• Item: Tube MM phono preamp  
  • Type: retro-thermionic "Calibre 834"  
  • Posted: 1 April 2019  
  • Builder: mwhouston  
  • Country: Australia  
  • Comments: 2  

Calibre 834

Esoteric, some years back, sold a tube phono preamp called the EAR 834p. It got excellent reviews. The schematic is available and kits based on the original schematic are plentiful. This is one of the cheaper ones by not providing tubes. I have three pairs of match 12AX7s - Mullard, Sovtek and Tung-Sol. Time to put them to use. I used the Sovteks as they had the smallest plates which is good for microphonic control. The third tube is a cathode follower for driving the next stage. GNFB is used.

The kit comes with top shelf components;- Vishay resistors and capacitors, Dales and other quality parts. The brd. is silk screened and double sided plated through. A trick I have used in the past (and used here) is to mount the passives on the bottom of the brd. and not on top. This allows the tubes to poke through the top of the preamp. The brd. is easy to assemble. Also mounting it in yet another Hammond wood cheeked light Al chassis was easy. Once more an XLR plug and socket bring in the HT and heater voltage from a choked external PS. The PS itself runs from a 24VAC 1A wall wart.

WBT silver solder was used and silver plated wire-warp wire used in the signal path. A light multi-stand hooks up the HT and heaters. The brd. is designed to utilise two separate PSs but I joined them to one. Excellent sounding preamp and well worth the cost of parts.


  • steinkare
  • 2 April 2019 at 05:01AM
  • A picture from inside the box would be great!
    Beautiful phonoamp!
  • mwhouston
  • 7 April 2019 at 12:37PM
  • Email me and I will.

Leave a Comment