Loxjie P20 Balanced 6N3 Tube Hybrid Amp for under $100


#21

Haha they are a great little pair of all around speakers for their price range!

$99 for a tube amp as well is definitely in the right price range for my wife to be happy with me!


#22

I was just wondering if you knew the listed impedances. If you want to measure output impedance, it can be done with any true RMS multimeter. I can write up some instructions if you’re feeling adventurous :slight_smile:


#23

Happy wife, happy life…a truer statement is hard to find…lol


#24

Now that I’m at a computer, it’s easier to share the instructions.

From NwAvGuy:

MEASURING OUTPUT IMPEDANCE: As seen in the diagram above the output resistance forms a voltage divider. By measuring the output voltage with no load, and with a known load, you can calculate the output impedance. This online calculator makes it easy. The no load voltage is the “Input Voltage”, R2 is the known load resistance (don’t use headphones), the Output Voltage is the loaded voltage. Click Compute and R1 is the calculated output impedance. This can be done using a 60 hz sine wave file (Audacity can create such a file), a Digital Multi Meter (DMM), and a 15 – 33 ohm resistor. Most DMMs are only accurate around 60 hz. Play the 60 hz sine wave file and adjust the volume for about 0.5 volts. Then attach the resistor and note the new voltage. For example, 0.5 volts with no load, and 0.38 volts with a 33 ohm load gives an output impedance of about 10 ohms. The math is: Zout = (Rload * (Vnoload - Vload)) / Vload

I had some extra ones of these lying around which makes it very easy to probe the positive and ground terminals.

When you attach the load (resistor), make sure you’re attaching it in series with your multimeter (e.g. between one probe of your multimeter and the positive terminal). I once made the mistake of attaching it in parallel (i.e. between the positive and ground terminals) which resulted in a melted resistor when I attached the probes :frowning:

EDIT - That link to an output impedance calculator is dead, but here’s a working calculator.

EDIT 2 - My warning about connecting the load in series came from an experiment where I was trying to measure maximum output voltage. In practice, you’re supposed to connect voltmeters in parallel to the circuit that you’re measuring, so please ignore what I said :slight_smile: As long as you’re not cranking it up too high (e.g. the recommended 0.5 volts), I wouldn’t worry about burning out any resistors. If it helps any, here’s a description of how I measured my iPhone a while back.


#25

I did some listening back and forth between the Starving Student Millet Hybrid Tube Amp (diy kit from Beezar) and the Loxjie P20 tonight.

The SSMH was definitely brighter sounding and less extended than the P20 (w/ GE5670 tubes). The P20 was much warmer sounding and matches with my selection of headphones a lot better (Elex, Elegia, HE560).

The SSMH was a fun DIY project, but I haven’t really found a good use-case for it yet. It’s lacking extended low end and actually sounds brighter than a SS amp and sounds flat and dull in some cases. The tubes are rare so there is a lot of tube rolling choices and no adapters work with the amp.

Anyway, I think my point is, the P20 is still holding it’s own in my subjective testing.

I will try to measure the OI once I read through and understand what’s going on. I


#26

Agree on both points. Especially the 2nd point. :slight_smile:

The Yu2 is a really nice desktop speaker set up because its small, compact, and feels rock solid. It also sounds good for computer speakers. They are priced competitively vs the AudioEngine too so that’s kind of why I ended up with them. Plus the bamboo look is awesome!

The one issue I have with them is sometimes they pop excessively loud when I turn them off. Or they will continually pop when I turn them on. I feel like some capacitor or something isn’t properly discharging or something? Contacted Kanto about it but never got a reply back a while ago.


#27

We actually sell both Kanto and Audioengine so that’s very interesting! I find Kanto to be a bit of a jack of all trades speaker due to all the built in features and its more consumer friendly sound while Audioengine doesn’t have all the features but it does have the more typical audiophile flat response.

I actually had a pair of YU4s hooked up to my TV specifically for gaming because they sound really good with FPS games. I replaced them with some Vanatoo Transparent Zeros but I really liked them!

Weird about the popping noise. Did you try contacting them direct or through the dealer?


#28

I contacted Kanto directly about it the issue.

I had gotten the yu2 during a sale. They were quite a bit cheaper than what they normally sell at now too. I think I paid $159 for them.


