[Onik]

video for non german speakers who are rolling op amps on p20: ""

 

[JazzArtist123]

Figured I’d post my thoughts on this Loxjie P20 amp since I’ve been using it for about half a year now. IMO, this little amp is only worth it if most of your headphones can use a balanced connector (because the single-ended output is quite noisy) and if your DAC has balanced outputs it can connect to this amp’s balanced inputs. Using the RCA inputs with the balanced headphone output on this amp is still good, but balanced in + balanced out is the way to go with this amp.

As is, I think it just sounds ok; it needs some upgrades to sound great. The first upgrade is the power supply, I bought the Jameco Reliapro KPL-060F power supply along with a Tripp Lite P007-006 Power Cord, 14AWG. Next, I had some Dim It Light Dimming Sheets (basically static cling tint film) lying around so I cut a part of that to cover up the ridiculously bright blue LED screen - much better with the dimming sheet applied. Third, I got some 9-pin tube socket savers, which accomplished several things at once: 1) it raised up the tubes so they could more efficiently dissipate heat and the amp wouldn’t get so hot, 2) it covered up most of the blue LEDs coming from inside the amp, and 3) it allowed me to use shorter tubes if I wanted.

I tried the 6N3P-E tubes, which instantly sounded better than the stock tubes. I also tried the JAN-5670W GE tubes, but I liked the 6N3P-E tubes better. I lastly tried the GE 5670 5 Star tubes and liked them the best. I have not tried the 6N3P-DR tubes, maybe at some point in the future, I will try them.

I’ll note three of the headphones I’ve used this amp with (@dimoniet79 this might answer your question): The Sennheiser HD600, the AKG K712 Pro, and the Beyerdynamic DT880 600 ohm. I’ve modified all three of those headphones to run balanced and this little amp has no problem powering any of those three headphones. The DT880 600 ohm takes the most power, but it is only powered enough by the balanced output, not on the single-ended output. The HD600 and AKG K712 Pro can be powered just fine by this amp’s single-ended output, but as I said earlier, the balanced output is really what you want to be using on this amp because its noise floor is way lower than that of the single-ended output.

With all these upgrades (including at least the JAN-5670W GE tubes), if I’m using the balanced in + balanced out configuration on this amp, I enjoy listening to this Loxjie P20 more than my THX AAA 789 (my DAC being the Topping DX7s). If I ever must use the RCA inputs on the amp (my DAC being the Sennheiser GSX 1000), then it’s a very close call between the Loxjie P20 and the THX AAA 789, but I must give the edge to the THX in this case. If I must use the single-ended output on the amp, then the THX AAA 789 for sure sounds better than this Loxjie P20. Hope this helps future readers trying to decide what amp to buy.

 

[Sebasistan]

I can go next.

I had my P20 since October. It's running off of the balanced out of my ifi ZEN DAC, and I got an XLR-> 4.4mm balanced adapter for my headphones.
It's my first amp, so I lack comparisons to other, similar setups. Out of the box it was an improvement on the ZEN DAC alone. I did get a matched set of 6N3P 2C51 tubes to replace the stock ones which people on here said would improve the sound. After running with those for a bit I ended up going back to the stock tubes. I prefer that sound over the others.

I am mainly using the P20 with the Takstar 82 Pro which match pretty well. Generally to me the P20 sounds pretty good with all my headphones. The 82 Pro sound pretty amazing to begin with, and even better off of the tubes. I guess the biggest improvement between my Shanling M6 and the P20 happens with my Meze 99 Neo though. They sound pretty good off of the DAP, but pair really well with the P20.

I'm not sure if I want to keep fiddling with this. I like the tube sound of the stock tubes over the more analytical 6N3Ps. If any of y'all can recommend a set of tubes that sounds better while also sounding "tube-y", I might reconsider. But overall I'm fairly happy with my setup now. It's not much but it's honest work - I mean it's nothing super fancy, but to my ears / budget / sensibilities it's kinda endgame. As in, I know there's better gear, but at this point, the stuff I have is already so good that to get marked improvements to the sound would require exorbitantly higher expenditures, i.e. diminishing returns.

 

[Basick]

I'm getting a P20 soon and I've ordered 4pin XLR to 2x 3.5mm cable for balanced output to my HE-4XX. Question is, since I do not have a DAC, is it worth buying a 2x XLR to TRS (3.5mm) that plugs the amp to my PC's audioport? Or would a TRS to RCA suffice?

Thank you!

 

[SoLame]

I'm getting a P20 soon and I've ordered 4pin XLR to 2x 3.5mm cable for balanced output to my HE-4XX. Question is, since I do not have a DAC, is it worth buying a 2x XLR to TRS (3.5mm) that plugs the amp to my PC's audioport? Or would a TRS to RCA suffice?

Thank you!

IMHO, since you don't have a source (DAC, comp, etc.) that can feed balanced signal to the P20, you gain nothing, at this moment, from spending money on those 'balanced' cables.

 

[Basick]

IMHO, since you don't have a source (DAC, comp, etc.) that can feed balanced signal to the P20, you gain nothing, at this moment, from spending money on those 'balanced' cables.

So even the XLR cable feeding into my headphones won't do anything since I don't have a DAC?

