the sound of transformers

[dharma one]

how would you characterize sounds of different transformers? what do they actually do to the signal (apart from their textbook electrical properties)? i understand some people prefer the sound of some over others but why is this - how do they sound different?

 

[CJ]

That's a tough one. I think the circuit And the transformer have to be taken together in order to figure this one out. I also think that putting a sine wave through a transformer is a lot different than putting music through it. Ever look at music on a scope? All kinds of stuff going on at the same time.

I think the answer might lie in here somewhere:

 

[ToobieSnack]

ya cj is right
this could be a whole book by itself.
or several lol :grin:
but the good news is your at the right palce to find the answers.
i promise tranformers are a HUGE topic here.
search read search read search read :shock: lol
that's the process ... :grin:
get some coffee your gonna be a while :grin:
later
ts

 

[analag]

ya cj is right
this could be a whole book by itself.
or several lol
but the good news is your at the right palce to find the answers.
i promise tranformers are a HUGE topic here.
search read search read search read lol
that's the process ...
get some coffee your gonna be a while
later
ts

Yup he's right, these guys made me put a transformer into my beloved optical compressor and you know what...it's rocking hard than before.

 

[mikka]

A few searches will give you a lot of information. CJ is the main researcher here and has already passed on a lot of good info. But to a large extent, you'll pay for what you get.... like most things..... and quality design, workmanship and materials cost. Of course, there is also the law of diminishing returns. At some point you're paying for small improvements...... then there's personal opinion..... then there's.......

So search and read. You'll learn a lot.

 

[CJ]

You might hear a 10% change in sound between transformers in a circuit if your lucky.
Most 600:600 types are pretty flat. Soundguy likes the WeCo 111C for a fat sound.
A 1:10 ratio can give you a lot of different personalities due to leakage differences. Mainly at the top. Lams will change the bottom. Plug and play is the best way to figure it all out in a way that you understand, because everybody has different ears and different software running those ears. (the brain). It's like music, hard to describe. Soundstage, transparent, vintage, crisp, mellow, dosen't really tell you what's going on, does it?

Most current brands seem like they are shifted towards the top end nowdays. We have better equipment to hear it, thats why. You can always eq your signal, so if one transformer gives less bottom, just add it in with the eq.

I have not even scratched the surface as far as listening tests. There are a zillion x-formers in each company catalog. Listening to all would take a lifetime of time and money. Some have a good rep so you don't need to go hunting. The LL 1538 seems to be quite popular.

My favorite transformers so far are the ones used in the Langevin AM-16.
Thay also happen to be the most complex as far as winding structure.

 

[dharma one]

thanks a lot for the detailed information CJ!
ill go through the archives next

 

[CJ]

I have a friend who says he can tell how a transformer will perform by the winding struture and core. I believe him.

I just thought of a cool new test. Input music into the primary, hook a dual trace scope up to the input and output and match amplitudes, then X-Y it and look for differences among different brands. The signals will cancel if out of phase, so only the artifacts will show up. I will give it a try.

 

[NewYorkDave]

Use X10 probes and be sure they're properly compensated.

Unless your vertical amplifiers are giving exactly identical performance, and you can match the amplitudes exactly, it won't be a perfect test. But done carefully, it does seem a worthwhile one.

The test could also be done with a well-designed differential amplifier.

 

[PRR]

> X-Y it and look for differences

You will see a lot of high-frequency phase shift, which fills the scope screen but does not really have large effect on the ear.

Try it, but also try band-limiting both inputs to 100-5KC. This will require matched filters, and in most cases buffer amps.

Of course differences with level will be important too.

 

[soundguy]

[quote author="dharma one"]how would you characterize sounds of different transformers? what do they actually do to the signal (apart from their textbook electrical properties)? i understand some people prefer the sound of some over others but why is this - how do they sound different?[/quote]

I cant tell you what they actually do which would lead to an understanding of how they sound different, but I have spent great deal of time auditioning transformers and can tell you that some transformers will make your circuit sound different the way blue, red or green paint will make your house look different.

A good test of extremity is the comparison between lundahl and beyer transformers. The beyer transformers I have played with have a VERY up front midrange with kind of a gravely top and a somewhat rolled off bottom. The lundahl transformers I have played with all pretty much do exactly the opposite in all respects, they have a sparkly top end, a scooped midrange and an extended big low end. On a graph, I bet the midrange is probably flat but appears "scooped" because of the high and low end characteristics. If you take the beyer, it fits exactly inside the lundahl, if that makes any sense.

I built a rev e 1176 earlier this year and wasnt happy with the 0-12 input and tried a lot of different stuff. Wound up using a 31267. The difference there was sorta light and airy vs led weight authority.

