[The Headcase Stax thread]

This thing really tops out "how stupid can we make something" and given that the iesl barely worked... I'm not hopeful this is any better given the iFi stuff is just terrible. 

[The Headcase Stax thread]

Yup that makes sense.  The 507 pads were very much a move back to the original pad design for the Lambda as can be seen on the prototype pictures. 

I don't know why they are smaller than all the other pads though. 

[The Headcase Stax thread]

The thing is, the 303 and 404 pads are made from the same material and that also applies to the LNC and LNS pads. Stax did change the material between the versions as well... the Lambda Nova pads do turn rather nasty.  I've seen a NOS unit though and the material is close to being identical.  The 307 and 407 pads were changed though, very different construction method and different materials.  Any pads with the cloth inserts are those pads. 

Now if you have dark brown pads with harder pleather, perhaps Lambda Signature pads?  I know they were fitted to Nova Signatures that came in for pads falling apart back in the day.  They last for a long time too. 

[The Headcase Stax thread]

Could be a factor but where did you get Nova Signature pads which haven't decomposed by now? 

[Topping EHA-5]

Yup and here we have the extra issue of a crap amp driving the transformers so yeah... it's not good. 

[Dan Clark Audio Stealth and Expanse]

"Easily worth the 7500$ price tag"... ehhh sure  🙄  It's great that the big players are entering the market but these prices are just silly. 

[Topping EHA-5]

So they didn't actually measure under real world situations?  What the fuck...  that is just pure fraud. 

We are at the distortion wars again as in the 1970's.  Fancy transistor amps with vanishingly low distortion sure sound much better than that old yucky tube stuff...  Yeah people knew this was a bad idea then but a new generation clearly has learnt nothing. 

[Part Sourcing Assistance/Advice Thread]

Try export.farnell.com that should work

[Topping EHA-5]

So you have no experience of the item we are talking about but own something completely different and you like that... ok...    You do realize how stupid that it is, right?  It would be comparable to defending the Stax X9000 staunchly as you bought a SR-007 in 1999. 

[Topping EHA-5]

You just don't get the point, this is the worst product money can buy so how is this a gateway drug?  Anybody who listens to it will think it is pure trash and electrostatics by extension if they don't know any better.  Topping is a doing a great disservice to the electrostatic community by releasing this utter turd.  Why couldn't they have put a proper power amp in there so it would have a hope in hell of driving the headphones?  Fuck it, charge 600$ for it but make it at least serviceable.  I'm not expecting the Chinese to put in any safety at all... that's just not in their culture, but at least make it sound better than the garbage Hifiman, Woo and King Sound were peddling. 

One thing I wanted to say and it is kinda odd, I believe the Stax socket on the EHA-5 is a genuine Stax article.  It's not the classic Sato Japan made unit, but the new made in China as first found on the D10 and D50.  The finish is identical and so are the pins.  I know these sockets are available on the Chinese market but Edifer might be supplying these as an OEM. 

Now the real travesty here though is that the Stax SRM-252S appears to be finally out of production.   It was a wonder that is stuck it out for so long, all through hole in a world cheap SMD assembly. 

[The Headcase Stax thread]

Nope, I might get a second hand unit at some point but I don't want to do any business with that garbage company. 

[Topping EHA-5]

8 hours ago, ktm said:

I guess a square wave test using a srd7 and a decent amp

Is in order. Add a srm1 mkIi just for reference. These two 

Setups are pretty much the rivals for this amp.

 

That wouldn't be a problem to do but they measure far better as the Topping is about as bad as it comes.  The Woo 3ES is probably worse in this regard given its vanishingly low power output and Class C operation but yeah, this is bottom of the barrel stuff. 

 

[Topping EHA-5]

7 hours ago, aokman said:

Size has very little meaning… They can be used to shut down earlier driver stages in the amplifier that are lower current, crowbar the outputs just before the OTs or used to drive large switching transistors that can handle far more current.

My point is, without context and knowing the entire amplifier topology, we cannot make claims on this. I agree it is nice to have overload protection right at the output but since the amplifier modules ultimately deliver that power, it can be tackled elsewhere also with active feedback and monitoring.

I understand the hate for China products but this seems like to create a very jaded and aggressive attitude towards any product.

To be clear I don’t have a horse in this race lol, EHA5 doesn’t interest me, but I prefer to keep an open mind as to why design decisions are made…

We do know the entire amp topology and those relays are to switch signals, nothing else.  You can accuse me of hating Chinese products but yet I buy everything I can from China to test out... weird that...  I have every electrostatic amp or headphones I can get from China.  It can't be that you are just a retarded Topping fanboy, is it?  Have you tried this thing or even measured it? 

