J&K Audio Design: March 2014

Monday, March 31, 2014

Hitachi Metglas AMCC-400

Alright... I surrender! I will have this as special order item. I will build 2 types to try out - single ended and push-pull output transformers.

I've got enough mails asking about the previous post on Hitachi Metglass AMCC-400 C Core. It looks like we have a lot of DIY audiophiles with good audio sense, ears or taste that want these kind of high quality Amorphous C cores for their amplifiers.

Now I've to make 2 new pairs of it to try myself before I can really offer output transformers based on the Hitachi Metglas material for sale. I'll need 8 sets of them make 2 pairs of double C core output transformers, using 2 sets each for a piece of output transformer.

Hitachi Metglas C Core in original packing materials.

Hitachi Metglass C Core revealed!

Why are they so good? A few reasons:

low core loss compared to silicon iron cores
high operation flux density - due to high saturation flux density
high operation temperature - class F insulation grade (155 degC)

Take a look at Hitachi Metglass & Finemet literature yourself. Oops, what is Finemet? It is the higher end range of Hitachi cores that is better than Metglass. It is super high end stuff that I will not go into. The Finemet core price is ~4x the price of Metglass where Metglass is already expensive enough.

I'm looking for brave souls to venture into Finemet core and order it from me, made with Precision Winding method for an ultra high end output transformer.

Alright, back to topic, the Hitachi Metglass materials will take a few weeks to arrive, and add another few weeks to experiment with this core before a final product can be ready for sale. For those eager to secure the units 1st hand, kindly place your order now to avoid disappointment.

There are some very limited pairs of used Hitachi Metglass AMCC-400 cores available to be used for this purpose. Do book them before they run out. This size of AMCC-400 cores will be able to produce 12W for single ended and 50W for push-pull, rated conservatively.

J&K Audio
31st MAR 2014

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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!

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Friday, March 21, 2014

Ultimate Amorphous Core Output Transformer

We often got asked about what is our best output transformer available at our store, and how much would it cost to make a pair. My standard response would be, Precision Series winding method, amorphous dual or quad C core, silver wire primaries and secondaries.

How much would that cost? This is usually the follow up answer. We would say, it depends. Because, it really depends. It depends on what power/size and impedance he or she is looking for.

On our no.2 seat in the line, a pair of 300B single ended output transformers, I would guesstimate it to be at whopping of > USD$3000 or more. I'm dead serious. It's no.2 on the seat. I would not say who's no.1 as the sky is the limit. I challenge you to show me what's call no.1!

Recently I embarked on a journey to find out how much would I go in terms of making the ultimate (My ultimate of course, not yours! I believe you could be more extreme than me!) I'm going for the Precision winding method, amorphous double C core with copper magnet wire.

(Wait a minute, that's not extreme! One may say! Just wait and see!)

The extreme part is on the amorphous double C core itself. I'm gong to use Hitachi Metglass cores, with a size of AMCC-400! Some may still ask, what's so special about AMCC-400. I can tell you that it is simply HUGE! Single C-core of AMCC-400 size is already quite hefty. With double C-core of AMCC-400, it is humongous. If you want to be more extreme, go for quad C-core. I'm not going to do that as I would not be able to carry the damn amplifier when it is done.

A single C-core of AMCC-400 is 2820g. Double C-core would be 5650g, just the core itself, mind you. Added with the windings, frame and bobbin, it would be about 7Kg++, just for a single piece of the output transformer alone. This should get me to +/- 0.1dB at 20Hz at full power or more! Now you see what I mean?

Precision winding is already the ultimate. I like warmer tonality and therefore copper wires suits me more. If you like airy highs, then go for silver wires.

Let's talk about price. Hitachi Metglass C-core on AMCC-400 size is USD$568 per piece (2 C's). You can search for the price online and you might find cheaper source but it won't deviate very far. 4 C's are needed to create a double C-core and that would be USD$1136 a piece of output transformer. For a pair for stereo amplifier, that would be USD$2272, just for the cores alone. Shipping + taxes of importing the cores are NOT included yet, not to mention the price to ship the made transformers to you.

Also, do we still have any guys that want silver wires with the cores I'm using? I'm waiting for your email. That's how far I would go. I'm not sure about you. Maybe 1 day someone would email me and ask for Precision Series Hitachi Metglass Quad C Core AMCC-400 Size Silver Wire Output Transformer.

I'm real glad to build you one. The Number One! Don't worry, it would be as expensive (not even close!) as the top transformer from UK, that's £9,695 a piece.

