Peter, is your Teres TT a unipivot? I have a VPI Classic which is a unipivot. I adjust azimuth using a tiny bubble level which is part of the stuff in my protractor kit. I also use the Sound Smith couter-intuitive device to fine tune VTF and azimuth. As far as I know, the azimuth on my unipivot is perfect. |
I need to update my system! Now I've got a Technics sp10ii with an SME312S tonearm and an Airtight PC-1 cartridge. Thanks. |
You don't need mono... or test records.
Fact: inaccurate azimuth increases crosstalk between channels.
Fact: increasing crosstalk "fattens" sonic images, making instruments/vocalists sound wider or fatter than they should.
Fact: our ears are most sensitive to the directionality of upper midrange sounds.
Therefore: we can best hear azimuth changes in live instruments and voices (because we innately know how big they should sound) in the upper registers (the range our ears are most sensitive to).
So, choose records with a well-recorded female vocalist and/or prominent, upper-range acoustic instruments (flutes, clarinets, oboes, acoustic guitar, etc.). Listen for the tightest imaging. A vocalist should sound human sized. A flute should sound flute sized. A guitar should sound like a small, hand-held instrument, not a billboard.
Technical note: azimuth adjustments must be made in VERY TINY INCREMENTS, the smallest possible adjustments your tonearm allows. Start by making the stylus appear vertical when viewed from the front whilst playing, then listen for the above and adjust in tiny steps. Try both directions until the image sounds as tight as possible.
|
Thanks Doug. I'm sure you are right, and will give it a try. It's a bit intimidating with the SME 312S. It has a detachable headshell, and they instruct you to just grab the headshell near the tonearm and apply rotational force to it. Hard to imagine making small changes that way.
That said - I wonder what the easiest designs are for adjusting the azimuth?
Any advice with the SME? |
If you want to supplement Doug's typically excellent suggestion with the test record method, it would most likely be ok to use either of the y-adapter approaches you asked about. The one circumstance in which I would be hesitant to do so is if the output impedance of the phono stage is particularly low, meaning significantly less than perhaps 50 ohms, especially if the tracks being played may have significant content that is off to one side (i.e., mostly in one channel). In that situation I would seek the manufacturer's opinion before shorting the two outputs together.
To the extent that the output signals of the two channels differ at any given instant, the output stage of one channel will have to drive a load impedance equal to the output impedance of the other channel, resulting in current flow that is much greater than under normal circumstances. The lower the output impedance the greater the current. With most and perhaps nearly all designs I would expect no harm to result from that, even if the output impedance is very low, but better safe than sorry IMO!
Regards,
-- Al |
Peter,
I haven't used the SME and from your description I think truly fine tuning azimuth may be difficult. The adjustments needed are on the order of 1-2 degrees at most.
The easiest and most repeatable designs I've used are of two types:
- TriPlanar, Kuzma Airline: loosen two set screws along the armtube; adjust azimuth with a third, finely-threaded screw that rotates the armtube (1/24th of a turn makes an audible difference); retighten the set screws.
- Durand Talea: rotate a finely-threaded screw that moves a magnet toward/away from a second, fixed magnet that's located above the arm pivot; the opposing magnetic fields hold the armtube at a fixed angle, varying with the distance between the magnets.
The Talea's is the best I've used and unique. It's the only arm I know of that allows azimuth adjustment on-the-fly. This lets you hear exactly what you're doing, a great feature. It's a great arm generally, sonically head and shoulders above either the TP or the Airline IME.
Good technical advice from Almarg, as usual. I tend to avoid technical measurements if listening will do, since for me listening to music is more fun and I can perform most adjustments that way... but as always, YEMV (Your Ears May Vary!). |
Dougey Dougey Dougey. As always, your comments are always bang on. When I had the Tri, your emails helped me immensely.
May I make an observation?,..........thank you.
