Solid State Power Transformer

Another state of the art solid state power transformer is born. We make our Level 3 power transformers like a piece of art. Everything are done to perfection. This solid state power transformer is made with OFC magnet wire from UK and custom made Super Hi-B C cores from Nippon Steel. Even the lead outs are using Teflon insulated wires.


This unit takes quite a while to complete as we pay special attention to getting everything right, from winding, labeling and etc and finally to finishing. This unit will last a lifetime! With the special winding method and shielding, the noise floor will be very very low. This is a super high end power transformer - period!

This unit will travel to a gentleman with extraordinary taste in Europe soon.

CNC cut labeling on copper shield

Thick copper foil as shield with voltage label

Fitting the copper foil to the dounle C core power transformer

Power Transformer Voltage Ratings

High Purity Thick Copper Foil for absolute shielding.

Labeled copper plate - before polishing

Finished power transformer

Power transformer before vacuum impregnation and finishing

Super tidy winding

XL super size Super Hi-B C cores

Power Transformer - side view

High Grade Magnet Wire

Double C Core Power Transformer

Another view of the double C core transformer

High grade insulation film on each windings

Check out the weight of this baby! This is weight even without the core!

Copper shielding even in the internal layers

Shielding done for the wires

The key to good sound starts with the proper power source. Without this, no matter what you have down the line, it will be sub-optimal. It will never achieve high end sound without proper power source.

If you have the golden ears to be able to differentiate the sound even with the change of power cords, you owe it to yourself to get better power transformers for your gears because this will bring more significant improvement than just changing fuses or power cords and such. Power cord is only 2-3 meters. Fuse is only a few centimeters. Do you know how long the wires are inside the power transformers before the current / power source reaches your electronics? Go figure yourself.

27/11/2014
J&K Audio Design

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Level 3: depends on type, size and complexity. Email us for details.

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* Finished amplifiers, DACs, audio gadgets, upgrades and repairs - this is not our core business and we do it out of passion. We do not have fixed models, fixed price and we customize for each individuals. The sky is limit of creativity.  

* Our product lines are always improving and increasing. If you do not see what you want, contact us!  

* Please email for volume discounts, distributor and OEM pricing.

300B Tube Amplifier

J&K Audio Design 300B Tube Amplifier

Here's another lovely 300B tube monoblock amplifier that we've made for a local audio enthusiasts. As what we always do, our designs are always extraordinary and is not done elsewhere. This is a very unique design that fully maximizes the capability of the 300B tubes that uses 5687 as pre-amplification stage and Telefunken EL803S as driver. Here are some highlights:

• Telefunken EL803S driver for tone and control
• Low noise LT1083 300B DC filament supply with soft-start function for absolute quietness and safety
• High torque, critically damped, tube rectified pseudo choke input B+ power supply for excellent low frequency response and driver control
• Stepped attenuator with Dale resistors - super accurate and stable imaging
• Grid choke application for pre to driver stage - wide bandwidth low frequency extension
• Carefully selected high grade components - optimized tone and body
• Special tweaks at mains input for low noise operation - super dark clean background
• Z11 overspec power transformer and Z11 choke - super dark clean background
• Cobalt SiFE 40W double C core output transformer - tuned for optimized mids to low bass response
• Teflon and high grade ceramic tube sockets
• 5X4G and 5U4G interchangeable tube rectification
• 3MM turret board for component mounting - absolute vibration control for components
• Full aluminum, rigid chassis - non-magnetic and rust proof with 5MM front plate
• J&K proprietary grounding scheme - zero hum and noise even if ear is placed near high sensitivity speakers (ex: Zu Audio Soul Superfly with 100dB/w/m sensitivity)
• J&K proprietary tuning for mid to low frequency resolution and extension 

300B Direct Heated Triode Amplifier

300B Monoblock Tube Amplifier

300B Monoblocks

300B Triode Amplifier

300B Class A Amplifier

Low noise 300B DC filament supply with soft start

Genalex 300B Tube

Telefunken EL803S

Telefunken Pentode

300B Amplifier Construction

J&K Audio Design
25/11/2014

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Level 3: depends on type, size and complexity. Email us for details.

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* Finished amplifiers, DACs, audio gadgets, upgrades and repairs - this is not our core business and we do it out of passion. We do not have fixed models, fixed price and we customize for each individuals. The sky is limit of creativity.  

* Our product lines are always improving and increasing. If you do not see what you want, contact us!  

