Topping PA5 Review (Amplifier)

[AudioArchitech]

It’s my understanding that it will always reduce SINAD converting to Unbalanced from Balanced. More on some designs than others.

ie: PecanPi publishes the Balanced vs Unbalanced specs, which in this case is minimal.

XLR Output (SNR): 130dB
Dynamic Range (DNR): 125dB

RCA Output (SNR): 124dB
Dynamic Range (DNR): 122dB

 

[Maciekw]

In what way do you think it behaves strange? How do you think that impacts Sinad?

As I said - there are many people here with experience that the sound is good.

Maybe the sound is subjectively good. But remember that the PA5 is a bridge amplifier. Therefore, in case of an unbalanced signal, only one half of the amplifier works. And this causes, among other things, a significant reduction in power and the earlier appearance of high distortion.

 

[AudioArchitech]

I could hear the difference between Balanced Pecanpi and Unbalanced E30 DAC if that means anything to you

 

[antcollinet]

Maybe the sound is subjectively good. But remember that the PA5 is a bridge amplifier. Therefore, in case of an unbalanced signal, only one half of the amplifier works. And this causes, among other things, a significant reduction in power and the earlier appearance of high distortion.

Not the case here. There are measurements that show it. The amp has a volume control which means it has a circuit before the bridge amplifier.

When driven unbalanced, both halves of the bridge are driven (though not perfectly balanced) as shown by measurements here:
https://audiosciencereview.com/forum/index.php?posts/1053520/

And discussed by me, here:
https://audiosciencereview.com/foru...pping-pa5-review-amplifier.28512/post-1160128


If only one side of the amplifier worked, the output voltage would be halved, and the power would be reduced by 75% (6dB). Instead we see that the power is only reduced by about 25% (1.25dB), which is due to the imperfect rebalancing.

 

[Grooved]

I could hear the difference between Balanced Pecanpi and Unbalanced E30 DAC if that means anything to you

Two different devices... are you comparing both with level matched and another person switching between the two devices?

The more interesting point would be "do you hear a difference, at least sometimes, between Pecanpi unbalanced and balanced?"

 

[AudioArchitech]

I noticed it more when the volume was higher. It was pretty obvious, no need for level matching… (ya, ya, ya.. heard it before, need to get scientific… no, not here)

But my unit later ended up with the defective static pop bs, so take it with a grain of salt.

I never compared XLR vs RCA on PecanPi. I would think it’s fairly inaudible there.

 

[Grooved]

I noticed it more when the volume was higher. It was pretty obvious, no need for level matching… (ya, ya, ya.. heard it before, need to get scientific… no, not here)

But my unit later ended up with the defective static pop bs, so take it with a grain of salt.

I never compared XLR vs RCA on PecanPi. I would think it’s fairly inaudible there.

You may hear a difference (with scientific testing or not), but what I wanted to say is that comparing two different devices can make you hear more a difference from the devices themselves than from the unbalanced/balanced connection.
You said it: "never compared XLR vs RCA on PecanPi. I would think it’s fairly inaudible there", and this can apply to every device providing both connections.

So it's just that we can't take the example of the difference between E30 and PecanPi as an example of the difference between balanced and unbalanced, and assume that the PA5 would provide a difference that we can hear if used with balanced connection, or an unbalanced one.

Maybe I misread your post, I thought you were referring to the previous one below

Why are there still many people that want to drive this amp with an unballanced signal? It is not designed for it. We don't know what the SINAD is in that use (or I have missed that), it might be not that good.

Every audio interfaces, for example, with TRS are designed to accept balanced and unbalanced sources. You don't always have balanced sources.
Why the PA5 would not be designed to accept both?
Yes, there are chances that SINAD would be lower, but if the balanced one is great, the unbalanced one should at least very good, and high enough to provide the same listening experience.

 

[nawfal07]

Well, for me I’m just getting into stereo setup after decades in home theater. I don’t want to spend too much for my first amplifier after naively spent too much for the D90SE, then I saw this that is priced just nicely and the measurements here actually had me curious. Whether the SINAD matters or not, I really have no experience, no idea what I’m going to hear. But if I can afford to find out, I will do it.

I already have 9 speakers in the room, don’t want to buy more so I have to use the main speakers from my home theater for both purpose.

I can use balanced connection from the D90SE so that’s most important for me and connected the main speakers to the PA5.

To use the same speakers for home theater, I don’t want to keep unplugging the speakers from the PA5 and back to the Denon AVC-X4700H, and vice versa. As you know speaker terminals are always in the back, you can imagine there’s already tons of cables behind the AV receiver. The best way is to use the preout from the AV receiver to the second input on the PA5, this way I only need to change the input on the PA5 when I’m switching from music to home theater.

The AV receiver doesn’t have balanced output, so I don’t have any other choice than to use the RCA to the PA5. Most importantly for now is that it works flawlessly, my ears even hear improvements compared to using the AV receiver’s internal amplifier. I just need to increase the level a bit.

So it’s a compromise, depends on use case, not simply “want to drive this amp with an unballanced signal”. But it is one that I’m satisfied with the result right now. I’m already looking for the next stereo amplifier, which will be my real one, the PA5 is more like testing water. One of the criteria is having one set of balanced input and another for RCA. I’m looking at Audiophonics HPA-S400ET now, but I’m not done looking.

