[Ufanco]

@Ufanco I have been hesitating to buy Oriolus. Some mixing reviews and also the fact that it does not have a volume control.
Could you please tell me what equipment are you pairing with it ?
Thanks !

Shanling M6 pro 21 and mest mkii. Bought the Loxjie p20 to see if i liked the tube sounds and since I did, decided to try out the Orioles.
There are some people on here that are using with a ibasso 312 and mest mkii and are pleased with sound so figure it is worth a shot. The new model of the Orioles now longer has the 3db of gain so be using volume on the Shaling instead of the line out.

 

[Audiophile PT]

Shanling M6 pro 21 and mest mkii. Bought the Loxjie p20 to see if i liked the tube sounds and since I did, decided to try out the Orioles.
There are some people on here that are using with a ibasso 312 and mest mkii and are pleased with sound so figure it is worth a shot. The new model of the Orioles now longer has the 3db of gain so be using volume on the Shaling instead of the line out.

After having tried the Loxjie P20 (which I like with the ge5670 tubes) I decided to go a little further and got the Xduoo TA-20 which is of course better (although pricier).
I'm enjoying the sound of TubeAmps and now I'm looking for a portable solution.
The Oriolus BA300S is an option and the other one on my list is the Cayin C9, but the ideal was to find something in between prices...!
Cayin N3Pro is also an option, but there are users reporting serious problems with the volume control knob !

 

[DBaldock9]

Does balanced headphone output work if you input rca unbalanced signal?

Loxjie P20 works RCA SE input to balanced output. It’s not the best signal path available (balanced to balanced) but it will play.

Back near the digital volume control chip, there's a NE5532 (SOIC-8) op-amp, that appears to be the phase splitter to make the L- and R- from the L+ and R+ inputs on the RCA jacks. It's possible that swapping in a different op-amp could improve the sound of the Single-Ended inputs.

 

[Cobra71]

Hello, I'reading for some time in headfy org, but never postet something till now.
I also own two P20 and one of it stopped working from one day to the other.
I can switch it on but there is no sound, balanced or unbalanced inputs and outputs.
On the working one there is a short click after switching from unbalanced to balanced, but on the non working one there is no click.
I opened it and the first input capacytor at the 12V input was blown of an had 220yf instead 330.
I changed ist with a working one, but that was'nt the problem.
I measured all the voltages at the testpoints on the board and all are ok, the tubes are glowing.

Did anybody has a complete schematic from the P20 and an idea where could be the problem?

 

[lantian]

Hello, I'reading for some time in headfy org, but never postet something till now.
I also own two P20 and one of it stopped working from one day to the other.
I can switch it on but there is no sound, balanced or unbalanced inputs and outputs.
On the working one there is a short click after switching from unbalanced to balanced, but on the non working one there is no click.
I opened it and the first input capacytor at the 12V input was blown of an had 220yf instead 330.
I changed ist with a working one, but that was'nt the problem.
I measured all the voltages at the testpoints on the board and all are ok, the tubes are glowing.

Did anybody has a complete schematic from the P20 and an idea where could be the problem?

Check if the relay is in order, seems like might have died.

 

[Cobra71]

Thx for the answer, the one relay behind the xlr connector has gnd and 12V, so it seems so that it is switched.
The other relay behind the led screen has 12V and 11,9V on the Input, so it can't switch.
I'm not sure where the relays are for, one for switching between balanced and unbalanced and the other a mute relay?

 

[lantian]

Thx for the answer, the one relay behind the xlr connector has gnd and 12V, so it seems so that it is switched.
The other relay behind the led screen has 12V and 11,9V on the Input, so it can't switch.
I'm not sure where the relays are for, one for switching between balanced and unbalanced and the other a mute relay?

Yes, should be configured like that, one mutes and the other switches between them, if either one is dead signal won't get through.

 

[Cobra71]

OK, i will try if the other relay works by switching between balanced and unbalanced.
Am I right that boths relays will bei driven by the chip behind the volume knob?

