Transformers for vintage microphones
Many older ribbon microphones (and some dynamics too) were designed for a 30 ohm or 50 ohm input. However, most modern mics have a higher impedance and consequently most studio preamps are designed to give best performance with microphones of 200 to 600 ohms. Other ribbon mics were made for use with PA systems, and have high impedance output. So, if you have an old microphone and a modern recording system, you may not be getting the best out of your signal chain. Or a mic may simply have a faulty transformer that needs repairing or replacing.
Transformers for modern microphones
The last decade has seen a revival in the popularity of ribbon microphones, with many budget models now available, often made in China. These are made to a price point, and inevitably some components – the transformer in particular – are not of the highest quality. Replacing the ribbon and upgrading the transformer can greatly improve the sound quality and noise performance.
We have several transformer solutions
1. External matching transformer
The first option is to use an external impedance matching transformer. The advantage of this is that it leaves the vintage microphone intact, and can be used with dual element mics such as the STC4033 and Altec / Western ‘birdcage’ microphones. It is also a good solution for studios with a collection of low impedance ribbon mics, but who only use one or two at a time. These may also be used with dynamic microphones. Click here for more information about our transformer boxes.
2. New transformers
A second approach is to replace the internal transformer with a new one. This is useful for modern budget microphones where the original transformer has been made with cost, rather than performance in mind, and for microphones with vintage value, where the transformer can be swapped back to the original at a later date if required.
Our own transformers come in two flavours – vintage and modern. Both are made here in York from components sourced in the EU, and are custom wound for each microphone. Both use laminated metal cores.
Our R series transformers have been developed as replacements for vintage microphones, and are inspired by the hundreds of classic ribbon mics that we have repaired over the years. They have a higher iron content than the X series, and use traditional materials and techniques to give a rounded, classic tone. We also have specialist transformers for Reslo, Cadenza, Beyer, and B&O microphones.
The X-series transformers use more modern materials than the R series, and have a higher nickel content in the laminations. This gives more bottom end detail and an extended top response.
On request, we can also supply and fit transformers by other manufacturers, including SAMAR, Sowter, Lundahl and Cinemag.
3. Transformer re-winds and repairs
A third option is to replace the secondary winding of the mic output transformer with one of the desired impedance. This can be done for many (but not all) microphones, depending on the construction of the transformer. We will normally keep or copy the original primary winding, and re-use the original laminations. This retains the original sonic character of the mic, whilst optimising the output for connection to your studio equipment.