Loxjie A30 Amplifier Review

[voodooless]

Modded Loxjie A30

Why?

I’ve changed the coupling capacitors from my unit, it shipped originaly with 22uf 35v Muse capacitors between the NJW1194 and MA12070, i put metal film polyester 1uf, that config puts the unit in low gain mode.

Not, it does not! Gain is selected via a software register, you cannot configure this in hardware. The only thing you did is raise the high pass frequency by a bit.

The Next was the output coupling capacitor, ir shipped with 3300uf eletrolytics, i ordered some solid types with 1000uf, the maximum capacitie i found on internet, but datasheet recommends 470uf, so its enough,

As far as I can see, the design doesn’t have any coupling caps on the output. The datasheet only shows them for a 4-channel single ended configuration, which the A30 doesn’t use. So you only lowered the the power supply capacitance and by that lowered the PSRR.

the fact with this is it has much faster transient response and quicker charge and discharge habilitie so more fidelitie on speakers

Is that a fact? Do you have any proof? How would that even work?

The final result was awesome on ears, i cant believe how good the change was, feels like im wearing headphones now.

It may not have hurt audibly, but it certainly would not have made a measurable improvement.

For who wanna try this mod, believe me, you Will not be disapointed .

Best not do this

 

[antcollinet]

Modded Loxjie A30



I’ve changed the coupling capacitors from my unit, it shipped originaly with 22uf 35v Muse capacitors between the NJW1194 and MA12070, i put metal film polyester 1uf, that config puts the unit in low gain mode.

The Next was the output coupling capacitor, ir shipped with 3300uf eletrolytics, i ordered some solid types with 1000uf, the maximum capacitie i found on internet, but datasheet recommends 470uf, so its enough, the fact with this is it has much faster transient response and quicker charge and discharge habilitie so more fidelitie on speakers

The final result was awesome on ears, i cant believe how good the change was, feels like im wearing headphones now.

For who wanna try this mod, believe me, you Will not be disapointed .

Have you calculated (or measured) the impact on the frequency response.

By chaning the input capacitor value you wlll likely be rolling off the bass now. Perhps not a problem if your speakers don't go down that low anyway but certianly a problem if you want to get bigger speakers later.

Again, the output coupling capacitors significantly impact the low frequency response (they form a filter with the load impedance). Reducing those by a factor of 3 will shift the bass roll off frequency upwards by a similar factor. 1000uF may be OK (according to the data sheet, but I'd want to measure it) for 8ohm speakers, but for 4ohm, you may now be filtering out bass below about 50Hz.

I suspect if your modded amp was tested it would be getting a headless panther due to unacceptable frequency response.


Summary : By changing capacitor values willy nilly without calculating the effect on the circuit, you are going to dramatically change the performance of the device - and the values have been chosen by the design engineers for a reason - you won't be making the performance better.


EDIT - and if you have actually changed PSU caps rather than output couplers, as suggested by @voodooless , what are you thinking? If you don't know enough to even identify the function of the parts you are changing, you have no business doing anything. Best case, you might not actually kill your amp.

 

[Ismapics]

Modded Loxjie A30



I’ve changed the coupling capacitors from my unit, it shipped originaly with 22uf 35v Muse capacitors between the NJW1194 and MA12070, i put metal film polyester 1uf, that config puts the unit in low gain mode.

The Next was the output coupling capacitor, ir shipped with 3300uf eletrolytics, i ordered some solid types with 1000uf, the maximum capacitie i found on internet, but datasheet recommends 470uf, so its enough, the fact with this is it has much faster transient response and quicker charge and discharge habilitie so more fidelitie on speakers

The final result was awesome on ears, i cant believe how good the change was, feels like im wearing headphones now.

For who wanna try this mod, believe me, you Will not be disapointed .

Hello as a Loxjie A30 owner I am curious about you mods. I really like it as is. The only comment that I would add is that this community - I am sure you are completely aware - looks at circumstantial observations differently than objective ones. So I ask you, again you don't need to address this, after doing the mods, would you have been able to discern real differences. Al in good spirts , cheers. im

 

[mARCELOCM]

Ok, as o said my unit had come with 22uf ac coupling caps, in the ma12070 datasheet has the image shows, os recommended 2,2uf for high gain, 26db, and 1uf for low gain, 21db, is not by software, and the pvdd coupling capacitor also have a table with values, with my speaker, Cambridge audio sx-50, that are 8ohms i choose the 1000uf, that gives -3db at 20hz, my speaker -3db is 50hz, so no complaint.

In reality o bought this amp for the good review amir give it, but when i heard it for the first time i really dont like how it sounded, it was so muffled, besides the good measurements, i was almost puting it to sale and i decided to mod it, and it gave it a much more lifelike sound, much more dynamics and the spacialization, i dont have how to send it to amir review it, because i live in other country, and decided to share the mod with you guys for who wanna try, it wont kill your amp, maybe you like or not, now im in love with my loxjie, and that is what is important to me.

 

[voodooless]

Ok, as o said my unit had come with 22uf ac coupling caps, in the ma12070 datasheet has the image shows, os recommended 2,2uf for high gain, 26db, and 1uf for low gain, 21db,

These are just the the minimum values needed to not have too much bass roll off. They are different for the gain settings because the input impedance changes when you change the mode. Bigger value has no impact other than lowering the bass roll off point.

is not by software,

It is most definitely software. Look at chapter 16, page 78, address 0x25.

and the pvdd coupling capacitor also have a table with values, with my speaker, Cambridge audio sx-50, that are 8ohms i choose the 1000uf, that gives -3db at 20hz, my speaker -3db is 50hz, so no complaint.

It’s power supply caps, not coupling! The table you show is irrelevant to the design! It uses this configuration:

No coupling caps needed!

