This article originally appeared in Tape Op Magazine.
Technical editing by Scott Hampton
A transformer is a device that transfers electrical energy from one circuit to another via inductively coupled conductors – coils of insulated wire wound (most often) around a ferromagnetic core. Transformers are useful in audio recording, as they can block DC voltage and facilitate electrical isolation between gear, but they also shape the sound of signals sent through them by introducing subtle, and often very desirable “coloration”. This may be a result of any combination of frequency response, time response, distortion, or a number other factors for a particular transformer. These effects can be especially attractive when working in the digital realm, where sounds can be perceived as too “cold” or “digital”.
With all the talk of the sound of transformers, which reside in different pieces of audio gear, why not skip all the electronics and strap bare transformers into the audio path directly? The first time I heard this done was at a mastering session with Nick Blagona in Toronto, when he ran a pretty crispy sounding record through a pair of vintage Marinar transformers that he had lifted from a Neve module. The sound was just right for this record – fat lows, punchy mids and a silky top. I personally hadn’t had a chance to do much with this idea until I recently pillaged my repair guy’s stock bins, and now I’m hooked on trying all kinds of transformers in all kinds of situations.
What you’ll need are 600 ohm to 600 ohm “matching” transformers. These will generally work properly with the gear in our racks. Be careful of center tapped transformers (center tap to ground), If these are exposed to +48 volts (from phantom power) in your system they could easily be damaged. Simply wire your transformers up to cables that work with your gear or patchbay and you can insert them anywhere in your line-level signal path.
I’ve now tried transformers on all kinds of sources, and have fallen in love with many of the sounds I’m getting. My favorites so far have been a pair of vintage Triad HS-66s, as they add a mid-range thickness to the signal that really warms things up without obscuring the lows or the highs. On a full mix, they add a heft and three-dimensional quality to the sound that, while certainly not achieving the full effect, leans in the direction of a vintage console. On individual instruments they have a fattening affect that’s especially cool on kick drum and bass guitar. Pushing the signal can drive the transformer into distortion – sometimes a desirable lo-fi sound – though the need for an attenuator crops up pretty quickly. In one case I was tracking male/female duet vocals for the Brooklyn band The Loom, and found that the female singer had a strong midrange warmth that made the male voice sound a little thin in that area. By patching in one of the Triads after the compressor in his vocal chain, his sound warmed up just enough to match hers beautifully. Without disrupting the flow of the session, the transformer gave me just that little bit of harmonic complexity that I needed. It was like stirring a little more flour into the gravy, thickening to taste.
Another interesting pair of transformers were pulled from some odd quad encoder that the Japanese company Sansui was trying to develop in the ‘70s. As they were attempting to impress the pro audio market, they used some serious matching transformers. These add a harmonic richness to the midrange that can only be described as warm and fuzzy, and they also round off the highs well enough to function almost as a de-esser on certain vocals tracks. I wasn’t able to use them with any success on a mix, but on individual tracks they are able to add a strangely satisfying vibe I just couldn’t get with any other gear.
A UTC transformer that NYC engineer Matthew Agoglia liberated from a vintage compressor made a female vocal go from rich dark chocolate to three-dimensional licorice, adding a harmonic complexity that gave each syllable its own distinct vibe – way more interesting than it had been before. The same UTC on electric bass added a weight that seemed to get the signal out of the speakers and into the room, and that’s a big deal for me when working on my Pro Tools system.
With pairs of matching transformers slowly making their way to my studio, I’m beginning to see the possibility of putting them all in a (shielded) box, wiring them to DB-25 connectors and having them ready to be inserted between my converters and my Dangerous Audio summing box. Buying them in pairs allows me to send stereo stems out through matched left/right pairs, or to run full mixes through them. The cool thing about having multiple pairs is that you can have any number of different flavors on hand, rather than just multiples of the same sound as you would with a console. Then again, there is something to be said for the unifying effect of many of the same transformers. Experiment and see what works for you.
There are all kinds of transformers available, from vintage units by UTC, Triad, Marinar, CineMag and St Ives to brand new transformers from Carnhill, Jensen, CineMag, Lundhal, Sowter and others. While most of these companies are set up to supply gear manufacturers, I’ve found they’re all very approachable and willing to help a guy like me buy a pair. Most quality 600 ohm to 600 ohm transformers hover just above the $100 mark, so it’s a relatively inexpensive way to have some extra audio processing at hand. I highly recommend that anyone who is curious about this to try it out, and if you find some cool, obscure transformers with a vibe, do drop a line and let us know!
