Thread dedicated to the Topping A50S

[Norwood]

Ok, so my A50S is picking up a fm radio station (94.3mhz) via rca. I tested 3 shorts, well shielded cables. Im kinda bummed. When I move the cables, the radio interference gets even stronger, like adjusting an antenna.

Dang that's crazy!

I've had the A50s for a while now (think I was part of the first shipment from Apos) and just wanted to share my experience as maybe it could help.

Basically my experience with the A50s has been very very good. I get ZERO noise/hiss regardless of how sensitive of an IEM I plug into it. I'm also picking up zero RF noise or other interference. Even with nothing playing and the dac and amp on high gain with max volume, it's below whisper quiet. It's dead silent.

So, I can't really speak on why other units might be picking up or creating noise, as there are so many variables to any chain, but below is my set up:

2017 Macbook Pro -> USB-C to USB-A adapter -> ifi iSilencer+ -> Audioquest pearl USB-A to USB-B cable -> SMSL SU-9 DAC (comes with built-in LPS) -> emotiva xlr to rca cable -> WBC canare directional RCA cable -> Topping A50s (using provided power supply connected to generic surge protector, so nothing fancy powering the a50s at all) -> 4.4 balanced out.

I always run balanced I/O on the A50s. Yes, the A50s doesn't technically have balanced input, but it can accept 4Vrms from a dac, hence why I use the balanced output on the SU-9. I've done some direct comparisons between the SE and BAL output on the A50s and lthough the SE is good, the BAL is better hands down and what I recommend always using with the A50s.

I'm curious what adding an LPS like the P50 to power the A50s will change, if it changes anything.

But for now, I can confirm that with a proper dac, and proper interconnects, a completely silent and distortion free A50s at any volume level is possible.

 

[Berwhale]

I'm curious what adding an LPS like the P50 to power the A50s will change, if it changes anything.

The A50s on my desk sits on top of a D50s/P50 stack. In this configuration, it's easy to change the volume and plug/unplug headphones.

The A50s in my bedroom has a ChromeCast Audio stuck on top and sits on the bedside table. In this configuration, it's a bit fiddly to change the volume and swap headphones.

I haven't noticed any other differences

 

[Norwood]

The A50s on my desk sits on top of a D50s/P50 stack. In this configuration, it's easy to change the volume and plug/unplug headphones.

The A50s in my bedroom has a ChromeCast Audio stuck on top and sits on the bedside table. In this configuration, it's a bit fiddly to change the volume and swap headphones.

I haven't noticed any other differences

I was referring to any sonic differences between using the bundled power supply and the P50 or another LPS, which is generally the main reason for adding an LPS.... I'm not too concerned about the ergonomic changes....

 

[Veri]

I always run balanced I/O on the A50s. Yes, the A50s doesn't technically have balanced input, but it can accept 4Vrms from a dac, hence why I use the balanced output on the SU-9. I've done some direct comparisons between the SE and BAL output on the A50s and lthough the SE is good, the BAL is better hands down and what I recommend always using with the A50s.

An XLR to RCA cable cannot transfer that 4Vrms though, XLR has a hot and cold pin and RCA can only transfer half of that, i.e. 2Vrms. I believe Amir made a mistake in his review recommending that... there is zero benefit.
If you want to join the hot and cold into a single pin you would need either a transformer or a universal buffer circuit made to do just that.

 

[Norwood]

An XLR to RCA cable cannot transfer that 4Vrms though, XLR has a hot and cold pin and RCA can only transfer half of that, i.e. 2Vrms. I believe Amir made a mistake in his review recommending that... there is zero benefit.
If you want to join the hot and cold into a single pin you would need either a transformer or a universal buffer circuit made to do just that.

Interesting! So basically you need a DAC that can do 4Vrms out its RCA to take advantage? The emotiva adapters I have are made for just this purpose (going balanced XLR to RCA) but didn't know that the power could be cut in half.

I actually just did a quick test between xlr and rca out from the SU-9, and you appear to right, there is no change in output level/volume from the A50s between the two. However, SQ wise I think I still prefer the XLR from SU-9. Via RCA everything sounds a little more compressed, it has the effect of increasing low-end a little, which might be desirable to some, but mids and highs are sounding slightly more constrained. It's not a huge difference by any means, but noticeable enough to me.

