• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Lundahl vs. One Electron

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I did some comparisons, both distortion and frequency response, and the Hammonds, when they say 30-30K, they mean it. No matter what I did I couldn't get it to extend further. Plus there is about 2-3% even order distortion (through the whole range) that is also plainly visible in a scope, and with NFB will not change.

Gabe

Maybe i misunderstood the above but voltage NFb will most certainly reduce the open loop distortion irrespective of whether it originates from the output transformer, output valve or driver stage.


cheers

peter
 
Ah! I see what you mean.

Oddly enough, what I reported is what I saw and measured. I agree with you, which is why the particular example I mention is noteworthy. I suspect though that it is due to my use of a 25 watt transformer with only about 3 watts power, and that I may have been on the low end of the specs of the transformer.

And believe me, there was no way to stretch the bandwidth of the Single Ended Hammonds.

Astonishing, and against all theory and practice, but true.

Gabe
 
Agree, I was glad I got the same point of view as U.

pls see some information about the core from japan TaXXX
factory.

Hi-B
Max. flux density Very high (¡Ö18000gauss), easy to maintain high inductance> good bass comparative



Permallory high(¡Ö15000gauss), depends on Nickel % content, middle between 3 materials

Amorphous low to high (¡Ö10000-15000gauss), need more winding to maintain high inductance>> higher low freq loss or weak bass


High freq. Iron loss (>10kHz) High Low Very low, good high freq. response
Distortion high low low
General Application Industrial power transformer High freq filtering choke (>20kHz) in switch-mode power supply, Moving coil step up transformer
High freq. filtering choke, distribution power transformer, high freq. pulse transformer


pls study.

thomas

ww.diyaudiocraft.com
 
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