Setting Azimuth


Details:
VPI Scoutmaster
JMW 9 standard tonearm
Soundsmith Zephyr cartridge band new
Using a Fozgometer and Hi Fi News Test LP both also brand new
I'm measuring at the interconnects off the turntable.
I cannot seem to achieve a proper azimuth that will give even channel balance. The only adjustment on this tonearm is the counterweight which is weighted a the bottom so turning it side to side should effect azimuth. Only extreme changes are affecting channel balance. I changed the interconnects in case they were causing the problem, but I get the same results. The right channel is a few decibels louder no matter what I do to the azimuth unless I make an extreme adjustment which has the tonearm cocked to one side and obviously this is not correct.
arnold_layne
"How does one adjust channel balance?" When all else fails, you need a classic balance control on your preamp/linestage. Modern equipment frequently omits such a control. The two channels may be different in output for any one of a number of reasons. All you have to do is think about the signal chain. Anything in the chain where gain is added to the signal could be creating the imbalance you perceive. Starting with the cartridge itself. Then we have the phono section and the linestage, if you are using two boxes. But even one-box preamps have a phono stage feeding a hi-level or linestage. Both sections add gain to the signal, so either could be at fault. If you have tube gear, it would be a simple matter to swap tubes between L and R channels, and see whether the problem follows the tube swap. If tube swapping does not reveal that the problem resides in either the phono section of the linestage, then one has to blame the cartridge.
Actusreus....nope...making those arm adjustments are not that difficult at all. There is a weight IN the rear of the arm adjustable with a large Allen wrench to make the arm lighter unscrew the weight a bit..to make it heavier, screw the weight in a bit. From the factory, the weight is totally in, so before you start, just unscrew the weight a bit. The counterweight can be forced around the arm tube without damage. The tightening screw captures a plastic piece, so its friction controlled. With the counterweight firm, just rotate the weight while holding the arm headshell. This is not a difficult proceedure,
I agree with Lew,
Apart from the reasons given.......the room itself can often give 'unbalanced' sound to the channels?
My left speaker fires into the room with a lofty angled ceiling over whilst the right-hand speaker has a flat ceiling.
The left channel generally sounds louder with almost all my cartridges even when I sit off-centre closer to the right?
I also used to fuss about this but now I simply set my channel balance 2 dB higher on the right.
Why do you think most amplifiers have this facility?
Relax and enjoy :^)
Dear Arnold, Last night I realized that the suggestion I made re tube swapping to localize the source of your channel imbalance, in my last post, was needlessly laborious. Whether your phono and linestage are tube or transistor type, all you need to do is swap L and R channel leads, between tonearm and phono and then between phono and linestage (if you have a 2-box system). If the problem resides in the cartridge, the louder signal will move from one channel to the other when you swap leads between tonearm and phono input, etc. If the imbalance is unaffected, etc.
Lewm's interpretation of my comment was correct. The experiment described in the OP clearly demonstrated that azimuth has little effect on channel output. Like many useful experiments it proved that the going-in hypothesis was false. That's just as useful as a positive result.

How does one adjust channel balance?
Cartridge alignments and adjustments have little effect on channel balance. If you're actually getting significantly different output from one channel vs. the other then the flaw is probably internal to one (or more) components. Adjusting the cartridge won't change that.

You should perform a diagnostic:

1. Is the sound balanced when playing a CD or other line-level source?
- if yes, the imbalance is occurring somewhere in the phono reproduction chain.
- if no, the imbalance is occuring in your line stage or after.

2. If #1 demonstrates that the imbalance is occuring in the phono reproduction chain, try reversing the cartridge clips. Does the imbalance flip sides?
- if yes, the imbalance is internal to the cartridge. Repair or replace the cartridge.
- if no, the imbalance is internal to the tonearm wiring or phono stage.

3. If #2 demonstrates that the imbalance is internal to the tonearm wiring or phono stage, return the cartridge clips to their normal position and reverse the phono leads at the phono stage inputs (or at the TT if you have a detachable phono cable). Does the imbalance flip sides?
- if yes, the problem is in the tonearm/phono cable. Check and clean all connections. If the imbalance continues you probably have faulty wire (seems unlikely).
- if no, the problem is in your phono stage. Check tubes if you have or try another phono stage.

The diagnostic process is tedious but critical for accurate problem solving. Isolate the cause first. Then decide what needs adjusting/repairing. Making adjustments without examining what needs adjusting is just, "Ready - Fire! - Aim." ;-)