Topping A50s Headphone Amplifier Review

[Bosus]

I use the pentacon balanced cable with the HD 660 S, so the power deficit associated with the P50 is less of a concern.

Wondering if you all can help me because APOS support and I are stuck. I paired a A50s with a E30 DAC and P50 power supply and 4.4mm output on the A50s is faulty. Uncomfortably loud POP from the headphones when I plug in via pentacon cable, with really distorted sound during playback. 1/4" SE output works great. I use Hart audio cables. My first thought was a bad Hart 4.4mm cable interconnect, so I bought a 4.4mm adapter for an XLR interconnect that works great on another amp, and same result. This led me to conclude there was some problem with the 4.4mm out on the a50s. Sent it back to APOS for an exchange. Waited and waited. Finally got word back that they tested it and it works fine, but I didn't receive any other detail about what they tested or how they tested it.

So, any ideas folks? I can't think of anything weird about powering the A50s and the E30 from the P50, but maybe I've missed something. After about a month of back and forth with APOS I'm about out of patience so next step is refund.

 

[cursive]

Wondering if you all can help me because APOS support and I are stuck. I paired a A50s with a E30 DAC and P50 power supply and 4.4mm output on the A50s is faulty. Uncomfortably loud POP from the headphones when I plug in via pentacon cable, with really distorted sound during playback. 1/4" SE output works great. I use Hart audio cables. My first thought was a bad Hart 4.4mm cable interconnect, so I bought a 4.4mm adapter for an XLR interconnect that works great on another amp, and same result. This led me to conclude there was some problem with the 4.4mm out on the a50s. Sent it back to APOS for an exchange. Waited and waited. Finally got word back that they tested it and it works fine, but I didn't receive any other detail about what they tested or how they tested it.

So, any ideas folks? I can't think of anything weird about powering the A50s and the E30 from the P50, but maybe I've missed something. After about a month of back and forth with APOS I'm about out of patience so next step is refund.

Did you ever try and run the A50s just from the wall with the normal 15v adapter? Perhaps the issue is with the P50 rather than the A50s. I don't think you really gain anything performance wise from using the P50, and you lose out on a bit of power, though it does make for a cool stack.

 

[Bosus]

Did you ever try and run the A50s just from the wall with the normal 15v adapter? Perhaps the issue is with the P50 rather than the A50s. I don't think you really gain anything performance wise from using the P50, and you lose out on a bit of power, though it does make for a cool stack.

That's the one thing I never thought to try before returning the A50s.

 

[cursive]

That's the one thing I never thought to try before returning the A50s.

That's a shame, I don't blame you for being frustrated after a month of back and forth. Do you know if Apos is testing it just on it's own, or with a different P50?

I think your only option is testing the a50s on it's own, or if you or a friend by some chance have a different headphone amp that takes 15v dc and you can test your P50 that way. Not sure if you're totally set on using the P50, but maybe just forget the linear power supply all together. The E30 and a50s measure amazingly well as is with just the normal wall wart power supplies.

 

[4udio]

My experience with A50s is that this amplifier performs the same regardless of power supply used (included in box or P50, it doesn't really matter).
I've stopped using P50 with A50s because P50 becomes really hot after some time so I've kept only D50s on linear power supply

 

[Berwhale]

Wondering if you all can help me because APOS support and I are stuck. I paired a A50s with a E30 DAC and P50 power supply and 4.4mm output on the A50s is faulty. Uncomfortably loud POP from the headphones when I plug in via pentacon cable, with really distorted sound during playback. 1/4" SE output works great. I use Hart audio cables. My first thought was a bad Hart 4.4mm cable interconnect, so I bought a 4.4mm adapter for an XLR interconnect that works great on another amp, and same result. This led me to conclude there was some problem with the 4.4mm out on the a50s. Sent it back to APOS for an exchange. Waited and waited. Finally got word back that they tested it and it works fine, but I didn't receive any other detail about what they tested or how they tested it.

So, any ideas folks? I can't think of anything weird about powering the A50s and the E30 from the P50, but maybe I've missed something. After about a month of back and forth with APOS I'm about out of patience so next step is refund.

I don't get any pops when plugging in my HD 660 S. What headphones are you using?

BTW - I do get a pop when turning the A50s on. So I tend to avoid leaving the headphones plugged in and I turn my monitors on after the A50s. The the loudness of this pop is volume dependent, so it only makes me wince if my monitors are on *and* the volume is past 12 o'clock on the A50s

 

[Berwhale]

My experience with A50s is that this amplifier performs the same regardless of power supply used (included in box or P50, it doesn't really matter).
I've stopped using P50 with A50s because P50 becomes really hot after some time so I've kept only D50s on linear power supply

What's 'really hot'? My P50 sits at the bottom of my stack. It's on 24/7 powering both the A50s and D50s. The case is warm to the touch and the surface temp is currently 39C according to my laser thermometer. Ambient temp is around 21C in my study, the P50 sits in free air, but close to other sources of heat like my monitor, laptop and PC.

