I own the JoLida 502B. It was my first introduction to tubes. It is manual bias. Just use a long handled screwdriver...haven't burned myself yet. A 5 minute job at most.
11 responses Add your response
This may be old news but, this is what I use on my Jolida 502A. It is a Bias Rite model #BR-4 by Weber. It shortens the bias time and allows you to make very accurate bias settings and compare each socket to make they are all the same at the turn of a switch. The test points on these amplifiers are not very good in my opinion. I love using the Bias Rite it has worked very well for me.
i use shorter probes and a short screwdriver and have never had a problem. i have big hands as well. i think you may be overly concerned with forcing probes into a real tight and locked position. the probe slots are not top of line but then again you do not need to sink the probes in very far to get a solid read out. i use a digital radio shack unit and it is 1,2,3.
I'm not overly concerned. It's just an easier method that works for me. I don't have to hold on to probes with one hand while trying to make adjustments with the other hand. This way I can leave the amp where it is in my rack and make the adjustments. But hey if it works for you that's great, it doesn't for me that's why I chose this approach.
did not mean to imply your method was inferior, etc... i was speaking to OP. just wanted to point out that the connections to spikes do not have to be rock solid to get job done. if i had longer tools it probably would be easier as a matter of fact but the probes can stay in place free standing long enuff to let go of them for adjusting slot screws. ntl, i think auto bias is a gret option, i wish that feature was offered on mine but it was introduced later on.
Have you tried contacting JoLida in Maryland about a manual (also your tube placement question)?
However, from the image here, the 12AX7s are on the inside.
I recently sold my 502p…a great amp that served me well for years. The 12AX7s are on the "inside" of the small tube pairs. I had a "Littlite" gooseneck light over the amp that I would hang the bias meter cables over to keep them under control when using the meter to check the bias, but burning my fingers was part of the ritual…however, the bias LEDs were very accurate and I didn't really need the meter.