Recent content by dtrax

Absolutely. When I read bandit2031's initial reply to me correcting him, I had a laugh. But then I saw he'd been corrected by others and went at length to admit as much. With respect to Mesa's confusing schematics, all I can say is you just get used to reading them. My guess is they did not (at...

Not to derail this thread, but the above is incorrect. NFB is 100% disconnected in Modern mode for Rectos. The presence pot is rewired to a passive HF shelving filter connected to the treble wiper. This is confirmed in the schematics. Otherwise, Raw/Vintage mode operate in the traditional...

Treble and Bass at 0, Mid pot anywhere you want, but for sake of argument just dime it.

The clean channel loses some bass when doing a 2C+ mod. It's still usable though.

Without tubes the supply rail isn't loaded down. 500V sounds normal. I realize this post is over a month old, but did you roll tubes to rule out a bad one?

Sounds awesome dude! I wasn't aware the SP had revisions. When I modded mine V2B already had a 15uF cap across the cathode. Good call hardwiring it in!

It's been a long time since I sold my F30, but it's a good amp. Cleans are great. The dirty channel is unique. The tone stack works similar to a Mark series, in that it controls the frequency balance in the preamp. So you can go from tight to fuzz-like styles of distortion. In fact, one of my...

Voltage rail just means supply voltage. More supply voltage = more gain (generally), which translates into more headroom. This could be anything from an inferior design (on the part of the pedal), an impedance mismatch, too long a cable, etc. Sure. But said EQ will not have the same circuit as...

I modded mine a few years back. Off the top of my head: V1a cathode bypass cap changed to 0.47u - absolutely necessary for tight high gain, but you sacrifice overall low end for both channels. "Lead Fat" capacitor changed to 750pF - not much of a change, just a touch more gain in mid freqs...

That white wire needs to be connected to the reverb tank. Locate the tab, just below the green wire (in the photo) that has a bit of solder already. As to the low output/fizzy sound... start with the obvious stuff like swapping tubes (V4 drives the Main outs), trying the FX loop send (also, be...

Also, does anyone know the value of the cathode bypass cap on V3A (Lead Bright)? I'm guessing a 0.22uF like all other Mk's from IIC+ onward. Thanks again :-)

EDIT: I'm a dope. Relay A grounds the output of V3A, muting the Lead Channel. Nothing is mixed in after the the FX loop. I realize I'm talking to myself at this point, but I didn't want to confuse anyone. :mrgreen: I'm planning a new amp build, and am considering a MkIIB as inspiration. The...

This. 6V6s are typically biased around 20mA give or take. Neither 6L6's or EL34s would be biased that cold (normally). I suppose in variac/EL34 mode it might approach usable mA's... but my guess is that it would have those 6V6's running mighty hot. FWIW, JJ6V6S can take a beating. I'd give those...

You're right. And I misspoke (typed?) about jumpering it - I did simply lift it off the pcb. It's worth the effort for lower volume playing (a bit fuller). For gig volumes I didn't notice much difference. I've always kept the channel master for modern mode somewhere in the 10-11 oclock area...

Thanks for the a/b. The differences are subtle, but there. In a blind test I sure as sh!t wouldn't be able to say which one was which though lol. To my ears, the 3CH had a touch more top, and the 2CH had punchier low-mids. But realistically, there differences were <5% or so. Personally, ever...