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Of course the 6505 may or may not have different PCB layouts...but maybe you can key in on it. Verify w schematic if possible.

I think so, but use your meter to confirm. So very easy to double check it!

Mine was showing something like 42mA or whatever right at 70% was (based on 30W). Those 5881wxt are usually not prone to failure so I am not 100% sure what happened to it tbh for one to fail. As I said in the video you can certainly do the math using 30W instead of 25W for the dissipation factor but I was playing it on the safer side.

@@gremlinmachineshop so I have the combo version that came out earlier this year. The power tubes are different. They look like Tung Sol 6L6. I'm waiting on response from Soldano/BAD to find out what they are exactly. I tried some tube swapping, and I didn't think to check what it was stock. I just set it at 38mA when I swapped and when I put the stock tubes back in. The origin of my question was for comparison, cause I don't think it was in the 20s stock. Then I was doing some research and found that the big ones are cold biased. The manual is useless. No bias recommendations or even tube assignments mentioned.

@@1974zah just regular 6L6? or 6L6GC...we can do some math as needed. Well let's just say regular 6L6 are 25W and 6L6GC are 30W, and you can measure the plate voltage on Pin 3 still to calculate it. I'd guess you understood that part tho.

@@gremlinmachineshop I appreciate that. I'm not quite sure what they are. It's labeled 5881, but the only tube I found that resembles it is the current production Tung Sol 6L6 STR, the black base, not the red one. I should be safe with 38mA for now . I generally bias mine at 65% . I was mainly curious if yours was biased cold before. Hopefully BAD will get back to me with details soon.

@@gremlinmachineshop I actually had a good set of those Sovtek 5881 I had forgotten about. Popped those in this afternoon and the bias is still around 35mA with my probe. Now the amp is sounding like I had imagined. The stock tubes are just kinda bland sounding. Doing some tube rolling in the preamp now.

When Russia invaded Ukraine, everybody freaked out and hoard-purchased tubes for a bit there, kind of like toilet paper during Covid, et al. Prices went thru the roof for a few months. All the Russian-made Sovtek and EHX prices are still higher than before I think. Funny b/c the other 2 countries China and Czech still produce tubes, no problem. It was an ignorant freak-out, for sure.

Yvw! The video summary has the instructions also, if you want a quick reference guide anytime

@@gremlinmachineshop Thank You appreciate it! I have the SLO 100 and it's amazing. I'll probably make it hotter to see how it sounds. But for now, it's sounds awesome from the factory. They usually bias the amp on the cold side to make it safe probably

Maybe you just got a "strong" preamp tube(s). You could always run some lower gain factor tubes in the V1 or V2. Like a 12AY7 or 5751. If you're not familiar with lower gain preamp tubes Google it. There's a handful of other tubes that you can easily substitute for less gain without needing to re-bias the amplifier.

@@-DILLIGAF Ok, thank you.

@Zebram5 In some of the forums, some people shared the same sentiment as you. They went with lower gain tubes and said it worked a charm. I do it all the time in amps. In a way, it's kind of like having different wattage light bulbs. If 100w bulb is too bright, just lower it down to a 75, 60, or 40w bulb. It's about as easy as changing a light bulb to change to a lower gain preamp tube. Pull one out and put a lower gain one in its place. You don't need to re-bias as mentioned earlier. Good luck if you decide to do it!

Definitely xlnt choice