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Thursday, September 3, 2020

The best power transformer for audio!

The best power transformer for audio has just gone even better! Our Level 3 Ultra Isolation Power Transformers design has just been improved and enhanced with even better isolation properties and grounding techniques to achieve even lower noise than before. 

For those who are unaware of what Ultra Isolation Power Transformers (UIPT) are, here are 2 main pages we talk about our ultra isolation transformer or ultra isolation power transformer. If you have not tried it, you have to die-die (as we say it in locally) try one. The performance is Heaven and Earth apart from the ordinary on-the-shelf stuff.  

There is a price to pay but the ROI is well worth it. It is much better than just upgrading power cords or add more 3rd party gadgets to lower noise floor. 

Why do one use Ultra Isolation Power Transformer (UIPT)? In short, UIPT is a combination of power transformer with ultra isolation properties. You get the lowest noise and darkest background out of this by just 1 UIPT instead of the usual isolation transformer then power transformer combo.

For those who are not a follower of our J&K Audio Design page, please take a few minutes to visit our FB page, give us a "Like" and subscribe to our page:

All the best for audio! 

J&K Audio Design


Monday, June 22, 2020

Output transformer preamp transformer

Thanks to one of our great and frequent customer, this article is born.

Before we start our lecture, take a look at this picture below of Tamura A-4714 signal transformer. Do you see any peculiarity about this Tamura A-4714 signal transformer? 

Sorry, right guess does not win any prizes here. LOL! 

Yes, it is an output transformer. Yes, it is a pre-out / pre-amp output transformer. What? Two types in one? Yes, two in one! 

Based on the limited information available, it is a signal transformer with primary of 5K that is capable of ~50mA of DC current, and a mixed secondary of 150 Ohm + 150 Ohm + 6 Ohm.  
  1. Application 1 - use it as a power amplifier output transformer capable of ~3W output.
  2. Application 2 - use it as a pre-amp output transformer with either 150 Ohm (secondaries in parallel) or 600 Ohm (secondaries in series) output impedance.
  3. Application 3 - use the additional tap as a feedback tap to reduce distortion, as seen in some innovative designs in very old designs. It may be present in modern designs but I rarely see one. 
  4. Application 4 - use both! 
How to design the circuit - hmm... maybe next time. There are plenty of sample circuits online. If you buy one from us, maybe I shall consider spending more time to teach you how to do so. 

Now this sort of signal transformer is kind of fun, right? If you're undecided if your tube is going to be used in either applications, order this transformer! You can decide later and still have the right transformer to use - now ain't that cool! 

Of course, buyers be warned - universal design is a compromise. A dedicated transformer will be better, minimalist, as we always preach. For the fun of it, I see why not. Also, the user said it is one of the good transformers he owns. So, I believe, we can do better than that! Challenge accepted! 

Good old used or NOS Tamura A-4714 could still be found occasionally in eB*y or all sorts of online sellers out there. If the A-4714 fits what you need, perfect. If you need something that is out of ordinary, custom made, then you know who to look for - J&K Audio Design! We can make it to any primary and secondary taps that you need. So far I've not seen new ones being made - I may be right for now, and wrong later. You can check Tamura website and see if it is there. 

The sky is the limit! Seriously. We can use almost ALL sorts of cores available in the world. And we have 3 types of magnet wires to choose from - ordinary John Doe OFC, to exotic OCC Copper and OCC Silver cable wounded output transformers. Oh ya, any voltage (as high as your dare) and any DC current for the primary too (1A? No issue, been there, done that!). 

So, for those under-decisive souls out there, your savior is here!

Do I have an actual picture of it? Nuh... it looks the same like every output transformers out there - bare naked or potted. They all looked the same. You want special casing? Hmm... maybe we can do so now - since we've found a LOVELY LOCAL vendor here. He's a bit busy though - so expect longer lead time if you need a fancy output transformer case. 

Meanwhile, take care and stay away from being infected with COVID-19. Stay safe at home. DIY more audio amplifiers. Buy more transformers from us!

J&K Audio Design

Wednesday, June 3, 2020

Difference between audiophile isolation transformer versus technician isolation transformer

Do you know the difference between audiophile isolation transformer (or medical isolation transformer) versus technician / electrician isolation transformer?

If you do not know, then you are in for a very severe shock, both mentally and electrically. Both of them have a very distinct difference for different usage model - and it is related to safety and noise isolation. 

If you are ordering or going to use an isolation transformer in your system, you need, you DEFINITELY MUST know this, or else, you are risking your equipment and you're risking your life it there's a fire. 

J&K single ended isolation transformer, secondary is not grounded by default. 

J&K balanced isolation transformer, secondary center-tap is grounded by default. 

For J&K customers, if you're unsure on how to use them, email us.
For J&K customers, if you need to convert to technician / electrician isolation transformer, email us. 

For followers, please wait for our write-up before you do anything drastic.

We do not have the time to quickly do the write-up yet unfortunately. Watch this space if you value your life and equipment. 

Take care! 

J&K Audio Design

Wednesday, May 20, 2020

Retrospective - feedback

It has been 7 years since we started our blog, and much before that, the off-line presence through ordinary website, traditional brick and mortar business, and via words of mouth. 

Over the 15 years of history, we have changed our business models multiple times, tried aggressive expansion, worked with partners and vendors for different strategies to sell design or sell products, cooperate with our valuable customers to develop and fine tune our products and product lines based on feedback of our customers. 

