We are selling a stereoset of legendary vintage german tube compressors. Two TAB U73b tube compressors / limiters in a beautiful lunchbox. Here comes your oportunity to buy a real legend. A racked stereopair of the famous vintage german tube compressors TAB U73b. The U73 and U73b dynamic modules were developped by the german IRT and the NDWR in the late 1950´s. They are the successor of the Rhode & Schwarz U23 tube compressors and the predecessor of the Neumann U473 and U473A dynamic modules. The U73b makes the claim to be the best European tube compressor ever built, being the German equivalent to the American Fairchild 660/670 compressor/limiter.
The limiters were used as the last stage in the signal path of many european radio studios. Due to their high price only few studios such as Abbey Roads and E.M.I could afford to own them. The U73b´s are the equivalent to the Fairchild 660From the 1960´s up to the the 1980´s 90% of all vinyl masters in europe were processed with the U73´s later followed by the Neumanns in the 1990´s.
The stereoset offered here is in a very good technically condition. The modules are serviced and racked. They can be linked to stereo and work as good as they did when they were new.
The old caps are still installed, but we recommend and offer a FREE recapping service for the comps. You can check the optical condition also of the inside on the pictures attached. It is nearly impossible to find a stereoset of these modules.
History:
Looking for a solution that was fully capable of handling the full frequency response of FM radio broadcasts, the IRT and NDWR developed the U73 over a 3 year period. It was released in the early 1960´s. The U73 shared significant circuit features with the V76 and used many of the same components as the famous preamp.The IRT/NDWR licenced the design to tonographie Aparatebau Wuppertal (TAB) who produced it for almost 30 years until 1980. It was the last tube module made in the Telefunken/IRT gray series.The V72, V76, etc. were discontinued long before. TAB ended up making 5 different versions of the U73 compressor for Telefunken. The U73, U73a, U73b, U73bt, and the U73ts. They shared similar design aspects but each had it's own characteristics based on the build or the final intended usage. The U73 was heavily used as a mastering compressor in disk cutting laths. Over 90% of all records released from 1960 to 1980 were mastered with a pair of U73´s. Later from the 1970´s until the end of the viny era the Neumann U473 took it´s place.
Design:
The U73 is a three stage push/push variable mu design with a theoretical compression ratio of 100 to 1. It is the fastest tube compressor ever built due to its forward triggered side chain. It has no input, threshold, attack or release controls, but we can add these features with a slight modification when we rack your modules. When the U73 is in Limiter-Mode, level below +6dB will not be affected. All levels from +6dB up to +22dB will be limited to a level of +6 dB to +7.5dB. In the Compressor-Mode the limiter will still be active, but in addition to that all levels below -14dB will be raised. The higher the input level gets, the lower the amplification gets. This works up to the level of +6 dB were the amplification is 0 dB.
Sound:
The U73 is the ideal supplement to the V72, V76, V77, V78 tube amplifiers, but it also works great within other setups. Since it does not have threshold or input gain control pots, you will need an ampfifier before the U73 to make it work as a limiter. Driving the V72 - V78 hot and running it into the U73 will give you the ultimate vintage tube sound. When it comes to tube sound. There´s NOTHING better than this combo!
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