Sold Only in Quads, (4) Tubes - Apex matched set. Use the Mullard EL34 in the output stage of the Dynakit / Dynaco ST-70 and MKIV tube amplifier. Premium high-voltage power pentode. An extremely faithful reissue of the XF2 Mullard EL34 from the 1960s. Special grid windings give a unique sound. Perfect power tube for Dynaco ST-70 and MKIV Tube Amplifiers

Sold Only in Quads, (4) Tubes - Apex matched set. Use these EL34 Electro-Harmonix Tubes in the output stage of the Dynakit / Dynaco ST-70 and MK IV tube amplifier. Superior imaging and depth, fantastic realism and holographic presentation. Superb bass response.

Sold Only in Quads, (4) Tubes - Apex matched set. Use the JJ KT77 in the output stage of the Dynakit / Dynaco ST-70 and MK IV tube amplifier. This tube has an extended frequency response with exceptional lows (even deeper than the E34L's) and wonderful highs. Midrange is smooth, extremely rich with harmonic complexity.

Sold Only in Quads, (4) Tubes - Apex matched set. Use the EH 6CA7 in the output stage of the Dynakit / Dynaco ST-70 and MK IV tube amplifier. Electro-Harmonix 6CA7 Vacuum Tube Big bottle beam-tetrode version of EL34.

Sold Only in Quads, (4) Tubes - Apex matched set. Use the EL34  KT77 Genalex in the output stage of the Dynakit / Dynaco ST-70 and MK IV tube amplifier. Detailed imaging and depth with lush realism and a strong holographic presentation. Excellent bass response.

Sold as each. Works in the Dynakit / Dynaco ST-70, MKIII and MKIV Tube Amplifiers. Genalex Gold Lion U77 / GZ34 full-wave rectifier tube. A highly rated indirectly heated dual diode, full-wave vacuum rectifier. This tube insures a strong, dynamic response. Excellent sound and a reliable choice, the Genalex U77/GZ34 comes with a dark blue base. It has a stable tandem supported getter cup, industrial thickness dual mica spacers and full 30mm length internal plate structures. 

Sold as each. Pre-tested and burned in for quality assurance. For use in the Dynakit / Dynaco ST-70 and MKIII or MKIV Tube Amplifiers. Tung Sol 5AR4 rectifier tube is a premium grade directly heated heavy duty rectifier Diode. Helps extend the life of the other valves in the amplifier by allowing them to heat up before plate voltage is applied. 

Works with the ST-70, the MKIII and MKIV Amplifiers. This  custom made "Copper Top" Solid State Rectifier works great. Plugs right in the socket like a tube. Includes a protective "soft start" just like a regular 5AR4 / GZ34. If you're changing from a glass tube to this solid state rectifier, your amplifier will require adjusting / re-setting the bias, as bias will typically be slightly higher with this SSR, due to it being more efficient than a vacuum tube. Reduces transformer load, runs cooler, increases bass response and improves speaker damping. 

Sold Only In Pairs. Only the Best Quality Tubes that are Tested and Ready to Play. Use these for our ST-70 and the MK IV Tube Amplifiers. Quality Brands like Sylvania, GE, RCA, Zenith, Amperex and others.  (brands are subject to availability) 

These are not a replacement for a 7199 tube, you must have an amplifier with the updated driver board or use the proper tube adapters. Our amplifiers only come with the updated 6GH8A revision boards. We do not use tube adapters nor do we sell them. If you're buying one of our ST-70 amps, these 6GH8A or 6U8A are the tubes you need.

Sold Only In Pairs. Only the Best Quality NOS Tubes that are Tested and Ready to Play. Use these for our ST-70 and the MK IV Tube Amplifiers. JAN and/or JHS prefix tubes indicate tubes made to the highest standards for military equipment and communications gear. Quality Brands like Sylvania, GE, RCA, Philips, Amperex and others.  (brands are subject to availability) 

NOTE: These are not a replacement for a 7199 tube, you must have an amplifier with the updated driver board or use the proper tube adapters. Our amplifiers only come with the updated 6GH8A revision boards. We do not use tube adapters nor do we sell them. If you're buying one of our ST-70 amps, these 6GH8A or 6U8A are the tubes you need.