Or dc current at the primary winding…. As Tango did:
http://www.acoustic-dimension.com/tango/datasheets/Tango-X-10S-datasheet.pdf
Or the wrong way aswas done at the etf2009:
https://www.diyparadiso.com/lundahl/etf transformer test.pdf
But this can be easy modificated with a ccs(but a really good ccs).
http://www.acoustic-dimension.com/tango/datasheets/Tango-X-10S-datasheet.pdf
Or the wrong way aswas done at the etf2009:
https://www.diyparadiso.com/lundahl/etf transformer test.pdf
But this can be easy modificated with a ccs(but a really good ccs).
I am not sure if the chart says something real.
The I is 70 mA written on dc supply, then there is 10kohm in series with primary so the V across it is 700 volt!?!?
And the dc power supply is little bit more !
On the firsts tes in AUdioreview the inital test setup to run dc current on primary
was: ( always testing the OT in backward mode)
note: the firsts test are done considering the nominal impedance
This was the power supply made by Fabrizio for a particualr project sitting on desk.
Walter
In photo the proto of a test set where is possible to drive a secondary ( it is a ss power amp of 70 watt) and a section with some power resistors where is possible to connect a variable dc power supply. Is missing th chinese power supply, smart with meter for voltage and current.
The ratio between the Rdc of secondary and the R connected to power supply is around 70-100 times so we consider it a good compromise ( it is not a perfect current generator, of course) to set the current for secondary. In this case is 27 ohm but is possible to go up.
Due the facility to vary the Dc of power supply ( 0-60 Vdc) we can set different value of dc current
I left the use of this set up because the differences found on the trafos wer are testing with or without dc are not so evident.
I use it just in case
One example is here
Two types of trafo s.e. for 300B, left standard, right with a Litz cable on primary and secondary
Two protos
Backward tests
Frequency response and THD vs Freq for different current of bias. and no bias.
No I can't and I am not worry about
I made lot of test in two different tesrt set.
An example
Here is Sowter response in back ward mode
two equivalent poer
This is the same in a compete circuit
KT150 in triode mode (Rp 800 ohm) and input a srpp of e88c
This is the response of input circuit ( before KT)
-1 dB at 100kHz can be considered good.
Same for Hammond in the two method
If there is 4900 Volt the serie resistor should be about 70K Ohm and this resistor will disipate about 340Watt.
A ccs would be much easier and much better for the dynamic resistance. Look for schematics made by Walt Young, this would be a mayor improofment.
Last edited:
The best way is to test in circuit with 300B...
Good, lets say standard, is -0.25db@20KHz with abs. less than -10 deg phase shift. -8deg is fine
also for the low end -0.25db@20Hz with abs. less than +10 deg phase shift.
offcourse 🙂
Good, lets say standard, is -0.25db@20KHz with abs. less than -10 deg phase shift. -8deg is fine
also for the low end -0.25db@20Hz with abs. less than +10 deg phase shift.
Yes. These 340W of diss. has to be X 4 for proper heatsink even for short time use...
And it is dangerous.
Common sense is that transformer does not work in opposite dirrecton...
So should be tested with real drive - tube in real circuit.
with negative grid bias (not automatic, to avoid Rk/Ck impact on low end...)
Driver could be diskrete.
One measurement from anode with coupling C 10uF will be OK beacuse of high impedance of probe needed.
Second from loaded secondary with R load
Third same but with some loudspeaker to have reactive load of speaker net (equivalent speaker RLC has some huge values...)
You can calculate THD aproximatly by solving for thd_load
total_thd_measured = sqrt ( thd_anode**2 + thd_load**2 )
thd_load = sqrt (total_thd_measured**2 - thd_anode**2 )
The best way to test the OT trafo in different level until the max power described is the backward mode
Not necessary with dc current
And the graph without tube and tube confirm
Then the 4900 vdc was an extreme solution done to show some results of test
Walter
Walter,
What you prove is that all your results are different from the rest of everyone else in the world.
If you enjoy being different, then you succeed. If you like to be right, no, not at all.
But it's a free world if you want to keep going like this... it is allowed.
But dont complain that people call you stupid
What you prove is that all your results are different from the rest of everyone else in the world.
If you enjoy being different, then you succeed. If you like to be right, no, not at all.
But it's a free world if you want to keep going like this... it is allowed.
But dont complain that people call you stupid
No problem
You can show the right results simply buying the Sowter and Hammond trafo
The Audio precision system + accessories
The build a proto of amp
Then measure all stuff and publish the graph
Very simple
Otherwise yours are only words without any real facts
Walter
Note: it seems that you haven’ understood the last graph I sent in post 83 and 84
No need to buy the Sowter or Hammond, these are well know and respected companies and they know how to measure. Just you measurements differ, the right ones you can find on the site of those companies.
Btw they have Audio Precision equipment too (but better have some brains to understand what is happening).
Btw they have Audio Precision equipment too (but better have some brains to understand what is happening).
I suspect that you are in the same zone of the people that can’t show real facts to help the discussion but only words
I know Brian Sowter from 1992. Now he is out of the business
But I can assure you that for some proto stuff I asked and received I sent them my lab test to check
Last with the people of Carnhill ( owner of Sowter) around the trafo for my last LCR phono (also posted here)
What are you trying to say, that Brian Sowter is a liar and publish false measurements on his site? Send your Sowter transformer to me and you will get the measurements i will make. Ccs in Walt Young style and up to 20MHz equipment.
It happens that transformer discussions often get provocative.
I believe in Walter's reverse test can be accurate, if the reverse math is done right and no contributing parameter gets missed.
But I also believe, a critical comparison with correctly mirrored conditions should be proven practically for the final word.
For these, we need a low distortion, high voltage, controllable impedance amplifiers. For a start, one should equalize driving impedances for both impedance sides. Equalize source distortion vs frequency vs amplitude, if, measuring distortion.
I believe in Walter's reverse test can be accurate, if the reverse math is done right and no contributing parameter gets missed.
But I also believe, a critical comparison with correctly mirrored conditions should be proven practically for the final word.
For these, we need a low distortion, high voltage, controllable impedance amplifiers. For a start, one should equalize driving impedances for both impedance sides. Equalize source distortion vs frequency vs amplitude, if, measuring distortion.
I wrote about the test about the proto for me
Mr. Brian accept them and confirmed. One of proto was a clone of Tango 999
About s.e. Sowter I have SF08 not SA08
But I have the suspect that you are a guy named
Banned Sockpuppet
Tubes4allThat one year ago wrote this
It's a strange fact that the measurements of Sowter not match with your measurements, I trust the Sowter more, they have a good reputation.
I am asking to the moderator if is possible to check
Walter
If you look at the two graph of Sowter with response you can see one in backward mode only trafo and other yhe complete amp
Are similar
Yes, unfortunately that happens often.
When people present measurements from well-known companies, they should be careful about what they present. If they differ, it should be explained what happens especially when they present their own products that are supposedly better.
When people present measurements from well-known companies, they should be careful about what they present. If they differ, it should be explained what happens especially when they present their own products that are supposedly better.
The OT Nano is not in production
I wrote an answer about the possibility to be in the market
Then the SF08 is not in catalog of Sowter
The Hammond 1627 is suggested by me in a Article on Audioreview around a s.e. With KT150/ Kt88 and E88C already mentioned here
So what you say is not real
