The TFL-280 is an old broadcast limiter manufactured in the 70’s into a 1RU case. It was really intended for set and forget broadcast use, so an unmodified TFL-280 is a pretty unusual and inconvenient beast. However the brutal, dirty, and harsh character of this limiter makes it a very creative tool to have around, and well worth the effort of fixing it up, if that’s your thing.
I/O on this unit is originally done via a terminal block with screw heads. Yikes! I personally use TRS tails, which is probably the simplest solution although not the prettiest nor most reliable. It has a balanced in, out, and a stereo link facility. Controls are much like an 1176 in that they consist of an input level, output, release, but unfortunately no attack controls. Originally these pots are controlled via a screw set into a pot, intentionally making it difficult to change settings however mine have been replaced with brushed metal pots which compliment the look of the unit very well!
Typically found on the back are emphasis and de-emphasis toggle switches, which are essentially shelving EQ’s placed in the audio path pre and post compression, respectively. They can either be used as intended – both on or both off to change the compressors behaviour – or used to colour the sound, which can be very interesting. I’ve had these switches moved to the front, making them much easier to use.
And just to look extra funky and vintage the TFL-280s come with convex gain reduction meters. Cool!
Inside we’re talking Jensen 123s line transformers for input and UTC transformers for output.
All in all this unit can actually sound pretty nice if you want it to - you just have to drive it gently. But with a fixed attack you’re stuck with what it does to the transient and that will very obviously either work or suck. Alternatively driving this thing hard starts getting pretty distorted and intense around 10dB gain reduction. Which makes it a fantastic parallel compressor for bass, and my secret weapon.
It is possible to get a variable attack speed circuit installed, though I’m not savvy enough to do it myself, and have enjoyed the unit enough in it’s current state not to worry about modding it further. In fact, I’ve used it on almost every mix since I bought it.