SE 6EM7 Power Amplifier

Yet another 6EM7 power amplifier. This time some parts were down graded and a different internal layout technique was used. The power transformer and choke are isolated top and bottom by rubber grommets. This ensures no AC vibration reaches the tubes. The initial power supply filtering is preceded with a on-board power filter, a 20uF/450V electrolytic capacitor and a 20H/100mA Hammond choke. The HT is supplied by a Hammond power transformer and Sovtek 5Y3 rectifier tube. The second stage of filtering is 47uF and 100uF electrolytic with a large limiting resistor ensure the amp is totally free from of hum and noise. All power supply capacitors are snubbed.

This amp sounds better than the last and I think it may be the Sylvania NOS 6EM7 tubes. Sprague orange drops are used in the inter-stage coupling and once more large non-polarized capacitors for the bypass on the power tubes. For the first time I have used Chinese made H&K 15W audio output transformers, can't fault them. The look of the amp is almost under-stated "sexy" and the sound the same - sexy and natural.

Mark Houston – retro-thermionic

UPDATE - June 2015 - see the 6EM7 Single-Ended Triode (SET) Vertical Amplifier project page for the latest revision of this amplifier.