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ADL 660
Mono Fairchild Tube Limiter

Sale Price: $14,000

DEMO an ADL 660 TODAY!!
Call 978-744-2001 or email

FEATURES INCLUDE
  • All tube design (no IC's or chips)
  • All parts are designed based on the original Fairchild 660
  • All capacitors and resisters match values based on original Fairchild 660 / 670
  • XLR input / output
  • Handbuilt in the USA
  • Heavy-Duty Chassis
  • Great for analog & digital recording, tracking, as well as live
  • One Year limited warrenty
  • Tubes located in the rear for maximum ventilation
  • 24-VDC Cooling fan
  • Two PCB's
  • 3 U High chassis with swing down door as faceplate
  • ADDED FEATURE: DC threshold is located on front panel allowing for more of a tailored compresssion setting
  • recall sheet
 
SPECIFICATIONS

All audio transformers are designed according to original specifications which has allowed us to not only serve our needs, but also service and repair original 660 and 670 Fairchilds.
+4 input / 600-ohm Load Unit Gain Clockwise :
15.1dB @ +4 Output
Noise -82 with 400-Hz Filter = 89
THD 0.03% @ 100-Hz : 0.189%
IMP 0.100%
Frequency  Response 32-Hz............63-k (± 1db)
Input / Output Impedance 600-ohm
Output Level +4 or +8 VU (+27 dBm clipping point)
Gain 7 db (no limiting)
Attack Time (adjustable) 0.2 milliseconds in Pos-1, 2 and 6
0.4 milliseconds in Pos-3 and 5
0.8 milliseconds in Pos-4
Transformers 4 as per original
Tube Complement -4- 6386
-1- 12AX7A
-1- 12BH7A or 12AU7A
-2- 6973
Main Unit Shipping Weight 25 lbs.
   
  POWER SUPPLY FEATURES
 

ADL has developed a non-tube proprietary discrete design. This new power supply is versatile enough to be used with either the ADL Mono 660, Stereo 670, or the original 670 Fairchild. ADL has started to integrate this new power supply with the original 670 units too.
 
  • Remote Power Supply eliminating any transformer magnetic noise
  • 6 foot umbilical custom cable between power supply and main unit
  • 3 U High chassis
  6 Blue LED Indicators Displaying Low Voltages
 
  • 6386 Heaters 6.3-VDC
  • Remaining Four tube heaters 6.3-VDC, plus meter lamp
  • Ventilation Fans
  • 6386 bias voltage negative 6.2-VDC
  • 6386 Q point voltage negative 19.9-VDC
  • 6973 grid voltage negative 14.6-VDC

Additional High Voltages Include

  • 442-VDC
  • 242-VDC
  • 160-VDC

TRANSFORMERS.......................................2
SHIPPING WEIGHT....................................31 Lb
POWER CONSUMTION.............................47.5 WATTS
120-VAC FUSE............................................2-A S/B 5x20mm
230-VAC FUSE............................................1/2-A S/B 5x20mm

6386 BIAS VOLTAGE NEGATIVE 6.2-VDC
This voltage feeds both cathodes (pin-2, 8) of each half of the 6386, allowing the tube to operate at its' peak performance. As elevtrons befin to gather near the filament, they need a slight push toward the plate and because the grid is slightly more negative then the filament the electrons are pushed away from the grid and towards the plate.

6386 Q POINT VOLTAGE NEGATIVE 19.9-VDC
This voltage connects into the A-26 audio transformer which then feeds both grids (pins-3, 7) of each half of the 6386. Its' purpose is to set the operating or quiescent point. Because this voltage is negative relative to the cathode, it will draw electrons away from the filament and toward the plate which is considered positive in respect to the grid. Every tube has an operating window or region in which the tube operates at its' best performance. According the 6386, a negative voltage of 19.9-VDC will allow the tube to operate at its' peak performance facilitating proper electron flow from the filament to the grid.

6973 GRID VOLTAGE NEGATIVE 14.6-VDC
This voltage connect to the grid (Pin-3). As described before, this voltage sets the operating zone or window allowing the tube to operate at its' peak performance.