 

[Unroqqbar]

So i bought the Loxjie A30 to use with my PC.
I connect it via USB. And I have Q acoustics 3020i's.

Now after reading this thread, im not sure if i made the right choice.

Apperently the USB Input just uses the cheap DAC and not the good one?
And the Headphone-Connection-Amp isnt great either?

I am looking for an All in One DAC/Amp Solution for my PC Desktop with USB Input, Speakers connection (priority) and Headphone connection for some light gaming/voice chat.
So did i make a mistake getting the A30 for my use case?
What could you recommend for around 300€?

 

[voodooless]

Apperently the USB Input just uses the cheap DAC and not the good one?

I wouldn’t worry too much about it. The amp SINAD is still worse than that of the DAC, so it doesn’t really matter.

And the Headphone-Connection-Amp isnt great either?

It’s not super powerful. Depending on your headphone it may be enough. For serious headphone you may be better off with something else.

 

[Zek]

What could you recommend for around 300€?

Look at SMSL AL200 or new SMSL AO300.

 

[Unroqqbar]

I wouldn’t worry too much about it. The amp SINAD is still worse than that of the DAC, so it doesn’t really matter.

It’s not super powerful. Depending on your headphone it may be enough. For serious headphone you may be better off with something else.

I dont really know what you mean with amp SINAD.
Is this still better than just connecting my headphones or speakers directly to my PC via 3,5mm? Or is there no difference when im using the cheap DAC?
You see im very new to this, So i guess it doesnt matter for me either way?
I just dont want to have made a bad buying choice..

I have Sennheiser HD 599‘s, they dont sound bad, but not amazing either.
My q acoustics will arrive tomorrow, so i cannot comment on the sound yet.

 

[antcollinet]

So i bought the Loxjie A30 to use with my PC.
I connect it via USB. And I have Q acoustics 3020i's.

Now after reading this thread, im not sure if i made the right choice.

Apperently the USB Input just uses the cheap DAC and not the good one?
And the Headphone-Connection-Amp isnt great either?

I am looking for an All in One DAC/Amp Solution for my PC Desktop with USB Input, Speakers connection (priority) and Headphone connection for some light gaming/voice chat.
So did i make a mistake getting the A30 for my use case?
What could you recommend for around 300€?

Are you happy with the sound? Even relatively poorly measuring modern devices are usually still better than our hearing is able to make use of.

If you already have it - it is fine unless you are hearing something obviously wrong.

 

[mszczuwoj]

A question to Loxjie A30 users I guess - can you disable Bluetooth in Loxjie A30? I mean to turn off the BT radio, so that it's not transmitting anything.
It's possible in Topping MX5, but I can't find such an option in the A30 manual...

 

[Ismapics]

A question to Loxjie A30 users I guess - can you disable Bluetooth in Loxjie A30? I mean to turn off the BT radio, so that it's not transmitting anything.
It's possible in Topping MX5, but I can't find such an option in the A30 manual...

Hello: I just turned on the A30 to USB, no BT signal is detected by any of my tablets or my iPhone. Only when BT is selected that any signal appears as option to pair. Hope this answers your question.

 

[mszczuwoj]

Hello: I just turned on the A30 to USB, no BT signal is detected by any of my tablets or my iPhone. Only when BT is selected that any signal appears as option to pair. Hope this answers your question.

Yes it does! Thank you for verifying this.

 

[BPM]

Question:
Bought an American Audio TT2400 turntable and since it has a RIAA built in I’m thinking of connecting it to my A30. Problem is ground.. Is there any screw on the bottom or on the back of the A30 I can use to connect the ground-cable?

 

[antcollinet]

Question:
Bought an American Audio TT2400 turntable and since it has a RIAA built in I’m thinking of connecting it to my A30. Problem is ground.. Is there any screw on the bottom or on the back of the A30 I can use to connect the ground-cable?

With the TT having built in preamp it is likely that the ground via RCA is good enough when using it. Try it - if you get no audible hum/noise you are good to go.

 

[Boegmunken]

Did someone else notice that the SUB OUT volume doesn't really increase after 30-35 together with the speaker volume?

Anyone got a fix for this?

 

[BPM]

With the TT having built in preamp it is likely that the ground via RCA is good enough when using it. Try it - if you get no audible hum/noise you are good to go.

Works like a charm! Thanks!

 

[Boegmunken]

Anyone find the main volume a little too low using USB? Because of this, my subwoofer volume is too loud even with the sub gain at its lowest.

If I use analog-in or Bluetooth, volume is fine.

To match the analog-in volume with USB, I have to set Windows volume to 62 for analog, and 95 with USB. When measuring with REW with mic at 3 feet, volume on the A30 via USB needs to be set to 26 for 75db.

Sub volume on my SMSL AD18 is fine. I'd have to increase the sub gain using the AD18.

Did you ever find a solution for this?

 

[CauliflowerEars]

1. How do you guys connect Apple iPhone (Lightning Out) -> Loxjie a30 (Optical TOSLINK/SDPIF Input)? The cheaper, the better, as this is for a 2nd (cheap) setup.
2. If I'm correct, the Loxjie a30's Optical input is better sound quality, than the Micro-USB input?

 

[Ismapics]

1. How do you guys connect Apple iPhone (Lightning Out) -> Loxjie a30 (Optical TOSLINK/SDPIF Input)? The cheaper, the better, as this is for a 2nd (cheap) setup.
2. If I'm correct, the Loxjie a30's Optical input is better sound quality, than the Micro-USB input?

I would use the USB adapter and feed it to the A30 in the USB input. They sell an adapter called the Apple Camera adapter. Has both USB and Lighting for power. From that USB you can connect drives and dacs. Apples nomenclature is Lightning to USB 3 Camera Adapter