The customer had purchased this vintage Bassman 70 with plans to clean it up, and while it initially worked fine, once he got it home it would only produce noise. The source of the madness was a missing nut and washer on the bias control pot. Without the nut the pot was no longer making contact to the chassis/ground. One little bit of hardware had thrown off the whole amp. I locked down the pot and biased the new power tubes. I also gave the front panel pots a good cleaning. Some people don't care for Fender's ultra-linear amps, but this one had a nice solid clean tone that was exactly what the customer was looking for.
Music Man HD130 - Rejuvenation
Things weren't working quite right, so Rian from These People Here decided it was time to spiff up his Music Man HD130. This particular amp started it's life with the older 12AX7 phase inverter. At some point in the 70s (remember those?) it was updated with the newer solid state drive board. Someone had replaced the power tubes and tried to bias it using the older method. With the solid state board installed you can spin the old bias pot like the wheel of a tall ship avoiding the Kraken and it won't make an ounce of difference. The tremolo effect needed some coaxing as well. We replaced the toasted EL34s with the correct 6CA7s, set the bias properly and the difference was immediatley noticeable. 130 watts of spacious, clean tone. Turns out it makes a surprisingly good bass amp too!
Fender Hotrod Deluxe - Retube and bias
Fender Hotrod Deluxe
I once had a previous employer tell me "all you know how to do is change tubes." I wasn't bothered so much by the fact that he was wrong (my lasagna making skills are unstoppable.) It was more that he somehow thought of the most common and requested bit of maintenance work as unworthy. It would be like telling the mechanic at Speedy Lube "all you know how to do is change oil" without realizing that there were multiple nation wide franchises doing millions of dollars in business all for providing a basic and much needed service. Anyway, all I did to this Fender Hotrod Deluxe was change its tubes.
