DIY Tube RIAA Phono Preamplifier Kit
Last year Mark built a number of the Oatley Electronics K272 tube headphone amp kits and he has recently got his hands on the new Oatley Electronics K282 Tube Based Stereo RIAA Preamplifier Kits. The kit is for moving magnet (MM) cartridges. The inexpensive kit costs $47AU (about $44US, $44CDN, $33EU, 29GBP) and includes a power supply.
Like the headphone amplifier kit, the phono preamp kit is based around new old stock (NOS) Raytheon JAN 6418 sub-miniature pentode tubes. The circuit is a tube hybrid with FET stages and a SMPS.
The kit is built on a through-hole PCB and also includes a "universal" 5V power supply that will operate pretty much everywhere. You will have to provide your own audio connections (RCA jacks) and an enclosure. As Mark notes, for best performance you will need to pay special attention to controlling vibration and mechanical noises as the sub-miniature tubes are extremely microphonic.
Mark reports that the inexpensive kit is a good performer. With the low cost of the kit, this is a great low voltage kit for those interested in tube or phono audio. Read about Mark's experience with the phono preamp kit and his tips for reducing tube microphonics:
- DIY 6418 Tube RIAA Phono Preamplifier Kit (Oatley Electronics K282)