I have the Talea ll. On some records the sound is bang on. On others it is not. I now have sticky notes on which albums are this, and which albums are that.
Could it be that the cutting lathe, which did the master, was not perfectly lined up on some.
This hobby of ours is maddening.
I will say that half the fun of listening, is tweaking till it's perfect.
Your lucky you have Paul, all I have is red red wiiine.
Should I start saving for the Telos?. |
Bifwynne....your bubble level on the head of the tonearm would give you good azimuth if and only if your stylus was manufactured properly and mounted square on the shank and square to the cartridge itself. If you have a cartridge manufactured by a trustworthy company, you could go with your method. I use a similar method..using a carpenters level holding its weight in my 2 hands and aligning the level to the tonearm head...I have a Benz LPS and trust the manufacturer. |
Al, what do you think about my use of the small bubble level thingy that comes with my protractor kit? Seems to me that if the air bubble is dead center while the sylus is sitting on the record, azimuth is perfect. Am I missing something? |
04-02-12: Bifwynne
Al, what do you think about my use of the small bubble level thingy that comes with my protractor kit? Seems to me that if the air bubble is dead center while the sylus is sitting on the record, azimuth is perfect. Am I missing something? Hi Bruce, Doug is the expert on that sort of thing, so it would be best to await his answer. Stringreen's response seems logical, but I have no particular feel for how much variation is typically encountered from cartridge to cartridge (between identical models as well as between different models) in how precisely the stylus, cantilever, and generator mechanisms are aligned relative to the cartridge body. Also, of course, that methodology presumes that the turntable has been adjusted such that the platter is perfectly level, as it should be. Best regards, -- Al |
Very simple to do with Graham AZ-1 Azimuth Adjusting System. Use with monophonic record to determine the optimum azimuth position for the stylus tip. Works perfect. |
Any suggestions for the SME system (or apparent lack thereof)? |
Cousinbilly1,
The styli on even the best cartridges may vary 2-3 degrees from vertical (per JCarr of Lyra, who once posted candidly about manufacturing tolerances). It wouldn't be surprising if cutting styli varied similarly.
Aren't you glad you have the ears and gear to hear the difference? Welcome to the Yellow Sticky Note Club! <:~)
By all means start saving for the Telos... and ship the Talea II to us for the extended evaluation it deserves. ;)
Agree I'm very lucky to have Paul, and red wine too!
***
My blushes, Almarg!
I concur with Stringreen, except to note that even the best cartridge manufacturers' styli may vary from vertical by 2-3 degrees (see above). Therefore, levelling the headshell for azimuith is somewhat like levelling the armtube for SRA: it's not an unreasonable place to begin but in a resolving system it's not the place to stop either.
When feasible, my own preference is always to adjust what matters, which is the attitude of the STYLUS in the GROOVE.
|
In contrast, I know of a guru who claims that if your optimal azimuth is more than 2 degrees off vertical, you should send your cartridge back to the maker as defective. I do not agree, but he is quite adamant that in most cases azimuth adjust is not necessary, off 90 degrees.
Doug, Perhaps this is blasphemy of another sort, but have you ever checked the actual electrically determined crosstalk after adjusting azimuth by ear? |
Lew,
I'll wager that guru made more pronouncements than cartridges. ;)
Yes, I've compared adjusting by listening vs. adjusting by measurement. I used to use a Wally Analog Shop (which allows measurement of crosstalk at the amp outputs using 1 KHz test tones). While using that, I learned that I could adjust by ear just as accurately and faster.
Peter,
Sorry for the thread-jackings and I wish I had something useful to suggest. Like Lewm's guru, SME's original tonearm designers tended to assume perfection in cartridges. Their arms lack the easy adjustability of all parameters that's typical of newer designs from other manufacturers. Build quality, finish and ease of use are excellent, but complete adjustability was evidently not a design priority.
|
The aforementioned guru does in fact use an SME V tonearm. Funny how that works. |
