Folks -- A while ago Carl KM1H told me about two modifications for the HQ-129-X receiver: 1) The 6SB7Y was done in a 50's CQ by Bill Orr for a NC-240D. Carl then did it for his HQ-129-X and said it worked fine. 2) The 6X8 was in a 60's CQ for the 129X. I've been unable to locate the CQ Magazine editions. Can anyone help? 73 Mark K3MSB