A Simple Transformer Explanation
A signal goes into one side of the transformer (usually the side driven is referred to as the primary), and the voltage that results on the output (secondary) is the input multiplied by the turns ratio (neglecting internal losses). The impedance ratio is the square of the turns ratio. Example: a 1:10 step-up transformer on a mic pre input would have a 1:100 impedance ratio. Meaning the voltage gain is x10, at a cost of increasing the output impedance by x100. A DI box is an example of going the other way, stepping the voltage down, to reduce the driving impedance. The lower the impedance a signal is being driven with, the less susceptible it is to noise. -SH
$100.00 apiece for a matching transformer is not “relatively inexpensive” as you curiously wrote. Considering that a good number of the older american made ones could regularly be had at hamfests and swapmeets for 10.00 to 20.00 apiece not too long ago, I would say unequivocally that 100.00 is a very inflated price and I do wonder if you as a professional writer realize that it’s articles like this that contribute directly to inflated market prices. And for what reason? The uses you describe seem somewhat capricious and quite indulgent. I’ve been out of the recording field for a while but back in the early 80’s when I was doing service calls for several small studios in the midwest, people were pulling transformers out of the consoles and tape machines because they didn’t want the bandwidth restrictions and distortions the transformers created. They were seen as a limitation and I think that in most cases the recordings sounded much cleaner without them. Their uses for isolation, hum prevention, and impedance matching though are invaluable and I for one hate to see the day when a good line matcher can’t be had for a reasonable price because of some silly fad. Pardon me for being an old crank but perhaps you should steer your readers towards a more balanced approach to getting a good sounding recording. A single pair of matching transformers isn’t going to make a poor recording sound like a great recording. There are no magic fixes in the methods you describe, but from the recent transformer prices I’ve seen on ebay people are sure behaving as if there were.
Hi Allen, great article in Tape op
I will definetely be trying this out
Its kinda hard to find matching transformers here in the UK
I came across this
w6nbc.com/articles/EE0576transformers.pdf
and wondered if I could use some power transformers
If the primary and secondary had the same voltage, wouldnt this be 1:1 ratio?
So if the voltage and amperage was calculation resulted in 600ohms, would that work?
Im not really versed in electronics, so Im trying to piece this stuff together
Thanks
Paul
Ebay is a great way to go!
Paul, it’s my understanding that using power transformers isn’t a great idea when dealing with line level signals. However, I’ve never tried it and can’t really comment from experience. My gut tells me that you’re going to really want to try line level devices. Try eBay.
Hi Mike – thanks for taking the time to write in.
Yeah, we were pretty aware of how the article would drive up the prices of transformers on eBay and such. Lots of information affects markets. I’m not sure my little article would be the real reason that’s happening – there’s a whole culture of reverence for vintage audio gear out there, and transformers have been mentioned in more pro audio gear ads than anywhere else in the past ten years. If you really want to know who the ones driving up the costs of the transformers are, it’s the ones selling them in their gear, IMHO. They’ve done the most to create the fetish.
As for $100.00 being relatively inexpensive, I’m meaning relative to buying a whole piece of pro audio gear. Why buy a Neve channel when the transformer can give you some of that vibe along with the instant recall of your DAW. That was more the angle I was taking on “relative.”
I think that the reason people were taking transformers out of gear in the 80s and they’re putting it back in in 2010 is a two-sided phenomenon.
One side is cultural. The 80s were a time when cleaning up a recording and increasing bandwidth and headroom were really popular because people were making records that called for that sound. Those 80s recordings sound like ice compared to much of what came before it. Many people now – myself included – are interested in using the distortion characteristics of less-than-clean analog gear to great the sound of today’s records. Times change and so do preferences for sound and the recording techniques that achieve those sounds.
On the other side is technology. In the early 80s everyone was still recording to and from tape, picking up all kinds of harmonic distortion from that medium and from the amps in the machines – which usually had transformers. Today, most of us are using DAWs, and the inherent sound of tape and tape machines is missing from the equation. Transformers can help to re-introduce some of the harmonic distortion that we’re all missing these days, so the idea of using them is partially in response to the medium we’re dealing with. You also have to appreciate that mixing “in the box” means that for many the console is gone, and perhaps all that’s there is a summing mixer. My summing mixer doesn’t have transformers, so having a handful on hand is a very cool – and relatively inexpensive – way for me to pick up some of the 3D qualities I have yet to achieve without them in my current system.
What you call a “silly fad” may be no less silly than pulling out all those transformers from those consoles in the 80s. Hell, I’d call that sheer idiocy from today’s standards when a transformer balanced console can pull in clients. My sense is that your inclination to condem using transformers as per my article as “capricious” and “indulgent” is a bit out of step with how much many of us working in the field today are struggling to find ways to bring the subtle harmonic characteristics – or colors – of transformer based equipment into out recordings. Just look at the number of plugins out there that attempt to do the very same thing.
What was one man’s trash in the 80s is another man’s treasure in 2010.
Hey Allen,
I’m curious if there is a difference from the transformers you are using in this article and say for example, the Jensen transformers in a Jensen IsoMAX 1:1 output isolation model?
Great question, and I’ve kind of peeked at that Isomax a number of times thinking “hmmmmm…..maybe that’d be a great thing to get.” They offer it with 600 to 600 transformers, so yes it would work. By reputation and from my experience, Jensen transformers are excellent. They are not going to be as colored as some other transformers and they tend to have more headroom than some of the vintage stuff, like Triads and UTCs. But, transformers and transformers, and they will get you a certain amount of harmonic distortion (THD), as well as isolating your signals and reducing interference that can cause distortion in digital systems (a topic for a new piece I think I’ll write to follow up this article). So, in short, yes, that Jensen rig would work.
Hello folks
I bought a pair of Neve VT 24499 Toroidal transformers and was wondering how I would go wiring these up.
They have 5 wires:
Brown
Red
Black (Thin Wire)
Orange
Yellow
Has anyone used these before? Or know how to wire them?
Spanks
Salvador
Hey Salvador. I wish I knew more about all the different transformers out there, but unfortunately I can’t really guide you here. I’d reach out to a reliable tech who knows Neve stuff to first determine if those are 600ohm to 600ohm line-level transformers and second how to wire them up if they are. Good luck and let me know how it all comes together.