Monthly Archives: May 2020

UNITRA Tonsil MCU-53 Cardioid Condenser (1970’s/80’s)

History

In the early 1970’s MB Electronic (now known as MBHO) produced the MB C540. This was a high quality battery powered condenser microphone. It boasted an almost flat frequency response from 20Hz to 20kHz with a slight dip at the low end. The MB C540 was modular in construction and had the option of 2 capsules (omni or cardioid).

MB C 540 AdvertMB C 540 Frequency response

In the UK it appeared as the PEERLESS MBC-540.

Reviewed here in Studio Sound May 1977.Review. Peerless MBC 540 - Studio Sound - May 1977

Meanwhile in Communist Era Eastern Europe.

This German design was also manufactured under licence by the Polish state owned electronics company UNITRA Tonsil and marketed as the MCO-30 (omni) and the MCU-31 (cardioid). According to Polish sources, the only difference between the German and Polish versions appears to have been variation in quality control at the Tonsil factory. This lead to some Polish mics reputedly sounding rather better than others.

Around 1980 the design was modified and updated. Whether this was done by MB Electronic or by Tonsil’s own engineers is not clear. (MB licenced a number of different designs to Tonsil but sadly MBHO now have no records relating to this microphone !)…….. Anyhow, the resulting microphone was somewhat shorter in length, the battery powering was changed from 2 x 15v to 1 x 6v and the previously unbalanced output was upgraded to balanced. The WCU-31 and WCO-30 capsules were retained and the frequency response appears pretty much the same. The new model was the UNITRA Tonsil MCU-53 (cardioid) / MCO-52 (omni).  The Tonsil 50 series continued in production through the 1980’s. In the late 80’s a further modification was carried out to provide 48v phantom power. This model was the MC-265.

UNITRA Tonsil MCU-53

UNITRA Tonsil MCU-53UNITRA Tonsil MCU-53 exploded view

A clever modular design. Well constructed and finished in shining nickel plate.

Tonsil WCU-31 Cardioid capsule. Front view

WCU-31 Cardioid capsule.

WCU-31 Cardioid capsule. Rear view.

Unusual 5 pin DIN connection.  (below)

Pins 4&5 in the plug are shorted together to provide a ‘switch’ for the battery. When the cable is plugged in the power is thereby switched on. N.B. This also means that if you accidently leave it connected when not in use you end up with a flat battery!! Arrrgh!

5 Pin DIN socket on Tonsil MCU-53 5 Pin DIN plug Tonsil MCU-53 Tonsil MCU-53 5 pin DIN Plug

Technical Specifications.

Pages from MCO-52/ MCU 53 Owner’s Manual UNITRA Tonsil MCU-53 ManualUNITRA Tonsil MCU-53 Manual P2UNITRA Tonsil MCU-53 Manual P3

In Conclusion.

Being battery powered made the MCU-52 /53 suitable for use with cameras and tape machines which in the 70’s and 80’s often did not provide phantom power. This made it a popular choice for wildlife and location recording.

When there is once again an opportunity to record music I will be interested to see how the MCU-53 compares to the AKG C451E as their frequency responses appear to be somewhat similar. I suspect the Tonsil may have a bit more self-noise but tonally may give the AKG a run for its money. Let’s wait and see…………

Credits.

Many thanks to Adam Wilma for sending me this pristine example of the UNITRA Tonsil MCU-53. Very generous. And thanks to my old mate blues guitarist Keith Thompson for bringing it back from Poland. His March tour was sadly cancelled after only 2 shows as Poland went into COVID-19 lockdown. Luckily for me the second gig was in Adam’s home town of Torun and he kindly dropped the mic off for Keith to bring back before the borders closed!