Hello,
I modified my Oktava MK-219 with a PCb from Russel Technologies called RT-219.
Basically it's an higher quality pcb than the original and based on some small changes to values in the circuit as suggested by Scott Dorsey and a few others.
I built it and now I have very low volume, I had to bring the preamp gain all the way up.
I checked all cap values and Lytic cap orientation, resistor values, FET leg orientation - everything is fine.
Checked all connections to ground - fine
Checked all connection to Out transformer and from it - all fine
followed the schematic and checked all connections between components - all fine
changed the capsule for another working one - the same behavior
changed the FET - the same behavior
I'm out of options to solve the issue and I have no more ideas at the moment of what the problem might be.
In the RT-219 schematic there's references voltages for the circuit and my voltages are way off, I wrote my voltages in Blue and Red in the following schematic:
Any ideas of what the problem might be?
Any other troubleshoot I could do?
Thank you so much
I modified my Oktava MK-219 with a PCb from Russel Technologies called RT-219.
Basically it's an higher quality pcb than the original and based on some small changes to values in the circuit as suggested by Scott Dorsey and a few others.
I built it and now I have very low volume, I had to bring the preamp gain all the way up.
I checked all cap values and Lytic cap orientation, resistor values, FET leg orientation - everything is fine.
Checked all connections to ground - fine
Checked all connection to Out transformer and from it - all fine
followed the schematic and checked all connections between components - all fine
changed the capsule for another working one - the same behavior
changed the FET - the same behavior
I'm out of options to solve the issue and I have no more ideas at the moment of what the problem might be.
In the RT-219 schematic there's references voltages for the circuit and my voltages are way off, I wrote my voltages in Blue and Red in the following schematic:
![zHI2KgY.png](https://proxy.imagearchive.com/de0/de0cea97b0249f78888e25ef711ae8e7.png)
Any ideas of what the problem might be?
Any other troubleshoot I could do?
Thank you so much