Check back regularly or subscribe for updates. Email us at jnkaudiodesign@gmail.com, or fill in the form on the left.

Wednesday, April 8, 2015

Super Hi-B transformer review

We'd like to express our gratitude to David V for writing a review on our Super Hi-B double C core power transformer! We were blogging about how to increase your power amplifier by 2x perceptually. Now the answer is revealed here. 

What you read below has only 1 edit being done - changing "Hi Hi-B" to "Super Hi-B". We were calling it Hi Hi-B previously but Super Hi-B will be an easier term to use and therefore we've edited the content for that. Other than this, it is 100% original from David V. 

Here goes:


300B Mono-block Amplifier

Super Hi-B Power Transformer

Tango NC20F and Tamura OPT

Solid Wood Chassis




My acquaintanceship with J&K Audio Design happened by coincident early last year in 2014. I was searching for some information on power transformer in the net and this company called J&K Audio Design came to my attention. I was intrigued by their pictures showing how their transformers were wind, sealed and potted. From their pictures and their working processes, I know the transformers are going to be durable and long lasting. Soon I got in touch with the Ken of J&K Audio Design and enquired my need to order a pair of replacement power transformers for my 300B amp. Ken came back to me suggesting I use a pair of Super Hi B double C-core power transformers. He quoted me a price for a pair of potted version. The price for this Super Hi B double C-core power transformer is not cheap but I'm adamant to get a pair to try them out myself and see how good they are! I placed an order and they finally came after two months of waiting.

During my break during the 2015 CNY, I managed to swap out my original Z11 power transformer from my 300B monaural amp and in came the Super-Hi B C-core power transformers.

My 300B monaural amp is a direct couple SE with the 5687 or 6900 as the driver tube onto an interstage NC20 that finally drive the 300B to Tamura Amorphous OPT. The design was inspired by April Sound 50 amp and I'd it for several years but never am satisfied with the end result until I got it replaced with the J&K power transformers. When the power transformers were replaced and I  powered up the amplifier, the power output from these 300B gave me an impression that it's unusually powerful. I'd the normal listening level that I used to play but the sound level from my speakers seems to be twice as loud than when I were using the Z11 power transformer with my Tannoy GRF speakers.

I have about 50 hours of run in since replacing the power transformers. The music flavors of my liking are jazz, chamber, female vocal and orchestra (classical). Here are samples of some of the music and my general listening opinion.

I'd auditioned some live performance recording like a Jazz version of 'When I fall in love'. The sound coming out of my Tannoy GRF was remarkable, as though I was in the room where the piano was played. I can really feel the ambient, the reverberation of the piano's notes from the Steinways & Son piano. I also listened to the ODaiko, a traditional Japanese drum pieces. The rhythm, the pace and the vibration of the drum is tight and vivid. I can really feel the energy from the drum. I almost forgot I was listening to a 300B amp, as the music coming from it sounded as powerful as a push-pull 6L6 amp, but with more clarity, warmth, dynamic and detail.

I believed the J&K Audio Design Super Hi B C-Core power transformers played a big part in the improvement of my amplifier. I also sampled on some Violin piece (Zigeunerweisen Op.20 by Anne-Sophie Mutter), live Guitar piece (Lion Lai Small Town by Japanese Guitarist Kazahito Yamashita), Cello piece (The Swan), Orchestra pieces like William Tell Overture and Radetzky March Op.228. The music coming out from my 300B amp was fast, clean, dynamic, and transparent with superb imaging and they never run out of juice even with complex pieces. One would never believe it's coming from a 300B amplifier.

The J&K Audio Design Super Hi B C-core power transformer has really bring out the best of the
Tamura Amorphous OPT. My previous Z11 power transformer was lacking in some attributes that prohibit the OPT to perform optimally. My experience convinced me that for an outstanding triode SE amp, the choice of power transformer is as important as the OPT that you are using.

The J&K Audio Design Super Hi B C-core power transformer is not cheap but it's worthwhile. If you plan to upgrade your amplifier, I would suggest you have your OPT, power transformer followed by internal wiring, then the output tubes in that order of priority.
Here are some pictures of my 300B amplifier.

By David V 6th April 2015.

Product Lists  

Level 0

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.

Search This Blog

Product Lists

Product Lists

Level 0: link 1

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

Level 2: link 1, link 2, link 3, link 4, link 5, link 6, link 7, Link 8, link 9

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

Iso-trans: link 1, link 2

Power-trans: link 1

* 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.

Follow by Email

Follow us using Google+ Badge to get instant updates!

Google+ Followers