* Please email for volume discounts, distributor and OEM pricing.

PCL85 Tube Amplifier Review

We'd like to take this opportunity to thank Mr.Wong for posting his review on our custom made Night Light Tube Amplifier.

This is the tube amplifier that he ordered from us:
PCL85 Night Light Tube Amplifier


Here goes the review - unedited. :)

Custom designed and build PCL85 Single Ended Triode Amplifier by J and K Audio Design.

A few months ago, I was trolling the famous Ipoh Sunday flea market and found a box of NOS PCL82, PCL85, PCL86, and some other TV valves offered at flea market price. I bought the whole lot on impulse not having a clue what to do with them.

A search on the internet shows there are many simple spud amplifiers assembled successfully using PCL86 and PCL85 valves. These valves are equivalent (more or less) to ECC83/EL84 in one tube. As I own many valve amplifiers, I am curious how these valves sounds like. I called Ken Loo of J and K Audio Design whom I knew from previous purchase of his merchandise to find out whether he is interested to design and build a low cost simple amplifier using these valves on an aluminum plate.  A few weeks later, Ken replied that PCL85 valves are viable 2W in triode mode and list down the options on the components he would use and the associated cost. I have no illusion of what a 2W SET amplifier can perform as I already own a 1626 “Darling” SET amplifier rated at only 0.75 Watts per channel.

After several Whatsapp exchanges and a visit to Ken’s listening room trying out his Night Light tube amplifier paired with his 100dB Zu floor standing speakers, I eventually settled for the “over the top” option of using tube rectification and his propriety power and output transformers. This way, if the project turns out to be unsatisfactory, I would be still able to salvage the output transformer for a SET 300B amplifier and if it turns out to Ken’s confident claim it will be a keeper, I would have own the best endowed PCL85 SET amplifier (as far as I know) ever build. Ken informed me it would another month before he will start work on my project as he has a couple of ongoing amplifier projects.

The amplifier is ready for voicing out by September 2014 and after listening to some difficult music; Ken decided to do away with pentode and UL modes altogether as it sounded a little bright.

It was early September 2014 when the PCL85 is ready for audition. I went over to Ken’s place full of anticipation wondering how the amplifier would sound like.  When Ken greeted me with ear to ear smile into his house, my earlier worries just evaporated away when I hear the music coming from his listen room upstairs. 

We hurried upstairs into the listening room where the amplifier was cooking for the past two hours. I was greeted by another Ken’s regular audiophile client and listening session began.

As usual, the amplifier was paired up with Ken’s Zu speaker. My first impression was confirmed. The reproduced music is as immaculate as the amplifier layout and finishing. It captures the warmth and richness of music played. This little fellow got guts and bass! (Ken’s is a self proclaim bass freak).

We went through some audiophile recordings of my choice and the amplifier simply performed. It has soundstage, low frequency fidelity, texture, midrange clarity and treble refinement. It is a mini 300B! This is a keeper after all.

I am now a true believer of components synergy.  The choices of each components used requires the skill of a gourmet cook. Ken got the ability. 

Wong nit chuw

22^nd November 2014

PCL85 is identical to 18GV8 tube. It is also directly replaceable by PCL805. With a change of filament voltage, 6GV8, 9GV8, ECL85, XCL85 and ECL805 can be used too.

J&K Audio Design
22/11/2014

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Level 3: depends on type, size and complexity. Email us for details.

Iso-trans: link 1, link 2

* Finished amplifiers, DACs, audio gadgets, upgrades and repairs - this is not our core business and we do it out of passion. We do not have fixed models, fixed price and we customize for each individuals. The sky is limit of creativity.  

* Our product lines are always improving and increasing. If you do not see what you want, contact us!  

* Please email for volume discounts, distributor and OEM pricing.

Solid State Output Transformer

If you are interested to DIY Nelson Pass's Arch Nemesis or the SIT amplifier with Output Transformers, you've come to the right place. Before we go further,

Passdiy Arch Nemesis
SIT Amplifier (Static Induction Transistor)

SIT Amplifier - L'Amp - part 1
SIT Amplifier - L'Amp - Part 2

The Arch Nemesis or the SIT amplifier can be considered the simplest solid state class A amplifier there is. Even the ACA amplifier (Amp Camp) amplifier is not as simple as this. With SIT transistors behaving like a triode, it carries some of the sonic signature tube-o-philes like. For those that prefer triode sound without the tube hassle, SIT amplifier or the Arch Nemesis are good choices to consider.

