i worked on a tube preamp over the weekend
It has been a while since i worked on tube gear. Not that I don’t want to but ever since toying with Monica, Charlize, Beyonce etc, it doesn’t matter what is the technology, great sonics qualifies it as good gear!
But I agreed to working on this tube preamp as this guy been sucked dry by a local audio company. He bought the preamp, found some problems, sent back for repair, was charged heavily and then spewed some bullshit here and there…
I know the manufacturer, and know how bad his work is as I “rescued” a previous victim of his. I’m just fed up of listening to this smooth talker, giving other local audio companies a bad name…
When I got the preamp, I was kind of shocked.
The signal circuitry, component for component, is a direct replica of the Simple 5687 preamp on my site! This circuit was published on my site in 2003! It’s actually not my design but a take from vt4c’s design which was published in a local paper. The power supply circuitry is totally different from mine as cost is clearly a major consideration for the manufacturer so one choke and the tube rectifier was omitted. I can tell you this, out goes the sonics!
This “victim” came to me as this preamp, despite repairs, is still giving him problems. And I could see why!
In all, it’s a sloppily done job. And the components… there’s no regard for quality at all. The same type of resistor is used for plate, cathode and bleeder. The same size for all.
The manufacturer didn’t even try to optimize the sound. I know this as feedback from diyers who built this preamp told me the sound could be optimized further. If you spend some time on this circuit, you know the sound could be improved very easily by changing some parameters. Nope, this manufacturer didn’t bother doing that.
And the volume pot! It’s not even the usual Alps Blue but a cheapo Panasonic type I’ve used before. There’s a reason I don’t recommend this Pana pot ove the Alps. Wait, scratch that. There are many reasons not to!
There’s more to it but I’ll stop here. That’s the problem, the gullible public is always taken for a ride by folks like these. You have been warned!
20 April 2009 | diyparadise | 3 Comments
My friend Jonas sent me this. It’s so fitting in the current economic crisis.
6 April 2009 | Business | No Comments
The Barney Oliver Amplifier Story
Another audio brother, Thomas, sent me this link last week.
The Barney Oliver Amplifier Story
Doesn’t it sound like HP was a wonderful company to work in back then? If you read The HP Way, you’ll appreciate better the way Bill Hewlett and Dave Packard envisioned the company is run.
I was working in Agilent (the original HP later became Agilent) when I read The HP Way, and you can’t help but feel that in today’s cut throat, competitive, great-results-every-quarter biz world, a lot of what makes this company such a nice place to work in, is gone forever.
Thomas is right to say that visiting the site only makes you reminisce on the “good old days” back when people don’t go gaga for results every quarter, when management still take long term views when making decisions. Read The Barney Oliver Amplifier Story and you’ll realize, they even know how to have fun within the organization.
I would love to get my hands on this amplifier!
24 March 2009 | Business | No Comments
A great audio friend has passed
I received this email from Harry Zweben of twobaldguysaudio.com this morning.
Greetings-
I am writing with no small degree of sadness to share the news of Dave Merrill’s passing. Dave died last Wednesday after a long battle with heart disease. “Battle” is hardly the right word, as Dave knew that his time was limited over the past year or so. Despite news that he would not qualify for a heart transplant, he remained the epitomy of grace, equanimity and good humor– as I imagine that he was throughout his entire life. He was a fellow traveller to the end; the last time we spoke, a week or two before his passing, he told me of plans for a new cabinet design for his DCA 4 drivers as an alternative to the Zigmahornets, and he was still spending as much time in his shop as possible to finalize the prototype.
Kent and I attended Dave’s funeral service on Tuesday, which was a fitting tribute to our friend. The eulogy was memorable and the priest was both eloquent and funny; Dave would have enjoyed being ribbed as “the only sinner in Canby” since he would attend confession on Saturday afternoons and was often the only parishioner to be seen or heard.
Dave left a wonderful legacy and contribution to the audio arts with his miraculous little DCA 4 and DCA 5.5 speaker drivers, and music lovers world wide will miss him. And for those of us who knew him, albiet briefly, we are better off for the privilege.
