Dolby 363 Stereo Processor with two Cat 350 Cards


Out of stock

Email me when in stock


Dolby made a range of two-track noise reduction systems starting with the 360 & 361 in the 1970s, then the 362 and 363. These were found in every pro studio hooked up to two-track mastering machines, copy machines and tape delays. Dolby Spectral Recording (SR) gave a substantial increase in noise reduction over Dolby A and a good analogue machines with SR had a signal-to-noise ratio approaching that of digital recording. The 363 is compatible with two Cat 350 SR cards (supplied), Cat 300 SR / A and Cat 450 Dolby A cards

As a double-ended noise reduction system, Dolby SR encodes the signal and applies reciprocal decoding on playback. With a correctly-aligned tape machine the system is very transparent and gives a significant noise reduction (up to 25 dB), particularly at higher frequencies

A 363 is more compact, and far more convenient, than a pair of 361s. It’s ideal for noise reduction on tape delay machines, for archiving & tape copying work. By adding a pair of Cat 300 or Cat 450 cards it would enable Dolby A and could be used for the Dolby Trick

“I use Dolby SR via a 363 for mastering. On an Otari MTR 12 running at 7.5 ips I have a measured noise floor of -82 dB! In my experience I have never heard any detrimental artifacts generated by SR providing the system is properly aligned level-wise each time (the 363 has clearly readable metering to set this accurately)”

“Just make sure you calibrate the unit correctly when you first install it and thereafter ensure you record standard un-encoded line up tones at the head of your masters followed by some Dolby SR noise to ensure you can calibrate each time during your replay line up”

“I don’t want to say the 363 is over designed, but it is built to withstand a nuclear strike or the possibility of normal day to day operation”

“I like the 363 units and use mine while mixing to my MCI JH-110b all the time. With decent alignment (I favor IEC curve at ref level, 15 ips) the sonics can be great!”

The 363 has four inputs & four outputs on XLR connectors plus multipin connectors for remote control. It's designed to be patched between a console and the tape machine, and the tape machine and the console - hence 4-ins & 4-outs

Inputs & outputs are electronically-balanced on XLR connectors. Power is switchable 110 / 220 Volt AC. Power input is via and standard IEC power connector. UK or Euro Schuko power cable supplied on request

The 363 is normally patched into tape machine feeds & returns and switched from record to replay mode as required. There's a remote socket on the back panel for automatic record / repro switching

It's a deep, heavy 1U rack unit weighing 6.3 Kg. Essentially it's a housing / buffer / switching unit for the NR cards. It has a power supply, dedicated input / output switching section and a slot for two noise reduction card. Inputs & outputs are transformerless

1U rackmount device compatible with standard 19" racks. 220 Volt power via standard IEC socket on the back panel. UK or Euro Schuko power cable supplied on request

Owners manual

Rap Mag SR Review


In excellent condition for a vintage piece of kit. The 363 has some rack rash & case scratches but is in good condition overall. The unit powers up and passes signal but we have not carried out end-to-end testing for encoding & decoding

Vintage gear

All vintage gear will have case scratches and marks. It may also have, or develop, noisy pots and switches. I make my descriptions as accurate as possible and note any existing defects. I test each item before shipping but please understand that vintage gear will not be perfect and adjust your expectations accordingly