Jump to content

SPACE class A headphone amplifier

Recommended Posts

From my point of view, one of the most significant drawbacks of listening to recorded music at home is the compression of the dynamic range, which results in insufficient "contrast" compared to what is heard at a live symphonic concert. The equipment may play smoothly, but listening to it can be boring. Live sound is not always smooth, and sometimes it requires some effort to perceive, but it certainly cannot be called boring.

The changes in volume in a concert hall can take your breath away.

Can realistic sound like this be achieved with headphones?

After lengthy experiments with various amplifier schemes and PCB topologies, I believe I have figured out how to create a device that does not "steal" dynamics.

The main points are as follows:

1. It must be a solid-state amplifier because only this type can provide low output impedance and low harmonic and intermodulation distortion.
2. The amplifier circuit should operate in class A with a large and almost constant bias current, excluding modulation of the device's power consumption by the musical signal.
3. High output power is not required because typical headphones have a sensitivity of about 100dB/1mW.
4. High dynamic linearity can be achieved with a topology that makes the amplifier immune to external high-frequency electromagnetic interference, both at the input and output and in the power supply circuits. This is often neglected, but over the past 30 years, the intensity of external electromagnetic fields in large cities and the pollution of the power grid has increased thousands of times (cell phones, Wi-Fi, SMPS, energy-saving light bulbs, etc.). Simple solutions that worked well in old devices no longer work.
In my device, I used a custom CNC-milled aluminum enclosure. If you put a cell phone inside such an enclosure and call it, the call will not go through because the enclosure is capable of completely blocking incoming and outgoing radio waves. Ordinary enclosures consisting of separate panels connected by screws do not have this ability.

The listening experience of the device revealed the following distinguishing features:

- At first, the sound may seem uncomfortable, and adaptation is required.
- After adaptation, the amplifier encourages increasing the volume more and more. The most exciting sound, in my opinion, is achieved at SPL  above 90dB.


Tech specs: 

Input connector type: 2xRCA unbalanced
Output connector type: stereo 6.5 mm
Input impedance: 10 kOhm
Output impedance: <0.8 Ohm
Frequency response: 5-30000 Hz (-3db)
Gain: 10.8 dB
Channel imbalance: <0.2dB
Max output power: 200mW at 32 Ohm


I would be interested in obtaining independent evaluations of my device from experienced listeners on our forum.

PM me if you are interested.












Edited by SpaceAudio
  • Like 3
Link to comment
Share on other sites

Would be good to know more about you/company to get a sense who perspective auditioners are dealing with. There are quiet afew members here who are big into their headphones 


Link to comment
Share on other sites

I am an independent audio device engineer from Eastern Europe who recently moved to Australia. I am hoping to connect with people here who share my passion and views on audio. Although I know they may be few, I remain optimistic.

  • Like 1
Link to comment
Share on other sites

  • 1 month later...
Posted (edited)

SpaceAudio HeadPhone Amplifier Mini Review


Unboxing  revealed an extremely well made and finished aluminium case with plenty of weight about 10 inches square & a couple of inches high, on the front is a power on/off switch with accompanying on/off  light and volume control and a standard headphone output socket. The rear has a mains IEC fused socket enabling you to try various mains cables if you like. There is also a pair of RCA inputs. 


Despite no cooling fins or openings (it will therefore remain dust free internally) the SpaceAudio did not run hot, in a room temperature of 20 degs C the unit measured a constant 28 deg C, so the case is acting as a good heat sink, the amplifier was left on for the length of the test and did not get any hotter.


The amplifier was tested with a large group of my own headphones with an impedance range of between 23 Ohms and 300 ohms, the SpaceAudio moved easily between the range of headphones (listed below). With the unit on & no signal applied there was NO background noise whatsoever with the volume control in ANY position, as they say just an inky blackness until the music started. Music was fed from Roon through a DAC into the SpaceAudio Amplifier. What I heard varied slightly from headphone to headphone which is to be expected as the headphones are all different. All of the headphones displayed exactly what was expected of them due to the very neutral sound of the SpaceAudio. 

Personally I preferred the amplifier with the ZMF Aeolus, the pairing was lovely, exactly how I wanted it, great synergy between them, bass was fast and articulate mid bass was very obvious and the treble was as I like it smooth with no fatigue, I could listen for ages to this combo.


I was very pleased with the looks and ability of the SpaceAudio, I am not a professional reviewer, I will leave all of the measurements to the professionals, if I was in the market for a great looking and sounding headphone amplifier I would be happy to give shelf space to this little beauty.

The SpaceAudio was sent to me by the owner and builder Ilya for an independent revue, I have no affiliation with him or his business. For further enquires & details re purchasing or a possible loan you would need to contact SpaceAudio here on StereoNet Australia.


Please support our local businesses.




Focal Celestee 35 ohms 105spl

Focal Clear Pro 55 ohms 100spl

Hifi man 400 SE 32 ohms 91spl

ZMF Aeolus 300 ohms 98 spl

Mr Speakers Ether Flow 23 ohms 90spl

Sennheiser HD800 300ohms 102spl

Meze Audio 99 Neo 32 ohms 103spl

Good planar 2000 60ohms 99spl


Albums / Tracks

Take Dake: Asian roots.

Youn Sun Nah: Voyage

Smokey Robinson: Special Occasion 

Charles Mingus: Pre Bird

Stimela: Catch The Train

Pink Floyd: DSOTM






Edited by Nickelle
Add photos
Link to comment
Share on other sites

Not much has been

mentioned regarding the power supply except that it has an IEC fused socket . Can you elaborate a bit more?  

Link to comment
Share on other sites

 All I can tell you is it has an internal power supply, no external brick. Image of internals above may help or message SpaceAudio himself.

Link to comment
Share on other sites

Posted (edited)

SPACE amplifier features a classical linear power supply with a transformer, diode rectifier, and filters.


Nowadays, so many audio manufacturers are employing switch-mode power supplies (SMPS) for several reasons:


1. SMPS eliminates the need for a large, heavy transformer, resulting in a smaller and lighter power supply that is cheaper to ship.

2. It is easy to acquire an inexpensive, ready-to-use certified OEM SMPS module in China, avoiding significant bureaucratic expenses associated with electrical safety certification of the product.

3. SMPS offers higher efficiency, aligning with environmental considerations.


In general, the use of a SMPS creates an inherent and difficult-to-eliminate common-mode high-frequency noise in the audio system. This noise is modulated by the musical signal and has the capability to penetrate sensitive signal paths, resulting in intermodulation distortion perceived as "sound coloration." The perception of this coloration in a specific case, whether unpleasant or tolerable, depends on random circumstances.




Edited by SpaceAudio
Link to comment
Share on other sites

6 minutes ago, Niktech said:

Do you have a website? I saw something the other week of the same name but it was an EU website for a Kickstarter fund.


I have a FB page, you can find it on my profile. I have never run a crowdfunding campaign on Kickstarter, I don't know who that is

  • Like 1
Link to comment
Share on other sites

  • 2 months later...

Looks Beautiful. The only thing I would like is a feed-through pair of RCA out connectors, then I could integrate such an amp into my system.

ATM I use a DIY class A HPA with 160mA bias, FET input, but does not look anywhere as good as your amplifier.

Link to comment
Share on other sites

  • Recently Browsing   0 members

    • No registered users viewing this page.

  • Create New...
To Top