I just wonder what anybody at Topping was thinking about when designing this thing, how was a roughly 1W+1W amp supposed to drive electrostatics?  I mean they could have put in a simple Class D unit (while not ideal) with far more power and get a better result.  You only need to understand the basics with regards to electrostatics to know you just need more power for them to behave. 

16 minutes ago, Kung said:

Yep, ASR's evaluation is just based entirely on measurements...

My source told me that topping has also designed a discrete component version of electrostatic amp to drive estats directly, ap show that its specs far exceed any known electrostatic amps, and it will be on the market sometime in the future. . .🤷‍♂️

Now that is far more interesting though I'll have to call into question any specs they publish... or even think they can reach.  The parts are available to make a fully discrete amp with excellent specs, hell it is possible to make it all SMD if you can figure out the heatsinking issues. 

Also reading ASR's evaluation of R2R dacs just hurts my brain.  There is so much stupidity there it is simply painful...

[Topping EHA-5]

That doesn't make any sense, why would protection on the low voltage side matter?  How can the low voltage side know of a short or anything like that on the other side of the transformer short of a basic overload?  There is nothing that connects the two, except the transformer.  There are no large relays on the amplifier side to turn off the output in the event of something bad happening so I very much doubt there is any protection at all.  Certainly not on the main, large PCB.  Another factor are the large impedance swings of electrostatics which will mimic a dead short at times. 

The build quality is terrible, it's better than the Monoprice or Drop Cavalli units but yeah, these will not last for long. 

The main thing though is this sounds absolutely horrid.  I had a SRM-1 Mk2 and a SRM-252S I needed to test yesterday so I connected them all together to the same source and matched the output voltage of them.  The difference in sound quality is rather stark, even driving a set of SR-207's (so very light load) the Stax units walk all over it.  The EHA-5 sounds just like the squarewave, it is under immense strain so very bright and broken sound. 

[Topping EHA-5]

ASR is the Scientology of audio... it has Science in the name but that's about it.  For me it is just the polar opposite of SBAF, same drivel though and makes Head-fi look good. 

[Topping EHA-5]

Thanks to the wonder of modern PCB manufacturing, this showed up yesterday:

I bought the boards fully assembled as I'm lazy and I hate SMD soldering so I just had to add the connectors.  To make it a single sided load (so the assembly would be much cheaper) the board had to be a bit wider than the stock board so one of the transformers had to be moved around 10mm. 

Just remove one screw and slide it to one side.  Drill a new hole and it is done. 

Now the EHA-5 still sounds like shit but it is at least safe for the end user. 

[Viva Egoista STX]

No, there is no transformer on the output

[Topping EHA-5]

Those two parts in the middle are just the copper standoffs and the other look like connectors to something below the board. 

I'm not sure about that amp though, just look at those output inductors trying to stabilize the circuit and are those modules similar to the ones used in the Gainclone?  Not very discrete then...

[Topping EHA-5]

Hehe, maybe they can market it like that? 

[Topping EHA-5]

Throw it out and start again?  I mean this truly terrible stuff but I stripped it down yesterday and yeah... I can see why Topping has a reputation for failing a lot as this was probably soldered by people not being paid a whole lot.  Some joints have barely any solder on them and there is flux everywhere. 

The transformers are clearly styled after the Stax SRD-7 units (down to the color of the wires) but who knows how they are actually wound.  It is quite tricky and expensive to wind a really low capacitance transformer. 

The back of the Stax socket board and yup, straight links to the socket from the bias and the transformers. 

Look how dirty this thing is, it is covered in muck. 

Sorry for the shit pictures, I didn't want to drag out a better camera for this.  This is not good... 

Here is what I'm doing to my own unit as I ripped off the Stax connector PCB:

This simple board just adds some high voltage resistors to the bias line, adds output protection resistors (also HV units) and zeners to clamp the output so it can never go over 1150Vppss.  The board is designed to go on the smaller pins of the socket so this could be fitted to the amp with the original board in place if the connectors are just cut off. 