Best-
Harry
It was Gabriel who introduced the Merrill DCA4 then DCA5.5 drivers to me. I was really shocked to hear how good these drivers are! The performance for price value of the Merrill drivers is simply way way way off the charts. Never have I come across such nice drivers. If you don’t even consider the very affordable price, it already beat all models of Fostex I have heard before.
So it’s really sad to hear of Dave’s passing. Attach is I believe the most extreme horn design built for the DCA4, built by Gabriel and we exhibited this at the 2008 KLIAV Show.
Rest in peace Dave!
20 March 2009 | Uncategorized | No Comments
No one is sacred from being layed off
Brother YH sent me this link about National Semiconductor’s Bob Pease being layed off.
Now this is a MAJOR, MAJOR disappointment. You will think that a company like NS will recognize top engineering talent, or someone like Bob Pease will be immune to being retrenched, but there you go. It happened!
YH introduced the work of Bob to me couple years ago. I have tried to read up all his columns when I have the time. If you like analog electronic stuffs, his articles are a treasure trove, full of little snippets of insights that could only be acquired over a lifetime of top engineering work.
Sigh, what more could we expect from folks who are only interested in the bottom line every quarter? Where’s the long term view?
On a personal level, the company I work for has been retrenching folks too. A few of my colleagues got the chop too. I could feel my turn is coming. Hey, if even someone like Bob Pease isn’t sacred, what chances does Average Joe Engineers have?
I could smell it coming…
19 March 2009 | Uncategorized | No Comments
The passing of a friend
Due to workload commitments, I have been working on the road since Christmas Day 2008 itself. Short for a week long break for Chinese New Year, been away throughout this time and only now things are settling down.
So I was shocked to hear from a friend of John Potis’ passing on 22 Dec 2008.
You may associate John’s work with diyparadise through this review of our products on 6moons, of which he gave us a Blue Moon award, but we got to know each other more than 10 years ago when I was just a college student in the US.
Why heck, I’ll tell you this. John was the one who set me on the right path in audio!
You see back then, all I knew of was mini-compos the likes of Sonys, Aiwas etc. You know, those black plastic pieces advertising glorious powers of 1000W PMPO? It was when I visited a friend Brandon, then I realized for the same amount of money, buying used audio gear, one could get some really decent sound. His was a pair of used Polk speakers and other stuffs which I can’t remember.
Piqued by the decent sound at such modest budget, I did what was considered really hip then – I surfed the Net. Hey, remember this was in 1997! And the Net was still in its early days.
I stumbled upon John Potis article on “Advice from a Friend to a Beginner in Hifi”, err, I can’t remember nor find the original article but it was something to that effect. Anyway, in that article, John was really nice to give some really useful advice to first timers (like me then) dabbling their toes into the hifi world.
I recall John featured particular models like PSB Alpha, NHT Super Zero, Paradigm Mini Mk3, Rotel integrated amps and a host of other goodies. As I then emailed him (I remember the email program was a Telnet. Wow!), he quickly replied and answered my queries and gave me more advice.
Why heck, he even told me not to be too concerned over cables and interconnects, telling me that even the $12 (back then) interconnect set of 4 cables from Radio Shack will do.
I took his advice and was rewarded with a pretty decent system which still works well till today. As I ventured into other areas of hifi, I realized over time his advice has held me in good stead. And over time, we sort of developed a friendship where we discussed many things. Why heck, like he said on the 6moons review, he even consoled me when I was going through a rough breakup. Looking back I realized I was just stupid with that girl but it showed what a nice chap John was.
After I left the US, I lost contact with John. Over time I lost interest in hifi too as hifi products are just so expensive in Malaysia. Besides when you first start working, buying a hifi system doesn’t seem like a priority.
Couple years later, got bitten by the DIY bug, and things have never been the same again.
When I finally found that he is reviewing for 6moons, I contacted him and couple months later, we decided to send him something to review. But after the review I have meant to contact him again but didn’t do so. Dang…
So I’m really shocked to suddenly learn of John’s passing.
He really touched the live of this fella at the other side of our planet.
Rest in Peace, John.
14 March 2009 | diyparadise | No Comments
season’s greetings and happy holidays
First of all, Merry Christmas and Happy New Year!
