Where Does Vintage Transformer Magic Come From? (Triad A9J, A12J) | Transformer Series Video #2
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- Опубліковано 7 сер 2023
- Intro to transformers: • A Quick Introduction t...
Thanks for listening along as I try to learn all that I can about the mysteries of vintage transformers. This is all certainly a journey in progress so I appreciate all the comments and knowledge out there online. Keep an eye out for the next one, because I think we are in for some interesting results.
Find my ribbon mics at www.alderaudio.com
Eric Valentine has a great video of him trouble shooting an old console he was trying fix up. One channel of his audio had a huge 10k boost in frequencies compared to the other channel. When it came down to it he wound up changing some wire length in the console which seemed to be affecting the impedance between the two channels. Pretty funny when you think about all the credit old transformers get for being able to create a "vintage" more pleasing frequency response when there might be other things being completely overlooked.
Great content, keep it up!
Thanks Dave!
Thanks very much for the video. It demystified transformers for me!
Catching up with your videos ... one thing that I suspect contributes to transformer "magic" is the Barkhausen effect, a small noise caused by the magnetic domains flipping as they're being magnetized by the varying magnetic field. There's a bunch of UA-cam videos on it.
Hey thanks for the comment, I will absolutely be looking into this.
Only dogs can hear it tho...get it...Barkhausen
I came across your video while researching the VTB2281, how would the A9J compare to this?
It looks like the VTB2281 is a quad coil 600:600 ohm transformer, sometimes called a repeating coil. The Western Electric 111C is a sought after vintage model wired similarly. You can wire them 1:1, 2:1, or 1:2. However this configuration is very different from the A9J, which is a ratio of 1:12. In this DI context we are actually using it backwards as 12:1. The need for the big ratio is to adapt the high impedance bass guitar signal to a lower impedance XLR input. So very different applications and not interchangeable, just on the ratio alone. All the other specs like the inductance and DC resistance would also be very different between the two based on their intended use.
Thank you for taking the time to explain that to me, very helpful.
Hey, who can help me identify a vintage transformer? And who is selling such things? Any one stop shop?
The one place I know to point you to is retrogearshop. They've got a lot of desirable vintage transformers and maybe comparing to their photos can help with identification? They have a lot but are priced accordingly.
Measure instead of listening.
Thanks for the nice video, I feel you explained some things very well, in plain terms. I appreciate that. I was really hoping you would have showed how you made those measurements.
Most measurements were done with an LCR meter at 100hz. Selectable measurement frequency at 100hz is important because higher frequencies get you into the resonance region of the transformer and give erroneous results. Primary impedance, Q, and DC resistance are measured on the leads of the primary with the secondary open. Leakage is measured the same with the secondary shorted. Mutual capacitance is measured by shorting both sides of the transformer, connecting guard to ground, and connecting meter clips one to each set of windings. Mutual capacitance is requires an oscilloscope, signal generator, and a calculation based on resonant frequency. I also used an oscilloscope resonant method to verify primary inductance.
Could you please share the name and model of transformers you used in the Information Window and links to the product’s data sheet? Also their ratio, plus their primary and secondary impedance?
I kind of want to, but as I am a maker and seller of products, including now a boutique DI transformer, I try to treat my competition the way I'd like to be treated. So I don't publish names of comparisons.
However, all three do have a nominal ratio of 12:1. Also, IMO Impedance stats on transformers are misleading. They are not actually a measurement of the transformer, but rather a statement of what impedance circuit the transformer is designed to be used with. Inductance, which hardly ever published, is a far more useful stat, and transformers listed as having the same impedance can have very different inductance.
@@alderaudio I wish you luck in your business. I mean that. Thanks again, it was a very useful video.
Yes, the inductance (permeability of the metal) is a great specification to look at and most TX makers don’t publish this. But so is density, and they don’t publish that either.
I asked, cause you published the name of Triad, which still makes the their famous transformers. Why not publish Jensen and Edcor or Cinemag and Neutrik or Hammond and Chinese off eBay, too? Oh well.
When people do a comparison, company or not, they usually tell you who the competition is.
The biggest difference seemed like a comparison between a transformer with higher nickel content vs higher steel content, but since you didn’t publish the names and models of all three, we can’t know for sure.
Nickel is clean, Iron is colored and steel is crunchy/dirty. All are useful for different purposes in the audio world.
Honestly, the Triad A series was a more modern transformer design, probably higher nickel content, right?
It still rivals the clarity of current offerings, like Jensen and Cinemag. You should compare an older design and maybe USA vs UK, German, Russian, or Japanese.
You have a good point in that Triad does produce a remake. I had thought of it as a vintage thing and therefore not active competition. If you really want to know what they are I'm willing to tell you over email. Shoot me a message at tyler@alderaudio.com if you are interested.
As far as inductance and cores, I don't tend to think there is as much in the idea of different metals sounding different as some believe. The inductance doesn't come from the core alone but rather a combination of the magnetic permeability of the core and the number of wraps. The number of wraps will change everything. So if you try to compare an iron core to one with some nickel content, you will need a ridiculously different number of wraps to get the same inductance between the two. Those wraps come with different resistance and distributed capacitance and whatnot, so I tend to think the difference in the sound is more dominated by those side effects of the material that change the overall design rather than something about the sound of the material itself. Saturation is also a big factor that is also changed by both material and wrap count. And yes, anything small enough to fit in a small box that can function as a good DI transformer is going to need very high inductance and thus a high permeability core such as 80% nickel. @@dickdixon6409
@@alderaudio those are all very good points, I see why you think of the difference in tone and saturation in all of the changes you have to make to a design to accommodate a new Metal with a different permeability, density, etc…. Thanks again, it is a very fascinating subject. I will email you.