 

[DBaldock9]

IMHO, since you don't have a source (DAC, comp, etc.) that can feed balanced signal to the P20, you gain nothing, at this moment, from spending money on those 'balanced' cables.

The P20 does have a phase splitter on the input - so it can take either Single-Ended (RCA) or Balanced (2x 3-Pn XLR) Inputs, and drive headphones on the Single-Ended (1/4") or Balanced (4-Pin XLR) Outputs.

 

[Basick]

The P20 does have a phase splitter on the input - so it can take either Single-Ended (RCA) or Balanced (2x 3-Pn XLR) Inputs, and drive headphones on the Single-Ended (1/4") or Balanced (4-Pin XLR) Outputs.

So does this mean I can still reap the benefits of a "fully balanced" setup with what I have? (4pin XLR to 2x 3.5mm output to headphones, and TRS (3.5mm) to 2x 3pin XLR input from my computer audio port)

 

[JazzArtist123]

@Basick, while the TRS (3.5mm) to 2x 3pin XLR cable should work for providing an input to the Loxjie P20, I do not know if it will provide benefits over just getting a 3.5mm to 2x RCA cable as you will not be benefiting from common-mode rejection (you could buy both and see if one clearly sounds better than the other, but I'll leave that up to you).

Also, it's unclear to me what the 4pin XLR to 2x 3.5mm cable is doing (why is it going to two 3.5mm female plugs? Are these wired for standard 3.5mm headphones, or is this creating the obscure 3.5mm balanced connection? If it's the balanced 3.5mm connection, I am not sure if this will work on your HE-4XX).

Can you provide more details on what 4pin XLR to 2x 3.5mm cable you're looking at?

 

[JazzArtist123]

@Basick, if you were to buy, say the "Geekria Apollo 4.4mm Male to 3.5mm Female" (which is unbalanced, or standard, 3.5mm Female, according to reviewers on Amazon) along with the "4 Pin XLR to 4.4mm Female Balanced 5 Pole Silver Plated Audio Headphone Adapter Cable 20CM", that would most likely work better with your HE-4XX. However, please read below:

Is there anyone else who has tried something like this? I'm only speaking from theory, not from experience. I don't know if there are any electronics that would short inside the amp if you used this type of connection on the balanced headphone output of the Loxjie P20. Does anyone know more about the circuitry inside this amp who could speak to this?

 

[Basick]

@Basick, while the TRS (3.5mm) to 2x 3pin XLR cable should work for providing an input to the Loxjie P20, I do not know if it will provide benefits over just getting a 3.5mm to 2x RCA cable as you will not be benefiting from common-mode rejection (you could buy both and see if one clearly sounds better than the other, but I'll leave that up to you).

Also, it's unclear to me what the 4pin XLR to 2x 3.5mm cable is doing (why is it going to two 3.5mm female plugs? Are these wired for standard 3.5mm headphones, or is this creating the obscure 3.5mm balanced connection? If it's the balanced 3.5mm connection, I am not sure if this will work on your HE-4XX).

Can you provide more details on what 4pin XLR to 2x 3.5mm cable you're looking at?

https://m.aliexpress.com/item/10050...tedetail&spm=a2g0s.9042311.0.0.40694c4dvBfXJZ

I bought these (the two 3.5mm will be plugging directly into the headphones)

 

[DBaldock9]

It is OK to have a Single-Ended Output drive a Balanced Input - but you don't get the "induced noise" reduction that Balanced Out to Balanced In provides. This doesn't mean that your system will be noisier, just that it could be noisier.

It's usually NOT OK to have a Balanced Output drive a Single-Ended Input - because the Balanced (L-) & (R-) signals are separate amplifier channels, but the Single-Ended Input has a common L & R GND - and you will generally damage the amplifiers when shorting (L-) to (R-).

 

[Basick]

It is OK to have a Single-Ended Output drive a Balanced Input - but you don't get the "induced noise" reduction that Balanced Out to Balanced In provides. This doesn't mean that your system will be noisier, just that it could be noisier.

It's usually NOT OK to have a Balanced Output drive a Single-Ended Input - because the Balanced (L-) & (R-) signals are separate amplifier channels, but the Single-Ended Input has a common L & R GND - and you will generally damage the amplifiers when shorting (L-) to (R-).

So what you're saying is that since I'm driving a balanced output (4pin XLR to 2x 3.5mm) that I should also run the 2x 3pin XLR to TRS cable for the input from my computer to the amp

 

[DBaldock9]

So what you're saying is that since I'm driving a balanced output (4pin XLR to 2x 3.5mm) that I should also run the 2x 3pin XLR to TRS cable for the input from my computer to the amp

No, not necessarily. If your audio signal, using the Single-Ended Input on the P20, doesn't have background noise - everything is OK.
If you do hear audible noise when using the Single-Ended Input, then try getting a device (PC sound card, or external DAC) with a Balanced Output to feed the Balanced Input.

 

[Basick]

Seeing as though I will have to buy either cable regardless (the TRS to XLR or the TRS to RCA), which would be a more appropriate choice for me?

If I'm understanding it correctly, you're suggesting the TRS to RCA first and if I hear no noise, then all is well. However, if I do hear noise then buying an external DAC with a balanced feed into the amp and computer would solve the noise issue.