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Monday, March 3, 2014

Output Transformer Frequency Response

Output Transformer Frequency Response

All talk and no data makes us a lousy liar! Let's look at some facts. These are plots generated by the famous HP8903B Audio Analyzer, using the GPIB software developed by Pete Millett (thanks Pete!) quote some time ago.

The plots are measured when the (Precision Series) output transformer is in ACTUAL WORKING circuit, instead of being under ideal environment driven by ideal function (frequency) generator. We are taking 2 output transformers as reference.


10K high voltage high impedance single ended output transformer
20Hz – 50KHz @ -2dB 60-80mA ACTUAL OPERATION
For those that designed and made output transformers will know - designing 10K high voltage high current single ended output transformer is not an easy task. You need thicker wires, higher voltage insulation, high number of turns, and high current. To balance all these for wide bandwidth flat frequency response, is not something for the faint-hearted.


300B 3.5K single ended output transformer 
22Hz – 50kHz @ -1.5dB 60mA ACTUAL OPERATION
Below measurements are made under optimized ideal conditions that reveals the real bandwidth if tube amplifier design is done right.
211 use 10K Single Ended Output Transformer, 20Hz @-0.5dB, 28kHz @-1dB


300B use 3.5K output transformer, 20Hz @ 0.5dB, 40KHz @ -1dB
 We shall let the pictures do the talking.

3 MAR 2014
J&K Audio Design

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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.