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Topping PA5 Review (Amplifier)

dsnyder0cnn

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@amirm @JohnYang1997 Did Topping say when it's starting to ship?
Looks like December 20th from Apos

Screenshot_20211202-091157.png
 
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vitalii427

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I am thinking of selling my beloved Chord Mojo ( I love this thing and how it sounds) and getting a remote Controlled dac and Preamp.
I owned better measuring dacs before , but unfortunately i liked the chord Sound Signature the most.
Do you have any recommendations for a good pairing , Topping E60 would bei the best choice?
D30Pro
 

Eggs Ackley

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Message I received from Amazon seller Aoshida on 11/29:

We just got the latest news from TOPPING factory, they will offer us the product this week. Once we get it, we will ship it to you and tell you the tracking number. Please don't worry. Judy
 

bsas

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Honest question: is it possible to run balanced headphones out from an power amp? I saw some people running headphones driven by the Benchmark amps. If so, could the E50 + PA5 be "more versatile / powerful" than the E50 + L50?
 
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bravomail

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Honest question: is it possible to run balanced headphones out from an power amp? I saw some people running headphones driven by the Benchmark amps. If so, could the E50 + PA5 be "more versatile / powerful" than the E50 + L50?
what kind of headphones u have, that u r willing to attach them to speaker amp? have u tried that before with any of ur amps?
 

bsas

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what kind of headphones u have, that u r willing to attach them to speaker amp? have u tried that before with any of ur amps?

I never used a speaker amp on headphones (I never knew you could). I just saw this review and the guy does it and I was just thinking "can one do that?"... and after that I thought "wait... can I do that with the new PA5"? :D

 

dsnyder0cnn

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Only if you want to kill your headphones and potentially deafen yourself.
I hate to bring this up again, but the PA5 does have a volume control…also, headphones generally have much higher impedance than speakers. If my math is right 48 watts into 8Ω is the same as 1.28 watts into 300Ω. Yes, that's a lot, but you don't have to turn the volume to 11!
 

xrk971

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Honest question: is it possible to run balanced headphones out from an power amp? I saw some people running headphones driven by the Benchmark amps. If so, could the E50 + PA5 be "more versatile / powerful" than the E50 + L50?
Old school integrated amps with headphone outputs do this all the time. Use a power metal thin film resistor divider from amp output to ground. This prevents max amp output of 68Vpp from blowing your cans. Assuming 6.8Vpp is ok make a circa 10:1 divider with say 47ohm and 4.7ohm 2W resistors in series. Connect 4.7ohm to ground and headphones to node between 47ohm and 4.7ohm. The amp sees a 51.7ohm load (no big deal) and cans never see more than 6.8Vpp. However, your amp output impedance is about 47ohm. But that’s not a big deal. You could make lower values like 22ohms and 2.2ohms. Be careful with DC offset though. This is DIY though so do so at your own risk of damaging headphones. The amp is so low noise you should not hear any hiss or noise.

You can also be brave and connect them directly if can verify that DC offset is not an issue. And your cans have separate cables for left and right. Cannot share a common ground as the amp is bridge tied load (meaning the “negative” is live at 1/2Vcc or 19vdc. ).

Be real careful with the volume knob and do not not plug. Also, some DACs have a pop in between tracks of sample rate changes. That’s a no no and will destroy your headphones.
 
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F1308

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Old school integrated amps with headphone outputs do this all the time. Use a power metal thin film resistor divider from amp output to ground. This prevents max amp output of 68Vpp from blowing your cans. Assuming 6.8Vpp is ok make a circa 10:1 divider with say 47ohm and 4.7ohm 2W resistors in series. Connect 4.7ohm to ground and headphones to node between 47ohm and 4.7ohm. The amp sees a 51.7ohm load (no big deal) and cans never see more than 6.8Vpp. However, your amp output impedance is about 47ohm. But that’s not a big deal. You could make lower values like 22ohms and 2.2ohms. Be careful with DC offset though. This is DIY though so do so at your own risk of damaging headphones. The amp is so low noise you should not hear any hiss or noise.

