Small Box Bias Adjustment Location?

[John 14:6]

I had one of my stock ARS/JJ EL34's go microphonic today. I bought some new power tubes and I am taking my amp in tomorrow to get biased. Should the bias adjustment screw be easy for the tech to locate? Is there something he should look for to find it? I know the bias should be set at 32ma.

 

[John 14:6]

THANKS again for the email Dave!!!

 

[MantraSky]

One of my TAD El34-STR power tubes was going bad (Been a couple of years) I changed them all and used my "Weber Bias-Rite" (Biasing Tool) @ 32ma V.I. switch to Ik . I checked my BE100 with a Tektronix Oscilloscope & Fluke 87 III DMM just to make sure the Bias-Rite was accurate, it's amazingly good after all these years and so simple. It measures Plate Voltage & Current just connecting the tube receptacles to your amp, then tubes let it warm up, adjust the Bias-Pot all within an hour. Just as an option to having a technician for future adjustments (I've adjusted so many friends amps because it's that simple) Extremely easy to do, there are hazards but after 30yrs I've never had an problem or incident. The photo clearly shows the "Pot", also a nice thing to do, if you do the biasing is that you can "Play the amp" while adjusting and adjust to your own preference, although 32ma sounds great to me (Dave recommend), I know a number of people that like to adjust a "little" higher for their particular style. If your apprehensive even in the slightest it's best to take it to a Technician.