[Steve]

Is this a hammond transformer?

What is the impedance and what are the Rdc ( primair and secondair) or copperlosses?
Just a nice sqaurewave dosn't make a good transformer alone but it's a very nice start.

I just got back from vacation. Sorry, did not mean to get in the way of your company's informational posts. I was just demonstrating an OPT in actual application. I agree, there are also other aspects to consider in an amplifier design for optimum sonic reproduction.

1)My designs are confidential.
2) Check the tube data for typical pri - pri impedances. (RCA tube manual, Duncan Amps, http://tdsl.duncanamps.com/tubesearch.php )
3) At the power level of my amp, any DC Ohm and core losses means very little. For instance 1/2 power gain or loss is only a 3db change, so any gain or loss means little. Distortion is quite low at 50 watts output, 1.3% with no global negative feedback.
4) The rise time and waveform at high frequencies indicates the degree of coupling between windings.
5) A supremely good high frequency waveform does not mean optimal "tonal" balance across the entire audio band. Having a bright or too full OPT will compromise the amplifier design.
6) The preceding stage designs, including the power supply, is just as important to quality reproduction as the OPT.

Trust me, the quality of the test amplifier is quite superior.

Cheers and hope all goes well with your new business.

Steve

[E55l2]

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[Steve]

I am just an amateur who winds occasional transformers, not a company.

I have seen plenty transformers with the same 10kHz as yours so without any further specifications it is just 1 of many, nothing special.

If copper and core losses dosn't mean much by you why do the best transformer companies do care? And why are these transformer famous and the others not?

And trust me, with a better core ( c-core)  your transformer would be a lot better.

Let me reply to each sentence in order if I may.

1) Sorry, it appeared to me that you were going commercial.

2) The answer to both your questions is marketing, or marketing tatics. Superior designing is not what makes a name or sells, but marketing always trumps superior designing. A very simple example is brand Bxxxx and other brands. Quite inferior but unfortunately the public believes otherwise. That occurs in all fields, not just audio.

3) In response to your third sentence, a myth that has been propagated; it is easily dispelled by:

     A. more and more companies would be manufacturing toroidals and with gaps for SETs. However, the problem with the toroidals I have seen are not
            enough core for extended low frequency response and handling idle current mismatches (P-P).
     B. using the amplifier as a fixed gain preamplifier and testing for musical accuracy via years of listening testing, besides instrument testing. EIs can
            be used for near if not perfect reproduction. This leaves designing the speaker to optimize the amp to speaker interface. 

Point "B" clearly destroys the misconception that C sections are necessary for better or close to perfection in reproduction. If the C core makes a sonic difference, then there is a problem(s) with the amp's design. This is not to say that all OPTs are accurate, whether EI, C etc.

Cheers and hope this helps.

Steve

[E55l2]

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[Steve]

You are right about toroids, i love them too ( but not manufactures make very good toroids output transformers specially PP)
The point is that the rolling direction is more optimal then the E I cores. Less core loss, better permeability.
And most important: its easy to get higher quality c-core and toroids then EI. I am not satisfied with M6 ( or even M 5 or M4) i am not satisfied with 0,35 mm laminations of the standard "audio" M6 EI.

And you can measure it easely too, distortion is lower.


In your opinion the top* brands are just a myth, maybe some of them are, and for sure overpriced but they are the most wanted because they have excellent bandwith and low losses and squarewaves reproduction is also outstanding.


* as Tango and Tamura

So what improvement is obtained? Virtually nothing at lower powers, as I noted in my last post. If the amp is accurate, what improvement can be had, except artificial flavorings. Simply overrate the OPT for the usage to lower the distortion. What is important is accurate reproduction, and looks.   

Of course if we are discussing higher powers, like 150 watts output and above, a couple of percent could accumulate 10 watts more output power, rather than heat. Another consideration is that higher voltages are usually present, thus higher voltage insulation. As such, the shunt capacitance and leakage inductance losses definitely increase and toroidal's offer a definite advantage. Materials also need to be improved to limit those problems. Examples are Mu metal, Permaloy C, 1040 if still manufactured, Radiometal etc.

About 20 years ago, I got to know the son of the company president, who built me toroidal filament transformers to heat 10 horizontal output tubes in an OTL amp I had designed. We were going to test and manufacturer higher output OPTs. Unfortunately, the father died and the son did not inherit the company, the aunt did and the son and family were swept from the company within a year. So much for a cool idea.

Cheers and happy new years.
Steve

[nicoch]

europen triode festival trafo test http://forums.melaudia.net/attachment.php?aid=1228
http://www.triodefestival.net/index.php?page=etf2009-shootout

[FullRangeMan]

europen triode festival trafo test http://forums.melaudia.net/attachment.php?aid=1228
http://www.triodefestival.net/index.php?page=etf2009-shootout

Nice contest, thanks for post.
This big Hi-B are gorgeous;

[E55l2]

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[Steve]

Also at lower power distortion get higher, specially for EI.

Look at this pdf: http://jensen-transformers.com/wp-content/uploads/2014/09/Audio-Transformers-Chapter.pdf

Page 9&10 for instance

You can also hear it, EI has dust muddy sound compared to HiB c-core

So it is information, but is it all encompassing? For instance, I have performed extensive listening tested for years, using dozens of musical selections, and found my monoblock amplifier to be accurate. By the way, the mono block amplifier has 0,05% THD (a conservative value to be safely within spec) at
1 watt. Please re read my last posts again.

Your last sentence, very generalized, demonstrates a possible problem with the amplifier design before the OPT (whatever brand it was). As just a simple example, if the tube circuitry is bass heavy, or uses high DA caps with high load resistance; then an OPT that is light in the bass will appear to alleviate the "muddy" condition of the tube circuitry. That does not mean the OPT is better quality, only that its tonal balance is tilted towards lack of bass, thus less muddy. One has to understand and consider the total design.

