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!

Saturday, June 6, 2015

Wavac PRT1 Tube Roll

We're helping a friend with a set of very high end audio gears to fine tune is system for better performance. His system consist of full set of Wavac amplification gears and Acapella Campanile speakers (huge)! 

The sound was rather noisy and the imaging was messy and rather veiled. Bass was bloated and could not dive as long as it could. A lot of steps had been taken and it brought significant improvements. Still, there were something wrong with the setup. It did not sound that "high end" considering the price paid for the system (>U$200K we think).

Since the Wavac PRT1 never had its' tubes changed, we decided to give it a try. The stock unit were unknown until we opened up the unit. It was JJ. We ordered a batch of Siemes E82CC, long plate, triple mica NOS, matched quads and gave it a go. 

The changes in sound is just substantial - deeper and more natural bass, veil is removed, soundstage deepens, tonnes of details revealed, vocals are warmer, clarity improved significantly. Now it sounds like a U$200K system.

After this change, the improvement was so significant that owner asked if we can upgrade the tubes and components inside Wavac PRT1 as well as his Wavac 300B and 805 power amplifiers! Well, that's for another time. We still have his EL84 push-pull power amplifier to complete and other customers' projects to finish before we can come back to his amplifiers again.

Here are some pictures for your enjoyment: 

Chassis milled from a solid block of aluminum

Some red wine to add flavors to the sound

Internal of Wavac PRT1

Tango Output Transformers (we think) is used at output stage

A bunch of JJ ECC82 are retired.

JJ ECC82 tube

Tube covers

Tubes rolling.

Siemens E82CC inserted

Observing the components used in Wavac PRT1

Capacitors used in Wavac PRT1 - certainly we have lots of room for improvements!

Input transformers (we guess, cannot see inside) for Wavac PRT1 (botom left)

On top of the tube roll, we've brought a secret weapon along too - a pair of J&K super-interconnects (RM1.2K a pair).

  • improved signal-to-noise ratio and interference rejection
  • high frequency shielding
  • shielding at bents (soft shield)
  • optimized cable capacitance and inductance, matched pair
  • meant for high speed transmission
  • extreme flexible body
  • multi-core cabling technology

This cable performed so well that 2nd pair were ordered to connect from Wavac PRT1 to Wavac EC300B and Wavac MD-805MK-II power amplifier to biamp his Acapella Campanile speakers, in replacement of his super expensive interconnects that cost many times over this J&K interconnect.

J&K Audio Design

Telefunken Integrated Amplifier

This is a an amplifier that we did not even think of building! I've been keep a pair of EL152 power pentode from Telefunken for quite some time. It was more for collection rather than building use. I was waiting for a free time that has yet to come to put the Telefunken EL152 into good use.

Just so happened that I have a good friend that wanted to build a tube amplifier by himself. I've designed the amplifier for him with 6B4G tube in mind for a 3.5W Single Ended DHT integrated. It did not get materialized as he moved to Singapore halfway during the process and now migrated to Australia. 

The whole set of transformers, chassis and components were stored at my place for at least 3-4 years if my memory serves me right. I have been bugging him to bring it back to complete it but it just never moved since Australia is quite far away from my place. Things got dragged on until several months ago where we decided to put it into action by building it ourselves using all the materials that were meant for 6B4G. 

The Telefunken power tube can output more power but due to the VA and voltages made for the 6B4G, it was generating only ~3W output. Anyhow, we were still quite impressed at the sound it produces. One day, perhaps, we will make the right power transformer to be used with Telefunken EL152 to fully optimize the circuit and output power.

Time for some pictures!

For amplifier pervs, here are the internal pictures:

J&K Audio Design

Friday, May 29, 2015

ALIS-5SE Ultimate User Comments

Another testimonial has arrived last night from our buddy, John. John has been discussing audio transformers build methodology with us for quite some time. He's a veteran HIFI/music enthusiast. It's our honor to be able to let our ALIS-5SE Ultimate be a part of his audio system. We'd like to take this opportunity to thank him for allowing us to post his comment on ALIS-5SE Ultimate in our blog!

Quote (unedited):

Hi, Jolin and Ken. I hope all is well on your side of the world. How were your travels?

I want to tell you how much I am enjoying your ALIS-5SE Ultimate transformers in my 300B amplifier! I only have a few hours on them so far, but from the moment I installed them, I was very impressed with the sound.

I have been using Magnequest FS-030's in my 300B amp for maybe 20 years. I have tried other transformers from time to time, but the FS-030's have been a constant in that amplifier. I like their "voicing". Their response is weighted towards the low end of the spectrum. Bass is very solid and goes very low, but the highs are not as delicate and extended as they could be. I know that Mike from Magnequest designs his transformers very conservatively. They have lots of primary inductance, something like 30-35H, and low winding resistance. But this does make the physical size of the transformer quite large, which in turn causes it to exhibit higher parasitic capacitances and hence lower high frequency bandwidth. I'm sure you know how all that works!

