Thanks for the tip! I assume you're referring to Martin Mug. I've come across his name before in a Dutch forum, but was unaware that he actually started a transformer winding business. Still, I would love to have some understanding of what makes a good power transformer before I contact a winder to have something wound to specification.
Tom
Hi Pieter, I've had a look at Thomas' transformers and they do look promising. He's the first source that I've come across that actually lists specifications of the transformers instead of just stating that they can be wound to customer specification. Also, he uses the transformers in his own builds (very beautiful stuff) which gives me some sort of confidence.
I' believe would need two transformers as he uses a separate filament transformer for the DHT's. Is there any benefit in using a separate transformer for this purpose?
Tom
Pieter,
you might recommend him because you are doing business with him, but he isnt willing to sell individual transformers build to the specs of customers other than his own that he uses for his designs. And he is more interested in selling complete kits incl. trannies not single transformers.
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I do think thats only your personal opinion, sir.
You cannot make a claim that counts maybe for yourself into a general claim. Because in the end its all physics. And in physics there are rules, no claims like "different strokes for different folks". Thats nonsense.
@Tom: separate filament transformers are a must, as with DHT's the filament (= cathode) is audio.
When using another way of heating, for example Rod Coleman's heater supplies, you might come away with a single power supply transformer, but, also for the sake of start up, a separate filament transformer is best.
@Schmitz: yes I do business with Thomas, but I have no commercial interest in what he does with parts.
I had a pair of his power supply transformers for a SE 300B, which are wound on "normal" EI cores, but very well finished. Very good quality with screening and so on. Thomas sources these with a German company to his specifications, and when I am right you can buy the standard transformers which you will find on his blog.
When using another way of heating, for example Rod Coleman's heater supplies, you might come away with a single power supply transformer, but, also for the sake of start up, a separate filament transformer is best.
@Schmitz: yes I do business with Thomas, but I have no commercial interest in what he does with parts.
I had a pair of his power supply transformers for a SE 300B, which are wound on "normal" EI cores, but very well finished. Very good quality with screening and so on. Thomas sources these with a German company to his specifications, and when I am right you can buy the standard transformers which you will find on his blog.
Brian Sowter is producing excellent all kinds of trannies, too. And he is willing to tailor exactly to the customers specifications.
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No I don't. No idea how much Thomas charges for his transformers; no idea how much Sowter or any company charges for a hiqh quality custom power supply transformer.
But, Schmitz, I quit discussing with you as it starts to go off topic.
Maybe the OP is not interested in price but primarily in quality, so what?
But, Schmitz, I quit discussing with you as it starts to go off topic.
Maybe the OP is not interested in price but primarily in quality, so what?
me neither, i only sell completed amps, not individual transformers,
and you are right PieterT, perhaps this thread ought to be closed, the OP seems
disinterested...
you know what? the owner of that 2A3 set i posted had a humdinger pot, and i set it for zero hum, but he was unhappy, he adjusted the pot to have a slight hum and he tells me he like the sounds after that, after all he says, you can not hear the hum when music is playing and at the listening position, hum can be heard only at about a foot away from the speakers...
What made a great power trafo is funds $$:
0,1mm C core NanoCristaline, secondary Silver wire.
Although I prefer OFC copper and HiB, I sure Martin are plenty capable of teach you he know it all just ask him and pick a place in the line-various waiting months.
I have experience of both E-I laminations and C-cores, for both power and output transformers.
Different cost in different countries. In RSA one pays about 20% more for C-core devices. Their sizes are about 70% of an equivalent standard E-I model.
I would find a reputable manufacturer and let him work everything out; they do it all the time. One could specify a cool transformer, and of course that one needs a screen.
Not to expand this to a design discussion, but I must respectfully disagree with Schmitt 77 regarding the 'sound' influence of a power transformer. A transformer provides the neccessary voltages; the dc after rectification and filters is determined by everything, and any single source has its own heavy enough bypass capacitor. Unless transformer windings are so thin as to influence regulation, I fail to see how the power supply proper is anything but plainly a dc short at audio frequencies.
