The finest tube compressor in history

Beloved by some of the greatest engineers and producers in the industry, the Stamchild has become a modern classic. While designing the SA-670 we had two main objectives in mind: first and foremost, the audio path, transformers and tone had to remain identical to the original units, and secondly it had to be affordable.

THE CIRCUIT

With the aid of premium transformers reproductions made by AMI in the US and Brian Sowter in the UK and the use of sixteen matched NOS 6BA6 tubes per channel as well as two 12AU7 tube in the control amplifier, we have managed to make this 18 tube monster virtually indistinguishable to the original.

In order to reduce the cost of manufacturing we have made some modern implementations which do not affect the audio path. We have changed the tube based power supply to a solid state one, which has no bearing on the sound. We also changed the side chain to a hybrid setup maintaining the original tube character of the control amplifier while maintaining the same DC Threshold setting (knee and ratio) as an original and untouched vintage Fairchild 670.

Just like the original unit the Stamchild-670 incorporates two independent limiters in one single unit (AGC Filter), which can limit
either two independent signals, such as the Left and Right channels of a stereo signal, or the vertical and lateral components of the same (Mid/Side). The latter is accomplished by first bringing the two stereo channels through a matrixing network, dividing than into their vertical and lateral components, limiting them independently, and recombining them through a second matrixing network into Left and right Channels.

THE IRON

The Stamchild 670 uses a total of eight custom made transformers. The input transformers are designed and made by AMI in the US and are identical replicas of the UTC A-26 transformers which were used on the input on the Fairchild 670. These transformers have a beautiful low mid saturation which gives each unit a hefty low end and a gentle roll off on the top end making everything sound smoother while retaining clarity.

The output transformers are designed and made by Sowter in the UK and are identical sounding replicas of the HS-52.  The SA-670 also uses two custom made auto-formers and two giant toroidal transformers to power the unit with both 115V and 230V voltages available.

THE TUBES

We have sourced a large stock of 6BA6 tubes which will allow us to service this unit for a lifetime. Each Stamchild 670 comes with eighteen tubes, sixteen NOS 6BA6’s that allow for the same compression behavior as the extinct 6368 when used in pairs and two 12AU7 tubes on the control amp.

NEW FEATURES

We have taken the liberty to add additional features to accomplish modern studio requirements and provide a more exciting experience in your mix and mastering sessions, such as:

AGC Filter

Four different positions, allowing the user to perform a simple multiband compression:
-OFF (full band sidechain)
-90 Hz High Pass Filter
-180 Hz High pass Filter
-MID RANGE (180 Hz HPF and 3Khz LPF).

Master Output and Dry/Wet

A stereo master output attenuator will allow you to push the tube stage harder, enjoying a more colored sound by adding a higher degree of harmonics to the audio material without clipping the next input stage (A/D interface). This additional feature allows the user to perform instant parallel compression of audio material,
by mixing the dry and wet signal in 10% steps.

100% satisfaction guarantee – if you don’t love your StamChild SA-670 MK2, we’ll refund you

If you’ve used an original Fairchild before, we’re extremely confident the StamChild SA-670 will put a big smile on your face every time you use it. However if you’ve never touched the original before, as gear-lovers ourselves, we understand that the only way to really know if this compressor is for you, is to put it through its paces. That’s why the StamChild SA-670 comes with a 30 day money back guarantee.

This allows you to get it into your rack and see how it impacts your recordings. If you love it (and we think you will!), great…keep the unit and create amazing music with it. If not, no problems. Just send it back to us and we’ll fully refund your purchase.

Fully Stepped Mastering Version is available per request.