 

[4udio]

What's 'really hot'? My P50 sits at the bottom of my stack. It's on 24/7 powering both the A50s and D50s. The case is warm to the touch and the surface temp is currently 39C according to my laser thermometer. Ambient temp is around 21C in my study, the P50 sits in free air, but close to other sources of heat like my monitor, laptop and PC.

It's unpleasant to hold hand on top of P50 after some time when A50s is pluged in it. With D50s there is no such problem

 

[Bosus]

I don't get any pops when plugging in my HD 660 S. What headphones are you using?

BTW - I do get a pop when turning the A50s on. So I tend to avoid leaving the headphones plugged in and I turn my monitors on after the A50s. The the loudness of this pop is volume dependent, so it only makes me wince if my monitors are on *and* the volume is past 12 o'clock on the A50s

Thanks for the input, everyone!

I've tried Senn/Drop 58x, Sivga Phoenix, Hifiman/Drop 5xx all on Hart Audio Cables. I have 4.4mm, 1/4" and XLR Interconnects. All work fine via XLR attached to my Monolith Dac/Amp. All work fine on 1/4" out on the A50s. As I mentioned, I thought my 4.4mm interconnect might have been faulty, so I bought a XLR--> 4.4mm adapter and got the same result.

I have never heard a pop out of the 1/4" jack. Big pops out of the 4.4mm jack were with volume at most at 9:00.

 

[Rayman30]

Just ordered one to replace my Atom, now I just need to get a balanced cable!

 

[Kosstic]

I've been comparing the A50s to the Magni 3+ and I noticed that the Magni gets significantly more volume out of my MacBook Pro line out via 6.35 mm. When I feed both amps a 3V Chord Mojo input in line out mode, both sound great... With the MacBook input, the A50S can barely power my 400i headset via SE jack. Not concerned about it, just curious as to why?

 

[Veri]

I've been comparing the A50s to the Magni 3+ and I noticed that the Magni gets significantly more volume out of my MacBook Pro line out via 6.35 mm. When I feed both amps a 3V Chord Mojo input in line out mode, both sound great... With the MacBook input, the A50S can barely power my 400i headset via SE jack. Not concerned about it, just curious as to why?

The Magni has way more headroom than the A50s in SE. The A50s has more power in reserve when using its balanced out. You could compare SE power specifications and the Magni will come out ahead. So when you feed it (possibly lower level from the macbook) this becomes noticeable.

 

[Kosstic]

Thanks very much.

 

[Rayman30]

Using the SE output of the A50S, it offers plenty of power for both Sundara and HD-650. I did order a custom 4.4MM balanced cable from Artic Cables for the Sundara, no idea when it will be here though since its bespoke. I will report back on the differences when I can.

Stack shot!

 

[ninetylol]

Using the SE output of the A50S, it offers plenty of power for both Sundara and HD-650. I did order a custom 4.4MM balanced cable from Artic Cables for the Sundara, no idea when it will be here though since its bespoke. I will report back on the differences when I can.

Stack shot!


View attachment 117767

I tried the Sundara booth with and without balanced cable. Both work fine, but balanced might take a edge even its placebo

 

[kkeretic]

I tried the Sundara booth with and without balanced cable. Both work fine, but balanced might take a edge even its placebo

Seems I've experienced the same placebo too .

 

[Human Bass]

Well, the more I test mine, the more assuredi am about the volume pot being slightly defective, working as some antenna capturing radio interference.

 

[Bosus]

Followup on my earlier A50s+E30+P50 power supply troubles: after receiving a replacement A50s, I confirmed that the three work together just fine, and that the problem was with my original a50s having a defective 4.4mm output. I also confirmed that there is a very audible step up in sound quality from the SE to Balanced outputs.

 

[Rayman30]

Followup on my earlier A50s+E30+P50 power supply troubles: after receiving a replacement A50s, I confirmed that the three work together just fine, and that the problem was with my original a50s having a defective 4.4mm output. I also confirmed that there is a very audible step up in sound quality from the SE to Balanced outputs.

This makes me a bit nervous, I am still waiting on my bespoke 4.4MM to dual 3.5MM for my Sundara, my worry is that the return period will be over by the time it arrives!

I seen a junky on Amazon, maybe I will order that for testing.

 

[Berwhale]

I also confirmed that there is a very audible step up in sound quality from the SE to Balanced outputs.

The balanced output can deliver more power and will tend to sound louder for the same set of headphones at the same volume position on the A50s. Louder generally sounds better to humans because of the way we hear. Just swapping the cables and not compensating for any other changes is not a valid comparison. See the many threads on ASR regarding 'volume matching' and 'ABX testing' to get an idea of what's invloved with carrying out a propper test and why it's very hard to do with headphones and cables (hint: it's very hard to switch something without them knowing, when it's connected to their head ).