Drip 660

DRIP Electronics is pleased to announce the release of the Fairchild 660 PCB. Our design is not a cheap imitation or an approximation of the Fairchild circuit: THIS IS THE FAIRCHILD CIRCUIT.

DRIP’s design is true to the original Fairchild 660/670 schematics.Nothing has been altered or added. We have incorporated all ten transformers and all twelve vacuum tubes (including four 6386 tubes).

Design purity. Pure DRIP.

Combining two PCBS will produce the Fairchild 670 stereo limiter. One Power supply and set of Sowter power transformers and chokes can power two PCBS. One of the unique features of the DRIP 660 PCB is that not only does it contain all the elements of
the 660 design, but in addition contains all the options of the 670 circuit. The PCB allows for seamless integration of Sowter's Fairchild line of audio transformers.

As with all DRIP Designs, the audio transformers are mounted on the PCB and integrated into the design.

Space is everything ... Considering the design calls for up to 440 volts, the DRIP PCB has up to three times the IPC Standards recommended track spacing. There are no zigzags or overlapping traces. DRIP designs forbid routing over and under.

Symmetry is the key.
The circuit is shielded by using a four layer PCB. ON the top and bottom of the audio circuit is a ground plane, essentially shielding the entire design from external noise and EMI. The bottom layer is used for all high voltage circuitry. This intelligent design is a proven method for further reducing noise in the audio circuit.

No expense has been spared in the design and manufacture of the PCB. DRIP designs only quality products for its vast number of clients.

Measuring 17x14 inches on a super thick FR4 substrate (.093" thick), each layer of the PCB is 2.5 oz. of copper - A custom manufacturing request for a very important design. The PCB has been designed using highly advanced techniques in high voltage audio design. DRIP has incorporated all the skill that brought you the tried and true DRIP line of audio products. The design is very quiet and more direct in wiring then the original 660/670.

For 670 builders, the AGC (automatic gain control) circuit will be available in the coming weeks as a separate 12 deck rotary switch and PCB. However, the AGC was designed primarily for record cutting , and most users will use the 'left-right' setting (meaning dual mono as used in the original Fairchild 670). The power supply is true to the original design. No chips all tubes.

Since the foundation of the Fairchild design is the power supply,
great care has been taken to preserve its integrity. A tube regulated 240v and a high voltage 440v supply line give the 660
a deep punch to your audio signal. Sprague atoms have been added for additional performance and filtering. This PCB provides the options to build a dream machine - all resistor footprints can accommodate up to five-watt metal film resistors. The capacitor footprints can also accommodate high end audiophile components such as Mundorf or Jensen.

The downloadable instruction manual contains a substantial amount of pages of information about the 660 and we have an upcoming release of video tutorials. All the guesswork will be taken out of the equation. Besides hooking up the five power transformers (six if going 670 ) the build is no more complicated than the Opto series PCBs or the DRIP 175.

This is an advanced build.

ABOUT THE PRICE: DRIP prides itself on presenting products which reflect the complexity of the design and the highest standards in manufacturing. Every one of these PCBs cost hundreds of dollars in raw costs just to print. THEREFORE, due to the extremely high cost of manufacturing this design, each batch is based on a three week order cycle and orders will be processed through Paypal.

Because of difficulties we have encountered with International Shipping, all PCBs are shipped express/global express (signature required). FedX and UPS orders will require an additional amount.

Please enjoy another exciting release from the DRIP family of products.

Price: $300.00

Purchase the 660 at the Drip Store
660 Photo Gallery

Specifications

• pcb is 17x14 inches
• .093" FR4
• PLATED THROUGH HOLE
• 4 LAYER DESIGN 2.5 OZ COPPER EACH LAYER

• 1 12BH7A
• 1 12AX7A
• 2 6973
• 4 6386
• 1 GZ34 (5YGT3)
• 1 EL34
• 1 5651
• 1 6084

• 1 SOWTER 8344E SIGNAL AMP OUTPUT
• 1 SOWTER 8345E CONTROL AMP INPUT
• 1 SOWTER 8346E SIGNAL AMP INPUT
• 1 SOWTER 9643S CONTROL AMP OUTPUT
• 1 SOWTER 0474S MAIN POWER TRANSFORMER
• 1 SOWTER 0475S BIAS POWER
• 1 SOWTER 0476S POWER TUBE HEATER 6.3V
• 1 SOWTER 1136S BIAS CHOKE
• 1 SOWTER CA15S HT CHOKE

1. Complete absence of audible thumps normally associated with other limiter designs and a complete absence of distortion or noise normally associated with conventional limiters.

2. Extremely fast attack time, the FAIRCHILD 660 or 670 can produce full limiting in the first 5.000th of a second.

3. Variable release time. The FAIRCHILD 660 or 670 allow a variable from .3 of a second to 25 seconds, conveniently available on the front panel in the form of a 6-position switch.

4. Can be used as a limiter or a compressor depending on the program material and personal preference.

• INPUT IMPEDANCE: 600 ohms
• OUTPUT IMPEDANCE: 600 ohms
• RANGE OF INPUT LEVEL: 0 dbm to +16 dbm. (-4 dbm to +16 dbm) (model 660) OUTPUT LEVEL: +4 or +8 dbm (+27 dbm clipping point)
• GAIN: 7db
• FREQUENCY RESPONSE: 20 cycles to 15 kc +/- 1db.
• SEPARATION: A-B position: 60 db vertical-lateral position: 40 db (does not apply to 660)
• NOISE LEVEL: 70db below +4 dbm
• LIMITING NOISES: Below audibility
• INTERMODULATION OR HARMONIC DISTORTION: Less than 1% at any level up to + 18 dbm output (no limiting) Less than 1% at db limiting +12dbm output
• ATTACK TIME: .2 milliseconds on positions 1, 2 and 6 .4 milliseconds on positions 3,4 and 5 (adjustable)
• RELEASE TIME: Position 1: .3 sec Position 2: .8 seconds Position 3: 2 seconds Position 4: 5 seconds Position 5: Automatic function of program material: 2 seconds for individual peaks. 10 seconds for multiple peaks. 25 seconds for consistently high program level.
• COMPRESSION RATIO: A function of the amount of limiting as well as setting of the two threshold controls which can be set to operate at ratios from 1:2 to 1:30
• POWER REQUIREMENTS: 115 volts, 50-60 cycles AC, 3 amps.
• STABILITY: Unit maintains stability of gain, gain reduction and balance over the range of line voltage fluctuations from 100 to 127 volts.