Topping PA5 II Stereo Amplifier Review

[john11]

If same as PA5 : 10K

A lot of amps use a 10k resistor and a capacitor as part of the input filter, do you know which is the input filter cap for the PA5 II

 

[daniboun]

A lot of amps use a 10k resistor and a capacitor as part of the input filter, do you know which is the input filter cap for the PA5 II

I dont have the PA5 II... Only the PA5
But if same as the PA5 should be exact

 

[TheLastGerman]

Does anyone know the type of plug fitted to the power supply of the PA5 II?

 

[daniboun]

Does anyone know the type of plug fitted to the power supply of the PA5 II?

Yes ) GX12, 2 pins :

Amazon.fr

I made my own PSU for the PA5 as well )

 

[TheLastGerman]

Yes ) GX12, 2 pins :

Amazon.fr

I made my own PSU for the PA5 as well )

View attachment 316322View attachment 316323

Great, thank you!

 

[john11]

I dont have the PA5 II... Only the PA5
But if same as the PA5 should be exact

Do you know which is the input cap. They are all 220uf aluminium electrolytics around the input stage, would have thought the input cap would be a lot smaller than that and be a polypropylene film cap

 

[anli]

They are all 220uf aluminium electrolytics around the input stage

What is the source of the information? Such cap looks more appropriate as rectifier one for opamp power lines.

 

[daniboun]

What is the source of the information? Such cap looks more appropriate as rectifier one for opamp power lines.

Not sure, but try to check here, many pictures from inside :

Topping PA5 II Stereo Amplifier Review

Any link with reliable measurements ? I saw that the new model (July 2022) is now using a fully differential chain + PFFB enabled. For 220W/4R you will need a solid 48V PSU For a finished amp count about $ 400 with an aluminium case. + good Connex PSU Meanwell / Morsun + connectors etc I’d...

www.audiosciencereview.com

 

[anli]

Not sure, but try to check here, many pictures from inside :

Topping PA5 II Stereo Amplifier Review

Any link with reliable measurements ? I saw that the new model (July 2022) is now using a fully differential chain + PFFB enabled. For 220W/4R you will need a solid 48V PSU For a finished amp count about $ 400 with an aluminium case. + good Connex PSU Meanwell / Morsun + connectors etc I’d...

www.audiosciencereview.com

Have not noticed any signs there the caps are in signal path.

 

[john11]

Yes, the caps do look like they are for the input op amp, am wondering as amps do usually have an input filter usually consisting of a resistor and capacitor. Danioun mentioned the input impedance of the PA5 II is 10 kohms so am wondering where the input cap is

 

[anli]

Yes, the caps do look like they are for the input op amp, am wondering as amps do usually have an input filter usually consisting of a resistor and capacitor. Danioun mentioned the input impedance of the PA5 II is 10 kohms so am wondering where the input cap is

All my own amps/schematics work from 0Hz (that is without capacitor in signal path). If this is the same case, why not?

 

[guddu]

Yes ) GX12, 2 pins :

Amazon.fr

I made my own PSU for the PA5 as well )

View attachment 316322View attachment 316323

are you aware of any adaptor from this GX12 2 pin to standard DC power supply jack?

 

[daniboun]

are you aware of any adaptor from this GX12 2 pin to standard DC power supply jack?

As far as I know no...
But you can make your own cable easy to do ) no need to have strong soldering skills

 

[guddu]

As far as I know no...
But you can make your own cable easy to do ) no need to have strong soldering skills

Thanks

 

[daniboun]

Thanks

If you do it. Make sure your cable can handle up to 5A

 

[Roland68]

Yes, the caps do look like they are for the input op amp, am wondering as amps do usually have an input filter usually consisting of a resistor and capacitor. Danioun mentioned the input impedance of the PA5 II is 10 kohms so am wondering where the input cap is

All my own amps/schematics work from 0Hz (that is without capacitor in signal path). If this is the same case, why not?

If there are electrolytic capacitors in the signal path (and that is very likely), then there will be 4 identical capacitors with approx. 10uF for DC suppression in the signal path. That's why a quad potentiometer is installed to operate the 4 signal paths.

 

[daniboun]

Have not noticed any signs there the caps are in signal path.

Maybe looking at the back of the PA5 pcb could help ?

 

[Roland68]

Maybe looking at the back of the PA5 pcb could help ?

View attachment 316793

This is the picture of the old PA5 board. These caps are in the signal path.

 

[TheLastGerman]

This is the picture of the old PA5 board. These caps are in the signal path.
View attachment 316844

I checked the capacitors in question in my Pa5 II: The marked ones have a ground reference, all others do not. The latter are therefore most likely in the signal path. I am tempted to swap the unmarked ones for Nichicon Muse bipolars ...

 

[john11]

I checked the capacitors in question in my Pa5 II: The marked ones have a ground reference, all others do not. The latter are therefore most likely in the signal path. I am tempted to swap the unmarked ones for Nichicon Muse bipolars ...

View attachment 316891

You could swap all the caps out. Try panasonic fm as replacements, these are cheap with high ripple current and low esr a favourite in the modding community. For the signal path you can't go wrong with silmic II. Try touching up the soldering joints as well. Also I cleaned both sides of my board with alcohol to remove any flux or crap left over from the manufacturing process then applied conformal coating. This protects from possible arcing if high voltage / current tracks are close and also protects from moisture.
The panasonic fm go up to 1000uf so i took out the big rubycon and replaced it with 2 x 1000uf and 1 x 100uf panasonic fm - amp sound better now, more detail