Ssl 4000 Bus Compressor Clone

1/6/2022by admin
Almost every cloner that makes an SSL 4000 style bus compressor seems to replicate the same 'true balanced' or 'electronically balanced' output stage which has separate IC op amps differentially driving the hot and cold legs of the output. This has some pros (+6 dB headroom) and cons (see below). In my opinion the cons vastly outweighs the pros, and it is what trips up most people. The recommended way to connect a transformer or cross-coupled balanced output to an unbalanced input is to ground the cold leg on the balanced side. On an XLR that would be pin 3. On a TRS cable that would be the Ring.
  1. Ssl 4000 Bus Compressor Clone Kit
  2. Ssl 4000 Bus Compressor Clone Trooper
Ssl

Ssl 4000 Bus Compressor Clone Kit

However, when you do that with what we call a 'true balanced' output stage (the one everyone keeps putting in the SSL bus compressor clones) you run into two problems:
  • The SA-4000 Stereo Buss Compressor is a recreation of the bus compressor found in the center section of the legendary SSL 4000 G Series Console.
  • SSL 4000 Buss Compressor Clone This is a very interesting project I first learned about from the Prodigy-Pro forum. As luck would have it, this project came along about the time I was beginning work on my own version of the SSL 4000 Buss Compressor.

Prized by top engineers for its ability to 'glue together' tracks, the SL 4000 G master buss center compressor is ideal for taming piano dynamics or adding punch to drums and percussion. SSL E-Channel The SSL E-Channel delivers the incomparable sound of the Solid State Logic 4000-series console's all-discrete design and its Class A, VCA chip.

Ssl 4000 Bus Compressor Clone Trooper

  1. You will experience a 6 dB level drop.
  2. You will short the output of the amplifer driving the cold leg. Ampliers don't like to be shorted. This will produce distortion if not harm the op amp.
For this type of output stage you will need to leave pin 3 floating. Then you will merely get a 6 dB level drop. This is no big deal - just turn up your make-up gain on the compressor to compensate.
If you are unsure what kind of output stage your gear has, you need to contact that manufacturer and ask. There are basically four types:
  1. Impedance Balanced - The hot leg is driven and the cold leg simply has a resistor to ground. It has no issue with balanced or unbalanced connections.
  2. Transformer Balanced - I hope everyone knows what this means.
  3. Cross-Coupled Output - This is essentially what a THAT 1646 chip is. It presents a floating output like a transformer and has no issue with balanced or unbalanced connections.
  4. Electronically Balanced (True Balanced) - This is what was described above. We dislike this output stage for the reasons given above.
Ssl 4000 Bus Compressor CloneSsl 4000 for sale

We recommend the BUSS COMPRESSOR by our friends at AudioScape Engineering Co. Ask them before ordering about setting up the compressor to interface properly with the Silver Bullet's inserts.

Almost every cloner that makes an SSL 4000 style bus compressor seems to replicate the same 'true balanced' or 'electronically balanced' output stage which has separate IC op amps differentially driving the hot and cold legs of the output. This has some pros (+6 dB headroom) and cons (see below). In my opinion the cons vastly outweighs the pros, and it is what trips up most people. The recommended way to connect a transformer or cross-coupled balanced output to an unbalanced input is to ground the cold leg on the balanced side. On an XLR that would be pin 3. On a TRS cable that would be the Ring.
However, when you do that with what we call a 'true balanced' output stage (the one everyone keeps putting in the SSL bus compressor clones) you run into two problems:
Ssl
  1. You will experience a 6 dB level drop.
  2. You will short the output of the amplifer driving the cold leg. Ampliers don't like to be shorted. This will produce distortion if not harm the op amp.
For this type of output stage you will need to leave pin 3 floating. Then you will merely get a 6 dB level drop. This is no big deal - just turn up your make-up gain on the compressor to compensate.
Ssl 4000 bus compressor clone kit
If you are unsure what kind of output stage your gear has, you need to contact that manufacturer and ask. There are basically four types:
  1. Impedance Balanced - The hot leg is driven and the cold leg simply has a resistor to ground. It has no issue with balanced or unbalanced connections.
  2. Transformer Balanced - I hope everyone knows what this means.
  3. Cross-Coupled Output - This is essentially what a THAT 1646 chip is. It presents a floating output like a transformer and has no issue with balanced or unbalanced connections.
  4. Electronically Balanced (True Balanced) - This is what was described above. We dislike this output stage for the reasons given above.

We recommend the BUSS COMPRESSOR by our friends at AudioScape Engineering Co. Ask them before ordering about setting up the compressor to interface properly with the Silver Bullet's inserts.

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