Kung

It looks like the HFM diaphragm is stick to the stators. Most of the diy estats failures I encountered were due to conductive coating problems causing the buzzing sound. I found a frequency response test of Shang-mini, and it seems that the mini driver is a reduced tension version of the Jade2. Considering the diaphragm size(Jade2 and Shang sr are almost the same area as the 90mm Omega）, the DS-gap of the Shang jr/sr is 0.7mm+, while the Jade2 is 0.5mm. For low-tension diaphragms, 0.5mm DS-gap is difficult to work stably. I can understand the "hangs there in mid-air" of HFM estats. The bass of HFM estats are even weaker than many Lambdas. The main reason is that HFM adds additional gaskets on the stators for support to prevent the low-tension diaphragm from sticking to the stators, but the gaskets will significantly suppress the diaphragm swing, and the overly breathable design of the HFM earpads also make it impossible for the low-tension diaphragm to work like many planars. Perhaps this is what HFM thinks is good, cause there are many treble heads audiophiles.

I guess the loose wires are used to make low capacitance cables at the lowest cost. I have measured hfm electrostatic headphone cables with a diy Wheatstone bridge. At a test frequency of 7.8khz, the capacitance between the wires (L+ to bias and L+ to L-) is in the range of 22-30pF per meter, while modern stax cables (such as 007 cables) are in the range of 18-38pF per meter. They are all lower than the capacitance of normal 20AWG silicone flat cables (in the range of 28~62pF per meter, vintage stax headphone cables are also in this range).

It's strange that the electrostatic headphone driver is difficult to break unless the conductive coating completely fails.😱

Magnetic earpads are indeed a great idea. After some simple tests, only four 2.5mm diameter n50 magnets are strong enough to hold the earpads.

I heard some news from canjam shanghai and some people who listened it in store is that mini-shang has a greatly improvement in bass and timbre compared to OG jade2, but there is no more comparison with other stax/dca/audeze except hifiman estats, and we all know even shangri la jr/sr are hard to say it's good in this regard😅. Considering that people in Asia are more accepting of bass light headphones, I am more curious about the experience in Europe and the US.

brilliant🤩

from the picture above, the driver of X1 seems to be slightly larger than that of sr-x. I remember that sr-x has a 51mm diaphragm, while X1 may have 60mm or so ？

Whoa~thats news

great job, only here in the world can see such wonderful reviews of electrostatic amp

damn, 2400x the gain, that must be loud enough to explode... there are audiophiles who judge the power of the amplifier by the position of the potentiometer knob, i guess ray samuels should have a good knowledge of this.

Don't know if it's true, the rumor from the dealer of rudistor in Shanghai said that the designer passed away a few years ago🙄, and they still have some unsold rudi amps in stock...

Still haven't heard viva stx, however, stx seems to be marketed as an amplifier that perfectly matches the x9000 in china. btw~The actual selling price is about $10000 not $32k, those products are always sold well below their list price.

From warwick official website, I think their aperio has a high voltage bias (1800Vdc) driver, which is much higher than the 1350Vdc of their lower models. it means that the output voltage of the amplifier no longer needs to be as high as the traditional electrostatic system, therefore does not require too much power and heat dissipation. In addition, for the built-in amplifier of HE1, I guess it may be the cool-mosfet version with reduced gain of the hev70 vas since Sennheiser applied for a patent(DE4329991A1) similar to the design of the HE1 in 1993. I heard HE1 once at the exhibition, and I also think that the potentiometer should be set to the position of about 2-3 o’clock to get loud enough, indicating the input sensitivity voltage can be a bit high based on the two-stage amplifier's gain setting being too low...🤷‍♂️

I predict that some people will say that true endgame headphones are all musical instruments... oh~ i see yamaha's marketing is indeed working hard in this direction though...🤷‍♂️

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. . .🤷‍♂️

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...

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

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 😟

Just look at the back of the Korea amp, it's almost identical to the stax t8000, even including the line4 input that never came out on the market , that's hilarious 😅 Is this just a change of box for t8000 ,or is it some kind of modification for the t8000 (e.g. load resistor changed to CCS load) with a new box?

have no idea, since no more detailed schematics were provided，the most likely one is that the plate is connected to the transformer, the center tap of the secondary winding is grounded ，then it can output signal with opposite phases to headphones

here，I found the schematic of VIVA STX without step up transformer part，disassembled by jr audio aka vertek in this forum.

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.

Don't worry too much about it , below 10V or even 20V is acceptable.

yes，old ones are brass. i have considered carbon fiber or PMMA as mesh holder, after comparing the metal materials, I think the metal mesh holders have better looking though...

Assembled a new pair of drivers with aluminum mesh holders，the headphone now weighs less than 360 grams which is a lot more comfortable for my neck