• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Phase inverter, your comments welcomed!

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
I was recently given this hand drawn schematic from some that has a lot more experience then me. I would like some opinions. I have attached the exsisting inverter as well. Sorry that the file is sideways, cant seem to turn it and I didnt draw it so sorry for that as well!!!
It is proposed as an positive alternative to the current Long Tailed Pair in my EL84 amplifier.There are several missing values that i could use help with those as well
 

Attachments

  • stereo20.gif
    stereo20.gif
    135 KB · Views: 124
  • ecc82m510.jpg
    ecc82m510.jpg
    178.6 KB · Views: 123
Two problems with the new circuit:
1. wrong valve - ECC82 is nowhere near as linear as an ECC83
2. wrong bias - it looks like your friend has tried to combine two different LTP bias methods so got it wrong.
There are two LTP phase splitter bias methods which work: the one used by Leak (self-bias), and the one used by Mullard (DC coupling, with the second grid DC coupled to the first grid and AC coupled to ground).

In addition, as the ECC82 has such low mu it needs a CCS as the tail unless you want significant imbalance. The ECC83 has just about high enough mu to get away with just a tail resistor.

Your friend needs to go away and do some more thinking and reading.
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.