We have just released our latest upgrade kit, Dyna-70AB, the ultimate Dynaco ST-70 upgrade kit WITH AUTO BIAS!
This kit will completely transform your tired old ST-70 using 6SN7's for the driver section and a solid state power supply.
For all the details, please go here, http://www.erhard-audio.com/Dyna-70AB.html
We are very excited and honored to be chosen as the official and exclusive agent and reseller of Audioamp, from the Czech Republic, range of Auto Bias modules in the USA & Canada.
These modules can be installed in just about ANY tube power amp which requires manual bias adjustment for the output power tubes.