transformer form factor: toroidal vs bobbin sonic impact: depth dimension 3D

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I also think, like abbey, that the only „phenomenon“ the word more 3D can be associated with, is the ratio between direct and diffuse sound. If I compare a good Omni mic to a cardioid or something and listening in mono the Omni mic has a much wider image between the two speakers. Especially the low end seems not to be so centered but broader which can be described as having more depth. I don’t know If I would hear the same on only one speaker. So there are more things at Play I would think.
I‘m quite sure that this „phenomenon“ is also explained in a microphone handbook. Will try to find it.
 
I can also imagine, if we allow two mics into the equation, that a very good match between a pair could do something for the image.

At the risk of belaboring the point (and I really don't intend to make OP feel unwelcome), I'm afraid there's kind of an inherent potential for conflating correlation/causation here.

If someone is using toroidal transformers in their ribbon mics, they're probably not just copying historic designs with inexpensive off-the-shelf parts. Maybe this means they're also more likely to optimize (or even just be careful with) other aspects of design and manufacture, like ribbon tensioning?

Even among historic mics, I never thought the Coles 4038 was more special than a good RCA 44BX (or an AEA R44).

If OP hasn't gotten frustrated and left us yet... do you feel that the great RCA mics (like the 44, 77, BK-11A, etc) lack this quality you're describing?

One final question: does @Marik still hang out here? He uses toroids in his ribbon mics. Maybe he'd be willing to share with OP why he made that choice and what he feels it does for the sound.
 
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Ha, not frustrated with @soapfoot @Murdock or others that are attempting to help me learn more about the devices in question and explore what, if any, role they play in what I'm hearing. Little point in going meta and talking about the utility, logic, or potential motivations of other responses. Much respect especially to you, @soapfoot, for hanging in there and not tacitly dismissing the topic.

Funny you should mention @Marik. Note on his page on transformers, he speaks to essentially what @abbey road d enfer mentioned in the reasons to use toroidals. But Dr. Fouxman also probably loses @abbey road d enfer (and others) for stating on that page "we chose the toroidal transformers because of their unparalleled sonics, low distortions, and 3D sound qualities."

At the risk of belaboring the point (and I really don't intend to make OP feel unwelcome), I'm afraid there's kind of an inherent potential for conflating correlation/causation here.

If someone is using toroidal transformers in their ribbon mics, they're probably not just copying historic designs with inexpensive off-the-shelf parts. Maybe this means they're also more likely to optimize (or even just be careful with) other aspects of design and manufacture, like ribbon tensioning?
Excellent point!
I've made a similar point with vinyl pressings in years past. I.e., to my understanding, there's no good technical reason that a 180gram record should sound better than one of say 120-140, but I suspect the claimed higher fidelity is in part the result that, with the higher costs charged by the plant, such pressings may be given a greater level of attention to detail in the actual pressing or in QC. Maybe @Brian Roth can offer thoughts as to this theory of vinyl weight and quality, lest he thinks this thread is still mired in some theistic nonsense.

Back to what you mentioned earlier Brad, I can likely build two pairs of 847 mics with tx as the only difference. I don't have the manufacturing chops, equipment, or capital to do the same with ribbon designs. Still, hopefully it will offer some insight. The budget for this hobby (and the intrinsic nature of 'hobby') means this won't happen for many months, but these builds are now on my list. This month my desk (and CC balance) is full of SCA pres!
 
Another very simple factor with the 180g records:

When you take them out of the jacket and feel that weight in your hands, it seems like it ought to sound better!

25-year-old-me would've scoffed at that, absolutely certain that I was way too smart and in-control of my mind to be biased by such a thing. But I've proven 25-year-old-me wrong on that count many times. It's so, so easy to hear things for no other reason than we're expecting to hear them.

That's another reason I've grown to lean more heavily on the quantitative when it comes to making decisions that are substantially-technical in nature. As much as I think my perception is pretty discerning, I've had to accept that when the margins become fine enough, the "noise floor" of cognitive bias is too high to reliably recover tiny amounts of "signal" through qualitative means alone.
 