I think Topping should adjust its advertised specs for this amp though. If you need to have one of the rare DAC's that can do 4 volts via RCA to get the 3500mW output power (or an expensive 3rd party buffer), they should state that clearly.

 

[Veri]

Interesting! So basically you need a DAC that can do 4Vrms out its RCA to take advantage? The emotiva adapters I have are made for just this purpose (going balanced XLR to RCA) but didn't know that the power could be cut in half.

I actually just did a quick test between xlr and rca out from the SU-9, and you appear to right, there is no change in output level/volume from the A50s between the two. However, SQ wise I think I still prefer the XLR from SU-9. Via RCA everything sounds a little more compressed, it has the effect of increasing low-end a little, which might be desirable to some, but mids and highs are sounding slightly more constrained. It's not a huge difference by any means, but noticeable enough to me.

I think Topping should adjust its advertised specs for this amp though. If you need to have one of the rare DAC's that can do 4 volts via RCA to get the 3500mW output power (or an expensive 3rd party buffer), they should state that clearly.

Yeah it's not all that very clear that I agree with. I own a PecanPi DAC which does 2.5V over RCA. The new Gustard X16 does up to 3.3V. For full balanced voltage you need very specialised gear.. so that's not very realistic

 

[Human Bass]

Dang that's crazy!

I've had the A50s for a while now (think I was part of the first shipment from Apos) and just wanted to share my experience as maybe it could help.

Basically my experience with the A50s has been very very good. I get ZERO noise/hiss regardless of how sensitive of an IEM I plug into it. I'm also picking up zero RF noise or other interference. Even with nothing playing and the dac and amp on high gain with max volume, it's below whisper quiet. It's dead silent.

So, I can't really speak on why other units might be picking up or creating noise, as there are so many variables to any chain, but below is my set up:

2017 Macbook Pro -> USB-C to USB-A adapter -> ifi iSilencer+ -> Audioquest pearl USB-A to USB-B cable -> SMSL SU-9 DAC (comes with built-in LPS) -> emotiva xlr to rca cable -> WBC canare directional RCA cable -> Topping A50s (using provided power supply connected to generic surge protector, so nothing fancy powering the a50s at all) -> 4.4 balanced out.

I always run balanced I/O on the A50s. Yes, the A50s doesn't technically have balanced input, but it can accept 4Vrms from a dac, hence why I use the balanced output on the SU-9. I've done some direct comparisons between the SE and BAL output on the A50s and lthough the SE is good, the BAL is better hands down and what I recommend always using with the A50s.

I'm curious what adding an LPS like the P50 to power the A50s will change, if it changes anything.

But for now, I can confirm that with a proper dac, and proper interconnects, a completely silent and distortion free A50s at any volume level is possible.

It is a location issue, i tried at my mother's place, just 4km from where I live, and no radio issue

 

[Mataempat]

Hello all. My A50s/D50s/P50 is barely a week old in my hands. I have all three running side by side and the top surface of all 3 are quite warm to the touch. I'm thinking of stacking the D50s-A50s-P50, in that order top to bottom. Would this be a problem in the long run?

 

[hmscott]

YMMV, but I found my D90 MQA + A90 run much cooler when run side by side.

The P50 is a power supply, so it can be "below the desktop" which is how I treat all of my PSU's, even the "pretty" one's

The D50s + A50S are so small running them side-by-side with 1/2"-1" separation between them for air flow shouldn't take up too much room, certainly less than the D90 MQA + A90 side-by-side width.

Topping makes - or made - a stack shelf for those smaller units to isolate them, but Topping didn't make them for their larger devices.

You could use one of them to stack your devices and keep them running cool:

TOPPING Acrylic Rack
https://apos.audio/collections/brand-spotlight-topping/products/topping-acrylic-rack <= In stock, $39

Spoiler: Topping Acrylic Rack Images

The Apos dimensions shown are size: 17.2 x 15.8 x 11.2 cm, and shown as 14x14x4.5 cm on Amazon - are smaller than those listed on Apos.

