Berlant Concertone 20/20

The Berlant Concertone 20/20 (also known as Concertone 20/20 Series or Berlant 20/20) is a professional-grade open-reel (reel-to-reel) tape recorder produced by Berlant Associates (later under Concertone branding) in Los Angeles, California. Manufactured primarily in the mid-1950s (circa 1954–1956), it was a broadcast/studio-oriented mono recorder designed for high reliability, timing accuracy, and professional performance, competing with early Ampex models.

It consisted of two main sections: the TWD (Tape Drive Mechanism, often rack-mountable on a 19" panel) and the TWA (Recorder Amplifier, also rack-mountable). The unit was sold as a complete recorder (TWR-1 or TWR-2) or in component form for custom installations. It emphasized no belts, clutches, or idlers in the drive system for simplified service, and supported professional NAB reels up to 10.5 inches.

Key Technical Specifications

• Track System: Dual-track (half-track) stereo/monaural standard (2-track record/playback); single-track (full-track mono) available in some configurations; provision for up to 5 heads (for simultaneous record/playback, multi-head monitoring, or custom setups)

• Tape Speeds: Two speeds — 7.5 ips (19 cm/s) and 15 ips (38 cm/s); instantaneous switch selection (some brochures note 3.75/7.5 ips variants in lower-cost options)

• Reel Size: Up to 10.5 inches (professional NAB hubs; supports up to 2500–3600 ft tape for extended runtime)

• Heads: 3 heads standard (erase + record + playback); expandable to 5 heads (interchangeable bracket mounting for professional applications)

• Motors: 3 heavy-duty motors (1 two-speed capacitor induction motor for capstan + flywheel; 2 shaded-pole motors for spooling; continuous-duty rated; no belts/clutches/idlers in entire mechanism)

• Drive System: Direct-drive capstan (two-speed motor with flywheel for timing accuracy); positive reel locks ("Reelok" design); automatic tape cut-off on breakage or run-out; fast rewind/fast forward (less than 60 seconds for 2500 ft); air circulation blower integrated with capstan motor

• Frequency Response: Usable 20–20,000 Hz; ±2 dB from 40–15,000 Hz at 15 ips; ±2 dB from 50–12,000 Hz at 7.5 ips (professional-grade for the era)

• Signal-to-Noise Ratio: 55 dB (measured per proposed NARTB standard at 400 cps, 3% T.H.D.)

• Total Harmonic Distortion: 2% at zero VU level

• Wow & Flutter: Less than 0.1% RMS at 15 ips; less than 0.2% RMS at 7.5 ips (excellent for mid-1950s professional machine)

• Equalization: NAB standard (US professional/broadcast curve)

• Inputs:Microphone: Low-level (high-impedance or balanced)
  Line: Balanced bridging input (50/250 ohms or high-impedance with plug-in transformer option)
  

• Outputs: Cathode follower line output (600 ohms balanced with plug-in transformer #T-2560); headphone monitoring; zero dBm across 600 ohm line

• Power Supply: AC mains, 115 V / 60 cycles (some export variants 220 V); power required ~220 watts

• Dimensions: Drive mechanism 14" × 19" (rack-mountable, 6.5" depth); amplifier 5.25" × 19" (rack-mountable, 6" depth)

• Weight: Drive mechanism ~35 lbs; amplifier ~10 lbs (total ~45 lbs for complete unit)

• Electronics: Tube-based (high-quality broadcast-grade tubes in TWA amplifier: 2× 12AX7, 1× 12AT7, 2× 12AU7, 1× 12BH7, 1× 6X5GT rectifier; D.C. on all filaments)

• Other Features: Bias current/record/output level indication; meter indication for bias, record, output levels; monitor output from tape or input; variable signal mixing from line/mic; interchangeable head mounting; operates in any position

Design and Performance Notes

The Concertone 20/20 was built for professional reliability: the 3-motor transport (no belts/clutches/idlers) simplified maintenance and provided excellent timing (99.8%+ accuracy). The expandable head provision (up to 5 heads) allowed custom setups (e.g., simultaneous record/playback). Tube electronics delivered high-headroom, clean sound with professional fidelity for the era—modern vintage ratings place it around 7–8/10 for sound (excellent mono performer) and 8/10 for build reliability/durability.

Common long-term service needs include:

• Tube replacement/check (aging tubes cause drift/noise)

• Cleaning heads, capstan, pinch roller, and tape path

• Replacing electrolytic capacitors (leakage common after 60+ years)

• Lubricating mechanisms

• Head alignment (especially in multi-head setups)

Historical Context

The Berlant Concertone 20/20 was part of the early professional tape recorder wave in the US (1950s), competing with Ampex. Berlant Associates later merged or rebranded under Concertone, producing high-quality portables/broadcast machines. Surviving examples are rare collectibles today, often prized for their professional heritage and condition, but most require restoration (tubes, capacitors, and mechanical parts) for reliable operation. They represent an important chapter in early US professional open-reel history, especially for those interested in 1950s broadcast-grade mono designs with expandable heads.