Altec valve compressors at EMI.

[Dick.1]

Having a circuit makes things so much easier!  

Try reducing the value of C4 and see what happens ...

That's what I've been suggesting to the owner (as stated in my post no1)

Currently using a 330 cap with a 1m r  in parallel has reduced the speed down to around 16ms but there is a slight low frequency rumble on the output that is interfering slightly with the music.

Using a 470 cap halves the speed to 25ms & works very well, but (as usual) my friend wants to get the speed down as far as possible.

The EMI version of this as used in Abbey Road studios to record the Beatles etc.....(RS124) uses what looks like a switchable resistive attenuator ( 6 way) with up to 6m loading available

The problem I have is that nobody seems to agree on what is the genuine cct mods used by the EMI guys................ 
People that have rebuilt these remain tight lipped about this cct 
There is a commercial operation that sells replicas understandably they do not release any details unless you buy from them (about £2,000)

As you say Terry, things would look a lot clearer if the cct diagram was available of this (now legendary) compressor


Dick.