Recent content by Fabmars13

Hi Wasnex, i will checked again for leaking capacitor coming from Pin3 of V1. I have a lot of NOS 12DW7 stamped magnavox and yes same results when i swapped the tube. I will let you know if i found a solution. Fabien

Thanks Wasnex, beans-on-toast, yes, i changed cathode resistor R25 by vishay metal film (measured 1.25k exactly), R24 measured 47k, tried a brand new 0.1uF in C7 capacitor, still the same. I'm not an expert but maybe something wrong in Pin2? In the Tube Amp Book , they troubleshoot a similar...

Wow Thanks a lot. I had the same feeling than you. I suspected a leaking capacitor that force v3 to draw some current. I already checked and swapped with brand new capacitor in C7, C2, C6, C3 , C14 with no change. I suspect maybe an issue in the PEC part but i'm not sure and difficult to test...

Hi, i just did what you said: i reflow socket, put deoxit in tube socket, retentioned pin, and i got the same voltage on v3. The 47k is brand new vishay metal film resistor and test good. Before the (R24) 47k,voltage 300VDC. After (R24) 47k (Pin 1 V3) 140VDC. Here is voltage i measure : V1 ...

Thank you for your reply agedhorse. Amp works okay except a little hum that i'm chasing ;) Voltages in v3 were the same before i changed some resistors out of spec in preamp section.It improved % voltages closed to schematic voltage in preamp except in V3 first triode. I double checked cathode...

Hi, i have a 69svt BlueLine and some weird voltage on V3 as well (12dw7). Pin 1 : 130VDC Instead of 200vDC Pin 3 : 5V instead of 3.2V Pin 6 : 180VDC Pin 7 : 12VDC (Normal???) Pin 8 : 20VDC I tried and swapped 3 different 12DW7 on V3 All others voltages on V1, V2, V4 and 6C4 are within 5%...