J&K Audio Design: July 2015

We just love feedback, especially from real users, especially the good ones. LOL. Below is the link to our 212 output transformer introduction and measurements.

212 Output Transformer

These below are comments and pictures from the initial testing of our customer from Thailand. They are really dedicated to this hobby and we respect such passion for audio!

More to come when he finally installs it into a proper 212 machine. This is just the preview! Some really, really high end stuff are in the room - it is a multi-million dollar setup, no kidding.

J&K replacing the stock Tango S2108 OPT

J&K Audio Design OPT in action

Initial user comments

J&K Audio Design
7/24/2015

Product Lists
Level 0

Level 1: link 1, link 2, link 3

Level 2: link 1, link 2, link 3, link 4, link 5, link 6

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.

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Output transformer for 212 tube. If you are a fan of high power class A single ended direct heated Triode, then you should take a look at this tube - 212. It has a plate dissipation of 275 Watts! Say if we go with 20% efficiency of class A Triode designs, we are looking at a staggering 50W output power!

Western Electric 212E

If you cannot find Western Electric or STC 212 tubes, worry not! Psvane has come up with a replica and is rumored to be as good as it gets!

Psvane 212

This tube has been featured in a HK magazine - read about it here.

We have received an order for Level 3 Nanocrystalline double C core output transformer for this tube and therefore we'd like to share the results with our followers as well. It is a 22KG pair of state of the art output transformers! For those that knows output transformer design, they would have understand how difficult it is to design a big size wide bandwidth output transformer as the parameters actually work against the results.

Parameters:

· Nanocrystalline double C core

· Output power: 70W (20Hz)

· Measured frequency response

o 20Hz (-0.23dB) – 1kHz (0dB) – 20kHz (-0.41dB), 8 Ohm, 1W

o Full bandwidth: 5Hz – 70kHz -3dB

· Primary impedance: 5KΩ，secondary: 0-6-8Ω

· Primary DCR: 130.1Ω （130.2Ω）（B-P，26℃）

· Secondary DCR: 0-6Ω tap - 0.27Ω，0-8Ω tap - 0.31Ω

· Primary inductance 28.9H（28.1）（measured at primary current 150mA，20Hz，5Vrms）

· Primary current: 280mA (maximum), recommended optimal at 150mA

· Efficiency：0-6（>93%），0-8（>93%）

Measurement condition: Shuguang 845 x2 (parallel), plate voltage 1000V, plate current 150mA，fixed bias, and secondary 0-8Ωtap connected 8Ω, power at 1W.

Matching results:

· Primary DCR <2%（0.2Ω）

· Primary inductance <5%（0.9H）