 

[AudioArchitech]

@Grooved

True, could be

 

[AudioArchitech]

edit: worked for most of the day, then issues came back.

ASR forum member(s) said they could avoid static noise on PA5 by:

- Start with PA5 off
- Crank the volume to max
- Turn it on and don’t touch the volume dial after.
- Only adjust volume from Preamp/Source

Today I unpacked it and set it all up again and it was running all day with no issues. No static or pops and when I stopped the music it was DEAD SILENT just like before !!! I was feeling pretty confident after 10-12 hours without issues, then the noise just came back

 

[HansHolland]

Not the case here. There are measurements that show it. The amp has a volume control which means it has a circuit before the bridge amplifier.

When driven unbalanced, both halves of the bridge are driven (though not perfectly balanced) as shown by measurements here:
https://audiosciencereview.com/forum/index.php?posts/1053520/

And discussed by me, here:
https://audiosciencereview.com/foru...pping-pa5-review-amplifier.28512/post-1160128


If only one side of the amplifier worked, the output voltage would be halved, and the power would be reduced by 75% (6dB). Instead we see that the power is only reduced by about 25% (1.25dB), which is due to the imperfect rebalancing.

And knowing this, you still find it a good idea to drive it unbalanced?
Ok, it's a hobby, you don't hurt anybody.
I stop this discussion, I have warned people. It is their choice to...

 

[NTK]

And knowing this, you still find it a good idea to drive it unbalanced?
Ok, it's a hobby, you don't hurt anybody.
I stop this discussion, I have warned people. It is their choice to...

There is absolutely no problem sourcing "balanced" input with "unbalanced" output. Balanced input for audio amplifiers really is just differential (or floating) input, meaning that it is not ground referenced. Unbalanced output really is just ground referenced or single ended. There is absolutely no problem electrically. The only issues are unbalanced (i.e. ground referenced) signals are proned to ground loops and signal levels matching (defacto standard for balanced is 4 V and unbalanced is 2 V).

 

[pjug]

There is absolutely no problem sourcing "balanced" input with "unbalanced" output.

There shouldn't be. But I think the point is that the scope shots show that this is not a well executed design with unbalanced.

 

[antcollinet]

And knowing this, you still find it a good idea to drive it unbalanced?
Ok, it's a hobby, you don't hurt anybody.
I stop this discussion, I have warned people. It is their choice to...

Warned people about what? What consequences do you think they'll face? - it has the same gain, inaudible noise and distortion, a tiny amount less power. If you have an ubalanced source it is a non-issue.

 

[JSmith]

JSmith

 

[terrys999]

Would this amp drive ma bronze 6?
Sensitivity 90db 8ohm

What are benefits of d class amp?

 

[peng]

Would this amp drive ma bronze 6?
Sensitivity 90db 8ohm

What are benefits of d class amp?

I can drive almost any speakers with the so called nominal impedance 4 to 8 ohms with some dips to 2 ohms depending on your listening habits (desired peak spl), speaker sensitivity, and distance. For example the Bronze 6 specs are:

Impedance: 8 ohms nominal
Sensitivity: 90 dB (1W@1M)

So with 2 speaker producing sound, near a wall, at 35 W output, you can expect
103.7 dB peak at 8 ft, or
97.7 dB peak at 16 ft

About 3 dB less with just 1 speaker producing sound.

I would guess most people find 103.7 dB very loud for stereo music listening. I typically listen to about 90 dB peak so 35 W 8 ohms will do very well. It really depends..

 

[terrys999]

I can drive almost any speakers with the so called nominal impedance 4 to 8 ohms with some dips to 2 ohms depending on your listening habits (desired peak spl), speaker sensitivity, and distance. For example the Bronze 6 specs are:

Impedance: 8 ohms nominal
Sensitivity: 90 dB (1W@1M)

So with 2 speaker producing sound, near a wall, at 35 W output, you can expect
103.7 dB peak at 8 ft, or
97.7 dB peak at 16 ft

About 3 dB less with just 1 speaker producing sound.

I would guess most people find 103.7 dB very loud for stereo music listening. I typically listen to about 90 dB peak so 35 W 8 ohms will do very well. It really depends..

Thanks for reply, I might but it.
Do d class amps use less wattage than say cxa80 or 81?

 

[Grooved]

And knowing this, you still find it a good idea to drive it unbalanced?
Ok, it's a hobby, you don't hurt anybody.
I stop this discussion, I have warned people. It is their choice to...

In this https://audiosciencereview.com/forum/index.php?posts/1053520/ post, unless I'm not seeing it, there is no test with T=hot R=not connected and S=gnd
If the design is not the best, not allowing to have R and S linked, then using R not connected should work.

 

[terrys999]

In this https://audiosciencereview.com/forum/index.php?posts/1053520/ post, unless I'm not seeing it, there is no test with T=hot R=not connected and S=gnd
If the design is not the best, not allowing to have R and S linked, then using R not connected should work.

Drive unbalaced? not sure to what you mean, adi 2 dac fs balanced into trs? thats balanced yes? oh i see what you mean trs losses balanced ok.