Street Rod Bias

[wildblue]

I've had my street rod for a year now and I can't say enough great things about this amp! However over the past few months the low end has been somewhat woofy especially with the amp cranked (both channels). To the point to where I had to turn the bass all the way down. At the most I could run the bass around the 9 o'clock range but it was in most cases too much. Again only noticeable with the amp cranked. Tried different guitars, cables, efx loop on or bypassed and through an extension cab... All with the same result. So it was time for some new power tubes. I used JJ EL34Ls. First so others that own the street rod know, the plate voltage on this amp is lower than the QR. Mine measured out at 405. So using the bias formula, I went with 70% which came out to 43.2 ma. I know a lot of users on the forum like to bias their Splawns somewhat cooler but to my ears 70% sounds great. Also I want to commend Scott on an outstanding solder/wiring job! I couldn't find a single cold solder joint or flux residue anywhere. Outstanding build! Anyway, low end problem is solved! Amp sounds great!

[akadave]

I spoke to Scott about biasing with my SR and said not to go over 40. My plate voltage is running about 465

[wildblue]

He did recommend between 38 and 40mA, which with my plate voltage of 405 would be running at about 60% to 65%. That does seem to be the consensus with a lot of Splawn users. I just prefer running it a little hotter with the tubes that I installed. On a side note, if your plate voltage is 465 and you bias your amp to 40mA then your at around 75%... which is biased hotter than mine. I will go back and double check my plate voltage tonight just to make sure I probed off the correct pin...