Bad low end tracking on RK27
Jan 1, 2006 at 3:07 AM Thread Starter Post #1 of 10

grasshpr

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Hi guys,

Just wanted to know if its normal for the alps rk27 to be bad at left/right tracking near the low volume end.
 
Jan 1, 2006 at 6:17 AM Post #2 of 10

Pars

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All pots have some tracking error, and as you noted, most noticeably at the lower end of the scale. I assume you resistors are matched well between channels, particularly the gain resistors (assuming this is indeed a DIY headphone amp)?

You will find variance among any given sample of a particular pot model also... you could go thru a box full and probably not find any two that match perfectly. The higher end (and usually $$) pots are supposed to match better. Not sure if this is true or not. I've had lots of problems with the Panasonic EVJs in the past in this regard (always seems like the right channel is louder on those). The Alps RK097 that I've tried seemed better. The RK27 I have in one of my Dynalos seems OK. The TKD in my other seems real good. This is one reason why stepped attenuators are touted so often.
 
Jan 1, 2006 at 6:23 AM Post #3 of 10

grasshpr

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Quote:

Originally Posted by Pars
All pots have some tracking error, and as you noted, most noticeably at the lower end of the scale. I assume you resistors are matched well between channels, particularly the gain resistors (assuming this is indeed a DIY headphone amp)?


Yes, my resistors are well matched, and I have only imbalanced tracking near low volumes. My mid and high volumes are fine.

However, I was under the impression that the RK27 do have good low end tracking compared with most pots (equal if not better than Panasonic pots). Currently, I think my EVJ pots have better low end tracking than the RK27's.

I just wanted to know if its normal for this type of inaccuracy for this brand of pots since it is my first time I using it for a build.
 
Jan 1, 2006 at 6:44 AM Post #4 of 10

ATAT

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I believe the RK27s and EVJs are about the same in quality

Dual mono pots for the win! =)
 
Jan 1, 2006 at 6:48 AM Post #5 of 10

grasshpr

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Quote:

Originally Posted by ATAT
I believe the RK27s and EVJs are about the same in quality

Dual mono pots for the win! =)



If only life were so simple
orphsmile.gif
 
Jan 1, 2006 at 9:46 AM Post #6 of 10

dokebi

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I find the alps volume/switch pots to track pretty bad at the low end compared to the panasonic which also doesn't track that well to begin with. The panasonic also feels much smoother when adjusting the knob compared to the gritty noisy mechanism of the alps.
 
Jan 1, 2006 at 5:51 PM Post #8 of 10

grasshpr

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Thanks guys for your input. I appreciate it!
 
Jan 2, 2006 at 3:37 AM Post #9 of 10

amb

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If you find that you're actually using the first few degrees of the volume pot then your amp has too much gain. All audio pots have some error in that region but if your gain is correct for your setup then your normal adjustment range shouldn't be anywhere near there. The Alps RK27 actually has very good tracking for a non-laser-trimmed, non-stepped-attenuator pot.
 
Jan 2, 2006 at 3:56 AM Post #10 of 10

grasshpr

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Quote:

Originally Posted by amb
If you find that you're actually using the first few degrees of the volume pot then your amp has too much gain. All audio pots have some error in that region but if your gain is correct for your setup then your normal adjustment range shouldn't be anywhere near there. The Alps RK27 actually has very good tracking for a non-laser-trimmed, non-stepped-attenuator pot.


In my amp, gain is not a problem. With a 10k alps pot, I have sufficient volume with half the pot turned. I'm using about 4.5.

However, I've been noticing that the left and right channels have really bad matching when I first move the pot (in the region of 5-10 degrees). Strangely enough, I've not had that problem with several (pretty much all my EVJ) 10k pots from Panasonic. They do have other issues though, but thats for another discussion.

I should have just used my new stepped attenuator in this build instead of the alps pot.

Also, I've even noticed this trend with the smaller RK09s, but had shrugged it off since it was alot cheaper.
 

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