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Saturday, April 22, 2017

J&K Transformer Volume Control

J&K Audio Design TVC - we just realized that we have not posted any pictures of our TVC, oops!

Here are two types that we offer - 23/24 steps, or 33 steps.

J&K 23 steps TVC

J&K 33 steps TVC

It is housed in a 80mm x 80mm x 100mm H steel casing, with 60mm x 60mm mounting holes, with a 50mm x 50mm opening. Other sizes may be available, depending on the casing availability.

It may not look perfect on the bottom side as we're running out of space to cramp in 33 + 3 taps at the small opening. The black compound is transformer transformer potting compound. Our secret multi-layer potting processes (for sound tuning) make it even harder for us to make the bottom to look perfect.

24 step TVC

33 step TVC

Fully built TVC in a chassis is available with workmanship surcharge, plus the costs of chassis, connectors, switches and internal wiring (variable due to difference in quality).

You can read more about our various J&K TVC posts here, and even the J&K OPTVC!

http://jandkaudiodesign.blogspot.my/2016/10/transformer-volume-control-tvc.html
http://jandkaudiodesign.blogspot.my/2016/12/transformer-volume-control-review.html
http://jandkaudiodesign.blogspot.my/2016/10/optvc.html
 
Now J&K TVC, and J&K OPTVC are available with OCC Copper and OCC Silver wires, on top of the standard OFC and silver plated OFC magnet wires, for maximum enjoyment and performance!

Till then, adios!

J&K Audio Design
4/23/2017

J&K OPT with LS3/5A

It has been some time since we last posted. Time really flies. It is almost mid of 2017, in a blink of an eye!

As usual, things are very, very busy behind the scene. We hardly have time to ourselves. Custom made audio equipment orders come in faster than we can clear them. Apologies for those that waited long, and are patiently lining up for their orders to be completed and delivered.

Ken has been troubled with migraine problem, and has been pushing some orders away to have more rest time to attend to his health. That makes things even more hectic! And, if you want to get your things done with a deadline, we'd advise you to place your orders early to avoid disappointment.

Let's get back to audio topic here! Nobody wants to hear all that ranting! :P

Tone accuracy and correct voicing are something audio designers always look for. Even if your frequency response, bandwidth, or measurements look perfect, the outcome of "sound" may not be "right". That's why we always try to pair our transformers with studio monitors, such as Tannoy speakers.

We have a customer that bought our SE OPT - ALIS-5SE Ultimate quite some time ago. He's a user of LS3/5A, introduced by none other than the venerable LS3/5A guru, JoKi, who is also a personal friend of Ken. He has been using a pair of famous very high quality OPT from Taiwan with his LS3/5A, and want something better.

At first, he was not used to the sound of ALIS-5SE with his previous LS3/5A (forgot what model). After a year of testing, and running in, and with his new Falcon LS3/5A, this is what he said!


And now he is considering the NanoCrystalline Double C OPT (Level 3), as next level of progression! Thank you for your feedback!

Having endorsement from Falcon LS3/5A users showed that our tonality and voicing are correct, to satisfy event the most critical studio monitors. This has always been our goal - meeting measurement results with sound quality.


You can further read up on ALIS-5SE here:
http://jandkaudiodesign.blogspot.sg/2014/05/output-transformers-alis.html
http://jandkaudiodesign.blogspot.my/2015/05/alis-5se-ultimate-user-comments.html

Till then, enjoy music!

J&K Audio Design
4/23/2017

Friday, March 31, 2017

Fake Capacitor

Fake this, fake that, fake rice, fake capacitors! You've seen them a lot online, have you seen one yourself?

We have been very, very careful, still, there are a few that we suspected are fakes, although being bought from reputable online seller. We were matching some Vishay high voltage 470UF 450V electrolytic capacitors for tube amplifier use, and 4 of them felt flimsier than the rest of the capacitors. When shaken, we can feel that the internal are not snug or fit the enclosure, like a can inside a can with some space left between them. The capacitance measured OK though, meeting the specifications.

The vibrating "core" is not good for any applications on our standards. Curious us, since we're going to throw such suspicious parts away as they failed QA, why not just open up and take a look! . 

Internal does not look as sturdily built like a high grade Vishay capacitors we have in stock. It has only 2 flimsy ALU foil connecting out to the external 2 terminals. Usually, those higher grade low ESR capacitors will have multiple higher gauge foils connecting the 2 positive/negative terminals. We think, probably it is some low grade cheap capacitors being re-sleeved as Vishay 156 PUM-SI capacitors to rake more profits. The capacitance may be OK but the voltage ratings may not, and will risk an explosion if used over its' rated voltage.