We would like to say:

Thank you! 

To our customers. To our partners. To our fans and followers! You guys rock!  

And, we would love to continue to hear from you on how we can improve ourselves to better serve you, and help you with your projects! So, please use the form on the LEFT PANEL of this blog, and send in your feedback, criticisms, ideas, proposals, topic for discussions, anything at all! 

We may have hiccups along the way due to a lot of reasons - we would like to take this opportunity to apologize on them. If you see any issues at all, please work with us and we would always try to satisfy your requirements and fix the issues for you. 

That aside, apologies - we do not want to buy pipes or buy construction materials. We also, do not have any dead or distant relatives that have a bunch of monies waiting to be inherited. We prefer hard earned monies instead. So, spammers, stay away please. If you think we are gullible, think again. 

If you like (or dislike) our services and products, and do not like to write emails, please leave a comment in our blog page below! 

If you have new product ideas, we would love to hear from you! We can work with you to market your business. 

Till then, take care and stay safe everyone! 

J&K Audio Design

Saturday, May 2, 2020

Shunt Reactor

People has been talking about the evil artifacts, such as, noises the active regulation brings, for example, those using a toroidal transformer with a motorized carbon brush, or even relays to switch to multiple taps in the transformer, to adjust the voltage when there are elevated mains voltage or brown-outs. Or, some audiophile just despises in-line or in-series regulators, saying that they choke the sound of their system, or restricts the dynamics  

So, is there a more elegant way of regulation other than the active way? Is there a way to regulate with passive components? Is there a shunt type of regulation device that can help with regulation? When it comes to transformer, or anything with a core and wire, ask us! 

Well, there is! And, it is called Shunt Reactor! 

Shunt reactor is used in industrial applications, more than home environment, where it is an absorber of reactive power to increase the efficiency of energy transmission, or to compensate (or consume) the reactive power generated by capacitive loads line capacitance - Ferranti effect). 

An inductive load consumes reactive power. A capacitive load generates reactive power. We have too MANY capacitive loads connected to our power line right now, especially with high power amplifiers that uses a lot of capacitors. Even an OPEN POWER LINE generates reactive power. 

The shunt reactor is normally connected permanently to the power line, or sometimes are switchable, or adjustable (VSR - variable shunt reactor) to cater for different daily-hour power draws or seasonal dips and peaks of power draw. 

In layman terms, shunt reactor automatically stabilize the voltage levels. minimize over-voltages. 

Usually the shunt reactor is permanently connected, or switched by a circuit-breaker (circuit-break is required ***important***). Several shunt reactors with different can be connected in parallel, or switched in and out to adapt to different power line conditions. 

A simple connection diagram of the shunt reactor is as above - across the live and neutral lines. For balance power, you will need two units of them to work in tandem. 

WARNING: It is dangerous and LETHAL mains / live AC voltages you are working on. Do it at your own risk. It is for qualified electrician only. WARNING. 

What consists of a good shunt reactor design? 

  • Air-gapped core - constant impedance, reduce loss, avoid saturation, promotes linear energizing, and minimize remanent flux in the core (flatter hysteresis B-H curve, lower inrush current) 
  • High inductance - high energy storage and resistance to changes 
  • Low DCR or thick wire gauge - quick charge and discharge
  • High grade core - minimize power loss, lower vibration and noise  

A shunt reactor may look like a transformer, but it is intended to consume or compensate reactive power, where as transformer is to convert one voltage to another, or one impedance to another. Shunt reactor has only one winding. Transformer has 2, and above for the conversion. 

Since it is switched on all the time, losses becomes important to avoid high electricity bill and heat. What are the major losses in a shunt reactor?

  • Copper losses in the winding - wire 
  • Core loss - iron core loss 
  • Eddy current losses

Therefore, it is critical to minimize losses, and have a good shunt reactor design for better reactive power compensation / voltage regulation. 

Now, are you ready to DIY a shunt reactor device and use it in your home environment? 

J&K Audio Design

Tuesday, April 28, 2020


We're always open to partners to help us expand our business and product coverage. 

If you are specialize in certain technology, or handcraft, or any work that is related to HIFI or audio industry, please contact us and tell us more how we can cooperate and benefit one another.

You can be - equipment manufacturer, gadgets maker, or even transformer manufacturer, we can work something out to benefit ourselves, as well as our customers. 


1. You are amplifier manufacturer - we can cooperate by supplying you transformers. 

2. You are HIFI gadget designer - we can cooperate by sharing technology and product ideas. 

3. You are CNC house, or capable of metal stamping, bending and such. 

4. You are a supplier of parts (electronics, electrical, irons, pre-fabricated chassis, transformer cases, transformer frames and etc). 

5. You are transformer manufacturer - we can cooperate by covering one another product gaps. There are some product segments that J&K do not cover, we can pass those business to you, or act as bridge; and vice versa. There are some geographic regions that is too far to ship J&K products to (too expensive, or not covered), and vice versa, we can leverage each other's network. 

We had outsourced some of our low end transformers to our partners previously as the pricing that our customers looked for were just too low for us to manufacture here. If we like your audio gadgets, we may even help you market it under your brand, or under our brand. 

6. You have idea on transformer design that you would like to design (by us, or by yourself), manufacturer, and sell (by yourself or by us), we can work out a deal.

Ideas are limitless! Complicated or simple. 

Email us and we shall discuss more. We are open to all ideas - no ideas are stupid ideas. 

J&K Audio Design

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