On the bench, differences may seem subtle, perhaps too subtle to bother paying attention to. The real test, which of course is where the time comittment gets crazy, is mixing with the stuff. The tiny bit of rise that one transformer did over the other on the bench is probably not the biggest deal and you may laugh at someone like me for insisting there is a difference between the two, but when you mix you may find that that tiny bit of rise at 5K made a vocal work without EQ where the transformer without the slight rise needed EQ lift to work. If you dont have any continuously variable EQs and only stepped gain eqs where your option is flat or +2 dB of boost, that tiny bit of rise all of a sudden is a HUGE difference between transformers...

Transformers make things sit in totally different places in a mix and thats where the real difference between this and that becomes really apparent and really really relevant. Unfortunately you really need to put in the time and listen to lots of stuff, Ive changed transformers in and out of some boxes dozens of times. If you have a patch bay you can save some time by wiring output transformers directly to patch points on the bay and then leaving your box transformerless and listening to the different outputs as you go, picking one and then going installing your pick into the box, I do that quite a bit. Save up some dough and wire in 5 or 6 common types that you like, saves lots of time with testing alternatives.

One other general thing, the cheaper steel lam transformers tend to be the ones that sound like a chunk of metal more often in comparison to the ultra high end expensive transformers which tend to have the "bulk" without the sound of a hunk of metal if that makes any sense. More expensive in my experience has translated to generally more transparent, good or bad depending upon what you like.

dave

 

[TedF]

I try not to jump in on discussions that are purely matters of opinion, but reading through this one started to make me 'tut tut' at the conclusions....

Audio transformers are simple components designed to either change impedance, and/or isolate audio signals. The primary function is easily worked out, and transformers can be made to perform it with great efficiency.
Now we come to the interesting bit.... At the low frequency end, the performance limits are governed by the core material, the operating level and the winding resistance; the use of mu-metal in the core allows lower frequency operation, but when the core saturates, it does so suddenly, and audibly. more simple iron and the bottom end is smoother.
At high frequencies the situation is more complex, the performance is affected by stray capacitance, winding resistance and mutual inductance, however all these factors are real and measurable, as are the performance deficiencies... which turn out to be the 'character' of the transformer!
So unlike op-amps, where differences in performance and sound are extremely difficult to measure and isolate, if there's a transformer in the circuit it's easy to look at amplitude response, distortions and phase shifts, and get a good idea of how to design something that's characterful, and yet still looks adequate on the spec sheet (!)

There's no magic in transformers, they're just excellent components with deficiencies, that purist engineers tried to make totally redundant....

Ted Fletcher

 

[jensenmann]

Ted, welcome aboard. Nice to have you here!
I´m using the VC1Qcs you designed alot and I love its character.
:guinness:

 

[CJ]

Oh boy.
.
.
.
.
.
Should I?



.
.
.
.
No.

 

[jensenmann]

Yes, CJ, you should. Pm me if there´s something I should know.

 

[CJ]

No, I'm cool, are you cool?
I think everything's cool.
I just got some cookies.
How cool is that?
And I don't mean in my browser.
Or my trousers.
Scored some chips from Mouser.
Wowwzer Zowzzer.

 

[Gus]

TedF posted "Audio transformers are simple components"

I don't think so. theory wise they might be somewhat understandable but the build is another story, alloys and treatment, winding method layers sectioning etc.............., winder used Human or machine, The overall design that tries to get everything wanted in a balanced design. Much that has to be controlled.

If transformers were simple, the china transformers would be as good as the ones made by the name brands.

Tu Tu what! what conclusions?

Dave stated how the transformers sit sound in the mix. Plus you stated what a lot of us "know" from books, the alloys are different etc. There are some of us that have bought a bunch of good transformers I have been trying to teach my ears/brain the "sound" of the alloys from amorphous to Si.

FWIW don't dismiss Dave he picked the brand of a transformer in a microphone of mine without knowing what what was inside it.

There might not be magic in transformers(what post had magic in it!!) But good design seems to be theory and a lot of work building different transformers protos until the design is as good as it can get.

 

[TedF]

Gus, You misinterpret what I mean by 'simple'....
A transformer is simple in the same way that a violin is simple, and there's no need to dismiss Chinese transformers (or violins); it's just that their requirements are different... given the exact spec of the lams and wire used in an old Souter or Marinaire, It wouldn't be too difficult for a chinese manufacturer to reproduce something very similar; it's not a complicated process.
Sure transformers vary enormously; they follow the leanings of the designer and it's the deficiencies you're hearing (he said ducking quickly!)

 

[CJ]

True, just wire and steel, and not as tough as getting ten zillion transistors on a wafer that sounds good, but still a lot of fun. It's hard to argue with people on transformers because we do not have any ammunition. If we still do not know what magnetism is, how are we supposed to explain the merits of a vintage Triad or Peerless? So we just sit back in a melancholy defeatist mode and let the engineers watch their Audio Precision printouts with glee while we enjoy our transformers.

 

[Flatpicker]

[quote author="soundguy"]...If you have a patch bay you can save some time by wiring output transformers directly to patch points on the bay and then leaving your box transformerless and listening to the different outputs as you go...[/quote]Good idea and a great post, Dave! BTW, where did you get the beyer? If you said before, I must've missed it.