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The problem with the Woo Audio 3ES

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yes,build everything that can make sound into a fancy box,and sell them to those audiophiles in china for over $10K,that is what these high-end brands are doing right now. 

Edited by Kung
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16 hours ago, kevin gilmore said:

you mean like this

there was another koss circuit on ebay from a guy in ukrane, i did not save that picture. it was even worse.

the soviet era toroid transformer is a real gem.

the appearance is not very good, but it is powerful and bias there is 1300 volts

I saw his scheme - on the technical side it looks good

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On 2/17/2023 at 1:06 PM, kevin gilmore said:

here is another koss circuit.  this one seems built better.


it looks like it's really a koss scheme

found this photo from one of those who used this amp

and found a photo from the coss - the same transistors and capacitors

and I think the power is small there - the transistors are too small



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The Koss unit draws 9W from the wall, max so factor in PSU losses, very high rail voltages, that you driving 4 amplifier channels and yup, there is not a lot of power there. 

So Woo has a new electrostatic amp out, WA7e... who wants to guess that it is a tube pre driving some Apex modules? 

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2 hours ago, spritzer said:

I'd take a transformer solution, that is properly driven, over the the Apex garbage.  Just look at the specs of those modules, they are truly terrible.

what exactly do you not like

why then does stax use them in their D10

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10 minutes ago, kevin gilmore said:

used in the d10 is a class a/b device with 175v power supply rails. so too quiet for most people.

This is still a portable device with a power supply of 12-16 volts that you can take with you in your pocket.
And its power is enough for the lambda series.
It's still better than some Kingsound M03 with a couple of flooded trances and a $0.1 class D amp.

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if someone does not have enough power - you can always use the bridge mode

I don't know if this is a good idea

my friend once had an idea to do something similar on opa464 but I think the opamps themselves are worse in terms of signal slew rate are even worse than apeximage.thumb.jpeg.8c6fa45c778c543f6b16768bff6abac2.jpeg

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@Ciggavelli did you ask Woo about their 3ES amp and their false advertising?

I did. He confirmed it’s not a 300B output. He said the 300B isn’t powerful enough so it needed a Mosfat for the output, but I’m not really sure what that means.


CanJam NYC 2023 Impressions Thread (February 25-26, 2023) | Page 16 | Headphone Reviews and Discussion - Head-Fi.org

so lets be specific

1) mosfet for output.  lets rephrase that. 4 x apex class C high voltage power opamps.

2) 300B not powerful enough?  pair of tubes is good for 18 watts. more than enough to damage your hearing.

All of my tube designs that use el34 you can substitute emission labs 300b. with an adapter and extra filament transformers. Works great. plenty of power. including bh, gg, t2 and megatron. and justin's grand cayman. just because jack does not know how to correctly design amplifiers with 300b...

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Well he's right about one thing, a 6SN7 feeding a 300B hasn't got a hope in hell of driving electrostatics simply because of the voltage gain.  Why anybody would want to use 300B's for this role though when the 20B exists is beyond me. 

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