I am working on a Urei 176 clone using original UTC input and interstage transformers and Sowter replica output
I am a bit insecure about some of the voltages on the original schematic vs what i am measuring in my unit
The strangest thing I see on the original schematic is that the voltage at R43-R44 junction is marked as 310V, but this is also connected to the output tube plate (V3 pin6) which shows 295V instead. One would assume this is a mistake on the original schematic and the two voltages should be the same ?
On my unit I used a power transformer with a lower h.t. voltage so I had to tweak R44 value in order to get closer to 310V. I have used a 680R resistor instead of 1K5 and I am getting about 308V and this is on the output tube plate pin6 as well. On the other plate (pin1) I have exactly 295V like the original schematic. Does this look ok to you or the two plates need to be at the same voltage?
Another difference is at V2 plates. I have about 167V here, instead 80V marked in the schematic. I am wondering if there might be another mistake on the schematic, because the Urei 175 who has basically the same circuit around V2 shows a 200V voltage instead. At the junction between R23 and R24 I have 265V which is not much different than 275V on the schematic. I suppose I am fine here as the voltage is within the maximum ratings of the 12AX7 and I am guessing there might be a mistake in the schematic, but it would be good to get some advice
One last concern regards V4 cathodes, I have 38V instead of 45V. But in this case I have found a thread that confirmed this is a mistake on the schematic, so this got me wondering about the voltages on the other tubes
The unit seems to be working fine, but it would be nice if someone more expert than me commented these readings and clear any doubt
I am a bit insecure about some of the voltages on the original schematic vs what i am measuring in my unit
The strangest thing I see on the original schematic is that the voltage at R43-R44 junction is marked as 310V, but this is also connected to the output tube plate (V3 pin6) which shows 295V instead. One would assume this is a mistake on the original schematic and the two voltages should be the same ?
On my unit I used a power transformer with a lower h.t. voltage so I had to tweak R44 value in order to get closer to 310V. I have used a 680R resistor instead of 1K5 and I am getting about 308V and this is on the output tube plate pin6 as well. On the other plate (pin1) I have exactly 295V like the original schematic. Does this look ok to you or the two plates need to be at the same voltage?
Another difference is at V2 plates. I have about 167V here, instead 80V marked in the schematic. I am wondering if there might be another mistake on the schematic, because the Urei 175 who has basically the same circuit around V2 shows a 200V voltage instead. At the junction between R23 and R24 I have 265V which is not much different than 275V on the schematic. I suppose I am fine here as the voltage is within the maximum ratings of the 12AX7 and I am guessing there might be a mistake in the schematic, but it would be good to get some advice
One last concern regards V4 cathodes, I have 38V instead of 45V. But in this case I have found a thread that confirmed this is a mistake on the schematic, so this got me wondering about the voltages on the other tubes
The unit seems to be working fine, but it would be nice if someone more expert than me commented these readings and clear any doubt
