You're welcome. Sometimes it IS the simplest problem and fix!

Gregg

Well, certainly the more time spent on lead dress, the better. The Bluesmaster that Nik built for me is dead quiet. That said, the S&M is a totally different animal from FM ME. The FM ME has a ton more high end sizzle, and sometimes more high end sizzle means more perceived noise and not as quiet a sound stage. That could be it, or the FM ME you have could just use a lil more tweaking of the lead dress, sometimes just spreading them out a lil bit helps.

Gregg

Yup, you can run the cathode straight to ground, just can't test the bias on that one without some different equipment, but you can bypass it.

Gregg

If it wasn't grounded, you would be getting zero current flow across. What kind of voltage are you getting at the plates (pin 3)? Also you said you unplug and plug your c-lator with the amp powered on? Is it on or off standby? Generally you shouldn't connect/disconnect that unless the amp is powered down or at least in standby. Also, when you do your testing are all your levels turned down?

Gregg

The 1 ohm resistors provide a way to safely read the bias current with a DMM, and connect the cathode (pin to ground. Instead of reading the actual current, your are reading the voltage drop across that resistor. Through the magic of electrical engineering and math that I barely grasp, the mV reading equals the current reading but is safer to measure. If V5's sensing resistor is bad it could cause a problem, as pin 8 and externally only pin 1 are the cathode and connected to ground. I would check the external connection between pin 8 and pin 1 along with changing that 1R 2W resistor, just to be safe.

Gregg

Yeah, could be the screen resisitors, the bias resisitors, or both. I'd check the readings on the bias pins (#4) and see what you get. you are defintely pulling more current on V4 for some reason.

Gregg

Thinking on it some more, it sounds like either the Mesa in V4 went kerplooey during the set, taking out the screen resistor, or the screen resistor went out during the set taking out the tube. Either way, I'd be checking V4. I'd still check the negative bias voltage on both sockets, though, just incase.

Gregg

I'd check the screen resistors and make sure they aren't melty or smell burnt. If they don't then I'd check the bias voltage on each tube, preferably with two new matched tubes from a reseller that tests them at the prescribed voltage. If that checks out, check the plate and screen voltage on each tube (pin 3 and the pin 4). The plate and screen voltage should be fairly close on the OTS, if not, something has gone awry. I'm not knowledgable enough to know if you can hurt the OT without destroying it, but if you can, I wouldn't doubt that red plating a tube could cause that. Hopefully one of the more knowledgeable guys will chime in. I will say, be sure to keep one hand in your pocket while testing, and be sure to have a load on the amp, either your speaker cab or a dummy load, and all controls turned down while testing. Also, it wouldn't hurt to change your PI tube. The PI is part of the output half of your amp and is the unsung hardest working tube in your amp. Most times it's the PI we hear breaking down in the power section when we overdrive the power end of the amp, and it handles alot of voltage, so it's a good idea to change it out and re adjust the trimmer when you change your power tubes

Hope this helps

Gregg

Pin 5 should be the same irregardless of which tube is in which spot. The current draw has more to do with the screen and plate structure of the tube, along with the cathode, and can be effected by the screen resistors going out as well. In other words, if the rest of the tubes you are trying aren't way out of whack like the original set, everything may be fine, and the one drawing 70 mA may have been red plating and on its way out. How does it sound now with the better matched tubes?

Gregg

Pin 5 will vary depending on his much negative voltage is being applied to bias the tubes, but the should be the same on both tubes. Pin 4 should be about the same on both tubes.

Gregg

Selling some pedals that I don't use. Here we go!

TC Corona Chorus. Toneprint enabled. Currently has the Boss CE-1 toneprint installed. I can't find the USB cable, but it's a pretty standard USB to mini USB type. No box. Had Velcro on it which I removed. $100.00 USD plus actual shipping to your location.

TC Hall of Fame Reverb. Toneprint Enabled. I can't find the USB cable, but it's a pretty standard USB to mini USB type. Box included.Had Velcro on it which I removed. $120.00 USD plus actual shipping to your location.

MXR Dyna Comp(modern version, not vintage).No box. No Velcro ever installed. $45.00 USD plus actual shipping to your location.

Ibanez TS-9 Tube Screamer (modern version, not vintage). No Velcro ever installed. No box. $50.00 USD plus actual shipping to your location.

Boss GE-7 Equalizer Pedal. No box. No Velcro ever installed. $70.00 USD plus actual shipping to your location.

PayPal only!!

Gregg

Are you able to drop the chassis and check the voltages on your tubes, specifically pin 5? Sounds like the bias resistors may be going out or maybe the screen resistors (pin 4)

Gregg

Very nicely done! Those Weber Alnico 1265's are quite nice indeed, i love mine in my Bluesmaster 2x12 Combo, very nice and not boomy or mushy at all. Did you get the pre rola doping and break in?

Gregg

Ah, yeah the dreaded VAT. Damn. Hmm I'm sure there has to be a used one somewhere in Ireland, maybe.
Gregg

Nik can build you a 2550 50 w for $850 USD or a 2555 100 w for $970 USD both with cabs, plus shipping.

Gregg