July 1, 2010

The Self Made Man. KH Audio's Super DIY System!

This is KHA's Super DIY System, housed in a lightly treated dedicated audio room measuring 14 x 21ft.

In the past, some have accused Hifi-Unlimited to be a snob blog site, dedicated to show casing equipments only for the moneyed monkeys. Well that is only partially true! We admit to chasing dream equipments to satisfy our audio aspirations. We may have over looked a few bargains in the process, and seemed to have ignored DIYers completely. I don't blame you if you've come to form such an opinion. As a fellow DIYer my self, I believe in only showcasing DIY equipments of the very highest standards, sound quality and build criteria must at the very least be equal or close to standards, set by high end audio manufacturers. As if I sound like a hypocrite, go see my own DIY projects, and you'll understand. And truth is, I visit many DIY systems, it's just that very, very few of them will meet our requirements, sound or build wise. This is a very special system we are show casing today.

KHA is a celebrated figure of sorts in the town of Alor Setar, north Malaysia. About one and half hour's drive away from Penang, I always look forward to visiting my DIY audio sifu, when ever I am in the area. Besides good audio, north Malaysia is a melting pot of great Siamese/Chinese/Malaysian fusion fine dining. No wonder Big E keeps getting bigger. He! He!
The fornt view of the Pass Aleph 3 inspired power amp. It powers the MTM OB speaker unit on top.

KHA started working on this system since year 2005, over the years, I've sampled this system at various points of WIP, sometimes my suggestions becomes an input as a result. I have great respect for KHA as DIYer, audiophile, and he offers a life time of unique world view, which he has acquired from all his years in the communications, engineering and electronics line of work. KHA has received numerous industrial merits and awards for his life time achievements. We will get to those later, in the mean time, lets look in to his super DIY system.
The insides of the power amp.

Let's start with the amplification, KHA is a long time Nelson Pass fan, just like me. We eat, drink, sleep and BS(Bull Shit) about Nelson Pass and his esteemed products all day long! Hence it was no surprise that some one in the US of A has a bonding effect on two hifi loving Malaysians. His DIY project of choice would be based on Nelson's favourite child, the Aleph series. KHA has chosen the Aleph 3 circuit as reference point, but expanded on the idea to fit in to his "grand" scheme of things. The 30W Aleph 3 circuit has been modified for higher current output, with beefed up power supply. Each mono block of Aleph 3 has two chanels. One chanel optimised for high frequency reproduction, and another optimised to drive the mids. You see, this is a full active 3 way system, fully adjust able, via a Pass Labs inspired electronic x-over design, again used as a starting reference point.
A cloer look at the full class A amp.

Most DIYers choose to build OB speakers for their simplicity of build and high sonic to cost performance ratio. KHA adds one to the list, "it has no box colouration, what you hear is the driver's true capabilities, nothing added, or subtracted". I can only agree with his views. He has chosen to build his OB speakers with all top of the range Scanspeak drivers, in MTM configuration. Then the bass bin is where this OB speaker gets interesting. Again KHA utilises the OB design, but with a twist. He uses a push-pull configuration for his reversed facing dual 10 inch Vifa supplied subs, stacked neatly a top each other, so that the two sub drivers, top and bottom, moves in phase. An LM4780 gain clone amplifier is used to power the pair of bass bins. Since this is an active system, with no power sucking passive x-overs used, the sensitivity of this system is very high.
The OB design speakers with reversed push-pull bass bin. The tweeters are Scanspeak 1 inch AirCirc type, and mid bass is Scanspeak 7 inch classic doped paper cone type, now discontinued. These are the best mid ranges that's ever made by Scanspeak, IMHO.

The OB design in detail. Simplicity at it's best!

The dual 10 inch Vifa supplied sub woofers mouted in reverse but wired to push-pull, so that the drivers moves in phase. The bass bin up close.

The 68W output LM4780 gain clone power amp for the bass bins.

Top: The Pass inspired 3 way electronic x-over. Bottom: Marantz M7 tube pre amp with simplified schematics.

KHA likes to add a little bit of tube magic in to his system, he has built a couple of tube pre amps before settling on a simplified Marantz M7 design. Again, KHA worked his magic on the Marantz circuit by beefing up the power supply and regulation stages. It was the "golden" tone of voice emanated from the Marantz pre amp that won him over. What chance does an audio slut like me have against resisting the charms of the Marantz M7?
The glow of tubes! Note the neat panel engravings.

The 3 way electronic x-over.

KH Audio product!