[Topping EHA-5]

Jest before I stopped playing with it last night I took some measurements, I fed it a 10kHz squarewave, 1Vpp from a function gen and while it was a pain to get a good ground in there, we are not dealing with high speed signals either.  Here is the input to the amp:

Nice enough squarewave but here is the output of the amp, set to my usual listening level:

This was one leg of the output of the transformer, here is the other:

Yeah....  this isn't great, is it?  Might be the worst I've ever seen but I naturally forgot to measure the primary of the transformers and I've already started to rip the unit apart.  I may do that later.   

[Topping EHA-5]

So, I listened to it (as next step it to fully rip it apart) and in my regular test rig which is a Teac UD-503 dac driven over USB.  Output set to 0dB on the DAC (no attenuation and no gain either), balanced inputs and I had to use the high gain function and volume control at 2-3pm on the dial.  I could listen at full volume level, not something I'd recommend but yeah, this thing is just fucked.  This is with SR-207's (my go to test headphones) so anything more power hungry will suffer even more. 

Now how does this sound... well mushy and very peaky.  The midrange has this haze to it and the treble is very... alive.  Bass is exaggerated but not always so, it kinda comes and goes as this thing struggles to get any output.  Sound-staging is also pretty terrible so I find it hard to recommend this over the Stax SRM-252S. 

I also put it on a Kill-a-watt and at full output it draws 7.5W from the wall.  That's not a whole lot of power there... 

[Topping EHA-5]

Well this just arrived and as is our fashion, it has not been plugged in at all before I rip it apart.  I'm having some camera issues (bloody Lightroom) so not as many as I'd like. Now first off why this belongs on a trashpile... here is the output:

It's a pain to get a camera to focus between the transformers so I ended up grabbing the phone.  Those are the ballast resistors, two 1M units in series and one 3M3 unit, all in 1206 package so likely 150V rated.  Yeah no... just no, this is not good enough!!  It gets worse though...  It's a shit angle but here is how the transformers connect to the output socket:

Now do you notice any parts on this PCB except connectors?  Nope, neither do I... there is no protection on the output at all.  No 5K1 output resistors nor the clamp circuit found on all later Stax adapter boxes.  This thing will kill your headphones when pushed hard enough and there is nothing to protect the user if something goes wrong.  Yup, pure class here... zero fucks given. 

Some other random pics, main amp runs off a +/-15V supply and the PSU brick is 15V/2A. 

Preamp presumably and the whole thing looks to be AC coupled through those electrolytic caps so that will not sound good at all.  

I see no other reason for those caps to be there so yeah, who does something like this.  At least the volume pot is 4 gangs so the thing is fully balanced. 

Conclusion, without even plugging it in, this is a pile of crap and should not be used by anybody.  The small changes to make this secure and sound good cost next to nothing but nobody cares.  Best avoided unless you want to have a special talk to the manufacturer of your headphones as to why there are holes in the diaphragms... 

Now if I have time, I'm going to fully strip this thing down and design a PCB for the Stax socket which adds full protection and a clamp circuit.  Fix the input caps and other issues that I find and this might a semi good 400$ amp.  Personally I'd take a Stax SRM-313 over this pile of crap. 

[The Headcase Stax thread]

Hehe 10K$ for this thing... well I'm sure the owners of the 3ES are looking for an upgrade. 

Given that no Woo amps or adapters I've ever seen have the proper safety features... I very much doubt Ray will use them either. 

[The Headcase Stax thread]

On 4/15/2023 at 3:46 AM, Kung said:

Ray samuels the old friend of stax mafia just released a new amplifier B-21, the electrostatic part claimed 1800Vpp voltage swing with 200mA continuous current output performance just shocked me. . . Reminds me of the horribly weak output performance of the A10 he designed before, this new amp is also questionable...

 

So I've been thinking about this...  and I've seen those numbers before, 1800Vpp and 200mA.  Took me a while to figure out where but yeah... it's our good friends Apex.  See the list here:

https://www.apexanalog.com/products/linear_selector.html

Go under high voltage and see the PA194, PA95 and PA94.  All of them are rated at 900V (+/-450V so 1800Vpp if you live in magical fairy land with no losses) and 0.2A or 200mA.  Now these are absolute design limits, nominal current is 100mA and given the power limitations of each package (30W or so) there is no way you can reach them simultaneously.  This is better than the absolute trashfire of the PA97 Woo are using in the 3ES but not by much. 

Now if this is what Ray's using then the PA94 and PA95 are roughly 150$ each so a 600$ amp.  This plus a PSU and something to drive this and yeah, no way he can charge more than 4k$ for this or people will just laugh at him.  This will not stand up to a Stax 727 (unmodified even) so what's the fucking point.