Tag Archives: tubes

Sonorus Audio ATR10 Vacuum Tube Reel to Reel

Sonorus Audio produces the ATR 10, a reel to reel deck based on the chassis from the Revox PR99 . The ATR10 is a 1/4” REPRO machine (playback only, no recording) for hi-end music listening.


Sonorus Audio ATR10 Vacuum Tube Reel to Reel

Electronically regulated tape tension,  dual EQ (NAB and IEC), wire remote controlling and Library Wind (FF controlled speed to prepare tape for storage) are all new functionalities.

Sonorus builds the tape transport with original mechanical components from Revox/Studer. Internal electronics have been redesigned to use parts currently in production. The playback board is completely new, featuring a vacuum tube preamp section.

Frequency response:

  • 15ips: 18Hz – 23kHz (+2/-3dB)
  • 7.5ips: 14Hz – 20kHz (+2/-3dB)

Signal-to-noise ratios: RMS, ASA-A weighted,  +6dBVU (510nWb/m)

  • NAB (7.5ips): 73dB
  • NAB (15ips): 71dB
  • IEC (7.5ips): 71dB
  • IEC (15ips): 73dB

Distortion: THD measured at 1kHz

  • 15ips, 0dBVU: <0.15%
  • 15ips, +6dBVU: <0.5%
  • 15ips, +13dBVU: <3%

Tape tension: Electronically regulated. Tested with 10.5” (26.5cm) reels.

  • Supply reel side: 0.45N +/-0.05N
  • Take-up reel side: 0.60N +/-0.05N

Visit Sonorus Audio site here, or direct-download the brochure and the user manual.

Upgrading Tape Recorder’s Electronics: Tube Preamps

An interesting way of modifying an open reel deck is to take the direct output from the playback head and route it to an external, higher quality, preamp bypassing the internal one.

Bottlehead, located near Seattle, produces hand-made dedicated tube repro preamps.These units are intended for 2 track systems.

Their top end model, Tube Repro, features:

  • XLR-balanced outputs +4dB
  • RCA-unbalanced outputs +10dB
  • CCIR  EQ
  • NAB EQ

Different custom EQ curves available on demand.

Bottlehead Repro

Bottlehead Repro

Another model, the Eros Tape Head Preamp, is available as a kit. To my knowledge this is the only tube repro kit available on the market as of 2012.

Eros Preamp

Eros Preamp

Bottlehead also sells upgraded replacements for mechanical parts along the tape path (Otari and Technics decks)
Visit their site here and head to the Reel To Reel section.