New Leckerton UHA-6S MKII Portable Headphone Amplifier Announced (Update User Impressions Added... - Page 81

Quote:

Originally Posted by lee730 

That is channel imbalance due to the volume pot on the Leckerton. Most amps suffer this having volume pots instead of digital pots. But with digital pots you do sacrifice some transparency so its a give and take sort of thing. By far my Triad L3 is the best portable amp (more transportable TBH) in terms of near to no channel imbalance at very low volume listening. In fact I think it is so good I'd be more apt to think it's a digital pot.

The reason why volume pots have noticeable imbalance at low volume is because that's where minor variations in manufacture become more noticeable.

Volume pots mostly work by having a conductive resistive surface that a wiper slides along. At the near point (where volume is highest), electricity travels a very short distance along the surface; minor differences between two surfaces don't add up to much. At the far point (where volume is lowest), electricity is traveling the full length of that resistive surface, and minor differences add up.

Higher quality pots are more expensive in part because they require either (or both) closer attention to manufacturing tolerance or higher rates of rejection. Buy a couple dozen identical volume pots of good-not-fabulous quality and test them all at the quietest position. Some will have louder left channels, some will have louder right channels; out of the batch, maybe a couple will have a channel difference subtle enough to be tolerable or maybe imperceptible.

Leckerton could spec higher quality pots, but that'd drive the price of the amp up noticeably. Really good pots for non-portable devices can easily go for $50 a pop -- without having to get into the audiophile stratosphere of exotic materials and proprietary designs. You're paying the manufacturer to either spend more time making and testing each one, or for covering the cost of the greater number of rejects they have to make for each one they can sell.

Stepped attenuators can get around this by using actual resistor networks rather than a sweeper over a surface, but since that's literally a cluster of tolerance-matched resistors, it's going to be expensive and bulky. Expensive can be tolerated, bulky's kind of a dealbreaker. Digital attenuators have a lot of advantages (compactness, consistency) but aren't necessarily audiophile-approved.

I have a SR-71B. Like the Triad, it has uniform channel balance pretty nearly all the way to ∞. Like the Triad, it also costs some multiple of the price of the UHA-6, and part of that markup is to cover the cost of the higher-quality volume pot. Save some money, accept some compromises.

Yeah, that's actually why I hedged myself with "not audiophile approved" -- I hear complaints about them but I haven't really seen much that proves that they're actually sonically inferior. What I don't really know (and am curious about) is how they compare price/performance-wise with conventional high-quality volume pots.

Yeah, that's actually why I hedged myself with "not audiophile approved" -- I hear complaints about them but I haven't really seen much that proves that they're actually sonically inferior. What I don't really know (and am curious about) is how they compare price/performance-wise with conventional high-quality volume pots.

I wonder how it differs from the LME49713. I have a set but haven't had time to try them yet.