I have had very good measured results with even mains toroids as output transformers when used appropriately. To quote 6A3sUMMER, "all generalizations have exceptions"!
If you think that smashing the advanced audio transformer winding techniques away is a good advise then it may be right.
WE hat great designs in toroid with the 111C repeater for example.
But that wasn't audio in the way we refined it today.
In fact, the sound of a transformer couldn't be measured. What you could measure are mathematical formulas and their physical expressions. Those are always simplified models of the complex reality. A reality with complex resistances and relations between a tube, the transformer and a speaker.
What the ear is capable of hearing is another story. Those parameters aren't fully measurable. And to classify a product like an audio transformer could'nt therefore be done by measurements only.
And in an audio forum several different stages of refinement could exist parallel.
Its the same with cars. One could say: I have good results in driving experience with my 34 horsepower Beetle. The next would say: Only the Porsche will do for me.
What you define as "good results" could be for an advanced listener poor audible qualities.
Thats the only exception from the rule that could be applied here.
And if you have ever heard (and not measured) a much more refined transformer done conventionally like all excellent transformers are being wound, maybe you stop saying that toroidal transformers are the right way to go for audio.
On the Autobahn, when one is driving in the wrong direction it is called "Ghost driver" because all others are doing correct. No discussion about who is right and who is wrong.
In audio, everything is possible. When one is doing wrong, for sure someone else comes and will say: thats OK, too.
They produce cheap and easy automated production transformers for audio instead of refined and complex with a high grade of precision wound transformers. Due to the nature of the toroid thats impossible. And thats a rule with no exception, its simple physics.
WE hat great designs in toroid with the 111C repeater for example.
But that wasn't audio in the way we refined it today.
In fact, the sound of a transformer couldn't be measured. What you could measure are mathematical formulas and their physical expressions. Those are always simplified models of the complex reality. A reality with complex resistances and relations between a tube, the transformer and a speaker.
What the ear is capable of hearing is another story. Those parameters aren't fully measurable. And to classify a product like an audio transformer could'nt therefore be done by measurements only.
And in an audio forum several different stages of refinement could exist parallel.
Its the same with cars. One could say: I have good results in driving experience with my 34 horsepower Beetle. The next would say: Only the Porsche will do for me.
What you define as "good results" could be for an advanced listener poor audible qualities.
Thats the only exception from the rule that could be applied here.
And if you have ever heard (and not measured) a much more refined transformer done conventionally like all excellent transformers are being wound, maybe you stop saying that toroidal transformers are the right way to go for audio.
On the Autobahn, when one is driving in the wrong direction it is called "Ghost driver" because all others are doing correct. No discussion about who is right and who is wrong.
In audio, everything is possible. When one is doing wrong, for sure someone else comes and will say: thats OK, too.
They produce cheap and easy automated production transformers for audio instead of refined and complex with a high grade of precision wound transformers. Due to the nature of the toroid thats impossible. And thats a rule with no exception, its simple physics.
Last edited:
Ok guys, let's just stop now. Maybe Schmitz will too.
I think the OP has more than enough to think about.
I think the OP has more than enough to think about.
mctavish,
the distortion is a consequence of the torodial shape, high material density, high permeability, that is, high efficiency. High efficiency implies high distortion. No exception to this generalization.
the distortion is a consequence of the torodial shape, high material density, high permeability, that is, high efficiency. High efficiency implies high distortion. No exception to this generalization.
The original (first) Toroid power transformer from the 1800s, is at the Deutsches Technical Museum in Munich Germany.
kodabmx uses a pair of cheap $18 toroid OPTs per channel for his 6P43P (=EL84) amp -
https://www.diyaudio.com/forums/tubes-valves/354877-stereo-tube-amp-build-father.html#post6214657
https://www.diyaudio.com/forums/tubes-valves/71300-photo-gallery-946.html#post6194886
VPT12-2080 Triad Magnetics | Mouser
https://www.diyaudio.com/forums/tubes-valves/354877-stereo-tube-amp-build-father.html#post6214657
https://www.diyaudio.com/forums/tubes-valves/71300-photo-gallery-946.html#post6194886
VPT12-2080 Triad Magnetics | Mouser
Last edited:
This claim doesn't make sense at all.
