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Saturday, May 25, 2019

Class A Amplifier

Trying out a MOSFET class A amplifier. 
Something for a change once in a while after trying so many tube amplifiers.
Pretty decent I would say! 
If added with a tube preamp, it will be just perfect! 


Frequency response measured on scope.








J&K Audio Design
25/5/2019

Tuesday, March 26, 2019

Audiophile Toroid Transformer

Good day folks.

Our Toroidal transformer is excellent, but is still not as good as the EI transformer counterpart. We still like to use EI transformer for most of our audio applications but sometimes Toroid / Toroidal transformer is still needed for high power applications or for equipment with limited real-estate, and requires smaller transformer to be used. 

We have been researching on this for quite some time and we have finally found several parameters to improve on the Toroidal transformer performance. These brings the Toroid / Toroidal transformer closer to the EI transformer, not 100%, but close enough! 

1. Usage of higher grade 0.23mm lamination thickness Toroid / Toroidal core
2. Usage of grain oriented silicon (Hi-B)
3. Laser welded full strip of silicon steel from a full roll to ensure no air-gap present
4. Special formula of Nitrogen / Hydrogen during silicon steel cooling process to improve magnet properties 
5. Double shielding technique, 50 (non-potted) and 95% (potted) reduction in magnetic interference

Results? Toroid / Toroidal transformer that works substantially quieter, and sounds absolutely HIFI. 

Try it now! 

J&K Audio Deign
27/3/2019

Friday, January 25, 2019

J&K TVC User Feedback

Happy 2019! 

It has been a while folks! You know we've been busy! 

For those who'd like to have more updated news and discussions from us, please follow our Facebook page! 

Below are some very nice pre-amplifier pictures from a customer of ours in USA - using the OPTVC that we've built for him some time ago. He's looking for more transformers for upgrades, and that's why the pictures have measurement tape being shown instead of being a studio-like photos for publishing. 

Here are some details of his OPTVC: 
26K:26K
33 step OPTVC
Pri inductance ~150Hy
Pri DC 10mA 
Potted with turrets 
OFC wires 






Comments from customer:

"Last year I got a TVC from you for a preamp my friend Oliver built for me. I'm liking it a lot. Very nice sound. Very happy with it. "

"Here is a photo you requested of the TVC preamp Oliver built. It is an active preamp with combined volume and output TVC with 33 steps. The TVCOPT are in the back to the left. It uses a type 82 rectifier with 6AX4 TV damper warm up buffer. Shown are 01a preamp tubes. It can also use 112a, 31 or 71a DHT tubes."

Some may ask, what the h*ll is OPTVC? OPTVC = Output Transformer Volume Control - It is TVC that can tolerate primary DC and use as a load for a tube stage. Some details can be found here: 

http://jandkaudiodesign.blogspot.com/2016/10/optvc.html

Enjoy! 

J&K Audio Design
1/26/2019

Monday, December 24, 2018

Western Electric transformers

Hi guys,

Merry Christmas and Happy New Year! 

We've an important announcement to make.

Western Electric cores are running low on the market. We're working on a customer order and got a shock. A lot of these cores are swooped by some vendors and make them to sub-par transformers - what a waste. As a result, these Western Electric cores are no longer abundant and choices are very limited. 

If you intend to use Western Electric cores to make transformers, please be quick and order soon. In future, we may need to buy those sub-par ready made transformers to obtain those nice Western Electric cores for rewinding to something much better.

We've made some in the past, as you can see below: 

http://jandkaudiodesign.blogspot.com/2016/01/western-electric-output-transformer.html
http://jandkaudiodesign.blogspot.com/2016/12/western-electric-we-618b.html
http://jandkaudiodesign.blogspot.com/2016/01/western-electric-transformers.html

There are still some original WE cores, untouched at decent price. Make a move quick before it is gone. The WE1048 that used previously are no longer available at our previous source. What a sad news! 

Apologies to break such a news at such time, but I think it is a good news that we discover it early. Else, it will be as rare as the 1950's - 1960's WE 300B tube. 

25/12/2018
J&K Audio Design

Friday, December 21, 2018

Transformers repair

Repair transformers? Call us trans repair king! I think hundreds, if not thousands of transformers have gone through our hands over the years. 

We are very happy to hear that our customer's McIntosh amp are repaired. Well, this is just one of the message we get, there are many more that we're just too busy to post. 



We can learn the transformer winding method from others, and we help to restore the damage equipment - saving mother Earth from being overwhelmed with more electronics junk! 

Nobody (or very less, LOL) repairs transformers like us. We'll unwind EVERY unit received and record down all the data about the transformers so that we can rewind it back exactly, according to the original materials, if can be found. 

Your transformers will get a new lease of life for another few centuries as long as it is working in the original designed conditions. 

Repaired transformers get a 1 year warranty. Conditions apply, such as, as long as is not abused, or placed in a faulty amplifiers (well, that could be what caused it to burn initially, right?). 

Tips: it is very important to keep the original core of the transformers. Once it's gone, it's gone. That's the most important component in repairing transformers. We recommend to reuse the original core to get back the original sound signature of the transformer. 

Now, get your damaged transformers here! McIntosh, Marantz, Scott, Dynaco, AudioNote, any transformers, as long as they are not burnt to ashes, we can repair it. Satisfaction guaranteed! 

J&K Audio Design
22/12/2018 

Thursday, November 1, 2018

Alternative payment option

Dear all,

We've found a way to save customers expensive PP transaction fees of 4.5%-5%

Contact us and we shall inform you how to do so during purchase!

2/11/2018
J&K Audio Design

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