Csng1, I would go for a Classic 3 without a VPI arm and put on either a Graham Phantom or Tri-planer. It would cost you roughly the same as if you went for a Classic 4 with the 12.7 arm.
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To adjust Azimuth with a Multi-meter, you need a test record, HiFi News or Ultimate Analogue test records and a Root Mean Square (RMS) Multi-Meter. You use 2 tracks on the record, one that plays only the left channel and one that plays only the right channel. My procedure:
Disconnect the RCA cables after the preamp. So my process includes the cartridge, turntable, phono section and preamp. In other words, disconnect the RCA cables going into the AMP. They will be your test point.
Play the right channel track. Put your multi-meter into AC mode, Hook up the multi meter to the right channel and adjust the volume so you get between 0.3 - 0.5 Volts AC.
Play the left channel and this time adjust the balance knob to bet the exact same AC voltage. Pick a voltage between 0.3 - 0.5. Try not to pick a voltage lower than 0.3, because then your crosstalk voltage will be really low. If you pick 0.510, you cross talk voltage will be around 0.025. If you pick 0.3, your cross talk voltage will be around 0.014.
You might have to go back and forth a couple of times, but when you are ready, you are reading exactly the same voltage on the left and right channels with the left and right channel tracks. For example, let's say that it is 0.3 Volts.
Now for the test:
Play the right channel, and record the voltage in the left channel
Play the left channel, and record the voltage in the right channel.
You want to try and get those as close as possible, preferably within 1 db, 20*LOG10(V1/V2). If the right channel has higher voltage (when playing the left channel) than the left channel (when playing the right channel) then tilt your azimuth of your tonearm towards the right channel and the voltage of the left channel will go up. It takes a bit of practice, do it multiple times. Resist the temptation to make large changes in azimuth, you can usually find a good balance close to 0. If you are going over 2 to 3 degrees, then you might have missed it, or over compensating. In that case, go back to parallel and start measuring again. Rememeber, tilt the azimuth of the tonearm towards the channel that has the highest crosstalk value.
For example my last results were:
Left channel v1=0.3 v2=0.14 crosstalk(db)=-26.62
Right channel v1-0.3 v2=0.15 crosstalk(db)=-26.021
This is with an azimuth, tilted towards the right channel 0.19 degrees.
This is also my last step, I do my alignment first, adjust SRA to 91 degrees, re-do alignment, complete VTF, then I do Azimuth.
One last piece, when you measure cross talk, the meter will fluctuate, I use the reading that it stayed the most stable at, for the longest time.
Hi Captain winters
Thanks very much for your full explanation,
i do not have a test record. i should get one,
Regarding the SRA to 91 degrees, how do one measure this, i have read many times, the VTA on classic 1 as long is parallel
to the plate. i know it does not mean it is 91degree. What measuring devise is needed?
I pretty much used the procedure by Michael Fremer on Analog Planet > Setup tips> How to use a USB Digital Microscope to set 92 degree Stylus Rack Angle (SRA) with some modifications. Link below:
I used a different digital microscope (it was around $40) and is very high power, 800x. It is a little hard to use at that power, and I also needed to take off the front protective piece so I could get it close enough for the focus. I took the image, transferred it to Powerpoint, then drew my graphic lines on the image. Then I measured the angles with a protractor on the screen. I repeated the procedure, raising the VTA tower, until I achieved the desired angle, 91.5 degrees. So the only additional software I use is Powerpoint, and the software that comes with the USB microscope. The protractor is your standard grade school protractor.
Every stylus is different and my goal is to get it to 91 or 92 degrees SRA. I needed to raise my VTA tower significantly to get to 91.5 degrees. What is nice, is it gets you in the ballpark and then you can fine tune by ear.
Also, make sure to check your MINTLP (alignment device) again, since as you raise the VTA, you will also change the geometry of the arm, and you will need to re-align on the MINTLP (alignment device) and re-do VTF. That is why I do the SRA first, then re-align cartridge, then VTF, then finally azimuth.
- 31 posts total