KHA was a firm believer of the SACD format advantage, but the music market did not moved in step with the techies. He is left with a Marantz SA8260 SACD player, playing with what ever SACDs he has in his now static collection. The SA8260 has been stripped of all it's un necessary multi chanel boards, and simplified output section fully discreet class A board. A Marantz CD63 SE has instead joined the source feed. Mind you, an itchy fingered KHA, just would not allow the lowly CD63 SE to stay stock. He has since re-clocked, reworked the power supply and analog output section. The Marantz HDAM output modules have been dumped, in favour of a full discreet circuit, that outputs in full class A.
The SACD and CD source. Marantz SA8260 and CD63 SE. Both are highly modified units.

The sound of the system is open, free from boxiness and big scale, as to be expected from a well executed OB design. With it's twin reversed, push-pull sub woofers, the system's bass slam and dynamics is almost un matched, except for some mega watt amp based system. The mids have that Marantz M7 "golden" tone signature, with density and convincing body. The "honeyed" tone highs are dark, yet smooth and remark ably grain free. Playing live recordings, the system portrays good hall ambiance and "air", with space around each performer and vocalist. This is a super DIY system, that all audiophile/music lover worth his/her salt should make a bee line to reference. Choice, taste and preference be dammed!
The Isobar doing PLC duties.

KHA also uses an Isobar filter for clean A/C supply. All power cords are DIYed. Inter connects are DIYed using high grade Belden stock. Speaker cables are customised using Analysis Plus stocks.

KHA is already in to his last phase of system building. He plans to replace all those AD797 op amps in his 3-way electronic x-over with full discreet class A output boards, now under testing as you can see below. This will improve the system transparency factor by leaps and bounds, he says. KHA also plans to reduce the MTM OB baffle size, by bringing the mid-tweeter-mid drivers closer together, for improved point source integration. Some acoustic isolation fabrication, for the bass bin to floor decoupling is now being investigated too(my humble suggestion this!).
Some of KH's ham radio equipment. The call authentication cards are sent to him, each time he communicates via satellite in the old days.

Prior to DIY-ing audio his system, KHA is already a celebrity in the ham radio operator's world. In the good ol' days, people built signal amplifiers and transmission towers, so that they can transmit signals over very long distances, bouncing them off low/medium orbiting satellites, to communicate with one another in continents of all over the world. KHA is one of those people. He's probably one of the only 2 stations in Asia to talk to the international space station. NASA extended KHA an invitation to tour Cape Canaveral, where they launch space shuttles, some time last year. KHA's call sign is 9M2FL for Shack Radio Amateurs who wishes to contact him.
The bass bin under going some test measurement during construction. Now, how many DIYers do this?

The source of KH Audio's inspiration for the 3 way electronic x-over. This original Pass item set belongs to a friend.

The Pass 3 way electronic x-over clone under goes testing!

The fully discreet class A output board for the Marantz CD63 SE under going testing.

KH's self made mini CNC cutter.

KH's play room, er........... work shop!

Not only did KHA build his own sonic dreams, he built his own DIY work shop, complete with test equipments of the most extensive varieties. He also builds and commissions CNC machines in his own work shop! These are the very CNC machines used to make his DIY aluminium face plate for his Pass look a like face plates.

KHA, we at Hifi-Unlimited salute your un dying dedication, to pushing boundaries and doing us Malaysian audiophiles and DIYers proud.


Capernaum Creative Solutions Inc. said...


亦妮亦妮 said...
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Sting - not the english man in New York! said...

ok, who is KH btw?...:)

Big E said...


KH is a very low profile person. I can't divulge too much information here, except that he is a great sifu when it cmes to DIY audio.

Sting - not the english man in New York! said...

Wilson (puchong)my DIY guru will be delighted to met him. They must be friends by now..:)

Suci Dalam Debu said...

His hi fi is simply superb. In fact, after listening to his system, I have learned to appreciate music like never before.

Keep up the goodwork A Chen :-)

Lye said...

Dear friend Kok Hoon, your equipment looks very delicious and tokkong. de 9m2LR

Big E said...


Wilson, the famous Puchong DIYer sifu has met KH before.

As the saying goes, great minds think a like, and fools seldom differ!, the two great DIYer sifu share and exchanged ideas, but could not agree on certain hifi paths.

Never the less, we are richer in experience with the diversities of opinions. This coming from my point of being a student of all hifi matters.

PuchongWong said...

My personal take on diy:
technical skill is always number 1
Learn from the design of excellent commercial products exensively.When you're done with your diy piece,do listening test with an excellent commercial item. Many times a lot of diy frends just change some tubes,some capacitors,the power pocket, and then say my diy work already sound better than the leading commercial products. They don't or con't recognise the obvious problems with their diy effort, but think that a little tweaks here and there have brought huge improvement.
Diyers say the commercial products are overpriced, they could achieve the same with diy. Those into commercial product say diy will never ever reach the same latel of quality. Hehe, which one are you?

maestro said...

Congratulations HiFi Guru, my friend of over 40 years. You have always set the standards in audio since the early days of your Tiger Amps.
Well done. Keep it up.