HiFiStor

Natural extension after building Zen 4 amplifier was this small DoZ amplifier built by Rod Elltiot. Must say that setup of this amplifier is not easy and not for unexperienced builders. Need knowledge , experience and patience to make it working good. If make mistake , output transistors will be burned immediately . Rod already explained everything about setup on his page however in short I tried to explain it again. Between speaker and amp output need to put 2200-4700uf electrolyte capacitor , it is not on board, must put it outside pcb. Quiescent current should be 1.7A however after burned few expensive MJL21194 transistors I stopped at the 1.3-1.5A . If must compare with Zen 4 I can say that my vote goes to DoZ in fact I like it very much. Design is more similar to JLH amplifier and do not know why name is DoZ but for me it is worth to built it . Test is HERE .

Setup:

1. Before applying power, set VR1 to the middle of its travel, and VR2 to maximum resistance (minimum current)
2. VR1 is used to set the DC voltage a the +ve of C3 to 1/2 the supply voltage (20V for a 40V supply),by setting the voltage at the base of Q1 (in my case 13.5V due to I have used 27V supply)
3. VR2 is used to set quiescent current , which I found needs to be about 1.7A for best overall performance