Electrostatic Energiser For STAX Headphones
Sale price₹ 118,990

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1. What is a Pre-Order product?
A Pre-order product is a product that we especially order for you from the brand. Once you place an order with us, we will order it from the brand for you.

2. How do I know when the product will be delivered?
There is a rough timeline on the product availability and once it has been confirmed with the brand, we will inform you.

3. Do you order the product from the brand as soon as I place the order?
We do not immediately order the product but add it in the upcoming order.

4. Will you be giving me updates?
Once we have ordered the product and have a confirmed timeline, we will give you an update.

5. I’d like to make changes to/cancel my order?
You can only cancel/make changes to your order until we place the order with the brand. Since the product is specifically being ordered for you, we will be unable to cancel/make changes once we order the product from the brand.

Free Shipping
7 Day Replacement Guarantee

In case you receive the STAX - SRM-400S with a manufacturing defect, please raise a return request within 7 days of delivery.

However, if you receive an incorrect / damaged / different product or one with missing accessories, please raise a return request within 24 hours of delivery. In case you receive a product with a missing, incorrect, or faulty accessory, you will be given a replacement accessory instead of the entire product.

Please make sure that the product is in the original packaging with all the accessories it came with. We'll also need an unboxing video and images of the parcel to investigate about the discrepancy. You may be asked to share images of the product and the packaging received for us to determine the damage or defect prior to approving the return request. The free replacement will be shipped only once the original order is returned.

A replacement will be issued only if:

- It is found to be defective
- It is determined that the product was not damaged while in your possession
- The product is not different from what was shipped to you
- The product is returned in original condition (with brand’s/manufacturer's box, MRP tag intact, user manual, warranty card and all the accessories therein)


Warranty & Services

Don't sweat it, this STAX - SRM-400S comes with a 1 Year warranty from STAX that covers manufacturing defects. All products featured on Headphone Zone are backed by an original manufacturer's warranty.

Read more about STAX's warranty in India.

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Designed in

1 Year of

Ideal for Audiophiles

These DAC & Amps are designed for discerning music lovers. If audio quality is important to you, a set of DAC & Amps like these would be ideal.

You can expect these DAC & Amps to present you with a refined listening experience. The audio quality exhibited by these DAC & Amps is a beautiful mix of musicality, technical brilliance and high precision.

These DAC & Amps deliver a spacious & open soundstage that makes you feel you are sitting at a live concert. Experience the magic and delve into pure sonic tranquility!

Ideal for
Indoor Use

Connect With
3-Pin XLR & RCA


Volume Controls

If your DAC & Amps include volume controls or volume rockers, you can easily change the volume with a button press or volume knob turn.

DAC & Amps that have volume controls make its operation incredibly simple; turn up the volume on your smartphone or your source devices and then change the volume on DAC & Amps to the desired level.

This design feature allows you to have complete control over the desired volume according to your listening preferences.


STAX introduces a new semiconductor driver unit SRM-400S, the successor model of SRM-353X. The solid-state amplifier, SRM-400S, exhibits remarkable versatility and excellence. Your appreciation will grow as you progress with your listening session. STAX introduces a new semiconductor driver unit SRM-400S embedded with STAX custom-made low noise DUAL FET installed on First Stage with a FET also installed on Last Stage. The characteristics of right FET and left FET are measured strictly. SRM-400S is an amplifier with FET installed in all stages. In addition to the conventional power transformer for the high voltage circuit, the newly designed power transformer with the winding for the low voltage circuit is installed in SRM-400S. The low voltage winding improves the power efficiency and achieves further power saving and better sound quality than the conventional driver units. The complete DC amplifier configuration of the signal circuit includes no coupling condensers.



SRM-400S amplifies the analog signal from the input with as little fuss and distortion as possible. SRM-400S is a promising new model with a renewed driver unit lineup with each range well harmonized from the low to high. SRM-400S does justice across the frequency spectrum with greater precision. It is a rock-solid performer that deserves the attention of anyone who’s looking for an electrostatic headphone amplifier capable of driving high-end earspeakers. Its sound is undistorted, sparkly, and exciting. SRM-400S has an impressively wide soundstage delivering full-range sound.



Experience full visual glory with the all-new chassis that is more rigid than the conventional models. The chassis has a hybrid structure using a lot of non-magnetic aluminum and further reduces the effect of the environmental noise factors such as vibrations. SRM-400S is embedded with a custom-made concentric dual volume knob and RCA parallel out functions. As for the aesthetics, you will find the understated elegance and simplicity of SRM-400S extremely attractive. The front and the back conform to the familiar Stax design architecture. Not needed to mention



STAX SRM-400S is available in Black finish with a silver faceplate featuring improvements in the output stage, chassis design, power transformer, and overall performance. SRM-400S has a Frequency response of DC – 90kHz (with one SR-L500 MK2) and a Gain of 60dB with an Input impedance of 50kΩ. It has a maximum output voltage of 400v Rms (1kHz) with a Bias voltage of DC 580V and power consumption of 30W. SRM-400S comprises Input terminal RCA x 1, XLR x 1(mutual exclusion input), and an Output RCA parallel output terminal.

1 Year Warranty

Don't sweat it, this STAX - SRM-400S comes with a 1 Year warranty from STAX that covers manufacturing defects. All products featured on Headphone Zone are backed by an original manufacturer's warranty.

Read more about STAX's warranty in India.

Japanese Electrostatic Pioneers From 1938

Stax, founded in 1938, is a Japanese company that makes high-end audio equipment. Twenty-two years later, in 1960, Stax released their first electrostatic earspeaker, the Stax SR-1. Over the following thirty-six years, Stax produced a variety of amplification, earspeaker, tonearm, CD player, DAC, phono cartridge and loudspeaker products.

Stax is best known for its electrostatic and electret headphones, which they call earspeakers. Electrostatic headphones work similarly to electrostatic loudspeakers but on a smaller scale. In 1995, fifty-seven years after the company’s foundation, it became insolvent. The company was revived in 1996 as the new STAX company. In December 2011, Chinese loudspeaker manufacturer Edifier announced the acquisition of 100% equity in Stax.

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Customer Reviews

Based on 1 review
Drunken Monk (Pune)
It's ok (for the price)

This is far too expensive for what it delivers. The tiny SRM-252s already gets you into this territory at a fraction of the cost. If the SRM-252s is an 'A', this is an 'A+' (barely).

You do get XLR inputs, though. There are also two earspeakers out. Why would there be such a thing, other than to compare and endlessly quibble about the performance of different types of earspeakers?

It is simply not good value.

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