Topping PA5 Review (Amplifier)

[AudioArchitech]

Useless as you do not know the input impedance of the amp and what blocking cap is in these.
Amps run from 10 to 50K typically.

You can get a simple crossover from folks like Rolls. Not as bad as it looks. You can DIY a really good crossover like the X-Kitx. I agree with your want. A really good 2nd order HP filter for the mains. I suggested that to a couple companies. In the mean time, I am just doing my own.
If more people asked, maybe someone would produce one. People like JDS, SMSL, Topping and Schiit have proven you can make a very very good preamp very cheap, so a $100 box seems reasonable.

Yes, really hoping to find out those values so I could build some PLLXO's

 

[Martinvb]

So now I have ls50 meta to test the pa5 with. Sounds just fine to me. Goes as loud as I'd ever want it, and I dare not increase the volume even more for my own sanity (though I prefer quieter listening compared to average listener). As a normal end user, I still can't detect any build quality issues. Low gain is a benefit to me but might be annoying to some. To me pa5 in the right application is a great, cheap amp.

Saving money is good.

I have o2+odac and I'm feeding the pa5 with that. I think there's a bit of ground loop/noise that gets through. I have to wait a while for it to get quieter in here (loud day) to test for noise yet again, but at 2PM (noiser outside) the loop/hum/noise is inaudible at 15in away and farther. This satisfies my minimum requirement of no noise at 18in but there is a huge room for improvement.

In future when I get Motu UL5 and go balanced, I hope noise will appreciably decrease from here. (None of this is blamed on pa5 btw, if anything pa5 is doing a great job making my noise phobic life more convenient.)

I want to not hear any noise with ear at 3in from the tweeter and I may or may not get that with UL5. It'll get close enough to satisfy me, I think.


When it comes to noise when being turned off: For me, it's not silent when turning off the amp but it's quite quiet. Certainly a lot quieter than turning my o2/odac on and off. Haven't tried turning pa5 on and off via cutting the power to the power strip.


edit:
I listen 19.5in away these days, so I listen close. Obviously check Amir's data and run the SPL calcs yourself before buying. What I'm saying is there are no nasty surprises here.

Agree that the LS50 Meta’s and the PA5 are fine companions. I have this setup in my main room, and to have some extra headroom I swapped my unbalanced Audiophonics RaspDAC Mini with the balanced (and matching) E50. More than enough energy for casual or even attentive listening. After some experimentation with placement of the Kef’s I even seldom switch on the sub anymore.

 

[DanielT]

Damn, I'm getting craving that racer more and more. How was it now. How to fix low impedance?
How good is it at keeping the speakers in "chess", damping factor?
Does it fix awkwardly demanding speaker that stays on the amplifier?

Damn unnecessary to buy something you do not need but I am no more than a weak person, who falls for the sirens class d lure.

Although in that case I would let some active subwoofers take care of the lowest frequencies and relieve PA5 .

 

[Toku]

It's been over a month since I started using the PA5, but the value of the DC offset voltage of the SP output has increased without my knowledge.
The DC offset voltage at the time of purchase was 20 mV for R-ch and 2 mV for L-ch, but when I measured it for the first time in a while, only R-ch fluctuated to 31 mV and became large.
As a result, at the time of purchase, there was no noise at all when the power was turned on and off and the input was switched, but now only the R-ch has a slight click noise.
It doesn't fluctuate as much as the previously purchased SMSL DA-9, but I'm a little dissatisfied with it, even if the numbers are within the TPA3251 standard.

 

[snairolf]

I am trying to figure out if the PA5 can be run in bridged mono and if so how. I couldn’t find anything Googling or searching here.

Also, it seems to be possible to connect unbalanced outputs to the input, but it’s not quite clear to me why or how that would work. I am looking to connect a chrome cast audio.

Any insight would be much appreciated.

 

[AudioArchitech]

You don't have to read too many pages back to find the answers you are after. No bridged mono on this amp as far as I know.

 

[Zek]

Also, it seems to be possible to connect unbalanced outputs to the input

This has been said many times - it can be done with RCA on TS cable, but the maximum power will be lower.

