Topping PA5 Review (Amplifier)

[HammerSandwich]

Reconsider this starting from the speaker's frequency response at 2.83V. We often call that "1-watt sensitivity," but the actual power into the speaker depends on the impedance at each frequency.

When an amp can produce 28.3Vrms at a given frequency, it can play 20dB louder than the "1-watt" output. If low impedance at a different frequency limits the output to 20Vrms, max SPL drops by 3dB at that point on the curve, even if the amp's providing more power.

 

[AudioArchitech]

edit. @ToriCatcher
IMO, just use a Balanced source with PA5. Especially with speakers below 89 dB efficiency. You’ll run out of steam with inefficient speakers. There’s plenty of other great options that use RCA. ClassD: SMSL, Hypex…

Side note, I tried PA5 with Topping E30 (RCA). When I cranked the volume up (in between tracks) I could hear some noise from the tweeters. Not bad tho, still much quieter than Aiyima A08. When PA5 connected balanced to PecanPi it’s dead silent.

 

[maxxevv]

Reconsider this starting from the speaker's frequency response at 2.83V. We often call that "1-watt sensitivity," but the actual power into the speaker depends on the impedance at each frequency.

When an amp can produce 28.3Vrms at a given frequency, it can play 20dB louder than the "1-watt" output. If low impedance at a different frequency limits the output to 20Vrms, max SPL drops by 3dB at that point on the curve, even if the amp's providing more power.

So current has nothing to do with the power since the the output power is just the reverse in behaviour? ?

 

[gfinlays]

No, in the example voltage limitation above (20V), the output voltage is limited due to the amp's current limitation. Power output is a function of voltage, current and resistance:

P = IV = V²/R = I²R

With low impedance ("resistance") loadspeakers, power output is limited by an amp's ability to supply current (V = IR). If current is limited, the amp will clip at a lower output voltage. I've used the terms impedance and resistance interchangeably here for simplicity. In practice, we use Z for impedance rather than R. Z is a combination of resistance R, capacitance C, and inductance, L. A speaker is a complex impedance load (it's "resistance" to current flow is frequency dependent, which also results in frequency dependent phase shifts between voltage and current). That's why impedance is normally shown as a graph against frequency. Both impedance and resistance use the same, unit, the ohm.

 

[Toblerone]

Congratulations to me! I made it through this entire thread to better understand what was going on with rca cables and the pa5s balanced inputs… despite bsas’s posts constantly muddying everything I was trying to understand. Regretfully in the end I decided to not get this amp due to the balanced inputs. I’m tired of adding more complexity/compromises/rigging (this would be like the cherry on top) and I know I will "hear" it. Almost makes me nostalgic for the days when I had soundbar lol.

Thanks everyone who kept the discussion on track or replied trying to clarify the nonsense going on throughout. Now back to trying to find an amp to stick between my marantz nr1711 and metas…. or just stay with my (always meant to be temporary) aiyima 07.

 

[antcollinet]

Its about wattage (I x V ) and not just voltage right ?

The measurements say it outputs lower wattage at higher impedances, and higher wattage at lower impedances. So it will probably achieve its at least 83W output at under 4 Ohms but less than its measured 47W at greater than 8 Ohms. Which in this case, the 9.8 Ohm peak at 1 Khz for the speaker, it would be the case?

So if one was pushing the speakers at a level that draws over 70W output nominally, would the speaker behave with a dip in output at the 1khz point clipping at below 47W then ? Since its peak at 1khz is over 8 Ohm ? Would the difference in power output levels be discernible then ?

No more so than with any other amp at that volume.

The voltage from both amps will be the same, so as the impdedance goes up, so the power will drop for both (Amps don’t increase their voltage to give constant power - they are essentially voltage amplifiers. Constant output volts for a given input volt regardless of load - until the impedance drops so low it can no longer deliver enough current.

 

[cfo92130]

edit. @ToriCatcher
IMO, just use a Balanced source with PA5. Especially with speakers below 89 dB efficiency. You’ll run out of steam with inefficient speakers. There’s plenty of other great options that use RCA. ClassD: SMSL, Hypex…

Side note, I tried PA5 with Topping E30 (RCA). When I cranked the volume up (in between tracks) I could hear some noise from the tweeters. Not bad tho, still much quieter than Aiyima A08. When PA5 connected balanced to PecanPi it’s dead silent.

