• 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.

Transformer distortion (THD)

Post 72:
Oh! my error for 84%
the value is 250 times; look at around 0dB to around +18 dB; from 0,004 to 1%
then 3rd line
the 84 nichel probably goes to +20dB with a lot of thd. The diagram is truncated.

Ciao
Oh, now it’s +18dB….. and no again it isn’t 0,004% at 0dB it’s about 0,0055%

But more important, do you understand what saturation means? Your example is rediculous.
 
Don't worry, be happy, even you can't understand!
And I am waiting to see your beatutiful stuff; I will pay for them, take a note!


Walter
That's Walter, you are a nice guy. I have a link for to upgrade your transformers:
https://www.ebay.co.uk/itm/284647348166?hash=item42464dd7c6:g:s~EAAOSwBVdgrWLY&amdata=enc:AQAHAAAA4N9/BtF7LWk4F7PeWjm/awABGNCOJ5VfR/YbvkDmO6nXqvCmFV7+TbOBK8swftFHISWrWmaT1OLEMSZWJo2MHR1W/WjETDkzYh/gTm5vpJMkxpsdIh86iheNHwcyEqMb8FNZSwkSuy8vWGt01qyh9Y4c1mEjHodZq5syJ/uqzb7gUb77zquzStK56r3wM55gt5lhtd0yxg+p5B/zJV/83Wrci1nwc5EXYIxuXxOTLbfyM6dUFQW7C9NdX0lSj9V2KCm5iiW6W3MXTfRCx47xKJDcM3KWOTFHOO65xr3/JSSj|tkp:BFBMvJKB571g I think this would be a lot better, maybe yours where cheaper but what can i say: you looking for quality.
But you can find more better stuff on aliexpress for your budget.
 
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These are some of my OT s.e. I am playing with test

1657619605052.png


I have a confirmation that yours are only words.

Ciao
 
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Juso another consideration

Each OT trafo is a bi-directional device.

Then it is funny that a tech consideration from who sent a square wave of +/- 80 mV can explain the life of one OT trafo.

Is the same if we demonstrate that a fomula 1 car at 50 Km/hr can go at the best at 300 km/hr.
Incredible!

Ciao
 
Now are Kg not mV?

My Sowter SA08 ( on photo ) weights 6,4kg. And now?
What does it means?
The transformer of Sowter is potted so minus 2 kg , the Sowter is EI core, so minus another 40% ( at least) . So the real weight in c-core is about 2,6-2,8 kg max!
This means less transformer efficients. This means less low frequency performance, more saturation problems. And also high frequency performance will be less because it isn't a high quality c-core.

Walt, don't try to be an expert here because you are NOT.
 
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Very good paper.
In MY opinion, there are some test that are redundant but this is not a problem. of course.
And the diagram of the impedance is exatcly the same to the ones I have sent with the program of Fabrizio.
With rew you have a similar results; the only variant is tha with the program of Fabrizio there is one intermediate step to measure the residual of the connection cables.
And also show that with a good sound card you can have a wide range of tests.
Interesting from page 30


"""""Partridge are the only manufacturer known to publish a distortion curve for their OPT, as shown in Figure 28.
The reported distortion dips below 0.5% THD for power below 0.01W. The testing in this article is down
around 0.001W due to the relatively low excitation voltage, and hence core flux level, and really needs
measurement data at higher voltages to show the distortion curve characteristic approaching the design limit
of the OPT as presented by Partridge.""""""
 
Waltube,

Yes, dual or "redundant" sets of measurements are a good idea.

When and if I can, I measure parts, amplifiers, etc, by two different methods, different setups, and different techniques.
Then, if the answers agree, I know one thing . . .
Either both measurements are correct, Or both measurements are wrong.

A dead 12 hour clock is correct 2 times every day.
A dead 24 hour clock is correct 1 time every day.

Trust and Verify.
 
Hopefully I'll update the distortion results in the post #95 link in a few months. I'm just setting up a test amp based on IXCP10M45S in a parafeed output stage (either with a FET pass element or the IXCP10M45S itself) to see if I can get suitably low distortion using an opamp drive and global feedback - if that goes ok then I have some IXCP10M90S on backorder coming in a few months to continue that effort - the hope is that I may be able to exercise those test transformers at up to circa 10W in an upgraded simple balanced test jig.
 
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