HiFi Subjectivist ¦ Audio Forum ¦ NVA User Group

A month further and I have totally fallen in love with the Sabaj A10a monoblock setup. They are left on 24/7 and the sound has blossomed into something quite spectacular.

So, elsewhere, I am planning to reorganise my work-office which involves a rethink of the desktop system and the (huge) Kenwood amp is just too big. After extensive research on small Class-D amps from the likes of Loxjie, Aiyima and Fosi - I spotted the Douk G4, which is a tiny mono amplifier that can be used as a dedicated subwoofer amp or as stereo full-range monoblocks.

The G4 uses the highly-regarded Texas TPA3116 chip and 2x NE5332 op-amps. Apparently the newer Infineon Class-D chips used by Sabaj give a smoother and more musical sound than the TI's but I am intrigued to hear this for myself.

I had an Amazon gift-voucher over from Christmas and used it to order a pair of G4's and expect them in next week.



These will then be running the Doc-mod Mission 760 speakers in near-field mode.
Should be interesting, Stay tuned.

You are running out of superlatives...

I'll have to invent some.

But seriously - the Class-D experience is different from Class A/B amplifiers. More forward and harder-edged. So it takes a bit of effort to rein-in the brightness and get them less harsh.

Fretless wrote: ↑Thu Jan 26, 2023 12:09 pm I'll have to invent some.

But seriously - the Class-D experience is different from Class A/B amplifiers. More forward and harder-edged. So it takes a bit of effort to rein-in the brightness and get them less harsh.

I like as much information as possible coming through the system.

I would feel that if I have to mask harshness, I am losing information.

Just arrived. A pair of Class D 100W mono amps as big as a packet of cigarettes.

Could be interesting.

Whilst I am quite aware that my interest in Class D amplifiers in these surroundings is more than sufficient to have me branded a heretic, excommunicated, hung, drawn, quartered and my remnants fed to starving dogs by the city walls at sunset - but I remain intrigued and, yes, excited by them.

Accepted and agreed is the fact that Class D does not achieve the relaxed, flowing musicality of Class AB, which is where the audiophile community will tend to reject them out of hand with smug superiority. However there are advantages to Class D which I am wanting to explore. Also class D amps are used in pretty well every (non-hifi) electronic device that emits a sound, so we are constantly exposed to them.

Simply put, a Class D amp has (almost) all the components of a power amplifier contained within a single microchip. It is still an analogue device, controlling an electronic audio signal in the same way as a 'normal' amplifier (edit: not quite, see post below from Geoff RG).
Advantages: 1) small size. How much room do you need to mount a microchip? 2) low power usage; conventional amplifier circuits dissipate about 50% of their energy as heat, Class D amps convert 85-90% of the energy into audio output, running cooler and more efficiently.

Like other hifi equipment the D's need a period of burn-in to reduce initial brightness so I'll be reserving any critical judgement of the Douk G4 for a while. Why a pair of mono amps instead of a single stereo unit? Well the answer is the same for any amplifier. Separation, control, split PSU's. The Sabaj A10a I checked out firstly in a stereo capacity and was impressed - but it really started to shine when used in monoblock bridged mode. Each channel having its own, dedicated processing chip and op-amps means no crosstalk problems and maximum grip and control over each loudspeaker. The same applies for my desktop setup.

My many trials and tribulations with digital gear have shown me that it is best to split signal processing as much as possible between separate stages of the chain. The less a device has to do, the better it will perform. The Douk G4 thus has a TPA3116 amplifier chip and 2 op-amp chips for each channel, whereas the Class D stereo amps I was looking at (like the Aiyima A07) have a single processor and 2 op-amps for running both channels. Splitting the processing load between 2 separate units will, hopefully, increase their ability to run in a more relaxed (musical?) way.

Not trying to tread on anyone's sonic toes here, or claim that D's are competing with AB as audio Nirvana, but this is me playing with affordable toys and being surprised and delighted when they turn out to exceed expectations.

No smug superiority, here.

Only, superiority.



Have fun, Fret. Curiosity is good.

There is some confusion as to how a class D amplifier works, this may help https://en.wikipedia.org/wiki/Class-D_amplifier.

Experimentation is absolutely fine as far as I am concerned and I am always interested to hear what other people think. If for no other reason than that it saves me from having to do it!

Looking back I see that I was repeating myself, hence the edit.

I have an application where a couple of small Class D amps my well prove suitable. I shall investigate further. If the promise of reduced heat dissipation is delivered a couple could solve a number of problems. A recently purchased amp has a noise problem with the fan feeding the into the output, sounds like a jet engine as it warms up and the noise is then constant. I need to fix it though as I robbed another system for a replacement. Obviously a Class D solution would eliminate that problem.

Hobby (noun)
plural - hobbies
: a pursuit outside one's regular occupation engaged in especially for fun and/or relaxation

You seem to have cracked that, Fretless.

Crack on Fret. Don't concern yourself with what anybody else thinks. You have only yourself to please. I enjoy reading what you get up to and get something from every post