When I installed the ALIS-5SE Ultimates, I heard a number of changes. First of all, and quite surprising to me, was the improvement in bass definition and detail. Although your transformers don't quite have the ultimate weight of the FS-030's, I can follow bass lines much more easily, and the pure extension is very good, despite your only having maybe 2/3 the primary inductance.

I am finding the high frequencies to be most appealing. I am hearing improved definition and transparency. Sonic images have more space and separation around them than I am used to hearing. There is an ease and naturalness that I really enjoy. I am also pleased to hear a reduction in upper midrange "glare", a touch of hardness that I would not have associated with the output transformers.  All in all, a very transparent and natural sound that I am looking forward to living with.

This is not to say that the FS-030's sound bad or substandard in any way. Every designer makes certain conscious choices on how to "voice" his/her product. Mike chooses lots of inductance and low DCR, whereas you guys have chosen to achieve a wider high frequency extension with modest inductance. I can see someone with, say, a single-driver full-range loudspeaker preferring the FS-030's, as they would balance each other well. In my case, my loudspeakers use high-efficiency pro drivers. I have good bass extension from 12" drivers in vented boxes. I now find the bass nicely balanced and "tuneful". My high-frequency compression drivers/horns are very sensitive and have very low distortion, so I am able to hear the higher-frequency attributes of your transformers quite clearly.

This is not a formal review by any means, just an email from a satisfied customer! I look forward to living with these wonderful transformers, as well as integrating more of your products into my system in the near future.

All the best!


End Quote

P.S. - For those that likes heavy bass, we have another model: ALIS-5SE MK2 that is meant for high Rp (plate impedance) tubes. The bass will be much better if used with low Rp Triodes! Using ALIS-5SE MK2 will have very good bass extension and quantity at the expense of some very high frequency loss. Still, ALIS-5SE MK2 specifications is very, very decent!

* Pentode: 20-65kHz(-1dB)
* Triode connected Pentode: 10-40kHz(-1dB)
(Note: pure Triode will have much better / wider bandwidth!)

Click this link to jump to our ALIS Output Transformers: 
J&K Audio Design ALIS Output Transformers 

J&K Audio Design

Saturday, May 23, 2015

R-core transformers

Introducing low cost R-core transformers! 

Textbook says (not us), the benefits of R-core transformers are, but not limited to:

  • Stray magnetic flux is low, x10 lower that EI transformer
  • R-core transformer is smaller than EI by 30%, slimmer by 40%, and lighter by 40% 
  • R-core transformer generates 50% lesser heat than EI transformer
  • R-core transformer generates lesser noise compared to EI or gapped core transformers
  • R-core is more reliable, easier to install and better stability than toroid transformer
  • Etc...
Well, a lot of the statements above are questionable since the properties depend on a lot of other factors too, but one thing for sure is that R-core does have its benefits and sound signature.

R-core transformer employes a circularly wound steel core. The primary and secondary coils are wound on it. Due to the minimal gap between the coils and core, the loss is very low. Also, annealing treatment can be applied directly to the core to condition it at its best magnetic state to reduce distortion.

Our R-core ranges from 10VA (~U$25) to 1250VA (~U$340) per unit, depending on customization. If higher capacity is needed, customers can go for toroid transformers or parallel R-core transformers to go to as high as 2500W. Such parallel usage would be for balanced isolation transformer where the +ve is by a 1250VA unit and the -ve is by another 1250VA unit to make 2500VA in total.

One good example would be to make isolation transformers with R-core transformers! Due to the low profile nature of the core and windings, it can be made very compact with very good electrical properties! 

On the other hand, those who does not prefer R-core or still do not believe in R-core can still go for single C core transformers. We are introducing the economical C core power transformers as well ranging from 5VA (~U$28) to 1600VA (U$460), depending on customization. Parallelism can be done to get 3200VA unit too if needed. 
Single C core transformer - horizontal version
Single C core transformer - upright version
 Email us for a quotation with your customization needs. 

J&K Audio Design

J&K Isolation Transformer Review

Greetings followers! 

Apologies for not sharing more news in our blog. We've been quite busy lately with new orders + R&D on making our products better and better.

Still, we would like to share with you what our trial uses said about our audiophile isolation transformer (J&K Isolation Transformer). Check out the Whatsapp screen capture below! We can't be more happy about the loss. 

He had taken a unit of 1KVA fully built isolation transformer, with J&K DC blocker, plus 2 units of J&K noise eliminator integrated into the unit. He brought it home for almost a week and this is what he wrote to me. 

User Comments
Isolation transformer and ALIS-5SE Ultimate Output Transformer Shipment

We would like to thank our supporters for your orders too! It has kept us quite busy for weeks! For those that have not tried J&K isolation transformer and/or ALIS-5SE Ultimate output transformer for 2A3 or 300B tubes, you have no idea what you have been missing!

J&K Audio Design