#29

Do you have another site? I couldn’t find speakers on the Headphones.com site…Might be in the market for new living room setup, wife depending…lol


#30

Amir just informed me that he bought the P20 amp as well and will be doing his review/measurements in the near future.


#31

They have a matching DAC now:
https://www.aliexpress.com/store/product/LOXJIE-D20-HIFI-Digital-Audio-DAC-and-Headphone-Amplifier-Uses-DAC-Chip-AK4497-Support-DSD512-PCM/4470105_32955312313.html?spm=2114.12010608.0.0.386737117FGTFz


#32

Looks interesting. I’m on the fence about a desktop balanced DAC, and want to see reviews for the Topping D70 before I buy.


#33

I have also a Topping DX7s and I was looking for a separate Tube Amp to buy. Is this P20 worth buying for the Topping DX7s? Will I be able to discern much difference in overall tone and musicality? I own different headphones (Balanced Sennheiser HD6XX and 58X, Balanced Sony Z7, AKG 712 Pro, Audiotecnica Z5000. I purchased the P20 but still can cancel the purchase and have a refund before it gets sent. Will I see a significant difference switching from the Topping Balanced connection to the P20 connected to the topping via XLR? worth it? Thanks!


#34

Yea I was hoping it would have been balanced. I havent seen anything on the D70 yet. I am getting the Monoprice THX amp soon, so I may be selling my DX7 shortly after that.

I have the DX7 as shown above. The measurements for that do show a slight difference in “warmth” (elevate bass and lower mids) between the P20 and DX7. I dont know exactly how the circuitry works on the P20, but I don’t know if there will be any significant audible differences between connecting XLR or not, but XLR 3-pin cables are super cheap. I got a pair of them for L/R channels for $6 on amazon.


#35

I already have the xlr cables to connect the topping to the P20. What I really wanted to know was your honest opinion if it is worth to spend 140AUD to buy the P20 when I already have a good Dac/Amp like the Topping DX7s for just a marginal difference as you stated… Probably better stick with my Topping and save the money for a tube amp that does make more difference in sound? Thanks


#36

My question is what mods can we introduce for it? I’ve got an APPG pa1502a that was modded and frankly I’m still impressed how well it sounds, they didn’t just re cap it some of the members went so far as to modify the circuit itself! An so I executed what I felt was the most transparent of said circuits changes and again I’m quite content with it!!

That said I’m curious to see what improvements could be made for this little guy! As you don’t see many balanced tubes at this price point!


#37

I find that this is the first “budget” tube hybrid amp that actually presented something that sounds different than a solid-state. Some of the other cheapies I’ve tried in the past seemed more like decoration than actually “coloring” the sound. This one has a noticeably warmer sound and increased soundstage to me.

The Massdrop CTH is another hybrid tube amp that actually changes the sound. It changes it the other way – making the sound extremely clean and wider.

I have not tried any OTL Tube amps. I imagine those will give the most “effect” than these hybrids.

So, for me, I find the P20 totally worth the money. I kicked my MCTH downstairs. I found the P20 pairs well with my current crop of headphones which are neutral-ish (Elex, Elegia, HE560).

The Op Amps are soldered directly onto the board, so removing them might be tricky but probably not impossible.

These use 5670/JN3 tubes and theres quite a bit of choices there. I’ve also seen adapters for 12AX7 tubes too, which also have a lot of options.


#38

Aww oh well, still seems like it would be worthwhile!


#39

It may be too late now, but here are my comments for future reference. My opinion of tube amps varies by music source and setup. Sometimes clarity is important, and I don’t like tubes for everything. They distort the tone as follows, but these changes may not be apparent in frequency response charts. The differences are extremely obvious to me from listening.