So what?
Distortion at low frequency happens due to increase of magnetizing current, with increasing flux density, which, when approaching saturation, results in a drop of inductance, hence more elliptical load line for the driving tube.
Distortion in the micro-swing zero crossing region is dependent of the core hysteresis, which is dependent of core material type, air gap amount, but I'd like to see numbers of the significance of this before overall claims.
Distortion in the HF region occurs again due to ellipcal loadline resulting from total shunt capacitance and/or leakage inductance.
🙂
IMHO, the problem with toroid transformers has mostly to do with the use of mylar insulation, which sounds nasty.
Well said! That's exactly the kind of humour that attracts me 😀.
Do you say that toroids are made of cheap materials, applying a cheap winding method?
Why does it?
Well, let me try to think about it. The dielectric constant of Mylar foil is considerably larger than that of oil paper, for instance. That's why especially musicians or makers of boutique guitar amplifiers swear on oil or Kraft paper in their transformers. But what's the truth? I dunno, 'cause I never had the chance to compare two OT's, one with Mylar, the other one with paper insulations, in the same amplifier. And most probably I never will.
Best regards!
There is a huge corona related backlog of work in our labs but you guys are making it tempting to reserve one of our Alpha-A analyzers to venture into the world of audio related dielectric phenomena.
zintolo,
I built an amp that uses the 1609A (the 10K version of the 8k 1608A).
They both weigh 2.5 lbs, and are for 10 Watts, 4/8/16 Ohms.
Before I matched my tube currents, even the 100Hz sine waves were visibly distorted (early core saturation).
The 40Hz was worse, and 20Hz was ugly.
That is what the 1609A does when you do not balance plate currents.
Now, I have the currents matched, and it is good all the way down to 20Hz.
I designed the amp to run Very Cool, for Summer operation. It only puts out 6 Watts.
Some would say that I wasted the KT77 tubes (I say the amp is 'Cool', and has the same low distortion at 6 Watts that it has at 1 Watt).
I used the KT77 tubes in Ultra Linear, no negative feedback other than UL.
I drive them with a 12AY7 that has an LM334 current sink in the cathode "LTP" phase splitter.
It has low distortion for such a simple circuit that does not have global negative feedback.
The 1650E is 3.5 lbs. More laminations than the 1608A and 1609A.
It probably could work with a little more unbalanced plate currents.
It also can put out more power at bass frequencies (more laminations).
As to high frequencies, you are on your own, I only have the 1609A. I get 38kHz bandwidth on my KT77 amp.
But real important point, is to always balance your plate currents.
Push Pull transformers like that.
I built an amp that uses the 1609A (the 10K version of the 8k 1608A).
They both weigh 2.5 lbs, and are for 10 Watts, 4/8/16 Ohms.
Before I matched my tube currents, even the 100Hz sine waves were visibly distorted (early core saturation).
The 40Hz was worse, and 20Hz was ugly.
That is what the 1609A does when you do not balance plate currents.
Now, I have the currents matched, and it is good all the way down to 20Hz.
I designed the amp to run Very Cool, for Summer operation. It only puts out 6 Watts.
Some would say that I wasted the KT77 tubes (I say the amp is 'Cool', and has the same low distortion at 6 Watts that it has at 1 Watt).
I used the KT77 tubes in Ultra Linear, no negative feedback other than UL.
I drive them with a 12AY7 that has an LM334 current sink in the cathode "LTP" phase splitter.
It has low distortion for such a simple circuit that does not have global negative feedback.
The 1650E is 3.5 lbs. More laminations than the 1608A and 1609A.
It probably could work with a little more unbalanced plate currents.
It also can put out more power at bass frequencies (more laminations).
As to high frequencies, you are on your own, I only have the 1609A. I get 38kHz bandwidth on my KT77 amp.
But real important point, is to always balance your plate currents.
Push Pull transformers like that.
Last edited:
Menno Vanderveen is one of my Internet gurus, and he uses toroids. That's enough for me, but I haven't tried one yet.
Hi Steve,
Yes this is the circuit. thanks for the hint. Of course it always good to have extra taps, so I can later re-use the OPT for other circuits.
Regards,
Aviv.