We can make anything that you can dream of. Just shoot us an email at jnkaudiodesign@gmail.com or fill in the form below. Greetings from Penang, Malaysia!

Sunday, August 23, 2015

EL84 Push Pull Tube Amplifier

This is an EL84 Push Pull Tube Amplifier that we had made many months ago (sorry, we were too busy to update our blog) for one of our customers in Penang that will use it to power his center channel as well as main speakers, depending on this mood.

EL84 Push Pull Tube Amplifier
* Triode + Pentode mode - convertible
* Stereo and mono-modes
* Active auto-biased, with external pots for balancing tubes
* Level 2 Z11 Precision Wind Output Transformer
* Full Z11 power transformer and chokes
* High end - audiophile components used all over
* Tube rectified, pseudo-choke-input power supply 
* 5U4G / 5X4G rectifier, EL84 x 4 power tubes, E288CC x 1 driver tube
* High quality ceramic tube sockets with gold plated copper pins 
* Full aluminum chassis with 5mm thick top plate 

Enough with the chatter, here goes more pictures! 

J&K Audio Design

Sunday, August 16, 2015

Transformer User Guide

We are on a 3 months trip to USA as some of our close friends / customers know, and therefore it is a perfectly good time to discuss with them in on "paper" on their feel of our products. Production is slower than usual but we've got no choice - thousand apologies for the longer wait (it's totally worth it!).

We have some sharing after quite extensive and exhaustive discussions with a few of our usual suspects - our frequent buyers/users. They've used from Level 1 till level 3 quite frequently for their products and also for own use, and finally we came up with these BKMs (best known methods).

We feel that it is something worth sharing - our transformers user guide, so here it goes. We start with the best of course.

*  Level 3 transformers
- The best! Best apply on truly balanced systems. They will reveal any Gremlins in your systems.The -3dB low frequency response could be as low as 5Hz! The highs are adequate and usually extends above 65kHz and above.
- Focus on over all balanced, with excellent low frequency response and weight. Due to this, if your room or speakers have issues on bass, it will be revealed and it will not sound good until you rectify these problems.
- Sometimes one may feel that it is slower and heavier but this IS the true nature of full un-distorted reproduction of the low frequencies. They were missing all the low frequencies all this while! It is best to re-tune the system after the transformer run-in.
- If you have low power amplifiers, it is best not to use these transformers as the true low frequency response will suck more power out of the tube to the transformers/speakers, causing earlier distortion than what it used to have than other transformers. Not many speakers and rooms can handle <30Hz frequencies. Poorly designed amp may distort, speakers may boom or distort, and your room may create problems as such abundance of low frequencies.
- If you have big speakers, perfect room, perfectly designed amplifier, high power tube amplifiers, or aren't afraid of problems on re-tuning your system, this is the perfect output transformer to have! You have to re-tune your system for the new found low frequencies though, this is a must to capture the full potential of your new found system. 
- For some that feels that their system low frequency response is inadequate and they want to dig more out of them, this is something to try too if they have some power to spare. 
- Character - steady, warm, weighty, extended and thick.

* Level 2 transformers
- 2nd in line top quality for wider coverage of systems. This is our best seller too where it is not so finicky on system matching. The -3db or -2dB low frequency response is usually tuned to 20Hz. The high frequency response usually can go up to as high as 100kHz or more!
- Focus general purpose use, with excellent mid to high frequency response. Bass is not overly done so that is more friendly to the overall system. Since not much music are present below 20Hz, not many speakers can produce 20Hz faithfully, and not many tube amplifiers are capable of delivering full power at 20Hz, no energy is wasted at that region and your overall system may sound more power than it is. 
- If you love mid-highs more, have small speakers, have low power amplifiers, have smaller rooms, have room problems or others, this is definitely your ideal choice. It will create lesser issues for you. 
- Character - lively, fast, taut, with good PRAT.

* Level 1 & 0 transformers
- This is the budget but good output transformers. It is good for entry to mid level systems and 1st time builders. They can test out their systems first and later upgrade to Level 2 or Level 3 after they get to know their systems more.
- The standard models are quite decent actually especially the ALIS or ALOS version where it has been proven many times to excel and do better than branded transformers a few times the price. 
- These are something that users can buy/use everyday due to friendly price for excellent results.
- Character - very balanced, typical tube sound, slightly on the warm side.

That's all for now. Hope you enjoy the read!

J&K Audio Design

Friday, July 24, 2015

212 Output Transformer Review

We just love feedback, especially from real users, especially the good ones. LOL. Below is the link to our 212 output transformer introduction and measurements.

212 Output Transformer

These below are comments and pictures from the initial testing of our customer from Thailand. They are really dedicated to this hobby and we respect such passion for audio! 

More to come when he finally installs it into a proper 212 machine. This is just the preview! Some really, really high end stuff are in the room - it is a multi-million dollar setup, no kidding.

J&K replacing the stock Tango S2108 OPT

J&K Audio Design OPT in action

Initial user comments

J&K Audio Design

Friday, July 10, 2015

212 Output Transformer

Output transformer for 212 tube. If you are a fan of high power class A single ended direct heated Triode, then you should take a look at this tube - 212. It has a plate dissipation of 275 Watts! Say if we go with 20% efficiency of class A Triode designs, we are looking at a staggering 50W output power!

Western Electric 212E

If you cannot find Western Electric or STC 212 tubes, worry not! Psvane has come up with a replica and is rumored to be as good as it gets! 

Psvane 212

This tube has been featured in a HK magazine - read about it here.

We have received an order for Level 3 Nanocrystalline double C core output transformer for this tube and therefore we'd like to share the results with our followers as well. It is a 22KG pair of state of the art output transformers! For those that knows output transformer design, they would have understand how difficult it is to design a big size wide bandwidth output transformer as the parameters actually work against the results.


·         Nanocrystalline double C core
·         Output power: 70W (20Hz)
·         Measured frequency response
o    20Hz (-0.23dB) – 1kHz (0dB) – 20kHz (-0.41dB), 8 Ohm, 1W
o    Full bandwidth: 5Hz – 70kHz -3dB
·         Primary impedance: 5KΩsecondary: 0-6-8Ω
·         Primary DCR: 130.1Ω 130.2Ω)(B-P26℃)
·         Secondary DCR: 0-6Ω tap - 0.27Ω,0-8Ω tap - 0.31Ω
·         Primary inductance 28.9H28.1)(measured at primary current 150mA20Hz5Vrms
·         Primary current: 280mA (maximum), recommended optimal at 150mA
·         Efficiency0-6>93%),0-8>93%

Measurement condition: Shuguang 845 x2 (parallel), plate voltage 1000V, plate current 150mAfixed bias, and secondary 0-8Ωtap connected 8Ω, power at 1W.

Matching results:  
·        Primary DCR <2%0.2Ω)
·        Primary inductance <5%0.9H

212 Output Transformer Frequency Response
This pair is a very decent price of U$1300.

J&K Audio Design