Toroidal output transformer in the microphone.

[vmanj]

Greetings to all.
If a toroidal output transformer is used in a tube microphone, can this degrade the sound compared to a conventional transformer?

 

[kingkorg]

Greetings to all.
If a toroidal output transformer is used in a tube microphone, can this degrade the sound compared to a conventional transformer?

No transformer expert here, but i wouldn't say that, and i'm sure it will depend on all the other aspects of the transformer.

Soyuz uses toroidal transformers. I used a random toroidal 3.38:1 i got of eBay for my u47 with ef14 for testing. Somehow even with it's tiny size and low ratio it performed insanely well, and i kept it there. To this day i have no idea what transformer it is, where it came from, and how in the world it performes so well. Terrapin toroids get also great reviews, but i never got the chance to use one.

 

[vmanj]

I see, thank you.

It's just that for some reason toroidal transformers are not used in the mass production of top-end microphones.

I know that Soyuz microphones use toroidal output transformers, but it’s the sound of their top-end microphones that I don’t like.
Maybe it's just a coincidence...

 

[Voyager10]

Just FYI, BeesNeez make a couple of toroidal transformers, which they recommend for tube mic applications - https://beesneezproaudio.com/transformers/

 

[vmanj]

Of course, I know that there are several microphone manufacturers that use toroidal output transformers.
But these are small-scale manufacturers and their microphones “do not play in the first league”...
I meant top, popular manufacturers and their models (67, 87, 251, 800, etc.).
None of them use toroidal output transformers.
Surely they know what they are doing.
Perhaps this type of transformer somehow spoils the sound.

 

[Khron]

You need much more complicated machinery to wind toroidal transformers, than just a wire around an axial bobbin, so there's that too...



Versus



Remember, profit's gotta come from SOMEwhere

 

[Murdock]

Also, toroidals were not that popular when the “classics” you listed were made, except the Sony.
I think toroidals were only widely used in pro audio since the 80s or late 70s.
Maybe it’s also because of size? I would think it’s harder to wind a small toroidal than a bigger one.

 

[rock soderstrom]

You need much more complicated machinery to wind toroidal transformers, than just a wire around an axial bobbin, so there's that too...

That is basically correct, although I don't believe that this was the sole reason. If, for example, Neumann wants a toroidal transformer, Haufe will certainly build one. They can do it, they have equipped the entire broadcast amplifier technology with toroidal transformers from a certain point in time.

Remember, profit's gotta come from SOMEwhere

Money always plays a role, but the products mentioned are not intended for the mass market. This weakens the argument somewhat, and the past also shows that costs have not always been a priority. Take a look at some old designs from German broadcast equipment, they use expensive transformers and chokes as if they were growing on trees. This could certainly have been produced more cost-efficiently, but the old guys intentionally took a different path.

I think toroidals were only widely used in pro audio since the 80s or late 70s.

I think that's a good point. You can see this clearly in the broadcast amplifier technology mentioned above. Around the same time period, toroidal transformers became very popular and gradually replaced conventional winding technology. (at least in german broadcast equipment)

Almost all of the microphone designs mentioned date from before this time.

Perhaps microphone designers are just a little more conservative than the rest of the electronics world.

 

[Khron]

Perhaps microphone designers are just a little more conservative than the rest of the electronics world.

Well, EI-core transformers are also easier to mount, perhaps? No danger to the windings if you crimp some "frame" around the core, with mounting ears. Not so much with toroidals, but i could be wrong.

 

[rock soderstrom]

Well, EI-core transformers are also easier to mount, perhaps? No danger to the windings if you crimp some "frame" around the core, with mounting ears. Not so much with toroidals, but i could be wrong.

Maybe, who knows? Or maybe it's the required size of the transformer. In my memory, toroidal transformers are actually smaller than conventional transformers for the same power. Perhaps this effect is reversed with relatively small signal transformers, so that the EI design can be realised more compactly? Which would certainly be a plus in a microphone.(...or, as mentioned above, are smaller toroidal cores generally more difficult to produce?)

If a toroidal output transformer is used in a tube microphone, can this degrade the sound compared to a conventional transformer?

With regard to the original question of whether toroidal transformers are inferior to conventional transformers in terms of sound, I would say that this is not the case. This came up in the WWW at some point in the context of the Telefunken V672 units, which were originally realised with square transformers and then equipped with toroidal transformers. Allegedly, the toroidal versions had a worse sound, but the fact that the circuitry (and the components) was also changed was not taken into account.

I believe that the quality and the "sound" of a transformer depends on the transformer manufacturer and its quality/knowledge/experience/material - not on the general design, i.e. toroidal core or EI construction.

 

[gyraf]

Toroids have very good magnetic coupling, i.e. can be made with surprisingly low leakage inductance. And for non-gapped use, its A(l)-value gets quite high because of magnetic circuit efficiency.

The upcoming microphone "Astrud", which is a collaboration between us and Campbell Transmitter (a commercial product), will have a toroid output transformer - so far I haven't found anything even close to these in traditional EI-core designs..

/Jakob E.

