[Hammarlund] HQ129X Distortion

[Larry Asp]

The subject of audio distortion  with the rf gain control turned up full on the HQ129X has come up a few times, and the standard advice given has been to back off the rf gain control. This problem existed with my set up until today, even though I have gone through it and replaced all the paper caps etc. What often happens with the HQ129 is their owners replace the  4 6SS7 tubes in it with one or more 6SK7s. The 6SK7 does work in the set and gives it a bit more gain (some say), but its not an exact substitute. Such was the case with mine - one of the 6SS7s had been replaced with a 6SK7. I had the good fortune of purchasing some NOS 6SS7s recently (JAN type) and replaced the 6SK7 and the  old  6SS7s with with them, and - the distortion went away - except for the signal from a broadcast station (10KW) located about 2 - 2 miles from my house (which I can control by backing off the RF gain). Hope this helps - worth a try if you can find the tubes.