670 version 3

made in america designed in santa fe


670 version 3

made in america designed in santa fe

A masterpiece

drip is pleased to announce the release of the 670 version 3 .

a beautiful and accurate recreation of the

classic fairchild 670 compressor limiter.

a new state of the art design 

available in pcb set 



fully built : 8000$ usd +shipping

(lead time 6-8 weeks)


main board features

expandable / state of the art 4 layer pcb

.093 thick -internal layers shielded- FR4

straight forward

the drip 670 version 3 is a manufacturing grade



designed in cad - tested in real life





specs and features

specifications and features  : 

original fairchild 670 circuit  - 

original tube regulated high voltage power supply

original AGC - lat/vert MS matrixring , dual mono .

original time constant values.

original signal amplifier

original control amplifier


original EVERYTHING.


the only alterations to the circuit are dual mono dc heater supplies to protect the 1200$ in tubes. and 1200$ in audio transformers .

also providing a hum less low noise sound stage .

a power supply voltage measurement port on the power supply to monitor the critical voltages of the units operation window

via a decade network of 909k resistors  (voltage meter bridge available on request).

high voltage metering and balance metering selectors are achieved through high voltage relays switched by

grayhill mil spec rotary selectors .

cathode balance uses 10 turn precision bourns wire wound potentiometers . 

this is a vast improvement from the original 1 turn cathode balance  pots, achieving a balance of the most stubborn 6386 tubes.

heater supplies for left and right channel are separate (dual mono)  linear type with whisper quiet maglev fans for cooling.

the high voltage regulator heater supply is also dc regulated and separate.

all heaters use high efficiency micrel LDO regulators and schottky diodes .

all with highly filtered input and output rails  and the highest quality components.

the tube bias power supply is same as the original design , however the +/- 10%  bias choke may be substituted

with a high accuracy negative voltage regulator . (protecting the performance and longevity of the 6386 cathode bias)

the control amplifier bias is unregulated like the original to match the line voltage of the HV supply during 

fluctuations in line voltage . 

all signal connections are at the front of the pcb ( no middle of the board connections)

all power connections and audio connections are at the rear  of the pcb .

xlr connections are done via a shielded cable from the main pcb to neutrik xlr sockets .

all front panel controls are pcb mounted  for ease of construction and reliability and safety.

fused heaters and double fused mains (one 5amp fuse in the IEC socket one 4 amp fuse on the front panel 

before the power switch)




tube compliment :


8 - JJ6386      1 - EL34

2 - 12AX7    1 - 5AR4

2- 12BH7A    1  - 5651

4- 6973    1 - EF80 (6084)