 

[Marik]

Toroids have very good magnetic coupling, i.e. can be made with surprisingly low leakage inductance. And for non-gapped use, its A(l)-value gets quite high because of magnetic circuit efficiency.

The upcoming microphone "Astrud", which is a collaboration between us and Campbell Transmitter (a commercial product), will have a toroid output transformer - so far I haven't found anything even close to these in traditional EI-core designs..

/Jakob E.

To add to Jakob's sentiment, the toroidals are by far superior in almost every aspect. Their only drawback is higher winding capacitance, but if addressed smartly it can be corrected.

The main question, though, any microphone is a system and the transformer is just a part of it. For example, 251, or C37 had rather poor transformers from technical point of view. The T14 wound on a small D core, which had no I pieces and had quite a big air gap. As a result--excessive DCR, leakage, and losses (not to mention the 12AY7 tube is not the best choice for a microphone).

The C37 was wound on low Ni core, without interleaving--they just slapped secondary on top of primary. However, those mics got iconic status because despite those deficiencies it all worked as a system.

Best, M

 

[Khron]

... But why would they spend likely millions on retooling and redesigning, for possibly no perceivable improvement, especially if the "originals" still sell plenty?

Don't kid yourself - especially today, it's all about money. Bragging rights are (or would be) just they "cherry on top"...

 

[Marik]

But if output toroidal transformers are so good, then why don’t top microphone manufacturers still use them, maybe they don’t know about it yet..?

First, they use them quite a bit in ribbon mics, where the efficiency of the core is of utmost importance--Coles, Oktava, our Samar ribbons. We also made toroidal transformers for expensive Pegasus mic from Ronin--the one Celine Dione really liked. But it is quite a bit more expensive to make the torroidals, so the price raises accordingly--that might be the main consideration.

Perhaps in the updated versions of 67-87-251-800, they will still understand this and finally start using them..

As I mentioned in the message above--the microphone is a system. It is like to take a beautiful woman and then to try to 'improve' her and add a nose from another beautiful woman. Would it fit? Maybe yes, maybe no, however, it is not the original beautiful woman, anymore. Besides, again--99.9% so called clones are not about quality, but budget... with very rare exceptions. Why to care if ignorant people still buy them, anyway?

Best, M

 

[vmanj]

First, they use them quite a bit in ribbon mics, where the efficiency of the core is of utmost importance--Coles, Oktava, our Samar ribbons.

I didn't mean ribbon microphones.

We also made toroidal transformers for expensive Pegasus mic from Ronin--the one Celine Dione really liked. But it is quite a bit more expensive to make the torroidals, so the price raises accordingly--that might be the main consideration.

This may be an expensive and innovative microphone, but these advantages can only be shown by the popularity, sales and demand for this microphone.

As I mentioned in the message above--the microphone is a system. It is like to take a beautiful woman and then to try to 'improve' her and add a nose from another beautiful woman. Would it fit? Maybe yes, maybe no, however, it is not the original beautiful woman, anymore. Besides, again--99.9% so called clones are not about quality, but budget... with very rare exceptions. Why to care if ignorant people still buy them, anyway?

I completely agree with you, this is a system.

It’s just that now they sell a lot of “clones” of “classic microphones” that have a toroidal output transformer installed.
At the same time, it is argued that these are technically advanced transformers that are as good as, if not better than, the original ones.
This violates this system and misleads buyers of “clones”.

 

[Khron]

It’s just that now they sell a lot of “clones” of “classic microphones” that have a toroidal output transformer installed.
At the same time, it is argued that these are technically advanced transformers that are as good as, if not better than, the original ones.
This violates this system and misleads buyers of “clones”.

... Yeah, and..?

 

[Marik]

It’s just that now they sell a lot of “clones” of “classic microphones” that have a toroidal output transformer installed.
At the same time, it is argued that these are technically advanced transformers that are as good as, if not better than, the original ones.
This violates this system and misleads buyers of “clones”.

It is not about topology, but implementation. It is possible to make a good transformer even on EI core. Also, it is possible to make a crappy toroidal. Devil is in details—core, its type, its material, stacking, size, winding technique, correct parameters calculation, optimization, and so forth—all of that affects the final result. All those things equal—torroidal transformer will be superior (of course, if made as a part of the system). Not to mention 99.9% of so called ‘clones’ have nothing in common with originals, so they can say whatever they want.

Best, M

 

[vmanj]

... Yeah, and..?

This violates this system and misleads buyers of “clones”.

 

[Khron]

And once again i must ask - what's the problem? When has it NOT been a case of "let the buyer beware", when not buying the original item?

 

[vmanj]

It is not about topology, but implementation. It is possible to make a good transformer even on EI core. Also, it is possible to make a crappy toroidal. Devil is in details—core, its type, its material, stacking, size, winding technique, correct parameters calculation, optimization, and so forth—all of that affects the final result. All those things equal—torroidal transformer will be superior (of course, if made as a part of the system). Not to mention 99.9% of so called ‘clones’ have nothing in common with originals, so they can say whatever they want.

I agree again.