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As many of you know, original Fairchild compressors have been out of production since the early 70's. They are rare in number and command very high prices. Refurbishing a unit and bringing it up to current production standards can be very expensive and may not necessarily bring a unit back to new sonic condition. Perhaps it's better to buy new?


Analoguetube builds and manufacture's classic tube technology of the 1950's and 60's using traditional electronic methods with parts that are sourced commercially and that are commonly available.


The AT-1 and AT-101 are beautiful natural sounding limiters that use the original circuits from the legendary Fairchild 660 and 670 limiters.


They are all built using original parts that include the transformers, controls and the new generation 6386LGP triodes developed from the original tube types.


The unique features of these gain crushing compressors allow all types of instruments and sound to sit up front sounding fatter and bigger in the mix adding depth, dimension and clarity, gluing the image together for all types of program making these natural sounding compressors indispensible tools for the music studio.


The AT-1 and AT-101 limiters are superior products using all original tubes and parts with long-lasting, close tolerance, non inductive modern components for the modern world.


These units have been built by hand as close to the original as possible using standard high quality components.


The standard features with the mono units are;

1/ Switched bypass

2/ Stereo linking between units (calibrated)

3/ 'Key' insert switching (fully transformer balanced)

4/ Variable AC threshold

(Optional Stepped AC threshold with 21 steps @ 1%/div available on request)


Optional features for the stereo AT-101 units are;

1/ Bypass switching

2/ Stepped AC threshold (21 steps @ 1%/div)

3/ Lat/Vert switching (mid-side processing)

4/ Stereo link standard


ALL units are fully transformer balanced throughout including the 'key' insert on the AT-1's.

AT-1 Manual

AT-101 Manual

AT-1 Mono Limiters
AT-1 Mono Limiters

AT-1 Mono Limiters Matched Pair (stereo linked)

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Studio B Metropolis
Studio B Metropolis

Analoguetube AT-101 and Fairchild 670 Compressors

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Anodised Analoguetube AT-101 and Fairchild 670 Compressors

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AT-1 Mono Limiters
AT-1 Mono Limiters

AT-1 Mono Limiters Matched Pair (stereo linked)

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So, whats it all about?


There are some historical and technical differences between both models they are; Tone, Presence and Gain - which is in keeping with both the original [660 and 670] models. From the perspective of the  AT-1/660 mono unit, the signal flow around the unit compares with the stereo AT-101/670 in terms of functionality - both are a feed-back limiters - however they are electrically different from each other specifically they have different tubes for the side chain (6L6's) and different tubes and tube power supply (6BL7) when compared to the AT-101/670 stereo units.


Whilst the VCA (6386 tubes) and time constants remain the same for both models the side chain is slightly different, offering different transformers and control output tubes. The design changes in the AT-1/660 models result in small tonal differences when compared to the AT-101/670 offering more gain and more 'presence' in the mids. Interestingly when the mono units are 'driven' they behave a little like the AT-101/670 gently dipping out the 60hz - 5khz range when pushed. 


Where the AT-1's are used together the side chains can be connected with both units 'linked' or run as completely separate units! Multiple AT-1 units can also be linked together.The AT-1's and AT-101's offer different flexibility in the case of the mono units this is having 2 completely separate units and all that that brings with separate power supplies, increased stereo separation. Additional functions include a separate transformer input 'key' insert for de-essing.


The basic difference between the 2 models are tone and functionality with the AT-1's offering more in the mids than the AT-101/670. The depth and dimension aspects often associated with the stereo units are to do with the Mids being progressively dipped down between 60hz - 5khz when 'driven' and compressed. The mids are often then eq'd back in at the board and brought 'forward' (in level) in the mix - this is sometimes perceived as the 'Depth'. The image dimension and separation aspects relate to the input and output transformers used in the AT-101 or when two AT-1's used.


The Mission:


Our mission has always been to build life back into products that have for many years been unavailable. With a unique emphasis on manufacturing that focuses workmanship, attention to detail and an open ended commitment to customer satisfaction we believe that once you own Analoguetube products you own them for life.


                                                                                      Simon Saywood - CEO Analoguetube Ltd


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