Source page with a standard explanation:
http://milbert.com/articles/tubes_vs_transistors_perception

Tube amps have similar characteristics to a greater of lesser degree. I generally hear low-end rumble with the bass, a more dynamic or abrupt onset with all notes, a warmer and huskier mid range, and a mellower top end. This profile is routinely used in the studio with vocals, blues, rock, and more–it can be recognized during playback on a solid state playback amp. You’ve heard tube production amps a million times…

Rock guitar takes distortion much farther, and goes into pure electrical torture. However, this is not used for playback. Sample guitar distortion effects (layered onto tubes) include:

I have three modestly priced hybrid tube headphone amps, and one guitar hybrid tube amp. Comments on tone:

  1. Bravo Audio V2 (tiny little headphone amp; about $65): Tons of distortion and limited image/clarity. But it can be fun for casual listening. This is an entry level product and I outgrew it.
  2. Loxjie P20 ($99): As discussed in this thread, it offers the tube profile with decent clarity and imaging per the balanced architecture. It works best with clean and neutral headphones, as warm headphones get too fuzzy for me.
  3. Massdrop CTH ($250): The least tubey of the three, with a modest background shimmer and added punch. Cleaner than the V2 by a wide margin.
  4. Blackstar HT1R (guitar amp; $350 if purchased new): Just twist the knob to shift from a clean, neutral sound to blues to hard rock and heavy metal. The intensity and distortion changes dramatically. It sounds roughly the same as a solid state to the 50% gain mark, and then goes from warm to rough to ragged.

Note that hearing or caring about the tube tone varies between people. For example, Audio Science Review tends to discount hybrid tube amps as ineffective, but I personally disagree with the listening tests at that site. A direct way to evaluate the impact of tubes is to visit a music store and try an electric guitar with REAL TUBE amps from the following companies. No software, no solid state simulators allowed!

  • Fender: clean tone found with The Beach Boys or mainstream pop
  • Vox: chiming or ringing tone of The Beatles, The Byrds, or jangle pop
  • Marshall: lots of rough harmonic distortion common to classic rock and hard rock
  • Mesa/Boogie: most heavy metal after Metallica

#40

[Listening to Old Releases as Intended, and Describing the Need for Tube Amps]

Bonus Content: A very special long-winded rant about 1980s music

TLDR: The original release of XTC’s Skylarking (1986) was arguably too bright and remastered/re-released with a phony controversy in 2010 – but the original version sounds wonderful through the tubes of the Loxjie P20!

One of the best remembered ‘college rock’ albums from the 1980s is XTC’s Skylarking. In the 1970s there was arty/classical Progressive Rock and this name was briefly applied to 1980s post-Punk music. However, ‘progressive’ was a gross misnomer so the label quickly changed to Alternative Rock or College Rock, as no one else would play it during the Michael Jackson, Madonna, and hair metal era. The Replacements Left of the Dial song directly commemorates the college rock era. These days this genre is called Indie, and Skylarking has stood the test of time far better than hair metal.

Skylarking received widespread acclaim upon its release, and was ranked near the top of many critics charts. What made it special was the superb production of Todd Rundgren. He was an influential record industry figure of the day with a strong track record, to include production of Meatloaf’s Bat Out of Hell album. He was seemingly brought in to make XTC’s music better, and succeeded with Skylarking. The nuanced songs flow together as a true album rather than random collection of music, and the subtle effects are just perfect. Other than this album, XTC was a forgettable band of the era.

I believe this was a pretty common assessment of XTC’s body of work, and it apparently got under the skin of the leader/singer (Andy Partridge). He also famously feuded with Todd Rundgren during the creation of Skylarking. So, in 2010 Mr. Partridge “discovered” Mr. Rundgren’s polarity error and released a “fixed” version of his one and only masterpiece. He also was finally able to replace the well-regarded and artistic original 1986 album cover with his own previously censored near-pornographic cover in 2010 [See Wikipedia link.]

I just played my original 1986 CD version of Skylarking through the Loxjie P20 and Elex. It sounds absolutely wonderful. This original has low gain, as was typical of albums released before the 1990s (i.e., keep all the dynamics and turn up the volume yourself). But I don’t hear any significant technical flaws.

My conclusion is that Mr. Partridge made a fool out of himself due to stubborn pride and competitiveness, or perhaps based his criticisms on the (then popular) thin and bright digital systems of the day. Mr. Rundgren, as a professional with experience dating back to the 1960s, likely understood and used tube amps during his work.

Quote from Wikipedia on the so-called polarity/mastering issue:

Rundgren commented: “I think it’s total bullshit. But if such a thing existed, it’s because they changed the running order on it and had to remaster it – which I had nothing to do with.”