stewen1
Responses from stewen1
| regulator in AR D70 Well , the only thing I can do is changing both the Darlingtontransistor and the TL071 . If that doesn´t help I guess the zeners might be bad . Its not easy to desolder components in this amp because there are printed circuits on both sides of the... | |
| Audio Research D70 mark1 + schematic Hallo again ! I have been working with other items lately but today returned to the nice D70 . Measured the voltages at theTIP 41 regulator circuit as the former advice pointed out as important . The correct values shall be 335VDC and 327VDC sothe... | |
| Audio Research D70 mark1 + schematic Now this D70 has got new filtercaps ! One thing I notice is that if the wipers on the biaspots should lose their contactcompletely or partial there will be a currentrush in the powertubes . Judging from the position that these wipers have now with... | |
| Audio Research D70 mark1 + schematic Thanks ! Well , these resistors are green , 3% , and have 33K written on them . ( total four resistors ). I´ll checkthe voltages You mention . Another question : if I can foundnew Cornell/Duplier to replace the large filtercaps ( 800 uF/450 VDC ) ... | |
| Audio Research D70 mark1 + schematic Thanks for Your interesting and valuable answer ! I am usedto measure high voltages as daily working with guitaramps .Another thing that puzzles me : both schematics I have show R31 and R32 ( anoderesistors for the last 6FQ7 tube ), 62kohms. The a... | |
| Audio Research D70 mark1 + schematic Thanks for Your answers ! Yes , Hifigeek 1 ! All components You describe is the same in this amp . I´d be very happy if you could give me the voltages you mentioned. Stewen | |
| Audio Research D70 mark1 + schematic Well , one more difference in this amp ( being a mark1 ormark 2 or something in the middle...? The anoderesistors forthe last 6FQ7 tubes in each channel is only 33Kohm compared to 62Kohms in the schematic I´ve found on the web..... ( a mark 2 vers... | |
| Audio Research D70 mark1 + schematic Thanks for Your answers ! Well , I might manage to fix this amp without a schematic .... the MK 2 schematic is a good helpeven if it differs some from this amp , many values are the same. I have soldered a 3K resistor in parallell with eachtrimpot... | |
| Audio Research D70 mark1 + schematic Thanks for answers ! Well , the schematic at www.arcdb is an early mark 2 vesion with R13,R14 511 ohm and R12,R15 110 ohm . "My version has 1,5K for these resistors and its very sensitive when I´m trying to set the +90V with the trimpot.Can´t read... |