The required minimum series impedance of the h.t. winding for the rectifier cannot all be built into the winding. If it is serious, one subtracts the winding resistance from the stipulated value and add the additional resistance as a separate part. (Do keep in mind that, as rectified a.c. contains ac, the series impedance is higher than the dc resistance. This inductive impedance also serves in series with the winding resistance.)
Different cost in different countries. In RSA one pays about 20% more for C-core devices. Their sizes are about 70% of an equivalent standard E-I model.
I would find a reputable manufacturer and let him work everything out; they do it all the time. One could specify a cool transformer, and of course that one needs a screen.
Not to expand this to a design discussion, but I must respectfully disagree with Schmitt 77 regarding the 'sound' influence of a power transformer. A transformer provides the neccessary voltages; the dc after rectification and filters is determined by everything, and any single source has its own heavy enough bypass capacitor. Unless transformer windings are so thin as to influence regulation, I fail to see how the power supply proper is anything but plainly a dc short at audio frequencies.
The required minimum series impedance of the h.t. winding for the rectifier cannot all be built into the winding. If it is serious, one subtracts the winding resistance from the stipulated value and add the additional resistance as a separate part. (Do keep in mind that, as rectified a.c. contains ac, the series impedance is higher than the dc resistance. This inductive impedance also serves in series with the winding resistance.)
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This is all theory. If you have real listening experience with different trannie designs and are unable to audition those differences, this is absolutely contrary to other peoples experiences. So why people should pay for a better design, if not audible? Besides theory, this makes no great sense.
The only claim I did make is that my and many other peoples experiences are that there are audible differences resulting in different transformer designs. So thats what you are confused about?
Its not enough for you that those differences are audible, you absolutely need measuring data to have a proof in what you are hearing?
In 40 years of audio DIY, one thing has been proofen for me with absolutely correctness: Not everything audible is measureable, measurements are just a model of the real world as mathematics are theoretical models of the real world. The ear is capable of auditioning so many effects- but you wont beliefe until a measurement paper is printed out which tells you the effect?
Its not enough for you that those differences are audible, you absolutely need measuring data to have a proof in what you are hearing?
In 40 years of audio DIY, one thing has been proofen for me with absolutely correctness: Not everything audible is measureable, measurements are just a model of the real world as mathematics are theoretical models of the real world. The ear is capable of auditioning so many effects- but you wont beliefe until a measurement paper is printed out which tells you the effect?
over a hundred in the course of 40+ years.....more than half of which is with SS.....
i have no problem with differing experiences, but if you do not know something, that will show in your post and readers will know....specially when you dismiss something as mere theory....
Hallo Tom, groeten vanuit New Zealand.
Here in New Zealand not even winders are easily to be found. Why not buy a Hammond transformer from Mouser? Above 100 USD they'll ship for free and that is cheaper than anything you can wind locally. Make sure to check out the way they calculate the load capability.
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Hi Schmitz77,
They are designing the next output transformers I'm going to use. Their power transformers are excellent. I have Hammond product in use here from the 60's and earlier installed in working amplifiers. Their owners would disagree with your statements too.
If you can't add anything positive to this discussion, why are you even here? You certainly haven't offered any facts to back up your position, and you are dead wrong about Hammond products.
-Chris
That might be your opinion, but it isn't true at all. They aren't cheap though and are built with very high quality. They do buy some for China for the commodity items.
They are designing the next output transformers I'm going to use. Their power transformers are excellent. I have Hammond product in use here from the 60's and earlier installed in working amplifiers. Their owners would disagree with your statements too.
If you can't add anything positive to this discussion, why are you even here? You certainly haven't offered any facts to back up your position, and you are dead wrong about Hammond products.
-Chris
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