Fake capacitor?
Buyers beware.

To be safe, we'd better stick to our 1st source for components - element14! More expensive, but definitely safer, and is made fresh from the factory instead of being sitting in the storeroom for extended period. Such capacitors long being in storage may still be usable, but the leakage current might have gone up the roof, and requires reforming. Still, we are not going to take such risk. 

The end products will be more expensive, but what you pay is what you get! These babies are U$43/pc each. With 6 per channel, 12 for stereo, it is already close to U$516 just for capacitors alone. Quality comes with a price, and extreme high quality is what we strive for. Often we hear people say, why are your stuff more expensive than others? I can just get in China or some online dealers cheaply. Dude, you pay cheaply, you get "cheapies"! Don't come crying when it exploded, sounded mediocre, or something bad happened along the way, like blown amplifiers and speakers go along with it to audio heaven. We've repaired many, and we know what's going on in the cheap audio industry, such as fake caps, re-branded caps, recycled caps, re-sleeved caps, and many more horror unknown to most stories.

Below are some guaranteed genuine Vishay highest grade electrolytic capacitors we ordered for our solid state amplifier. It costs a lot, but is definitely worth it. Check it out:

Element14

Ordering Caps from Vishay

Vishay PED-ST Electrolytic Capacitor

Vishay 106 Electrolytic Capacitor

Just how good are these caps? Take a look at the specifications!
  • Very long useful life: 20 000 h at 85 °C (even longer life at 40 degC)
  • Extremely low ESR and ESL allowing very high ripple current load (very important)
  • High resistance to shock and vibration (good for sound)
  • Polarized aluminum electrolytic capacitors, non-solid electrolyte
  • Large types, cylindrical aluminum case, insulated with a blue sleeve
  • Pressure relief in the sealing
  • Charge and discharge proof
  • High reliability (very important for amplifier stability and longevity)
The fake ones that we had certainly does not fit the criteria of "high resistance to shock and vibration", LOL! 

This capacitor screams of quality in every sense! Did I tell you that the ESR for the 33,000uF 63V unit that we got is only 8 mOhm at 100Hz, and rated current at 100Hz @ 85degC of 23.5A (will be much higher at room temp!)! These capacitors are used in super high end amplifiers such as Soulution, Vitus, Dartzeel, and many other legendary amplifiers - their reliability, quality, and most importantly, voicing (sound) are proven, which is something we heard & like, and have been promoting for our tube amps, now solid state amps.

Sneak preview: we are going to use at last 4 of these per channel for our 100W/8-Ohm, 200W/4-Ohm solid state amplifier, as part of the J&K solid state amplifier line of products. [This guy (amp) is not on the list yet, as it is made for demo for local enthusiasts.] If the chassis fits, we may even throw 6 of these into a single channel! Now that's what I call an amplifier for real men! Be prepared to be blown away.

Till then. Take care, and don't buy fake caps!

J&K Audio Design
3/31/2017






Sunday, March 19, 2017

J&K Isotrans User

We had an opportunity to visit a  customer in Butterworth, Penang. He is using our EI Balanced Power Isotrans to power all his equipment, including the Burmester 032 integrated amplifier. 

The effects of using J&K Balance Power Isotrans - cleaner & darker background, more precise and proportionate imaging.

He has upgraded his integrated to Gryphon Diablo 300 recently and is saving up for his next higher power 4KVA J&K EI Balance Power Isotrans to serve the new monster that is coming soon to his setup.

We took some pictures of his setup for your enjoyment and viewing pleasures.







J&K Audio Design
3/19/2017

Saturday, February 18, 2017

Audio Transformer Repair

Audio Transformer Repair

If there's something strange in your neighborhood.
Who you gonna call? Ghostbusters!


If there's trannies burnt in your neighborhood
Who you gonna call? J&K! 


Nothing beats getting back the original sound, original look, and original material for your beloved audio gears collection! We repair any audio transformers - be it input, output, interstage, power transformers or chokes. We do not repair SMPS chokes though - get a new SMPS for Pete's sake!

4pc of damaged vintage input transformers were sent to us for repair recently. It was cleaned up and rewinded with traditional Kraft paper with old-school technology, following the generation when it was manufactured. It is fully restored back to the older days glory! 