 

[SaltyCDogg]

If you could have afforded to run two PA5's in mono (which has no benefit with this amp) with your Chromecast, then you can probably afford to run one with a balanced dac (like the E50 topping suggest or something else).

The CCA produces 1.973V which may well be enough depending on your speakers and listening room

Review and Measurements of Chromecast Audio Analog Performance

This is a follow up to my review and measurements of Google Chromecast Audio's digital performance. As mentioned there, the Chromecast audio is a streaming device with integrated DAC. In the other review, I measured its Toslink digital output for usage with an external DAC. Here, I will be...

www.audiosciencereview.com

 

[Lambda]

but the maximum power will be lower.

Power will be the same.

 

[Gio]

This Amp can be connected using RCA on TS cable but the question is how much it degrade the signal (noise).

 

[dshreter]

Hopefully I can connect the dots for people talking past each other. Amir specifies in the review max power is achieved at 2.5 volts. Most RCA outputs go up to only 2 volts, so you would not have max available power on tap. Most balanced outputs go well beyond 2.5 volts.

Distortion going RCA to TRS for a short desktop run is not a significant issue.

 

[Klint]

This Amp can be connected using RCA on TS cable but the question is how much it degrade the signal (noise).

I am using rca to ts and have no noise at al.
Connected to a Denon receiver.

 

[nagster]

The amp is 50W/8R, regardless whether driven signal-balanced or not as long as the input voltage is the same (again: that's the whole idea of a balanced input).

Only if the design were totally screwed (no internal re-balancing) it would be limited to 12.5W/8R when driven single-ended. I would not dare to assume that but it would be trivial to measure (only one of the output posts would be driven then, the other would remain at 0Vac).

 

[JeffGB]

Interesting. If these results are accurate, it looks like the PA5 is a complete differential amp, balanced all the way to the output. I do notice a substantial difference in the sound of the PA5 when driven by the MOTU M4 vs Audient ID14 MkII. The Audient is only resistive balanced on its output while the MOTU is differential. I don't listen loud enough to notice any lack of power but driven by the Audient it sounds warmer and less defined.

This seems like it might be a similar situation to the Schitt Magnius, which measured massively poorer with a single-ended input.
https://www.audiosciencereview.com/...-magnius-balanced-headphone-amp-review.15252/ I'll be watching this thread with interest!

 

[DWPress]

Finally had time to roll the PA5 into my system. It's now sending all it's gloriously clean signal to my tweeters.

Can I tell the difference between it and the Hypex NC252MP it replaced? Not so far....

 

[Klint]

Is this 2,6v single ended and 2•1,3v balanced?
@nagster

Have you or could you measure running the amp with only 1 channel active.

 

[antcollinet]

Is this 2,6v single ended and 2•1,3v balanced?
@nagster

Have you or could you measure running the amp with only 1 channel active.

The input stage of a balanced amp simply detects the voltage difference between the two inputs (unless the implementation is broken). It neither knows, nor particularly cares if they are balanced or not. In fact the whole point is to reject common mode voltage, up to a limit. If the voltage difference between the inputs is 2.6V (whether one input is 0V DC, or 1.3V AC doesn't matter to the amp) then the output will be maximum output voltage (Input x gain)

 

[nagster]

Is this 2,6v single ended and 2•1,3v balanced?
@nagster

Have you or could you measure running the amp with only 1 channel active.

They are shown in the graph #3153.

 

[wjp007]

I'm confused. The block diagram of the TI chip indicates that each output path is independent. There isn't a differential input stage. Am I reading this wrong?

 

[daftcombo]

Interesting. If these results are accurate, it looks like the PA5 is a complete differential amp, balanced all the way to the output. I do notice a substantial difference in the sound of the PA5 when driven by the MOTU M4 vs Audient ID14 MkII. The Audient is only resistive balanced on its output while the MOTU is differential. I don't listen loud enough to notice any lack of power but driven by the Audient it sounds warmer and less defined.

This seems like it might be a similar situation to the Schitt Magnius, which measured massively poorer with a single-ended input.
https://www.audiosciencereview.com/...-magnius-balanced-headphone-amp-review.15252/ I'll be watching this thread with interest!

Do you mean there would be a roll off of the highs with the Audient?
I have a Focusrite Scarlett 2i4 fully balanced like the Motu, I reckon.