That is the question.
Everytime I do some trading around on Craigslist it is always something weird. On Tuesday I traded some items for this Fender Hot Rod Deluxe. I liked the first Fender Blues Deluxe I got enough to make me curious as to how the Hot Rod Deluxe stacked up. It is your standard fare 40 watt , 2 6l6 power tube, 3 12ax7 preamp tube amp.
The gentleman got here, set it up, let me play it, I said yes, then I saw him to the door and off he went. Now, before his tailights were out of my sight, I heard a horrible racket coming from inside. The new amp sounded like it was in self destruct mode with some vicious racket coming from the amp. I turned it on, then off to no avail. Needless to say, I was pissed. I figured this guy knew to make his exit before the amp got too warm.
I took the back panel off and looked at every single component. I then did a tap test with a drumstick and found the third preamp tube (v3) was acting up big time. This kind of shocked me because as the dude stated, the tubes were new JJ’s. That much was apparent as these amps come stock with Fender labeled Groove Tubes. So I switched the V3 tube with a Groove Tube I had laying around and the amp quit making noise.
The next day I turned the amp on, and no matter what, I could not get a good tone out of it. I swiched the newly changed V3 with V1 and it did sound a bit better but not very good still. I thought about the conversation with the gentleman the night before when I asked him if he rebiased the power tubes when he changed them. He told me it wasn’t necessary because it was a matched set. I decided to research this, it turn out, that is just a myth and the bias should be at least checked.
After scouring the web for a while I found the specs for tube bias on the web. It should be 60Mv when checked with a multimeter on DC. His: 49Mv. To cold, way to cold. At this level you get something called crossover distortion. The amp experts for this model amp really like 68Mv for a sweet sound, but you can pretty much go between 60 and 80 Mv, 80 being almost way to much. I set it at 69Mv and it sounds great now.
Quite a bit of work for something that should have sounded great from the get go. Now I just am not sure whether to get rid of it, or keep it. On the one hand it sounds great, but on the other, I think I have learned quite a bit lately to realize that the quantity of work necessary to keep a tube amp well sorted is almost not worth the effort when solid state amps and emulation technology have come so far these days.
Any opinions?
