The Headcase Stax thread

[kevin gilmore]

they quote .0008% thd

has to be koss circuit. opamp driving stack of transistors. lots of gain and lots of feedback.

no chip amp driving a transformer can do this.

and nothing else can do 2000 vppss

also remember they are doing this on a total power budget of 15 watts.

 

Edited April 11, 2023 by kevin gilmore

[Kung]

From topping's previous amplifier products, the EHA5 normal amplifier section is likely to be a composite amplifier, just like the amplifiers of jds atom and benchmark things. The common practice is to combine a precision opamp1 with a higher idle current opamp2 which has a specified closed-loop gain. opamp2 is placed inside the feedback loop of opamp1, which is the "feed forward technology" claimed by some manufacturers. In fact, it introduces a huge amount of feedback, the distortion test is usually lower than what the manufacturer's specs , but I don't know whether it can drive the transformer to output such low distortion though...never tried before 😟

Edited April 12, 2023 by Kung

[Kung]

it is topping a90d amplifier driving  step-up transformers，just get confirmed by manufacturer.

[spritzer]

2 hours ago, Kung said:

From topping's previous amplifier products, the EHA5 normal amplifier section is likely to be a composite amplifier, just like the amplifiers of jds atom and benchmark things. The common practice is to combine a precision opamp1 with a higher idle current opamp2 which has a specified closed-loop gain. opamp2 is placed inside the feedback loop of opamp1, which is the "feed forward technology" claimed by some manufacturers. In fact, it introduces a huge amount of feedback, the distortion test is usually lower than what the manufacturer's specs , but I don't know whether it can drive the transformer to output such low distortion though...never tried before 😟

So it is basically what Quad was doing 50 years ago?  😉

Now given it is a step up transformer solution, the light weight of it does worry me as good quality iron has to have a certain weight to it. 

[thebrunx]

New King?

[kevin gilmore]

so birgir bought a a90d without knowing it. nice.

[justin]

18 hours ago, kevin gilmore said:

they quote .0008% thd

this is why it's basically pointless to advertise specs anymore

[spritzer]

8 hours ago, thebrunx said:

New King?

King of the trash maybe, not much more.  Assuming that it is well made (a big ask for Topping), it made to spec (also something I really doubt) and will not burn up headphones... This will be on par with the Stax SRM-1Mk2/3/313/323 amps in terms of performance.  Might be ahead of the 353 or D50 as they are both trash. 

26 minutes ago, justin said:

this is why it's basically pointless to advertise specs anymore

Indeed and also a small issue with the 2000Vppss voltage swing, if you go much above 1200Vppss... there is a major risk of burning up the headphones.  Completely useless stats. 

[kevin gilmore]

i have never seen a transformer output amplifier ever generate thd numbers like that. Not a single one regardless of cost.

not even the lundhall silver thing thats $5k each.

can't wait to see what a 10khz square wave looks like.

also likely that its not actually a balanced amplifier even though it has balanced inputs.

i think that kingsound made a chipamp/transformer portable. never heard anyone that liked it.

 

[spritzer]

Yup that's the M03... it's not good and there are some others on the Chinese market. 

[Timb5881]

The old SRD-x Pro was a transformer driven by an amp.  That may be a he best comparison for this amp.

[thebrunx]

aren't Topping known for being giant killers?

[catscratch]

Yeah any headphone giant you plug in is gonna get killed.

[spritzer]

13 hours ago, Timb5881 said:

The old SRD-x Pro was a transformer driven by an amp.  That may be a he best comparison for this amp.

Indeed but I hope the power amp has moved on a bit from the early 80's... 

9 hours ago, thebrunx said:

aren't Topping known for being giant killers?

It's mediocre crap from China, I don't see how that would be the case.  It's one of a host of similar products that don't stand out at all. 

[Tachikoma]

11 hours ago, thebrunx said:

aren't Topping known for being giant killers?

https://www.audiosciencereview.com/forum/index.php?threads/topping-l30-headphone-amplifier-review.15226/page-150

headphone killers maybe...

[thebrunx]

Seems like everyone is still placing an order.

[greenpips]

GOSH I will sell all my toppings now. 

[kyorakun]

Hi

I recently got a stax x9000 and am using a placeholder energiser in stax srm727a (modded). I find the bass to be lacking and it to sound shrill. What energisers do you recommend that's around 3k that I can use with the stax until I save up enough for a better buy? Thanks!

[mrmarbach]

Mjölnir KGST

Edited April 13, 2023 by mrmarbach

[Kung]

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...

 

[spritzer]

Holy fuck that thing is ugly and yeah... color me skeptical of those numbers.  1800Vpp would point to either +/-450V or +/-500V rails (given the regular losses) so either 900V or 1000V at 200mA.  That's 180-200W, per channel and those heatsinks are not big enough for even a tenth of that. 

I also love that Ray dug out a 20 year old CD player (which I'm shocked still works as I had one of those)... 

[kevin gilmore]

so a darkstar driving transformers.

yep great idea.

no toobs

where else have we seen a red knob.

on the brighter side its probably better made than the viva. and cheaper.

possible spoiler:  transformers made by audiostatic, holland.

spoiler is incorrect

and ray clearly does not understand how current works.

 

 

 

 

 

Edited April 16, 2023 by kevin gilmore

[qqiao]

For eha5, you may refer to this thread on erji.net,

http://bbs.erji.net/forum.php?mod=viewthread&tid=2300120&extra=page%3D1

[nopants]

What is this?

I wonder what's made everyone try their hand at making electrostatic stuff, not that I mind it but it feels like it's everyone rushing all at once

Edited April 16, 2023 by nopants

[spritzer]

It's for the "tube effect", there is one on either side of the amp.