EDIT: I switched back and force between both inputs and outputs and in no case one of the relays got 12V on the coil, it is nearly 0V.
The resistance of the coil of both relays is ~550 Ohm, that's the same value like in the specifications of the relays, so it couldn't be a shorted "freilaufdiode" or broken coil.

All OP's have both voltages +16V and -16V and on all other legs I measure 0,08V against ground.

In germany we say "I'm at the end of my latin"

EDIT2: One step further...I pulled the gnd pin of the coils to ground with my amperemeter, the relays switch and I got Music out of the P20 and it sounds clear and good.
The Problem could be the transistors that pull the coils to ground or the cpu that does the job has a problem.
But its the same cpu that does the volume regulation and input / output configuration, so the cpu himself works.

 

[DBaldock9]

OK, i will try if the other relay works by switching between balanced and unbalanced.
Am I right that boths relays will bei driven by the chip behind the volume knob?

EDIT: I switched back and force between both inputs and outputs and in no case one of the relays got 12V on the coil, it is nearly 0V.
The resistance of the coil of both relays is ~550 Ohm, that's the same value like in the specifications of the relays, so it couldn't be a shorted "freilaufdiode" or broken coil.

All OP's have both voltages +16V and -16V and on all other legs I measure 0,08V against ground.

In germany we say "I'm at the end of my latin"

EDIT2: One step further...I pulled the gnd pin of the coils to ground with my amperemeter, the relays switch and I got Music out of the P20 and it sounds clear and good.
The Problem could be the transistors that pull the coils to ground or the cpu that does the job has a problem.
But its the same cpu that does the volume regulation and input / output configuration, so the cpu himself works.

(Emphasis added)

It's interesting that your P20 has ±16 VDC at the op-amps.
The P20 I bought several years ago has ±18 VDC at the 4x DIP-8 sockets (one of the mods I installed) - which limits the variety of op-amps that can be tried in the amp.
Since the ±18 VDC comes from the custom switching power supply transformer (near the back panel +12 VDC input jack), and not from any "user" adjustable voltage regulators, I'm stuck with that high voltage.

Does your amp have a Revision number or letter listed on the circuit board silkscreen?
When I get home from work this evening, I'll post whether my P20 has a Revision listed.

 

[Cobra71]

I am at work, but at the weekend I will look for a revision on the Board.

I located the area where the relays will be switched from.

It is the section with the transistors over the cpu.

The both ones in the middle of the transistor network are connected to the ones in front of the relays.



I wonder where they are connected with, and if it could be a voltage monitoring that stops switching relays when voltages aren't ok.
I will check th +/-18V patches and the capacitors for that, because I have only around 16V at both.

 

[Cobra71]

 

[DBaldock9]

I didn't see any Revision info on the top of the circuit board, or the outside of my P20's case.
.
This is a photo of the ±18 VDC test points, which come from the little square transformer, and feed the op-amps -
.

 

[Cobra71]

The both electrolyte capacitors have 670yf an 640yf, I think that's OK for 680yf caps.

Am I right that from the 12v DC would made a oscillating circuit that feed the little transformer with ac that has two outputs.
These outputs use one diode and the 680yf cap to do the 18v dc in positive and negative line.
From these both the two voltage regulators produce the negative and positive 7V dc?

It's the question if the caps with 670 and 640 are enough to built stable 18v from the single diode dc.

 

[Cobra71]

I measured that the 115V for the heater also only has 111V, the ac for the 18V only has 34,5V and both DC. Voltages have 15,64V instead 18V.
The circuit in front of the transformer oscillates with 45 kHz.
The quistion is if these voltages are. Critical and part of the main problem.

 

[trollchu]

Yesterday, my Loxjie exhibited some type of power failure where it wouldn't boot and instead would flick on and flick off. Not assuming it was the amp, I assumed that the power supply was the cause and tested the Loxjie with a different 12v power supply and my Loxjie actually went up in smoke making me realize that maybe my issue was indeed my amp. The smoke seemed to stem from the (internal) rear of the unit near the power input and my unit is roughly three years old, any tips on my next course of action? I would like my Loxjie to live.