakers.

So, what's the issue here? No problem with the speaker itself? Any issue with the preamp?

Strange enough, I had the same result from my 4311 in excellent condition.
I applied the same test to my 4311, with C29 preamp.
You know what? The left speaker of 4311 is much weaker in PINK NOISE from the right one, just like 4343.
I'm not sure if it's the preamp or speaker issue, or any other issue.
It seems like the problem's not the 4343 speaker problem itself, as I initially suspected.

[rusty jefferson]

Thanks so much for your observation and advice.

As advised, I swapped the far ends of the speaker wires to the terminals, and surprisingly, the outcome was different.
With this swap, this time the loud, clear PINK NOISE came from the left speaker in question, not from the right.
The curret power amp is Adcom GFA-555, with preamp Mcintosh C29.
I did test this initially with Marantz amp, instead of GFA, with C29.

Another result from GFA-555, this time with GTF-400 preamp:

When in STEREO mode of GTF, the result was about the same with the GFA/C29.
In MONO mode, however, I heard about the same level of PINK NOISE from both speakers.

So, what's the issue here? No problem with the speaker itself? Any issue with the preamp?

Strange enough, I had the same result from my 4343 in excellent condition.
I applied the same test to my 4311, with C29 preamp.
You know what? The left speaker of 4343 is much weaker in PINK NOISE from the right one, just like 4343.
I'm not sure if it's the preamp or speaker issue, or any other issue.
It seems like the problem's not the 4343 speaker problem itself, as I initially suspected.

Man, you've got a lot going on here.

In your other thread, http://www.audioheritage.org/vbullet...his-4343/page2 I suggested reversing the speaker wires at the amplifier (left to right-right to left) to see if the problem moved to the opposite channel or stayed in the same channel. You said when you tried this the problem was still in the same channel. But when you reversed the wires at the speakers, (left to right-right to left) the problem moved to the other channel. This doesn't make sense.

Now, with the Adcom amp/preamp in the system, you still have the"same" problem unless you put the preamp in "mono", in which case all is well. (i.e. normal output from both speakers) Clearly, something is amiss. It could be your source device, interconnects, or preamp.

I suggest it's time to borrow some known to be working equipment from a friend, neighbor, relative, etc. and get it set up and working. Then, and only then, replace a piece at a time, until you discover the problem piece. If you install this equipment, and the left channel is deficient, then it's probably safe to assume the speaker(s) is the problem. Right now, I'd be suspect of all the electronics you have, until you compare them against properly working gear.

[BMWCCA]

Seems to me the telling sign is that you didn't notice a problem at higher volume levels.

It's not uncommon for older pre-amps to be un-balanced at lower levels. Many volume pots just aren't that well regulated at the lower end of their range, or they're dirty, etc. I've had that problem with several over the years; old Mac's and old Soundcraftsmen. The stereo volume pots are really ganged potentiometers and I've actually lowered the input attenuators on my amps to make sure that at a normal listening level my pre-amp volume control would be at mid-range rather than the bottom 1/4 of the range. That generally provides a better signal match for an amplifier, anyway. Seemed to work for me and a small price to pay for continuing to enjoy vintage gear without going overboard on restoration costs.

[pyonc]

Man, you've got a lot going on here.

In your other thread, http://www.audioheritage.org/vbullet...his-4343/page2 I suggested reversing the speaker wires at the amplifier (left to right-right to left) to see if the problem moved to the opposite channel or stayed in the same channel. You said when you tried this the problem was still in the same channel. But when you reversed the wires at the speakers, (left to right-right to left) the problem moved to the other channel. This doesn't make sense.

Now, with the Adcom amp/preamp in the system, you still have the"same" problem unless you put the preamp in "mono", in which case all is well. (i.e. normal output from both speakers) Clearly, something is amiss. It could be your source device, interconnects, or preamp.

I suggest it's time to borrow some known to be working equipment from a friend, neighbor, relative, etc. and get it set up and working. Then, and only then, replace a piece at a time, until you discover the problem piece. If you install this equipment, and the left channel is deficient, then it's probably safe to assume the speaker(s) is the problem. Right now, I'd be suspect of all the electronics you have, until you compare them against properly working gear.

Hey, Jim.
Thanks a lot for your comment and advice, and sorry for the confusion.
When you suggested reversing the wires, I played a music CD, not the audio CD pink noise test. That's why I got the same result from the music CD, despite reversing the wires. But when I reversed the wires and played this audio CD PINK NOISE test, the outcome was different, as I already described...

[pyonc]

Seems to me the telling sign is that you didn't notice a problem at higher volume levels.

It's not uncommon for older pre-amps to be un-balanced at lower levels. Many volume pots just aren't that well regulated at the lower end of their range, or they're dirty, etc. I've had that problem with several over the years; old Mac's and old Soundcraftsmen. The stereo volume pots are really ganged potentiometers and I've actually lowered the input attenuators on my amps to make sure that at a normal listening level my pre-amp volume control would be at mid-range rather than the bottom 1/4 of the range. That generally provides a better signal match for an amplifier, anyway. Seemed to work for me and a small price to pay for continuing to enjoy vintage gear without going overboard on restoration costs.

Thanks for your obeservation. I'm leaning toward your analysis. The reason I chose this particular Mcintosh C29 preamp was that it was a good match with Mcintosh MC2205 or MC2500 to drive 4343. Basically this Mcintosh preamp and power amp were produced in the mid to late 1970s, about the same as 4343 produced first. I still value this 4343 as one of the best gear to listen to jazz, my mainstay music, as jazz-loving Japanese audiophiles used to favor 4343 in the 1970s...

[joelcwu]

If the problem goes to other channel after speaker wire swap, you may rest speaker issue. The probelm comes from either your pre or power amp. Now you may switcg the out-put cable from pre to power to see if problem goes to other side, if it does then you have isolate the probem to the pre not the power. If after interconnect swap the problem remain at same channel then it's your power amp's fault. There's no simple fix to the amp, could be a lot of things, leaky cap, bad/dirty attenuator,loose connection, etc. I'd advise you take it to a qualify technition for check up.

[pyonc]

If the problem goes to other channel after speaker wire swap, you may rest speaker issue. The probelm comes from either your pre or power amp. Now you may switcg the out-put cable from pre to power to see if problem goes to other side, if it does then you have isolate the probem to the pre not the power. If after interconnect swap the problem remain at same channel then it's your power amp's fault. There's no simple fix to the amp, could be a lot of things, leaky cap, bad/dirty attenuator,loose connection, etc. I'd advise you take it to a qualify technition for check up.

Thanks for your observation. I think you're right. Another issue here I've just found out is that the mid-range driver on the right speaker is 2121, while the one on the left is 2121H (used with 4343B). I hear the sound from the right one is a bit louder than the left one. So, I suspect this may have something to do with diffferent set of this mid -range drivers.

[Robh3606]

"I've just found out is that the mid-range driver on the right speaker is 2121, while the one on the left is 2121H (used with 4343B)"

How do you know it's a 2122? If it is it has the wrong dust cap installed. The dust cap on a 2122 has the dome out like most other drivers and is 3" in diameter so you can see the leads.

Rob

[Rolf]

Hi. I believe the problem can be two issues. 1): Network is not OK. 2): bad connection regrading the cables somewhere in between the source (pre to power - power to speaker.

Do you use gold plated connections??

Regards

Rolf