I've made a similar point with vinyl pressings in years past. I.e., to my understanding, there's no good technical reason that a 180gram record should sound better than one of say 120-140, but I suspect the claimed higher fidelity is in part the result that, with the higher costs charged by the plant, such pressings may be given a greater level of attention to detail in the actual pressing or in QC. Maybe @Brian Roth can offer thoughts as to this theory of vinyl weight and quality, lest he thinks this thread is still mired in some theistic nonsense.
I am far from any sort of expert about vinyl pressing. My projects at QRP have been with things like repairing Technics SP-10 turntables and related playback electronics they use in QC applications. I do much more work with other equipment found at Chad Kassem's other companies.

That said, I have to think that 180 gram pressings DO require more attention to detail in manufacturing and QC, and these pressings have higher reject rates at the factory due to flaws that are detected. Hence, the final products are the cream of the crop. But, that is just my thoughts on the topic.

Bri
 
I have a few old soviet toroids, that were designed specifically for audio, they are gapped.
After the core is wound, they cut a slit in it with a special cutter that uses electrified wire.
It's called "electric-erosion cutting"
In English it's called Electrical Discharge Machining

1670683643965.png
 
.........

Finally. Amek 9098 desks ("by Rupert Neve the designer") had some toroids beneath a metal cover on the input modules. These had a tertiary feedback winding. Example in attached pic.

So maybe a toroid has some usefulness?

Bri

In addition to above, first RN digitally controlled mic-amp prototype (as I was told). Toroidal output TXs.
 

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McLyman use to make ribbon wound cores with two different alloys. 80 Ni for the low level signals and regular silicon to avoid saturation. Some of these toroids want to the moon back in the 60's.
 
Torroidals especially shine in low signal applications—particularly in ribbon and condenser microphones. Since they do not have air gap, have near perfect magnetic properties, and the flux stays within the core they are very efficient, have low losses, and have an excellent coupling. The Amorphous cores have even better permeability, so all together that allows to greatly reduce the turns number and use by far thicker wire. That in turn greatly reduces the added noise. Say, 0.002 Ohm Pri and 3 Ohm resistance of 1:36 transformer gives us 5.6 Ohm resistance noise= —147.42 dBV level and the ribbon impedance and clamping losses are by far dominating. For comparison the EI core transformer usually has the Pri at least 1 Ohm and Secondary 70 Ohm. In this case the will have copper resistance 1.366 kOhm (!!!), which corresponds to noise of —123.55 dBV, which together with the ribbon’s impedance and losses makes it notably worse.

Also, there are stackable toroids and continuously ribbon wound. Since the ribbon in the core is much thinner than usual stacks it has lower distortions.

But then the advantage of high efficiency becomes disadvantage with higher signal sources. That is, since the core in toroids saturates faster we need to use larger one, which inevitably increases winding capacitance and requires tricks… but this is completely different story…

Best, M
 
Torroidals especially shine in low signal applications—particularly in ribbon and condenser microphones. Since they do not have air gap, have near perfect magnetic properties, and the flux stays within the core they are very efficient, have low losses, and have an excellent coupling. The Amorphous cores have even better permeability, so all together that allows to greatly reduce the turns number and use by far thicker wire. That in turn greatly reduces the added noise. Say, 0.002 Ohm Pri and 3 Ohm resistance of 1:36 transformer gives us 5.6 Ohm resistance noise= —147.42 dBV level and the ribbon impedance and clamping losses are by far dominating. For comparison the EI core transformer usually has the Pri at least 1 Ohm and Secondary 70 Ohm. In this case the will have copper resistance 1.366 kOhm (!!!), which corresponds to noise of —123.55 dBV, which together with the ribbon’s impedance and losses makes it notably worse.

Also, there are stackable toroids and continuously ribbon wound. Since the ribbon in the core is much thinner than usual stacks it has lower distortions.

But then the advantage of high efficiency becomes disadvantage with higher signal sources. That is, since the core in toroids saturates faster we need to use larger one, which inevitably increases winding capacitance and requires tricks… but this is completely different story…

Best, M
Thank you for this high quality post. (y) Now some things become clearer to me.
 
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