NOS Vacuum Tubes

We're always on the hunt for exotic NOS tubes. Our audio buddies and us have just scored a batch from UK and we'd like to share the pictures on our little treasure chest here. Some are mainstream and some are not.

One of our specialty is to use non-mainstream high quality NOS tubes in our designs. This way, our customers pay peanuts and yet they could get extremely high quality sound with those legendary NOS brands like Telefunken, GEC, Cossor, Mullard and etc vacuum tubes.

Cossor 41 MP triode

A box of NOS premium NOS tubes!

Cossor 45IU Rectifier

 This is my favorite! Antique shape rounded base old style rectifier, like the famous U52 rectifier. Yummy!!! Things do not get better than this!

Cossor Tube Boxes

NOS Cossor Valves

Treasures in old boxes!

Ain't this a beauty!

Cossor 41MP triode.

41MP triode. Modern tubes just don't come close!

A box full of premium NOS tubes! OSRAM, GEC, Mullard, Cossor, Telefunken, oh yes!!!

Match quad of Telefunken EL84

2nd match quad of Telefunken EL84, yummy!!!

Close up look of Telefunken EL84

STC 3A/108A triode

Osram 6J5G triode.

GEC Pentodes

Mullard GZ33, matched pair!

We can't wait to put these tubes into use!

J&K Audio Design
10/17/2015

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

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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!  

* Please email for volume discounts, distributor and OEM pricing.

Tannoy Autograph Mini

Greetings! 

If you know me, I'm a fan of Tannoy's dual concentric speakers. I've owned Tannoy Arundels and Tannoy HPD 385A previously. I nearly got hold of a pair of Tannoy Gold but I missed the chance and regretted until today. I've even posted pictures of the Tannoy HPD 385A multiple times in this and my previous website - diy-audio-guide.com. 

I still own the HPD 385A but it was retired as the surrounds had rotten and I do not have the space to place it for now as this pair of speakers is huge! It will resurface some day for sure, when I upgrade my house or retire to the country side where property prices are more reasonable.

Why am I bring this old story up here? Well, I'd like to share a picture of the setup number "n" of a personal close audiophile friend that I knew for over 15 years that is using the Nightshade Miniamp that I built quite some time ago with Tannoy Autograph Mini.

Tannoy Autograph Mini - grill off

Tannoy Autograph Mini - grill on

One would shun this type of placement or setup since it is placed on a shelf with no proper speaker placement at all. Also, the 0.7W output would be so under-powered for Tannoy Autograph Mini. Before you comment on all these, please bare in mind that this is just for casual listening, and therefore is just simply placed merely for convenience and ease of use. 

If you know him, seen and heard his real setup, you would be amazed by his masterpiece and how well it is setup meticulously to the very last details. He is one of the audiophile that I truly respect and praised.

Some background of Nightshade Miniamp is below:

Nightshade Miniamp introduction:
http://jandkaudiodesign.blogspot.com/2014/04/nightshade-miniamp-5687-gz32.html

Some experience of using Nightshade with difficult loads:
http://jandkaudiodesign.blogspot.com/2014/05/nightshade-amplifier.html

J&K Audio Design
10/7/2015

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

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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!  

* Please email for volume discounts, distributor and OEM pricing.

Linestage Output Transformer

Can you do linestage output transformer? I've seen a lot of publications about output transformers but I've not seen you said something about linestage output transformer, or preamp output transformers, one customer asked.

Of course we do! And here's the reward for asking that question! This customer requested a 8K:600 linestage output transformer for his 5842 simple preamp, running at ~25mA at 130V B+. 

Level 3 Nanocrystalline Double C Core Linestage Output Transformer

• In circuit measurement
• 600 Ohm load: 20Hz (-0.38dB) - 1kHz (0dB/ref) - 20kHz (-0.16dB)
• 100K Ohm load: 20Hz (-0.54dB) - 1kHz (0dB/ref) - 20kHz (-0.09dB)

• Primary DCR: 390.4 Ohm, 391.1 Ohm (B-P, at 22 degC)
• Secondary DCR: 30.4 Ohm, 30.4 Ohm (600-common)
• Primary inductance: 48.5H, 49H (DC bias at 25mA, 20Hz, 5Vrms)
• Lower bias current will yield higher primary inductance (68H at 0 DC). 
• Max. primary current: 30mA (recommended <=25mA)

 5Hz - 85kHz +/-3dB

FFT with difficult load (SS amp)

5Hz - 100kHz +/- 3dB

FFT with easy load (tube amp)

J&K Audio Design
14/9/2015

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.  

* 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.

212 Output Transformer Specifications

212 Output Transformer Specifications (refresh)

• Nanocrystalline double C core, Level 3 (U$1390 per matched pair)
• Single Ended Output Transformer, single tube use (PSE option available)
• Output power: 70W @ 20Hz (higher power available per request)
• Measured frequency response
• 20Hz (-0.2dB) – 1kHz (0dB) – 20kHz (-0.4dB), 8 Ohm, 1W
• Full bandwidth: 5Hz – 70kHz -3dB
• Primary impedance: 5KΩ，secondary: 0-6-8Ω (or 0/4/8, or 0/8/16, or user defined)
• 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 (absolute maximum), recommended (optimal) at 150mA
• For 212 PSE, will be 300mA (or user defined)
• 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.

Note: for customers ordering from us, please specify the ACTUAL running idle current to us. Please do not buffer the idle current since our transformers are designed to work at +20% over specifications. Buffering will cause the bandwidth to be less that ideal, especially for single ended output transformers with core air-gap.



Matching results:

• Primary DCR <2%（0.2Ω） 
• Primary inductance <5%（0.9H）

 FFT results (combination of 2 curves since the spectrum analyzer we used are limited in bandwidth:

5Hz – 70kHz +/- 3dB (ruler flat from 20Hz to 20kHz)

Note: 212 output transformer bandwidth can be tailored according to customer preference (with a price). If customer has no preference, we will optimize it to the best possible specifications.

J&K Audio Design
9/13/2015

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.  

* 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.