Just because a manufacturer/designer cannot produce an accurate sounding amplifier using an EI core does not mean another manufacturer/designer is not capable of using an EI core in their amplifier. The overall design is important.

I see no purpose in posting again as if the mono block amplifier is accurate via years of listening tests, then the amplifier is accurate. What else can I say. 

Cheers
Steve

[G Georgopoulos]

So it is information, but what about in actual practice. For instance, I have performed extensive listening tested for years, using dozens of musical selections, and found my monoblock amplifier to be accurate. And my monoblock amplifier has 0,05% thd (a value to be safely within spec) at 1 watt. Please re read my last posts.

Your last sentence demonstrates an obvious problem with the amplifier design before the OPT. As just an example, if the tube circuitry is bass heavy, or uses high DA caps with high load resistance; then an OPT that is light in the bass will appear to alleviate the "muddy" condition. That does not mean the OPT is better quality. One has to understand and consider the total design.

Just because a manufacturer/designer cannot produce an accurate sound using an EI core does not mean another manufacturer/designer cannot not design using an EI core. Design is important.

I see no purpose in posting again as if the mono block amplifier is accurate via years of listening tests, then the amplifier is accurate. What else can I say. 

Cheers
Steve

Steve

check out this    http://www.turneraudio.com.au/output-trans-theory.htm

[Steve]

Steve

check out this    http://www.turneraudio.com.au/output-trans-theory.htm

Too late tonight, just a skim. I also have an electronics engineering degree, besides the RCA Radiotron Designers Handbook, 1960, by 26 engineers, besides my college textbooks, helped professors in audio design using tubes.
 
Skimming I did not see anything that the RCA or my courses have not covered (1960's).

Just skimming it appears to provide some calculations for those learning how the OPT actually works.

Cheers
Steve

[G Georgopoulos]

Too late tonight, just a skim. I also have an electronics engineering degree, besides the RCA Radiotron Designers Handbook, 1960, by 26 engineers.
Skimming I did not see anything that the RCA or my electronics engineering courses have not covered (1960's).

Just skimming it appears to provide some calculations for those learning how the OPT actually works.

Cheers
Steve

engineering degree, in what field?,electronics in general?,but you have the handbook to specialise,that's good, i have a college certificate in analog tv servicing and an electronics handbook that covered every field
of electronics radar,tv,radio,hifi,medical-electronics,materials,components in summary of cource,didn't find any use of it so i ditched it. see through in detail the link i posted,there is also more pages on opt's.

Steve , all the best!.

cheers 

[Steve]

engineering degree, in what field?,electronics in general?,but you have the handbook to specialise,that's good, i have a college certificate in analog tv servicing and an electronics handbook that covered every field
of electronics radar,tv,radio,hifi,medical-electronics,materials,components in summary of cource,didn't find any use of it so i ditched it. see through in detail the link i posted,there is also more pages on opt's.

Steve , all the best!.

cheers 

In electronics engineering in general, and helped college professors in tube audio design. I started electronics/radios/audio when I was six, became a radio amateur at 16, designing much of my amateur equipment, got my degree, took care of the college lab, worked in industry, and my own lab for decades.

But all that is really immaterial when you consider that no other manufacturer or designer has performed the type of listening testing (for years) posted earlier. That is more than I have revealed in other forums.

Anyone who claims that a simple audition is enough to determine the quality of an OPT is sadly mistaken. A simple audition is virtually worthless.

Cheers
Steve

[E55l2]

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[Steve]

I am sorry to say but this test is really bad in many ways.
First the test set-up is not very good, r1 on the wrong place and the test equipment is very limited for the high frequency range. Some of the tested transformers are capable for more then 100kHz (-3dB) and none of the measurements shows the real high frequency bandwith.
Instead of a choke they should have used a good ccs and better test equipment ( at least till 200kHz, better 1MHz)

On the otherhand the low frequency test are a bit better, and also the 10kHz squarewave test.

The test amplifier is also one of the mistakes and the mono listening too.

The "best"  transformers in the listening test have all in commen a weak low frequency response and higher distortion.

So don't go blind on such test.

I agree with you E55. Not only completely unscientific and worthless, but actually worse. It is misleading as it teaches the public to perform or accept improper science. This garbage is similar to some of the capacitor "tests" I have seen in the past. As a result, the reward of the most accurate is the gift of extinction while the crap is glorified. No wonder the music lacks naturalness.

1) What is the "best" OPT with this particular amplifier design (which we do not know) may come in 2nd, 3rd, 16th with another amplifier design. We do not know how accurate the tube circuitry actually is in the design used.

1a) How good is the speaker? We do not know the accuracy, tonal balance of the passive transformer pre. How accurate is the mono line preamplifier? For example, if any of the components listed is bass heavy, the best OPT might be the lightest sounding. E55 appears to have perceived this scenario.

2) Different impedance OPTs, so the damping factor will vary with different primary/secondary ratios (Z).

4) The design of each transformer requires the circuitry to be at least tweaked to each brand for optimum performance. It appears that was not done. So
how do we know if X brand was really the best, or if a tweak was performed, Y might have been better.

10khz rectangular waveforms were quite bad, with exception of three or so. Wasn't exactly impressed with the low frequency response but then the setup was so poor.

Cheers
Steve

[E55l2]

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[nicoch]

sure we know that tango tamura are good and lundhal too and with the  amourphous we lose bass , is a lot of time ....
and the cheapers audionote are decent entry level...

[E55l2]

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[nicoch]

sure that lundahl is better ... sacthailand is not affidable
btw if is good for Thorsten is good for me !! TRANS-144 is 75£ +vat

[E55l2]

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