As I understand it Class G and H ( I couldn’t tell you the difference) are variations of Class B where the primary voltage rail is modulated to reduce power requirements.
They are complicated and have largely been superseded by Class D designs in power sensitive scenarios.
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Class G is close to Class B since the input signal drives both main transistors directly (as opposed to Class AB, where they are behind diodes).
If you were to stay between the pink lines, it would be Class B:
Class G does by some magic circuit determine when to increase the voltage available to the central transistors.
Class H is a bit more analogue in that regard. It increases voltage based on the amplitude of the outgoing signal by sending it through some (zener/shottky) diodes forming a special Class AB:
For high-power applications (Active Subwoofers and PA), Class G and H have largely been replaced by the even more efficient Class D.
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Interesting…don’t want to derail the thread, but thanks as always for the electronics/circuit education
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Just got a refund on an iFi Hip-dac2 because of too much hiss on the 4.4mm bal out, and picked up the L&P W2 as the replacement. I use the MiM Audio Dark Magician IEM, and the high sensitivity of this IEM made the hiss on the hip-dac2 unbearable.
The W2 is a joy to listen to, and has an absolutely black background – no hiss, no distortion, no problems. This little dongle DAC has instantly become a favorite, and I can more easily shove it all in a pocket without worrying about accidental volume changes or damage to the phone it connects to.
The sound signature of this thing is sweeter and more spacious than the hip-dac2, and I did a little A/B testing between them since I had the hip-dac2 replaced and had both DACs for a time. I didnt realize that all hip-dacs(as well as iFi’s gryphon and even iDSD signature) have that hiss when using sensitive IEMs, so I assumed it was defective and had it replaced.
W2 is just slightly more clear than the hip-dac2, and when using the “bass” EQ profile on the W2, the bass and sub-bass is just as heavy if not heavier. The most noticeable improvements I hear with the W2 vs hip-dac2 are in the upper frequencies, the sensation of wider soundstage, and the absolute silent background. The ultra-portability of the W2 makes the deal even sweeter.
The bass and mids on the W2 are able to be tuned to your preference in terms of low frequency rolloff speed & latency. The ability to tune LF rolloff, along with other tunings available, allow you to have a more “woofy” experience that might start to encroach on mids, or a more snappy and tight bass rolloff that ensures mids and highs are never encroached. EQ is profile-based (jazz, rock, pop, bass, games, movies, etc) and works well.
I’m loving the W2. I only have one other portable DAC to compare with, and it is that small, weak ddHiFi TC44b, and both the hip-dac2 and W2 are vastly superior to it. No contest there. I am a W2 fan, so far. (about 30 hours in)
EDIT: I forgot to mention - I use this on a samsung note10+, which provides plenty of power to the W2 (never had the clipping issue some spoke of above). The W2 consumes battery at a rate that is slower than the phone’s own bluetooth controller, which uses about 1%/minute and is obnoxious. 1 hour of use (screen mostly off, in pocket, streaming tidal, wifi) with the W2 seems to eat about 15% battery.
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Sweet, glad it’s working well for you 
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Welllllllll…
So I’ve found a problem with the W2, and I’ve verified and reproduced the problem. I have a support email out to Musicteck and I’m waiting for a reply.
The issue is… with MQA. This may not concern some people, but this is what I’ve found.
-samsung Note10+ phone or windows 10 PC, behavior identical.
-any headphone or IEM, balanced or unbalanced outs on the W2.
-Tidal MQA - specific format
I’m hearing loud distortion or what may be clipping ONLY when playing 44.1/88.2khz + 24bit MQA. I can play any other MQA format, lossless format, or lossy format with zero trouble.
The loud clipping I hear when the W2 goes into higher MQA unfolding modes is independent of volume and is at the same loudness whether volume is at 1 or 50. The clipping sound is present on PC, using the L&P WHQL driver.
My playlists have mostly non-MQA in them so I didn’t notice this sound earlier in my time with this DAC. I eagerly await a reply from the vendor, and I’ll update this thread with what I find.
I searched online for hours last night, trying to find other mentions of this issue, but I found nothing.
EDIT: weirdly, when this issue is present the W2 display says “32bit” but the phone or PC screen says “24bit”. I don’t know why that doesn’t match.
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I actually think the W2 doesn’t officially support mqa at all so I wouldn’t be surprised if it has issues with mqa files? Don’t have any music with mqa so can’t comment there
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According to the reviews Ive read, including specific MQA test cases, it does support MQA. And it plays most types of MQA just fine. Ive spent hours testing this since noticing this clipping sound last night. It seems that it is only the one specific format. : / Continuing to research this.
I mean it isnt a HUGE deal for me to lose some MQA, but there are a couple tracks on Tidal MQA that I cant find in lossless so I would lose that track.
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Huh interesting, I don’t remember it being on any feature list or product page for the unit, just assumed it couldn’t do it.
Will pm you
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What about possibly trying with USB Audio Player Pro? Whenever I used to have issues with Tidal when I used to have a subscription, listening through UAPP normally fixed any issues that I encountered.
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I almost always use UAPP Pro on android, and this issue is identical with/without it, and on mobile devices or PC.
