u73b 

 
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u73B

the drip design of the classic and out of reach u73b compressor limiter is an amazing feat of layout achitecure and electrical engineering . drip brings you the 1:1 design after a year of work  taking on the challenge to bring this rare bird

back to life, it was drips intention to keep the entire design as accurate as possible , we contacted SOWTER transformers to design us the new 1505E transformer a modern replacement for the T188 1:1 transformer. 

the plate choke and output transformer are also designed by sowter (V72 plate and output)

the u73b is one of the very few all tube feed forward Mu designs with a theoretical ratio of 100:1 . a push pull 3 stage design. (E99F :input amplifier(MU) / E88CC second stage and output amplifier) E80CF (6BL8) / E80CF : control amplifier) 

it is one of the fastest tube compressors on the planet due to its feed forward design.

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the circuit uses two E99F tubes as the audio amplifier input Mu stage and an e88cc as the output amplifier stage.

gain reduction is achieved with the E80cf tube .  5 signal transformers per channel compliment this beauty (input/signal amp interstage/signal amp output/signal amp plate choke/control amplifier output. 

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Feature 3

using the drip pcb you may wire the board as the original  , or add input and output attenuators and a more modern time constant . ( the drip design does not include the input pass filter circuit - of course you can add this simple passive circuit if you wish)