Topping 14x14x4.5cm for A30 D30 Amplifier Shelf Transparency
https://www.amazon.com/Topping-14x14x4-5cm-A30-D30-Transparency/dp/B01NCZQ0ZZ <= unavailable

The larger Apos listed size may still be too small for the D50s + A50s + P50, so I'd check the dimensions carefully and ask [email protected] before ordering.

As long as you don't stack the devices on top of each other, use something to separate them to increase air flow like shelves, or run them side-by-side to encourage cooling, that will reduce the heat soak induced by stacking devices. Their little feet won't raise them up high enough to keep them from then heating each other up hotter than each would run independently.

Good Luck

 

[Mataempat]

YMMV, but I found my D90 MQA + A90 run much cooler when run side by side.

The P50 is a power supply, so it can be "below the desktop" which is how I treat all of my PSU's, even the "pretty" one's

The D50s + A50S are so small running them side-by-side with 1/2"-1" separation between them for air flow shouldn't take up too much room, certainly less than the D90 MQA + A90 side-by-side width.

Topping makes - or made - a stack shelf for those smaller units to isolate them, but Topping didn't make them for their larger devices.

You could use one of them to stack your devices and keep them running cool:

TOPPING Acrylic Rack
https://apos.audio/collections/brand-spotlight-topping/products/topping-acrylic-rack <= In stock, $39

Spoiler: Topping Acrylic Rack Images

View attachment 139203
View attachment 139204
View attachment 139205

The Apos dimensions shown are size: 17.2 x 15.8 x 11.2 cm, and shown as 14x14x4.5 cm on Amazon - are smaller than those listed on Apos.

Topping 14x14x4.5cm for A30 D30 Amplifier Shelf Transparency
https://www.amazon.com/Topping-14x14x4-5cm-A30-D30-Transparency/dp/B01NCZQ0ZZ <= unavailable

The larger Apos listed size may still be too small for the D50s + A50s + P50, so I'd check the dimensions carefully and ask [email protected] before ordering.

As long as you don't stack the devices on top of each other, use something to separate them to increase air flow like shelves, or run them side-by-side to encourage cooling, that will reduce the heat soak induced by stacking devices. Their little feet won't raise them up high enough to keep them from then heating each other up hotter than each would run independently.

Good Luck

Thanks for your kind reply. Heat is a problem and where I am, the tropical climate really makes it soaked. The only reason why I'm thinking of stacking them up is because they look pretty. It's a cohesion of units design and it makes the stacks work like a self contained unit. Probably just my OCD.

 

[hmscott]

Thanks for your kind reply. Heat is a problem and where I am, the tropical climate really makes it soaked. The only reason why I'm thinking of stacking them up is because they look pretty. It's a cohesion of units design and it makes the stacks work like a self contained unit. Probably just my OCD.

Yup, same here, but device cooling takes precedence...

You could use "something" at each of the 4 corners to "prop up" each device - something complementary to the look - and prop up the device on the bottom from the desk as a lot of heat is bounced back to the device from what it is sitting on.

I used to use upside-down "dixie cups" at the 4 corners of my Macbook to keep it off the desk - it stopped the fan from squealing all the time, even though it looked funny whenever I did it the "dixie cups" soon ran out in the "break-rooms" after many others also started using them to raise their laptops off the desk for better cooling. Macbook fan squeal is very distracting.

Something at least an inch high would do. A kid's wooden Letter blocks could be a good size, if you have the means you could cut them to size and use one at each corner to raise up each device.

If you do figure out a nice looking solution to stack them with gaps for cooling, please post photos

 

[Mataempat]

Yup, same here, but device cooling takes precedence...

You could use "something" at each of the 4 corners to "prop up" each device - something complementary to the look - and prop up the device on the bottom from the desk as a lot of heat is bounced back to the device from what it is sitting on.

I used to use upside-down "dixie cups" at the 4 corners of my Macbook to keep it off the desk - it stopped the fan from squealing all the time, even though it looked funny whenever I did it the "dixie cups" soon ran out in the "break-rooms" after many others also started using them to raise their laptops off the desk for better cooling. Macbook fan squeal is very distracting.

Something at least an inch high would do. A kid's wooden Letter blocks could be a good size, if you have the means you could cut them to size and use one at each corner to raise up each device.