The in/out wires are following the original color coding as well!













If your transformers, be it power, input, output, interstage, or anything at all, are damaged, don't forget to drop us an email to have them restored! A close to original vintage gear, at anytime, has much higher value than those with damaged or non-original components on it. 

Spend now and you will be rewarded financially, or in terms of audio enjoyment.


J&K Audio Design
2/19/2017



Sunday, February 12, 2017

Solid State Power Amp

Introducing our very first solid state power amplifier!


We're working towards getting more write-up on our solid state amplifiers but that will take some time. For now, we will share some brief specifications, and later, detail write-up on the design methodology will follow to introduce more about our solid state amplifier technology.

We are using chassis from Breeze Audio. If you do not find the chassis that you like, let us know.

Alpha 1 - U$490

- Class AB dual mono stereo power amplifier
- MK1, 45W / 8 Ohm (high power version, made for high efficiency speakers)
- MK2, 26W / 4 Ohm, 13W / 8 Ohm (high current version, made for low impedance single driver speakers and general use)
- Ultra high bandwidth: 8Hz - 100kHz @-3dB
- THD 0.02%
- J&K sound tuning, absolute darkness and quietness
- Purist & minimalist design, for high quality high efficiency speakers, or high efficiency single full range driver


Beta 1 - U$890

- Class AB dual mono stereo power amplifier
- MK1, 85W / 8 Ohm
- MK2, 76W / 4 Ohm, 38W / 8 Ohm
- Ultra high bandwidth: 8Hz - 100kHz @-3dB 
- THD 0.005%
- J&K sound tuning
- Purist & minimalist design, for high quality high efficiency speakers, or high efficiency single full range driver 

Gamma 1 - U$1290 / unit

- Class AB dual mono stereo power amplifier
- MK1, 180W / 4 Ohm, 110W / 8 Ohm  
- MK2, 200W / 2 Ohm, 100W / 4 Ohm, 50W / 8 Ohm
- Ultra high bandwidth: 8Hz - 100kHz @-3dB 
- THD 0.005%
- J&K sound tuning
- Purist & minimalist design
- High current high power version for driving low impedance, difficult speaker loads, such as Dynaudio, Maggies or ATC. 

 


Delta 1 - U$1990 / unit

- Class AB dual mono power amplifier
- 520W / 1 Ohm, 260W / 2 Ohm, 130W / 4 Ohm, 65W / 8 Ohm
- Ultra high bandwidth: 8Hz - 100kHz @-3dB 
- THD 0.005%
- J&K sound tuning
- Purist & minimalist design
- Ultra high current high power version for driving low impedance, difficult speaker loads, such as Dynaudio, Maggies or ATC.

 


Features

- Upgrades available, such as up-sizing power transformers, upgrade coupling capacitors (Mundorf, Duelund, and etc) and power supply capacitors, upgrade internal wiring, mechanical hardware (speaker binding posts, RCA, IEC), customize add-on features such as volume control, remote switching, DC blocker, EMI/RFI filter and etc.
- High quality components, high precision resistors, low ESR/high current capacitors, oversized high quality power transformers, and etc. 
- Traditional linear power supply with high energy storage are used for low noise operation. 


Notes

- For higher output power, from 250W up to 1kW, please write us.
- SMPS option is available upon request for PA or high power version.
- Can be made as mono-blocks, 2 channel, 3 channel, and 4 channels, or depending on the power and size.

Design methodology



J&K Audio Design continuously, and relentlessly seeks for improvement and advancement in every aspects of our product design. The best technology, methodology, metrology, know-how, experiences and materials science, are always applied to our products and design, whenever possible, and applicable, towards giving the best audio results.

Why did we say “when applicable”?  In audio, it is all about tuning and applicability. One cannot throw all the best parts available in the world, and expect the end results to be out of this world, to be remarkable. You cannot. That is not how audio design works. Just like in the culinary world, everything has to be in the right proportion, the correct ingredient, the right processes, the correct steps, to produce the best taste and texture to the creation. It is just the same as designing and manufacturing amplifiers, which is out topic today.

We have seen many, many excellent recent, and vintage amplifiers being made by great designers all over the world, all since the invention of audio amplifiers, starting from vacuum tubes (we love vacuum tubes, we still do), until all the various classes (A, AB, D, H, T, all DHT, PP, SE and etc) of solid stage silicon based amplifiers today. There is not “the best” amplifier, period. All are made with different end in mind, for different markets, different applications, different segments, and different people!