If you celebrate neither and won’t be taking holidays, take comfort that you won’t be alone. I’ll be working throughout the last days of the year. Some hardware for my project is coming in so late that I have to work throughout the holidays to get things back on schedule. Pesky day job…
For diyparadise, it has been another bumper year. There were less new products than I hoped/planned for. However, this only means 2009 will be even more exciting!
It’s great to finally take part in an audio show. Though it’s local (in Malaysia), it’s still a good experience. Also, I finally listened to our Hedlund Horns in a totally different environment. This helps me to understand horn’s strengths and weaknesses better. If we didn’t participate in this audio show, I wouldn’t learn more about this. Hey, no one lugs around 80kg of speakers (each weighs that much!) around for audition!
The audio show also afforded us the rare opportunity to meet so many customers. You know, we are hermits. We only meet with our suppliers, vendors and Fedex delivery guys. Occasionally we meet up with customers, but it’s more of a one-to-one basis, and never more than 5 in one go. So imagine meeting up with over 2500+ visitors in 3 days!
Just before the end of the year, I’m proud we managed to launch Beyonce! – our volume control/preamp kit. You could view her as the successor to our earlier Maggie the autoformer volume control. And we have more products coming up!
On the forum, you noticed I showed pics of a DAC-Preamp, that’s Monica and Beyonce in one chassis. I really like this concept and feel that you get much better sonics this way rather than having a pesky interconnect cable in between. How do we know this? Because we have tried so.
In the pipeline for 2009, we should be releasing Charlize’s more powerful sister, at 100W per channel!
New speaker products! We are pleased to now distribute the excellent Merrill DCA speaker drivers and it just makes perfect sense to sell them in speaker enclosures! You could view these as the successor to Sophia, our SeTH Horn based on the Jordan JX92s.
Tube preamp/headphone amp. This has taken quite a while but I hope we could release in the coming year.
Phono stage. Oh yeah, we are not all DIGITAL crazy. We know some of you are anal, err I mean, analog guys too, so we got to have something for you guys too.
Oh well, that’s just some of the products we intend to launch in 2009. No promises they will see the light of day. *Sometimes I’m just talk!* But rest easy, as always, we have your sonics in mind.
Again, Merry Christmas! Happy New Year and Happy Holidays!
20 December 2008 | diyparadise | No Comments
Termites prefer hard wood?
In the Oct 2008 edition of Hifi World, there was a mention of us as Noel Keywood visited our room during the recent KL International AV 2008 show.
Hey! It’s nice to see our mug shots there! I believe this lends this mag a bit more of a “GQ” appeal? 
I thought of hanging around the newsstand and autographing buyers of the mag… Narcissus would have been proud!
Err, humbly allow me to point out 2 problems though.
Noel got our domain name wrong. It’s diyparadise.com, not diyparadise.com.my. When I first started the site, I never thought of restricting to a .my domain name. I was thinking who knows where will I be based in the future? Anyway, this is a minor gripe.
Noel remarked that he was worried whether termites will attack our speakers since we build with tropical hard wood here. He mentioned he saw some termite attacks at some hotel lobby in this country.
Hmm… Termites attacking our speakers? Being curious, I went all out to catch a few termites. Phew! Tok me some effort here! And finally caught some of these dirt burrowing insects. There was this piece of rotten wood on the ground and if you kick it, it’ll come apart due to the extreme efforts of these little gremlins.
I started my interview. There was a worker, a soldier and one fat looking ‘”queen” I believe.
I asked them, what’s their favourite food? Why, it’s wood of course!
Dang, have to be more specific. So given a choice of solid wood, fiberboard and chipboard, which would you prefer?
In order of preference, it’s chipboard and fiberboard first, then solid wood.
Huh? Why so? Why not go for solid wood first? Well, apparently solid wood is “denser”, “tougher to chew” while fiberboard and chipboard, being man made and processed, it’s a lot easier to their mandibles.
Among solid wood, then their preference is of course the softer variety, followed by the medium and they totally dislike hard wood.
Hey! So this means that our speakers, being constructed of a mixture of medium hard and hard wood will be a turn off to them!
And speakers constructed of fiberboard and chipboard are favourites of termites!
