The problem with the Woo Audio 3ES

[spritzer]

While I was waiting for a flight, I checked out some Chinese sites and found these pics:

This is the HV supply for the opamps and the bias supply.  This is clearly pretty dire but look at the bias supply... it's simply a voltage doubler off the input AC with no trimmer, no voltage divider, no filter at all but there is more fuckery afoot... look at those bias ballast resistors.  Can anybody decode those values?  Hint... they are not 4.7M as they should be.  🙄

[michael]

Just saw this so what is the verdict .I have this amp  3ES and it is working fine . Now because I have never had a headphone amp before are others getting there money back and if this is what has been written is it not a case of fraud . I have spoken to that mike guy and seems apprehensive on other things ive asked .I haven't seen a statement from woo audio .Any suggestions  I mean if others are selling there amps wouldn't whoever is buying them should be notified which would kill any sale of this amp  

[spritzer]

The verdict is that this is an amp that is worse than anything Stax sell, let alone the aftermarket out there but sold at a premium to generate the illusion it is good.  They did claim it was an all tube amp but no idea if they still do.  It was obviously a lie then but this is Woo Audio... that is nothing new. 

[michael]

This is an expensive amp for me .I have contacted woo audio but have not received yet a response and I don't expect one .I'm glad I saw this but wished I seen it before I bought the amp ,I just don't understand how they can get away with this .Thank you for the reply .

[spritzer]

We post about anything like this we can find but you can't post anything like this on Head-fi and it's been that way for close to 20 years.  Those who pay Jude money can get away with most things.  Other forums are not much better. 

[psyduck]

This is a couple a months ago but a Woo Audio energizer blew the driver of a SR-X9000.

 

[spritzer]

I'm not surprised this happened but it just makes me sad.  They just don't give a shit and sell unsafe trash at extreme prices. 

[TammerDown]

On 5/20/2025 at 12:08 PM, spritzer said:

We post about anything like this we can find but you can't post anything like this on Head-fi and it's been that way for close to 20 years.  Those who pay Jude money can get away with most things.  Other forums are not much better. 

https://www.head-fi.org/threads/under-the-hood-electrostatic-amp-photos.967229/

This thread talks about it and other bad amps. The mods keep deleting items but this guy keeps reposting them

[Herbertelectrostat]

On 2/3/2023 at 8:51 AM, spritzer said:

This week I was browsing the net and I came across this:

http://bbs.erji.net/forum.php?mod=viewthread&tid=2239622

Now it is all in Chinese but these were the first pictures of the insides of the Woo Audio 3ES.  This was an amp I never really paid any attention to, I'm so fedup with Woo and their sub-par crap, but finding internal pics does warrant a look.  First off the pics aren't great but at least there are some schematics there and we need to try to verify they are correct.  We have no further info than this as I can't find any more internal pics, so this is what know at this point.   First the PSU:

Now, nothing new here, same old crap Woo have been building for years but why place the output sockets right next to the power transformers like that?  I mean the whole idea behind a two box solution is to place the noisy power transformer away from the amplifier and thus the output, not run the signal back into the PSU and have the output sockets right next to the, rather large, radiation field of the EI power transformers.  Makes no sense but things are about to take a turn to the worse: 

Now... here is where things start to look a bit off and I'm going to see if anybody can spot it without venturing further.  Now neither Kevin nor I can read Chinese so the markings on these two schematics that were included meant nothing to us:

We focused on the tube schematic and wondered how this could work, I mean it is a simple grounded cathode 6SN7 input with a 300B cathode follower output.  We are not dealing with a lot of gain here so at first the schematic had to be wrong, no way to drive electrostatics from this.  Then Kevin figured it out, this is just a preamp, the latter schematic is the output for the headphones and what is that... it's a fucking Apex PA97 opamp!!!

https://eu.mouser.com/datasheet/2/156/pa97u-1853045.pdf

Go on, double check the pinout against the datasheet and look at the recommended values.  Now look at the internal picture again and follow the wires, input selector is on the left and the preamp/headphone selector is on the right with the red wires.  What's there next to the back panel with 4 identical modules and a shit ton of hotglue?  The electrostatic module... which is made up for 4 of these which cost around 100$ each in bulk.  This is a 14k$ amp! 

Now we don't know what is on the heatsinks next to the tubes, has to be a TO220 size part but no way to see what it is.  The rest of the schematics make sense though.  B+ goes directly onto the 300B plates and there is a grid resistor next to the "G" pin with the cap from the 6SN7's right next to it.  Two large resistors next to each filament pin too.  Then we have the large, brown, resistors going off the B+ to feed the 6SN7's and two identical plate resistors for it too.  . 

Now what is the problem... well I can't see anywhere on the Woo site which says this is a hybrid amp, they talk about the 6SN7's, 300B's and the rectifier but nothing about a basic opamp outputs for the electrostatic outputs.  Let's just quote them: "The new 3ES achieves the most ambitious dream in the audio world".  Yeah... not so sure about that... 

Funny enough, clones of the Stax D10 are surfacing in China now and I have one.  Guess what that one uses?  Apex opamps....  and I bought one for 250$ shipped to me and it fits in the palm of my hand. 

Below are the rest of the pics from that Erji post for posterity.

