Technical Details
Brand: Pentron
Model:TR-4
Category:Vintage
Application:Consumer
Electronics:Tube
Equalization:NAB
Country of Manufacture:USA
Release dates:1954 - 1957
Original Price: $190
Tracks:1/2 Rec/PB
Speeds: 3 3/4, 7 1/2
Max Reel Size("): 7"
Number of heads: 2
Head Composition: Permalloy
Head Configuration: Mono - Full Track
Voltage(s): 110-120v
Outputs: RCA
Frequency Response:50 to 9.5 kHz (all 3 dB) 7½ ips
Wow and Flutter:less than 0.5%
Signal-to-Noise Ratio:50 dB
Sound quality rating:5 / 10
Long-term reliability rating: 5/ 10
Additional Details
Description
Quite similar to the earlier 9T series, the TR-4 was a portable, dual-speed, dual track machine with push-button select for either 7½ or 3¾ ips. It was also available with full width, single track heads. Signal to noise ratio was 50dB and wow & flutter measured less than 0.5% at 7½ ips.
There was an edit key and magic eye level indicator and the in-built 5 watt amplifier drove a 6″ permanent magnet speaker.
The two input jacks (left hand side) were for radio, TV or phono and microphone. The outputs were for an external speaker and external amplifier or headphones. The Model HT-225 Hi-Fidelity was more or less identical to the TR-4 except that it had an extended frequency range due largely to the installation of two “woofer” speakers and a tweeter together with an LC crossover. Prices in 1954 were $190 for the TR-4 and $225 for the HT-225.
Additional Info
Valve complement: 5879 or 6J7 (mic pre-amp). 6SL7 (AF amp). 6V6GT (bias & audio) 6E5 (record level indicator) and 6X5GT (rectifier) / Rewind speed: 7″ 1200 ft reel in 70 seconds (20:1 ratio) / Audio output power: 5 watts / Inputs: radio / TV / phono and microphone / Outputs: external speaker and external amplifier or headphones / Speaker(s): 6″ permanent magnet (TR-4) two 6″ woofers and a tweeter with LC crossover (HT-225) / Weight: TR-4: 27 lbs (12.3 kg) HT-225: 33 lbs (15 kg) / half-track mono (full-track available)