Our team, and our panel of HIFI enthusiast’s beta version testers have been ear trained to prefer vacuum tube sound. Those lush, warm midrange, extended highs, absolute transparency, taut but not overly excessive bass frequency, and many more traits associated with vacuum tube amplifiers.  In order to achieve such decent quality in vacuum tube amplifier, significant cost is involved, to have the right design, component, and materials deployed. As a result, cost might be overbearing for some, and may need to seek a cheaper alternative to achieve similarly closed performance.

Therefore, our quest to design such amplifier started.

We explored different designs, different classes, different materials (FET, bi-polar, jFET, MOSFET, and etc), discrete versus integrated circuit, different power supply designs, different topologies, different components (R, L, C, wire type, chassis, transformer and etc), and many more parameters that constitute to sound reproduction. This takes up considerable time, money and resource, and finally, we found the solution! Initially we were quite fond of class D switching amplifiers, with the efficiency, and capability to pack a very low footprint per Watt ratio, but the load dependent bandwidth due to the LC filter at the output stage turned us off.


The design we found, and offer now, is an integrated chip solution. It offers super wide bandwidth, easily range from 10 Hz – 100 kHz (ultra-low frequency contents <10Hz, are restricted per board design to minimize noise and wastage of power – increase efficiency and power handling), with flexible and scalable output power, from low to very high power, from low to high load impedances, and from low to high supply voltages. With integrated chip solution, signal path are the shortest, component count are the lowest, meeting our purist and minimalist design ideology, and that minimizes the loss from PCB material, PCB trace inductance/capacitance/resistance, PCB joints, and solder quality impact. 

I wish we could do a point-to-point wiring method using OCC (Ohno Continuous Cast) copper, with this solution, but the time and cost to manufactur such amplifiers would be too significantly expensive compared, unless customers request and are willing to pay for it, in a custom solution format. 

In addition, integrated circuits minimizes interferences from external environment, especially for the sensitive front-end circuitries, and short internal traces enable very fast and short signal transfer, and tightly controlled feedback or control loop for absolute signal integrity and transient response. All the complex and sensitive circuitries can be packed and shielded in a small integrated circuit. With current advancement in silicon wafer process technology, device deviation, or skew are tightly matched or controlled up till micron level. Part to part variation is kept to a very, ultra-low figure that matching integrated circuit behaviors can be expected consistently.

J&K Audio Design is not that large in volume until we can order customized audio integrated circuits from big time manufacturers such as TSMC or UMC where they produce chips for large scale manufacturing houses for the PC or mobile phone segments. We are just leveraging the effort and millions of dollars of investment made by such huge conglomerates to our benefit.


Out of the box, such integrated circuits may not be working at the optimized circuit, or being properly treated in their partnering components, such as the passive components, and the power supplies supplying the important energy to power the chip. We, work hard to complement the already very excellent performance, to raise it to another sonic level, under achieved in the mass-produced electronics gears or gadgets.

The scalable nature of the integrated circuits enables us to customize the output power to match the segment the amplifiers are designed for, whether is to power high efficiency speakers, or power hungry huge floor-standers. With careful selection of design and components usage, we tailor made the amplifier to match the speakers, with excellent results.

The integrated circuit is designed with intelligence to sense the output power required, and determine if extra output transistors are required to be turned on to deliver the extra power, thus still keeping to the minimalist and purist path where single chip produces the power until further requests at larger loads. Such switching or crossover may introduce noises but due to the internal circuitries built it, such traits are minimized and of very little effects.

Still, we recommend high efficiency speaker users to go for the version optimized for high efficiency speakers. The higher power versions, are, for more difficult loads. The sonic character is the same. Only the output power and current delivery are scaled up for high power versions. Such scale up in components, with more component count, with larger PCB size, may cause unwanted stray and leakage currents, inductance, and capacitances, attracts EMI/RFI and other interferences, add in more coloration, which may be detrimental to the sound.

Conclusion



The J&K Audio design amplifiers combine the benefits of integrated circuit with audio technology to bring users the best listening experience.

As you would have noticed by now, branding, marketing, paid reviews, and packaging expenses are kept to a very minimum, while research and development, prototyping, component technology and product quality are our utmost priorities. Therefore you will not see much reviews being published on magazines or websites, but true word of mount from our real world, satisfied customers. That is what really counts.
 
J&K Audio Design
2/12/2017


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