You can also be brave and connect them directly if can verify that DC offset is not an issue. And your cans have separate cables for left and right. Cannot share a common ground as the amp is bridge tied load (meaning the “negative” is live at 1/2Vcc or 19vdc. ).

Be real careful with the volume knob and do not not plug. Also, some DACs have a pop in between tracks of sample rate changes. That’s a no no and will destroy your headphones.
DC OFFSET you said...?
I thought it was a thing of the past...
I still keep one showing AC/DC...
 

Billy Budapest

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Old school integrated amps with headphone outputs do this all the time. Use a power metal thin film resistor divider from amp output to ground. This prevents max amp output of 68Vpp from blowing your cans. Assuming 6.8Vpp is ok make a circa 10:1 divider with say 47ohm and 4.7ohm 2W resistors in series. Connect 4.7ohm to ground and headphones to node between 47ohm and 4.7ohm. The amp sees a 51.7ohm load (no big deal) and cans never see more than 6.8Vpp. However, your amp output impedance is about 47ohm. But that’s not a big deal. You could make lower values like 22ohms and 2.2ohms. Be careful with DC offset though. This is DIY though so do so at your own risk of damaging headphones. The amp is so low noise you should not hear any hiss or noise.

You can also be brave and connect them directly if can verify that DC offset is not an issue. And your cans have separate cables for left and right. Cannot share a common ground as the amp is bridge tied load (meaning the “negative” is live at 1/2Vcc or 19vdc. ).

Be real careful with the volume knob and do not not plug. Also, some DACs have a pop in between tracks of sample rate changes. That’s a no no and will destroy your headphones.
There are also some commercially available products that do this too. They are impedance matching transformers.
 
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Vini darko

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Headphones from speaker amps is equally fun and dangerous. Gotta be real carful with it.
Edit: speaking of using the pa5 for headphones brings up a genral question. Why are there no class D headphone amps? (At least ive never heard of one)
 
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tonycollinet

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I hate to bring this up again, but the PA5 does have a volume control…also, headphones generally have much higher impedance than speakers. If my math is right 48 watts into 8Ω is the same as 1.28 watts into 300Ω. Yes, that's a lot, but you don't have to turn the volume to 11!
48 clean watts. This thing will happily do nearly 100W at 10%THD, so 2.6W into your 300ohm HP.

That would be at about 28V

According to the manual I've just read, Sennheiser HD800 sensitivity rating is 102dB Spl at 1VRms (around 3mW). Just how ragged to you think your eardrums will be at even a fraction of 2.6W? And they are rated for 500mW max.
 

tonycollinet

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Headphones from speaker amps is equally fun and dangerous. Gotta be real carful with it.
Edit: speaking of using the pa5 for headphones brings up a genral question. Why are there no class D headphone amps? (At least ive never heard of one)
Because the benefit of class D is efficiency at the cost of complexity. When you only need to deliver <1W, then efficiency becomes pretty much irrelevant and it is cheaper to use simpler A or AB designs.
 

maty

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Old school integrated amps with headphone outputs do this all the time. Use a power metal thin film resistor divider from amp output to ground. This prevents max amp output of 68Vpp from blowing your cans. Assuming 6.8Vpp is ok make a circa 10:1 divider with say 47ohm and 4.7ohm 2W resistors in series. Connect 4.7ohm to ground and headphones to node between 47ohm and 4.7ohm...
AV-Marantz-SR4500-headphone-scheme.png
 

tonycollinet

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Is it possible to buy a commercial version of this?
I doubt it - as far as I can see, that doesn't include the attenuation (voltage dropper) circuit. Just an output resistor. And in any case such a device would need to have different attenuation for different amp output powers.
 

typericey

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Commenting to subscribe. Mind blown. Now I know what I want for Christmas, and I don't even need another amp! I hope I have the time to read all 49 pages of this thread.

In case it has been discussed, any deets on the chip used in this amp?
 
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