New Leckerton UHA-6S MKII Portable Headphone Amplifier Announced (Update User Impressions Added... - Page 84

Quote:

Originally Posted by fzman 

xinghui,

 

it's as much a function of the load you're trying to drive as anything about the opamps intrinsic sonic character.  I have 16 ohm iems, at 96dB/mw, so they take some grunt.  Opamps which deliver really low amounts of current into low impedances won't sound as good as ones that will.  Sometimes you can find this in the datasheets, other times, not so much.  I like the sound of LT1028s, but they are very low current, iirc, and i won;t bother trying them in the Mkii at all.  So far, the 627s sound very good, and i am wondering why a relatively fast opamp (the 627) has a reputation for being warm and sluggish.

I'm using low ohm and high sensitive iems/headphones too.

I don't think the datasheet could justify an op-amp's characteristics in audio performance.

Quote:

Originally Posted by xinghui0711 

I found that AD8610 is kind dry and lack of warmth. I was trying to see if there is any surprise after changing Opamps :D

Hmm I find 8610 to have a little be of warmth added to the sound. Still quite neutral but with just a hint of warmth added :). You'll find 209 super dry then :P.

Quote:

Originally Posted by ocswing 

What is your volume at with that setup? I use a 4th gen iPod touch -> LOD -> Leckerton -> UERM and I have my volume at about 10 o'clock for normal listening with no channel imbalance there.

I can barely move the dial above 0 before it gets too loud, assuming I want channel balance.  I think you guys may have a low-gain version of the amp.  Nick said he can lower the gain on my amp by about 12dB, which should be enough to give me more listening range with the UERM.

Unless there are any potential downsides to lowering the gain, like a loss in resolution, I think the standard gain level should be as low as possible.  If you intend to use higher impedance phones, then you can indicate that during your order and the amp maker can adjust accordingly, but I'd imagine most of us want to use a portable amp with portable headphones, which tend to be sensitive. 

I've had this gain issue with every portable amp I've owned except for the Pico Slim: RSA Protector, RSA SR71-b, TTVJ Slim, and ALO MKIII.  Ray Samuels told me he couldn't lower the gain on the 71b any further, while ALO lowered the gain but the amp still manifested hiss and the gain was still too high for IEMs. 

The UHA-6s II has a great black background with IEMs, so the the gain is the only issue, and I'm so glad Nick is willing (and able) to adjust it.

Well the UHA4 is also a good option if volume control is your main concern but you give up resolving power that the UHA6 has in spades :).

I kinda miss my UHA4 to be honest. I never ever had volume issues with that amps digital pot.

I got this directly from the Leckerton web site -

Two-position gain select (+0dB/+18dB)  

 The mkii has unity gain in the low setting.  I am using the amp with iems which are 96dB at 16 ohms (JVC HA-FXZ200).  I have no problems with it - here's how i was using it this morning at breakfast.... The cable is waaaay too long, but sounds very very amazing (Audioquest Yosemite)

Quote:

Originally Posted by zachchen1996 


Is that a rwak100? If it is, do you prefer the sound of your earphones straight out of the rwak100's HO or do you prefer the sound of them out of the uha-6s mkii connected to the rwak100? Btw. what op amp does your leck have?

I think he's got a stock AK100.

no, it's the stock AK100.  Sounds great thru the mkii especially with the DBS cable, which is massive overkill, but sounds great.  Not really pocket-able though, but could probably fit into a shoulder bag.

The rig this morning was with a dip-8 627a op amp.  I've got the soic 8610s on adapter boards and also ad797a dip-8s in the carry bag.  Many other opamps at home but the iems i am currently infatuated with are 16r @ 96dB/mw - they want some current, so i am trying to stick to the more potent op amps.  Nick thinks the 49713 may be ok in his circuit, and it can do 150ma, but it likes 34v to power it. I thought the 627s were just a touch more full-bodied than the 797s, but so far with a short audition time on both, and virtually none on the 8610s.  i am tryint to be good and keep a set of op amps in it for about 3-4 days before i swap out, to give them a chance to settle in, and to try to keep from stripping the screws!

Quote:

Originally Posted by ardgedee 


I don't think many people have specialty low-gain versions of the UHA-6 (if it was an option, I'd have gotten that done to mine!), but it's likely that you like listening at levels quieter than most people -- I like low volume, and I have the UHA-6 and SR-71B, and I can get the volume knob set at comfortable listening levels without channel balance problems (although the knob's right on the threshold on the UHA-6).

A large part of the problem is your choice of earphone -- the UERM has both high efficiency (112 dB) and low input impedance (21 Ohm). I'm guessing you're going to have trouble matching it with any external amp to get your preferred listening level. My customs are less efficient than yours and they allow me a little more give-and-take on the volume knob.

Have you considered using an impedance adaptor between the iPod and the amp? This will pad down the signal going into the amp by a few dB, and will not affect the sound quality in the same way as if the impedance adaptor was between the amp and your UERM. It'll make the connection between iPod and amp unwieldy, but if you like the result sonically you should be able to find a cablemaker who can incorporate the padding circuit into an LOD for you.

Thanks for the impedance adaptor suggestion, I may try that.  But I found the default gain on the UHA-6 to be a bit too high even with the Amperiors.  I've had the excessive gain issue with just about every headphone setup I've ever owned, including desktop ones.  So I'm thinking it may be the result of the audio files I have, even though they've been downloaded/ripped from a variety of sources. 

Even still, unless everyone out there is only listening to the absolute highest quality, least compressed stuff (like albums from Reference Recordings), I don't see why I'm finding the volume out of most amps/sources I use to be higher than other people who have the same amps/sources.  I definitely don't think I listen to music at abnormally low levels, nor am I particularly sensitive to high frequencies.

Anyway, I'm just happy that I like how the UHA-6 sounds and that the gain can be lowered.  With the OPA627 and the UERMs, the UHA-6 reminds me a bit of how I remember the TTVJ Slim sounding:  very natural, expansive soundstage, and warm but still crisp and detailed.  I'd have to have them together for a real comparison, but it's possible the UHA-6 is slightly more refined.

I'll report back after I get the lowered gain amp back from Nick.

I'm completely shocked.

Today I was not putting any expectation on JRC 5534DD in my Leckerton UHA-6S MKII.

Comparing it to AD8610/AD797, my ears actually preferred 5534 as more musical sound... 

Price wise, both AD8610/AD797 are at least 4x more expensive than cheap, low spec JRC 5534.

I don't understand this. It's irony.

Quote:

Originally Posted by DigitalFreak 

It's called personal preference and there's nothing more to understand besides that. The Leckerton itself is an example of a sub 300 dollar rig that swings with gear that's pricier.

Maybe... But finally I was able to identify the sound between op-amps. The differences weren't huge like it would change the sound signature, but it definitely affects amp's overall performance.

Now I'm gonna stick with JRC5534DD :)

leave the 5534s in for a week or so, and then switch back to one of the others and see what happens.

Quote:

Originally Posted by fzman 

leave the 5534s in for a week or so, and then switch back to one of the others and see what happens.

what would happened?