Netlist said:
I know that I have a simplistic view of the world, but, I follow this thread just to see where it goes and John's response to it. Why would you split anything off at this point?
The Blowtorch discussion has run it's natural course and the thread has turned into all things audio with John's slant. If the discussion of transformers comes up and it gets blasted and goes no further, that's a natural course of conversation. If someone intends to pursue a conversation that John has attempted a technical summation from his viewpoint and the author wants to turn it into a circular discussion, the moderators should consult with John and see if he sees anything technically to be gained from continuing (if not, split off the offending posts. If there really is an audience, the split off thread will flourish.).
I think most following this want to continue to benefit from his perspective and pursue his train of thought, not observe a p!ssing match with the next kid in town trying to take out the old gun.
Like I said, I have an overly simplistic view of the world. Mike.
As a general rule of thumb ferro-magnetic materials are a lot more non-linear with respect to magnet fields then dielectric materials are with respect to electric fields. Why do you think cored inductors are such a faux pas in passive crossovers? If capacitors in the signal path are to be avoided like the plague, then transformers are even more-so to be avoided. Jensen transformers have a THD specification that is worse than many power amplifiers, and perhaps thousands of times greater than a capacitor.
fizzard said:
And yet in spite of that, the finest, most highly regarded recordings, recordings used by audiophiles to gauge the performance of their systems, were likely made with half a dozen or more transformers in the signal path. As well, some of the finest, most highly regarded recording microphones use transformers.
If transformers are the plague that you assume them to be, how did such recordings ever come to be held in such high regard?
It's true that from a technical standpoint a transformer's weakness is at the lowest frequencies and at the highest levels. But as long as you don't overload the transformer, I haven't found this to be a problem.
Finally, I find it interesting that in your introduction, you say "...a tube amp is on my 'maybe I should' list..."
Why would you ever even consider such a thing unless the only tube amps you had in mind were the handful of OTL designs?
se
OK. I get it. So, it seems I accidentally brushed up against Steve's excitable parts when I mentioned transformer. I won't do it again. 😛
john curl said:
I tend to go out of my way to make sure any shielding is as far from the components as is humanly possible. I want the shielding, not the sonic signature of the shielding material from eddy currents, etc. For example, every time I see an encapsulated transformer, I want to bust the metal case off. I know there is still a core to the transformer, but..there is difference. And a notable one.
As for recording. Someone asked me a question on another forum. I told them phantom supply alright..but separate for each mike..and as local to the mike as possible, battery and buffered with filmcaps. No power in the signal cables, please.
This takes me back to the custom loom of the cable I used on the deflection yoke wiring. It was specifically 7 strand and it was a loom of 4 wires, Teflon shielded...and arranged so there was a slight 'hollow' to the 'core' of the wire, and self damped (mechanically) at the same time. The 'core' space provided a sympathetic space for field propagation, and also the presence of the wire provided for 'shield' for this propagated 'field'..and the exact right space when going from the inner to outer of the wire (DC to AC, or high delta) or any given point of the collapsing or decreasing 'size' of signal on the line for the purposes of deflection. This provided the best control of the deflected beam..when in that high field and high vibration environment of the CRT projector in the 'tube cavity' area.
This decidedly sensitive mass loading consideration of changing/modulating signal in the deflection yoke takes me right back to the point of the idea that the signal mass of the phantom power is quite detrimental to the delicate audio signal, if it is any way located near it. The mass slows it down..and the mass of the phantom power also has a resonant structure due to being a mass of some sort. The phantom power 48V 'field' itself provides a small amount of deflection of noise..but it also obscures fine detail. Besides skewing of linearity (re delta) in the -ve vs +ve signal components, in the micro sense.
Your thoughts?
Regarding signal transformers, they help to break ground loop induced noises and the above audio band, but still low frequency interferences. If we speak about RFI, it is pretty difficult to shield signal transformers properly against RFI pickup, and inserting them usually makes RFI level worse compared to well designed and shielded coaxial cable system (with multiple shields, e.g.). Also, transformers have their own sound colrations, I do not like to use them.
PMA said:
Haven't had any low frequency interference problems. But then I'm not parking them right up against power transformers.
What exactly makes shielding them from RFI pickup particularly difficult?
First, the transformers I use are encased in MuMetal cans, the only thing exposed are the transformer's leads which would be no less shielded than anything else inside the chassis. So if the leads are picking up RF, what's wrong with your chassis that it's allowing RF inside?
Huh? What have cables to do with anything?
Well, to each their own. Which is perfectly fine with me. But given what you've said above, I'm wondering if you've ever actually used any if you did, exactly how you were using them. What were you doing? Dangling unshielded transformers out the back of the chassis or using them as interconnects or something?
se
john curl said:
Yes, I am a hold out. I prefer to stick with what sounds best to me, not what sounds best to someone else.
I can only guess as to why some people are so intolerant of those whose preferences may be different from theirs that they feel the need to disparage them for it.
se
Signal transformer coupling (iron core) has an interesting property, naturally it will roll off as frequency rise. It performs somekind of HF junk filter at line stage. It sounds different than R-C lowpass filter.
There are signal transformers that perform well in RFI frequency range (like Mini-Circuits), but they do not transfer much in audio band.
Steve, try to measure transfer characteristics of your transformers from 10Hz to 2GHz.
Steve, try to measure transfer characteristics of your transformers from 10Hz to 2GHz.
Steve Eddy said:
Maybe the disortion improves the perceived quality of the sound? That's quite in line with general audiophile tastes in equipment.
Steve Eddy said:
Exactly, keep the flux density low with generous magnetic cross section. You've effectively zooming in on a non-linear curve and it appears straighter.
Steve Eddy said:
I'm a pretty curious person, and I have rather little experience listening to tube amps. Maybe it will grow on me if I have one around permanently. But for the most part it's also low hanging fruit, it's pretty easy to do. And I was planning on using a transformer output.
Hi, PMA,
You can look at this Jensen's response, in my view it is naturally good at filtering HF junk.
To many auditioner, this steep rolloff produces more sonic benefit over it's (not so good) THD.
The auditioner cannot say the difference is in the trebles or the bass or the midrange, but there is an improvement that they can hear (because of less HF junk content in overall performance, I think)
You can look at this Jensen's response, in my view it is naturally good at filtering HF junk.
To many auditioner, this steep rolloff produces more sonic benefit over it's (not so good) THD.
The auditioner cannot say the difference is in the trebles or the bass or the midrange, but there is an improvement that they can hear (because of less HF junk content in overall performance, I think)
Attachments
You posted a low frequency response from datasheet, not high frequency. 200kHz is low frequency. I am interested in frequencies 1MHz - 1GHz at least.
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