Allow me to ask you – I have only used UAPP for about 2 months now. I see all the advanced USB DAC tweaks, and Android hires driver tweaks, but I dont see any that jump out at me as being relevant to this issue. Do you think any of the driver level flags or USB DAC settings in UAPP might help here? Ive already tried buffer settings and that has no effect. Any way to force the Android device to do part of the MQA decoding before handing to W2, I wonder?
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So… this is strange.
Tidal has released a bit-perfect version of their Android app some time in the last 6 months. I was only using UAPP Pro to play MQA/Tidal on my phone, and allowed it to “auto start when DAC connects”.
I disabled UAPP and loaded Tidal, and Tidal connected to the USB DAC directly. Now it plays all MQA files without any distortion, and the W2 DAC now accurately shows “24bit / 192khz” for files that match that specification.
This needs further investigation. The distortion issue is present with Tidal on windows10 using L&P’s own WHQL driver. The issue vanishes on my Android device when using Tidal natively. I think maybe I will set UAPP to “disable MQA passthrough” to see if this affects this issue. Will update any other details as I can find them.
The version of UAPP that I was using had a bit perfect option that needed to be checked. I also had to lock in the proper quality rate. Also in settings I had to make sure that in the MQA menu I had MQA passthrough checked off so that the device with MQA capabilities was decoding the MQA. There also is an MQA playback option of UAPP that is an add on in-app purchase. I of course had to buy that. This was all almost 1 to 2 years ago, so things likely have changed since then.
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Ahhh, yes. As soon as I can take a few moments away from parenting Im going to disable MQA passthrough on UAPP and try that. I do NOT want to lose UAPP because of its many great features, and its software volume controls. Tidal only allows like 20 volume steps, and UAPP allows up to 100.
I ticked the “bit perfect when possible” option when I first started using UAPP. Ill try ticking “on” for that, and try again. Im sure UAPP will work with the right config.
MQA is obnoxious lol.
EDIT: sorry, yes – I also bought… the MQA add-on, lol. Damn UAPP. =P
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@M0N curious how you ended up tricking the auto gain on the questyle m12. Would like to give that a try myself.
I used an impedance adapter to force high gain
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Just gonna leave a brief note of impressions here as I recently had a chance to try out both the W2 OG and W2-131. To my ears the W2-131 is a small technical improvement but adopts a different tonality so those who really like the W2 sound may not like the 131. Compared to the OG, the 131 has a slightly less flat spatial recreation, a bit more depth, more realistic staging, slightly better resolution, better timbre for instruments but vocal is a bit dryer. In terms of the tonal balance overall it’s more neutral and balanced. One thing I notice with the OG is that at times it sounds warmer more relaxed in most of the FR spectrum but the upper mid tends to be also more forward whereas the 131 is more coherent and consistent throughout. 131 also has a bit more power, and the 3.5mm is closer to the 4.4mm performance compared to the OG.
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Hello,
A year ago I bought the Nuprime hi mdac as a dongel.
It does not convert Mqa, which is fine, and has a built-in Cirrus Logic chip.
The sound is solid, but a bit thin on the chest. overall it has a nice resolution and bass is enough. in the mid and treble range it is a bit narrow.
And I listened to it with the Aeon R/T closed as well as Emu Purpleheart.
For on the road it does its job well enough for a non audiophile and weirdo like us.
Fun aside, the battery consumption is moderate on both Android and Apple systems, and everything is tip-top in terms of function.
Typically, Apple devices require the USB camera adapter, which is not unavoidable.
And another 35$ are due for those who don’t have one.
Which will probably be necessary for every dac dongel.
My summary after buying the Ifi Hip Dac 2 is as follows.
The Dac dongels are better and also cheap to get.
If you want to go a step higher without draining the battery of your smartphone or tablet, then a mobile headphone amplifier is better.
There has also been a lot of progress in this area.
I’ll put it this way: there are the Hip Dac 1&2, Earman, which are quite inexpensive.
Or you can get them for the same price as a dongel.
You have to think about it carefully.
Especially if you have a battery-heavy smartphone, something like this can come in handy.
Apart from that, you can also use it at home without having to visit the listening place.
I also took the liberty of connecting the Nuprime dongle to the Little Dot 1+ via line in and the results are even better than using the internal amplification.
So you can do quite a lot with it.
Even via line in in the car it was more comfortable than connecting with the Ipad via Bluetooth.
Dac dongels are great, mobile headphone amplifiers even better.
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So I ended up rebuying the L&P W2 after selling my original quite a while ago. I’ve changed phones since and found that with my Samsung s20, when plugging the w2 in, it would not power on at all. Works fine on every other device but my phone. After much frustration built, upgraded to the latest firmware which gives the option for UAC 1 or 2, it now works as it should. Just wanted to put it here incase anyone else had a similar issue.
Also, I’ve seen the w2 being praised for having a dead silent noise floor. I found this to be the case with the Campfire Ara, with every filter except the NOS filter (typical as this is the one I’d like to use). I’ve also found that while the hiss is very much present while using NOS, the setting for Tune, where you have the option of 1 or 2, setting 2 reduces the hiss quite a bit. Again, just wanted to through this out there for information purposes.
Also, I’m curious if anyone else has experienced the noise floor difference with the different filter settings, specifically NOS and all others. I haven’t seen this mentioned anywhere so far.
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I just bought a W2, I’ll experiment and see if I have any thoughts to offer!
General question: are there different versions of the W2? I saw a classified of HFI today that was selling “the OG version” of the W2
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