Which points to roughly 99.99% of speakers made in the world! Chances are the speakers that’s playing in your room now is most likely made of Medium Density Fiberboard (termite food!). Don’t let the veneer fool you ok? It’s still not solid wood.
Phew! Am I glad to hear that! So happily I released them termites.
If they said they prefer solid wood, I would most certainly squash them…
10 October 2008 | diyparadise | No Comments
Buffer Tweak on all Monicas
One of the highest recommend tweak for all versions of Monica is the JFET buffer tweak. This tweak has been described on this page using 2N3819 JFETs.
Since I finally got the 2SK170s, thought it’ll be beneficial to show how it’s done to your Monica. Note that the tweak on the main site uses 2N3819 and had the output caps soldered out. This tweak here does not remove the output caps but involves cutting PCB traces.
FIrst off, solder your 2SK170s like this.
You then need to cut the trace linking the I/V resistor to the output Black Gates caps. Shown here is for one channel. Confirm with a multimeter the trace is open before proceeding with the next steps.
Installed the pair of 2SK170s. VCC (24VDC) could be tapped from upper most end of the trim pot.
Another view with both channels installed.
This view shows the cut trace for both channels.
After everything’s soldered. Power her up. All LEDs should light up as before and confirm voltage across I/V resistor measures about half of your power supply. Then play music!
If there’s no sound, you have made a mistake somewhere. Don’t blame me. 
As usual, with all mods, you are on your own. So be careful!
19 September 2008 | diyparadise | No Comments
KL International AV Show 2008 – 2nd & 3rd days
The second and third day, we were expecting the crowd and yes, there they were!
Printed out 2000 flyers and gave out the last one at almost the last few minutes of the show. And I was so close to printing just 1000 pieces.
My thoughts? Here’s a few thoughts. First the minus.
1. I find that many Malaysians do not even give their countrymen a chance. They passed by, had a look, and when they realized it’s all locally made, quickly walked away. Nary a listen. Sad…
2. Didn’t know there are so many speaker designers in Malaysia! Well, that’s what they claimed. Each gave interesting comments. Some were a bit strange like… where is your speaker driver? They couldn’t even locate the speaker driver!
3. Many did not bother to stay long enough. I believe we were the only room to play such a huge variety of music but in order to listen to different types of music and the different virtues of the system, you got to sit down for a while. I guess they weren’t keen to give us a chance after all.
4. Room acoustic simply sucks. Despite the room treatment we did, it still wasn’t enough. If we had more time to tame the room, we could certainly do more. The listening hall in my home has more width but less depth. The resultant sound is more open and “lighter”. Light as in being “more agile”. We don’t get this in the hotel room.
5. Some folks commented not enough bass. This being horns, we advised them to sit further behind as the bass waves would be thrown further. They wouldn’t and preferred to sit in front. Then complain not enough bass. Oh well…
Okay, the plusses.
1. Met many interesting folks! Made many new friends!
2. Interestingly, we had many listeners coming to our room for 2 consecutive days. Some even for all 3 days! I guess we must have done something right!
3. We received many positive feedback. Some say that they are proud to know that Malaysians can do something like this! Hey, after all, we are the ONLY one with a full 100% Malaysian designed and built system.
4. It’s refreshing to have folks ask for different types of music. It’s sickening to hear only of “audiophile approved recordings”. It’s refreshing to hear requests for AC/DC, Led Zep etc. And I believe we are the only room to play such music!
5. Many just love the speakers! Simply couldn’t believe their eyes. Gabriel’s craftsmanship is evident here.
6. The most important impression we made was to a close friend of ours. Just days before the show he called me up and asked me whether I’m sure I wanted to bring the horns there. “No highs, no lows” were his exact words. When he came on Saturday, he stayed the longest. He left and then came back again and stayed till the end of the day! And he admitted that all this while perhaps he has not had the chance to listen to properly designed horns. Well, late Saturday evening, we had a rock concert there. It was loud, it dynamic and it was alive! And our friend is not a convert!
Overall, we are glad to showcase our capabilities. We are glad to come out of our homes and meet people.
If you visited us at the show, many thanks for your support! Write to us and send us some pics!
28 July 2008 | diyparadise | 11 Comments
