2017 Chinese New Year Closure

2017 Chinese New Year Closure

We will take orders but there is no production or shipping from 22th Jan'17 to 6th Feb'17. If you need to have your projects delivered urgently, please do so early.





Happy Chinese New Year! 

Thank you!

J&K Audio Design
1/6/2017

J&K OPT Review

Happy New Year 2017 from J&K team! 

What's better than starting the new year with seeing great feedback on products using J&K output transformers and chokes? 

Quote:

Ben's 6l6....or may i say magic amp
To those still looking for an amplifier, try give Benjamin Tan a call....maybe this young talent can provide the solution to your search and do wonders to you as it did to me.
An excellent piece of equipment, designed and built from scratch by Ben....designed to cater to your requirement and budget...you name the desired tubes to use...ben will design the amp and the irons to go with it.
As for sound quality...dare i say its the best 6l6 i've heard to date...(until ben comes out with a new design ...lol)..thanks ben..you did well

J&K Audio Design
1/1/2017

HIFI Repair

Is this a trend or what - manufacturers not willing to repair their gears after warranty period is over, even if customers are willing to pay? Please share your experience in our comments section.

We occasionally take in some damaged HIFI equipment to repair, as a good will to get the gears alive again, or helping friends and customers, as a favor. This, however, has led us to discover some unhealthy trend that the after sales and service of certain manufacturers and distributors are as good as none.

Some HIFI equipment requires special parts and PCB to be replaced in order to get them alive again, such as the controller board for smart power management system for a battery backed power supply regulator, label masked off parts, special custom made integrated circuits (IC), and such. These parts are not available outside, except the creator/manufacturer themselves. 

To our dismay, multiple mails and phone calls are often, not successful to get their responses to entertain our requests, or even our customers' queries! What kind of customer service is that?

The most recent one, is to ask for just a replacement power transformer (willing to pay!) since the specifications is not made known to us, and the owner wanted the original part. Nadah... distributor is wiling to entertain for a few mails but at the end, nothing. Manufacturer just kept quiet since day one. Bravo service, really! Oh ya, your design sucks too, cramping all the parts in a small chassis, including a big hot power transformers, with very minimal venting. No wonder it failed, and failed twice - the unit has got the original power transformer replaced once, with a badly done job. I guess the repair guy could not get replacement part and just substituted with anything he can find on hand.

It is not that we are asking for free parts and free service! Our friends and customers are paying a hefty price tag for the HIFI equipment they purchased! It is their right to get replacement parts at least, if sending in for repair is not an option. Nadah... not even a reply of email sometimes, or sometimes a wait of eternity is presented to us, on the requests.

Gosh... even a little entity like us, provides better service than them! Shame on you!

Now you guys have 1 more thing to consider before buying any HIFI equipment - ask around first on the after sales service, the durability of the equipment, and how helpful is the seller/distributor!

Just venting out... thank you for listening, and share your good or bad experiences with us, in the comments section!

J&K Audio Design
12/27/2016

WE 618B Input Transformer

Western Electric 618B Input Transformer 

One of the benefits of offering transformer repairing service is, you get to analyze all the various exotic, excellent sounding, conservatively built, extraordinary designs in the past! Then, those knowledge and know-how can be applied to our products, combining the old school engineering with modern technology = best of both worlds. 

Below is the WE 618B Input Transformer that our Thailand customers ordered, to compare with another WE 618B clone from Japan.

http://jandkaudiodesign.blogspot.my/2016/12/western-electric-we-618b.html

Permalloy EI Core

Cloth Wire are used

We can make ANY transformers! We can contract manufacture too (ODM), building the transformers you need for your on the shelf products.

Contact us for more details!  

12/24/2016
J&K Audio Design

6C33 SE Output Transformer

Nanocrystalline 6C33C Double C Core Single Ended Output Transformer – for 6C33C tube, custom made for Melquiades 6C33C SE amplifier.

We have made this pair last year but didn't have the time to post it at our blog. Since there's a recent request to make 6C33 OPT, we took the opportunity to publish the specifications here. The user was concerned that there might not be sufficient bass if he chose Nanocrystalline (aka Finemet) core for better mid-high resolution. 

Worry not, friend. People often have that misconception as many of the amorphous core they used in their amplifiers are not optimized. Amorphous core output transformers require different design method compared to ordinary orient Hi-B / Z11 cores. Using the same formula for both will just end up with emphasized / tilting towards the mid-high frequency response, giving the amorphous core a bad / false reputation - of being detailed but lack of low frequency extension and mid-bass impact.

For those that have used our NanoC output transformers, they would have find that our OPT are balanced in low-mid-high (no BS, just look at the measurement below), and yet rich with harmonics and flavor instead of being overly colorless and flat. That's how a properly design amorphous based OPT should sound. Switching to Permalloy / nickel core adds more silkiness in the highs, and produces a golden tone to the mid-range. 

Optimize your 6C33C SE amplifier now by getting a pair of J&K 6C33C OPT home! Let your creation shine like a star!

Parameters

• Power: 40W(20Hz）
• Actual in circuit frequency response (360mA)
• 20Hz（-0.36dB）—1KHz（0db）—20KHz（-0.19dB）（12 Ohm tap, 1W）
• Note: measurement conditions, 6C33C, plate voltage 150V, plate current 360mA, fixed bias, secondary load with resistor, at 1W.
• Full bandwidth: 
• 7Hz – 70kHz +/- 3dB @ 360mA
• 5Hz – 100kHz +/-3dB @ 280mA
• Primary impedance: 650 Ohm (can be 1K-1.2K too)
• Secondary impedance: 0-6-12 Ohm (or 4/8, 8/16)
• Core: Nanocrystalline Cut Core (aka Finemet)
• Primary DCR: 18.1(18.3) Ohm (B-P, measured at 29degC)
• Secondary DCR: 0-6 Ohm (0.28 Ohm), 0-12 Ohm (0.4 Ohm)
• Primary inductance: 3.26(3.4)H @ DC bias of 360mA, 20Hz, 5Vrms 
• Primary inductance can be increased if the air-gap, primary inductance, core size are varied, tailored according to applications.
• Primary current (absolute max): 600mA (recommended <= 360mA)
• Efficiency: 0-6 Ohm (>92%), 0-12 Ohm (>93%)
• Matching results:
• DCR <2% (actual <0.2 Ohm)
• Primary inductance <5% (actual <0.14H)

Measured at 360mA

Measured at 280mA primary current

Measured at 280mA primary current

Look of the potted OPT before the cover is being added. Properly sized core is required to strike the right balance between low and high frequency response at rated output power.

J&K Audio Design
12/16/2016