Maybe I should build my ultimate to try it out one day. Stay tuned. Who knows that might happen. Tube amp has always been limited by the quality of the output transformers. Why not change the equation for 1 time and see how it is like to be tube limited 1 day...

P/s: 22 MAR 2014 - my vendor just offered me a batch of used AMCC-400 for half the price. I think I'm able to make 20 sets of 15W SE or 50W PP output transformers out of it. Now that's some good news.

J&K Audio Design
21 MAR 2014

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Sunday, March 16, 2014

Western Electric Transformer

Is anyone into Western Electric transformers?

I've some used Western Electric transformer cores that can be used for making power transformers, chokes and audio input or output transformers.Western Electric cores are highly regarded by audiophiles worldwide. There should be some magic on the sonic characteristics.

If anyone is into Western Electric cores, please let me know an we can discuss either here or offline. We would love to hear your feedback and experiences on this.

J&K Audio Design
16 MAR 2014

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Saturday, March 15, 2014

J&K Audio Design - listening room

Taken using just Samsung Note 2 cellphone - just for the fun of it.

J&K Audio Design
16 MAR 2014

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* 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.

Friday, March 14, 2014

Output Transformer Performance

Good day to all! (1/1/2015 - Obsolete - we have added so much more options now, email to ask for more options!)

We've received a question from our followers: "You have so many types of transformers. Which one sounds the best? Can you let me know the ranking to make my purchase decision easier?" We hear you. So, this is what we rank our transformers from top down:

Sound ratings

Precision Series
Vintage Series / Value Line
Miniwatt Series

Note: Value Line is limited edition and will be removed once British C core runs out.

Core ratings

New Japanese amorphous C Core / Recycled British amorphous C Core
Laser etched silicon iron C Core
Normal silicon iron C Core
Z6 - Z9 - Z10 - Z11 EI Core

Wires

Silver wires
Silver plated wires (depending on applications)
Copper wires

Notes:

Some combinations will not be available - ex: Precision Series on British amorphous C Core. Pleas email for more information.
Precision Series - created by 30+ years true master winder, combining theory, practical, and high tech test & measurement equipment.
Vintage Series - created by 30+ years master winder, following the old school method of transformer making.
Miniwatt, Value Line - created for the best balance of performance and price.

Pick your poison!

J&K Audio Design
14 MAR 2013

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Amorphous Push Pull Output Transformer

We just can't resist the temptation of having amorphous double C core output transformer. We just can't have enough of them, can we? It would be great if the whole tube amplifier are made up of amorphous C core transformers, from power transformer, to choke, input transformer, inter-stage transformer and finally to output transformer.

This is a pair of 20W push pull output transformer suitable for EL84 tube. It has UL taps and configurable output impedance.

20W Amorphous Double C Core Push Pull Output Transformer

Amorphous Double C Core

Sealed in high quality plastic bag for moisture protection.

Wrapped in layers of folded foam sheet for protection.

Output transformers boxed with cushions and foams.


Double boxed and layered with foam sheets for final layer of protection and ready for shipping!

This pair is traveling far away, to Budapest, Hungary!

J&K Audio Design
14 MAR 2014

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Thursday, March 13, 2014

British Amorphous C Core materials running low

Urgent Announcement!

British amorphous C core materials are running low. Some of the core sizes has depleted (for example the 2A3/45 type) and we could no longer offer customization for all models. Standard models are still available for purchase but they are running out as well.

Please email us early to secure your British amorphous C cores.

On the other hand, new C core materials are still available and should be available at all times. Of course, for these, it will be full priced instead of discounted price for the British amorphous C cores.

Apologies for any inconveniences caused.

P/s: no, I'm not going to sell you my own memorial stock. :)

Thank you for your support!

J&K Audio Design
13 MAR 2014

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Wednesday, March 12, 2014

C Core Output Transformer

This is how the quad C core output transformer is packaged and shipped. 1 more DIY audiophile has fallen to the dark side, who's next? Express seats are limited before it runs out... join us or be lost forever...

Protected by thick layer of foams and sponges. Nobody can harm it!

A thick foam piece is added on top for total protection! It will survive any drop test!

2nd box for further protection, layered with a few thick layer of protective foam sheets.

Box in a box! Total peace of mind.

Vader welcomes the buyer to the dark side.

J&K Audio Design
12 MAR 2014

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Thursday, March 6, 2014

Transformer Materials

Transformer Materials - check out some of the cool customization stuff we have.

We offer high purity silver and silver plated copper wires for custom-build output transformers (power transformers too if you want!). Those who wanted the famous Ongak* will have your chance of getting for a fraction of the price.