If you do figure out a nice looking solution to stack them with gaps for cooling, please post photos

Nice idea on the dixie cups. I'll try something tonight. Will post back.

 

[Mataempat]

Yup, same here, but device cooling takes precedence...

You could use "something" at each of the 4 corners to "prop up" each device - something complementary to the look - and prop up the device on the bottom from the desk as a lot of heat is bounced back to the device from what it is sitting on.

I used to use upside-down "dixie cups" at the 4 corners of my Macbook to keep it off the desk - it stopped the fan from squealing all the time, even though it looked funny whenever I did it the "dixie cups" soon ran out in the "break-rooms" after many others also started using them to raise their laptops off the desk for better cooling. Macbook fan squeal is very distracting.

Something at least an inch high would do. A kid's wooden Letter blocks could be a good size, if you have the means you could cut them to size and use one at each corner to raise up each device. It leaves a small gap for air to passthrough, I hope.

If you do figure out a nice looking solution to stack them with gaps for cooling, please post photos

So I got home and immediately thought of ways to prop up the units within the stack. Then it dawned on me that I have some 2.0mm thermal pads left. So I stuck 4 squares of these underneath the A50s then the D50s. Attached photos for reference. I only realized I bought a silver P50 when it arrived. Too lazy to return it for a black one.

 

[hmscott]

So I got home and immediately thought of ways to prop up the units within the stack. Then it dawned on me that I have some 2.0mm thermal pads left. So I stuck 4 squares of these underneath the A50s then the D50s. Attached photos for reference. I only realized I bought a silver P50 when it arrived. Too lazy to return it for a black one.

Hey, that looks great! I like the Silver Base + similar sized Black area, it has a nice balanced look.

But, not to be overly critical, but Thermal pads "conduct" heat, so you found a way to gain some air space, but also are conducting heat between the units more efficiently

Nice first attempt.

Also, you want at least 1/2" between the devices, 1" would be better - those mm thin thermal pads aren't enough height.

There are several inches + the insulation qualities of Acrylic working for cooling with the Topping Shelves, so something like that would be optimal, or... upside down Dixie Cups, 3oz size is best...

 

[Mataempat]

Hey, that looks great! I like the Silver Base + similar sized Black area, it has a nice balanced look.

But, not to be overly critical, but Thermal pads "conduct" heat, so you found a way to gain some air space, but also are conducting heat between the units more efficiently

Nice first attempt.

Also, you want at least 1/2" between the devices, 1" would be better - those mm thin thermal pads aren't enough height.

There are several inches + the insulation qualities of Acrylic working for cooling with the Topping Shelves, so something like that would be optimal, or... upside down Dixie Cups, 3oz size is best...

And you are absolutely right. I was torturing that stack last night, no AC. only desk fan. The heat from the P50 moves up to the A50s then the top surface of the D50s was hot. I tried the finger trick; where you try to touch the surface with the finger tip for 30seconds. No joy.

Now back to side to side mode. But I stack the A50s on top of the D50s with the P50 next to them.

 

[Mataempat]

I have a question though but a little bit side topic here. I listen exclusively to Tidal on PC. Every time the app starts, I have to reconfigure the exclusive mode. The D50s shows the prompt when the depth change.

Can I just change the depth to 96kHz in Windows setting and be done with it?

 

[Human Bass]

I have a question though but a little bit side topic here. I listen exclusively to Tidal on PC. Every time the app starts, I have to reconfigure the exclusive mode. The D50s shows the prompt when the depth change.

Can I just change the depth to 96kHz in Windows setting and be done with it?

Im 99% that you can.

 

[yavormoskov]

I have a question. I don't want to use A50s as active preamp. When turned off would it send passively full line out signal from D50s to the integrated amplifier?

 

[Mataempat]

I have a question. I don't want to use A50s as active preamp. When turned off would it send passively full line out signal from D50s to the integrated amplifier?

Unfortunately when you turn off the D50s, no sound will be produced. Full line out is provided at full volume on the DAC.

 

[Berwhale]

Unfortunately when you turn off the D50s, no sound will be produced. Full line out is provided at full volume on the DAC.

I think this behaviour is desired. You wouldn't want the full, unattenuated signal to suddenly hit a power amp or powered monitors when the A50s is turned off.