The use of output transformer in transistor amplifier can actually be traced back to 1980's where Jean Hiraga wrote about having a simple Mosfet amplifier named Nemesis. There are several methods of coupling for such simplistic amplifiers - RC coupled, DC coupled or transformer coupled and we prefer the latter, transformer coupled SIT Amplifier or Arch Nemesis.

• RC coupled - R dissipates a lot of heat, and C needs to be huge and therefore high quality capacitors cannot be used.
• DC coupled - needs bipolar supply and is disastrous if something fails and fries the speakers.
• Transformer coupled - safest, dissipates least heat, but bandwidth limited.

Worry not! With the properly designed transistor output transformer, the bandwidth issue can be resolved by careful design of output transformers. For a good start, we are offering 2 models of output transformers for Arch Nemesis or SIT amplifier.

• EI Z11 Level 1, 10W @ 20Hz - U$299/pair
• EI Z11 Level 2, 10W @ 20Hz - U$599/pair

In actual fact, both the above transformer can be customized to suit other solid state class A amplifiers. Just let us know the details on what is needed. If it is not significantly more complex than what we have above, then the price will be similar.

Both are significant upgrade to the RC coupled class A amplifier, be it Arch Nemesis, SIT amplifier, or any class A solid state transistor amplifier that you care to build!

[10/1/2020  update]

We've request from DIY-philes that they are looking for Tango FG-50S Solid State Output transformer for class A amplifiers and would like to have the same specs. We can do so too. 

Specs (other specs can be custom made): 

* Output power: 30W @ 40Hz

* Primary: 64-32-16-Ohm

* Secondary: 16-8-4-Ohm

* Primary DC: 2A (64-Ohm, 32-Ohm), 4A (16-Ohm)

* Primary inductance: 280mH @ 5V, 50Hz, DC 1.5A 

* Level 1, MY$2,500 per pair (U$625/pair)

* Level 2, MY$3,050 per pair (U$765/pair)

* Level 3, please email us for details. 

J&K Audio Design
11/20/2014

Product Lists  
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Level 2: link 1, link 2, link 3, link 4, link 5, link 6 

Level 3: depends on type, size and complexity. Email us for details.

Iso-trans: link 1, link 2

* Finished amplifiers, DACs, audio gadgets, upgrades and repairs - this is not our core business and we do it out of passion. We do not have fixed models, fixed price and we customize for each individuals. The sky is limit of creativity.  

* Our product lines are always improving and increasing. If you do not see what you want, contact us!  

* Please email for volume discounts, distributor and OEM pricing.

Mains DC Blocker

Good news guys!

Our mains DC blocker has been redesigned for ease of use and better effects! For those that is new to mains DC blocker, please refer to this link below:

http://jandkaudiodesign.blogspot.com/2013/12/dc-blocker.html


We present you mains DC blocker MK2!

• It is easier to use.
• Just plug your existing power cord to the inlet and the outlet directly to your gears! 
• We find that having dedicated unit per device improves the functionality and dynamics!
• It is more effective.
• Redesigned circuitry is safer and more effective to remove the DC on the mains.
• EMI/RFI noise filter is optional - depending on user demand.  
• Options
• Audiophile grade plugs and receptacles.
• Audiophile grade internal components.

Basic mains DC blocker unit starts at U$99 + shipping for a 500W capacity.

Audiophile IEC plug

Pure OFC plug for absolute power transfer

IEC plug cover for protection

This unit plugs directly into the equipment and the power cord plugs into this unit. Simple as that! No more messy extension. Suspension for the unit will make different to the sound too, and what to use (ebony cones, ceramic cones, wood blocks, and etc) will be at user preference. 

Note: the outlook may change slightly depending on the availability of the enclosure and components.

J&K Audio Design
11/19/2014

Product Lists  
Level 0

Level 1: link 1, link 2, link 3

Level 2: link 1, link 2, link 3, link 4, link 5, link 6 

Level 3: depends on type, size and complexity. Email us for details.

Iso-trans: link 1, link 2

* Finished amplifiers, DACs, audio gadgets, upgrades and repairs - this is not our core business and we do it out of passion. We do not have fixed models, fixed price and we customize for each individuals. The sky is limit of creativity.  

* Our product lines are always improving and increasing. If you do not see what you want, contact us!  

* Please email for volume discounts, distributor and OEM pricing.