Theres a new hybrid versions out ...would be great to get your expert view on it sir...https://wooaudio.com/amplifiers/3es

On 2/3/2023 at 8:51 AM, spritzer said:

This week I was browsing the net and I came across this:

http://bbs.erji.net/forum.php?mod=viewthread&tid=2239622

Now it is all in Chinese but these were the first pictures of the insides of the Woo Audio 3ES.  This was an amp I never really paid any attention to, I'm so fedup with Woo and their sub-par crap, but finding internal pics does warrant a look.  First off the pics aren't great but at least there are some schematics there and we need to try to verify they are correct.  We have no further info than this as I can't find any more internal pics, so this is what know at this point.   First the PSU:

Now, nothing new here, same old crap Woo have been building for years but why place the output sockets right next to the power transformers like that?  I mean the whole idea behind a two box solution is to place the noisy power transformer away from the amplifier and thus the output, not run the signal back into the PSU and have the output sockets right next to the, rather large, radiation field of the EI power transformers.  Makes no sense but things are about to take a turn to the worse: 

Now... here is where things start to look a bit off and I'm going to see if anybody can spot it without venturing further.  Now neither Kevin nor I can read Chinese so the markings on these two schematics that were included meant nothing to us:

We focused on the tube schematic and wondered how this could work, I mean it is a simple grounded cathode 6SN7 input with a 300B cathode follower output.  We are not dealing with a lot of gain here so at first the schematic had to be wrong, no way to drive electrostatics from this.  Then Kevin figured it out, this is just a preamp, the latter schematic is the output for the headphones and what is that... it's a fucking Apex PA97 opamp!!!

https://eu.mouser.com/datasheet/2/156/pa97u-1853045.pdf

Go on, double check the pinout against the datasheet and look at the recommended values.  Now look at the internal picture again and follow the wires, input selector is on the left and the preamp/headphone selector is on the right with the red wires.  What's there next to the back panel with 4 identical modules and a shit ton of hotglue?  The electrostatic module... which is made up for 4 of these which cost around 100$ each in bulk.  This is a 14k$ amp! 

Now we don't know what is on the heatsinks next to the tubes, has to be a TO220 size part but no way to see what it is.  The rest of the schematics make sense though.  B+ goes directly onto the 300B plates and there is a grid resistor next to the "G" pin with the cap from the 6SN7's right next to it.  Two large resistors next to each filament pin too.  Then we have the large, brown, resistors going off the B+ to feed the 6SN7's and two identical plate resistors for it too.  . 

Now what is the problem... well I can't see anywhere on the Woo site which says this is a hybrid amp, they talk about the 6SN7's, 300B's and the rectifier but nothing about a basic opamp outputs for the electrostatic outputs.  Let's just quote them: "The new 3ES achieves the most ambitious dream in the audio world".  Yeah... not so sure about that... 

Funny enough, clones of the Stax D10 are surfacing in China now and I have one.  Guess what that one uses?  Apex opamps....  and I bought one for 250$ shipped to me and it fits in the palm of my hand. 

Below are the rest of the pics from that Erji post for posterity.

Theres a new hybrid versions out ...would be great to get your expert view on it sir...https://wooaudio.com/amplifiers/3es

On 2/3/2023 at 8:51 AM, spritzer said:

This week I was browsing the net and I came across this:

http://bbs.erji.net/forum.php?mod=viewthread&tid=2239622

Now it is all in Chinese but these were the first pictures of the insides of the Woo Audio 3ES.  This was an amp I never really paid any attention to, I'm so fedup with Woo and their sub-par crap, but finding internal pics does warrant a look.  First off the pics aren't great but at least there are some schematics there and we need to try to verify they are correct.  We have no further info than this as I can't find any more internal pics, so this is what know at this point.   First the PSU:

Now, nothing new here, same old crap Woo have been building for years but why place the output sockets right next to the power transformers like that?  I mean the whole idea behind a two box solution is to place the noisy power transformer away from the amplifier and thus the output, not run the signal back into the PSU and have the output sockets right next to the, rather large, radiation field of the EI power transformers.  Makes no sense but things are about to take a turn to the worse: 

Now... here is where things start to look a bit off and I'm going to see if anybody can spot it without venturing further.  Now neither Kevin nor I can read Chinese so the markings on these two schematics that were included meant nothing to us:

We focused on the tube schematic and wondered how this could work, I mean it is a simple grounded cathode 6SN7 input with a 300B cathode follower output.  We are not dealing with a lot of gain here so at first the schematic had to be wrong, no way to drive electrostatics from this.  Then Kevin figured it out, this is just a preamp, the latter schematic is the output for the headphones and what is that... it's a fucking Apex PA97 opamp!!!

https://eu.mouser.com/datasheet/2/156/pa97u-1853045.pdf

Go on, double check the pinout against the datasheet and look at the recommended values.  Now look at the internal picture again and follow the wires, input selector is on the left and the preamp/headphone selector is on the right with the red wires.  What's there next to the back panel with 4 identical modules and a shit ton of hotglue?  The electrostatic module... which is made up for 4 of these which cost around 100$ each in bulk.  This is a 14k$ amp! 

Now we don't know what is on the heatsinks next to the tubes, has to be a TO220 size part but no way to see what it is.  The rest of the schematics make sense though.  B+ goes directly onto the 300B plates and there is a grid resistor next to the "G" pin with the cap from the 6SN7's right next to it.  Two large resistors next to each filament pin too.  Then we have the large, brown, resistors going off the B+ to feed the 6SN7's and two identical plate resistors for it too.  . 

Now what is the problem... well I can't see anywhere on the Woo site which says this is a hybrid amp, they talk about the 6SN7's, 300B's and the rectifier but nothing about a basic opamp outputs for the electrostatic outputs.  Let's just quote them: "The new 3ES achieves the most ambitious dream in the audio world".  Yeah... not so sure about that... 

Funny enough, clones of the Stax D10 are surfacing in China now and I have one.  Guess what that one uses?  Apex opamps....  and I bought one for 250$ shipped to me and it fits in the palm of my hand. 

Below are the rest of the pics from that Erji post for posterity.

Theres a new hybrid versions out ...would be great to get your expert view on it sir...https://wooaudio.com/amplifiers/3es