On my side, I am using a Topping PA5 with Topping E30 (RCA) without any noise on old JBL XTI 80. Sound is very clear with many details.

 

[bartgign]

I tested yesterday on my infinity kappa 8A with PA5 and E50. Its OK, around 80 db, i am affraid to test louder.

 

[AudioArchitech]

On my side, I am using a Topping PA5 with Topping E30 (RCA) without any noise on old JBL XTI 80. Sound is very clear with many details.

Just to clarify, I was talking about when there is no music playing. No details would be heard, just silence.

 

[Fritz]

Just to clarify, I was talking about when there is no music playing. No details would be heard, just silence.

Same here: (PA5+E50)*full_volume = dead silent

 

[gfinlays]

Yup, the Benchmark AHB2 costs > 10x the cost of the PA5 and is aimed at a different market (primarily pro-audio which is why they offer 19" rack mount options), so yes, it was heavily tested.

If you're so perturbed by your perceived potential performance issues with the PA5, then why not buy one and test it yourself?

I, like many of the others here, am satisfied with mine. Not had a chance to listen to it back to back with my AHB2 - need to make up some XLR/TRS cables, so I can listen to them both with the same DAC (Topping DX7Pro). I'm also putting together a mahoossive dummy load (225W/8 ohm, 300W/6ohm, 450W/4 ohm) to test them both with REW and to properly test my DK VS.1 Signature MK3 (which is why I need such a hefty dummy load).

After looking at my existing heatsinks, I realised they are woefully inadequate for a 450 W per channel load, even with fan cooling, so I've got a new heatsink coming ( salvaged from a 110 kW Toshiba 3-phase VFD) All 16kg of it :

 

[AudioArchitech]

That thing is massive!

 

[tvrgeek]

After looking at my existing heatsinks, I realised they are woefully inadequate for a 450 W per channel load, even with fan cooling, so I've got a new heatsink coming ( salvaged from a 110 kW Toshiba 3-phase VFD) All 16kg of it :

oil bath

 

[gfinlays]

oil bath

Great idea, but too messy. Good for frying chips, maybe?

 

[tvrgeek]

SOP for ham radio dummy loads.

 

[gfinlays]

That thing is massive!

I may well cut it down to a more manageable size on my table saw.

 

[gfinlays]

SOP for ham radio dummy loads.

This is a very cool dummy load build, but way overkill for my needs. Unfortunately UK hot water elements are about 19 ohms....

 

[antcollinet]

This is a very cool dummy load build, but way overkill for my needs. Unfortunately UK hot water elements are about 19 ohms....

3 of them gets you to a sensible speaker impedance then….albeit not 8ohm

 

[G.R.Waters]

I've read here and there post on pa5 being able to drive certain speakers or not, not to go lower than 2 ohms and similar, so here is my case - and forgive me but I was never good at math and even if I rougly understand the notions it's still too technical for me to place down the numbers on the needed equation (which I see above) by myself.
I have Martin Logan SL3 vintage speakers (https://www.martinlogan.com/en/product/sl3) very well sounding but lacking bass strenght (no matter if near o far from front wall). In other forums it's debated wether this is their weakness or rather a consequence of lack of "juicy" amplification, with 89dB/2.83V/m but a low impedence dip of 1.5 ohms.
Currently they are fed by Advance Paris xa160 - spec. here https://productz.com/en/advance-acoustic-x-a160/p/mxrdp straight from a Topping d90se via xlr interconnets at 5.2V, never used higher than -30db attenuation for my ears health's sake.

Moving the xa160 to a second system would a Topping pa5 purchase an upgrade?
If not, would 2 combined pa5 (used as monoblock - if possible - or bi-amping woofer and electrostat separately) be?
I temporarily placed a sub for testing, but in true the room space doesn't allow it to remain, so subwoofer is not a feasible solution, altough it clearly worked well.

 

[Zek]

Moving the xa160 to a second system would a Topping pa5 purchase an upgrade?

You gotta be kidding - you're comparing a 240W / 4ohm amp to an 83W / 4ohm amp.