Finished modding Mesa .50 Caliber+, and it saved me from selling my Rhoads.

[DesolationBlvd]

I was working on a mod for the Mesa DC-5, after finding its sound rather dull. But then I started reading the schematics. I was scratching my head at the lead channel having two tone stacks, moved the tone controls to the first one earlier in the circuit as is traditional in the Mark series, but just couldn't balance the gain. I found a .50 Caliber+ and a stock DC-5 in a store, and compared them. The 50 Cal+ blew the stock DC-5 away. I then saw the price on the .50 Cal+ and figured it was cheap enough to buy as a reference.

But the more I played it, the more I realized this was the Mark-series tone I had in my head all along. I swapped in the logo plate (it was missing its logo plate) and the Celestion Black Shadow from my project DC-5 shortly after getting it home. However, I had one quibble, the presence knob did nearly nothing at low volumes. Apparently, it's not a real presence control, but a simple tone knob after the master volume. I re-implemented it as an actual presence control and it now opens up. This extra note definition made all the difference.

I was going to put my '84 Rhoads on the chopping block, after dropping it to B Standard tuning and trying it through the project DC-5 and the cascaded Marshall Studio Vintage, but it now sounds so right through the .50 Cal+ with an actual presence control.

[Number Of The Priest]

As a non-amp-technical guy and a Mesa DC-2 owner, this was a fascinating read. Thanks for posting this topic.

I've owned the DC-2 since 2005 and I always found the crunch and contour modes to be not my cup of tea, and subsequently I never use it for its intended purpose. To get distorted tones that are more to my taste, I always used a Boss GT-6 processor as a preamp into the effects return of the DC-2, essentially rendering the DC-2 as just a glorified poweramp.

Would like to use the DC-2 on its own if it had more useful character. Sounds like your presence modification and speaker swap on your 50 Cal+ changed its character for the better. What would you suggest for DC-2 mods to improve it? Now that you partially cannibalized your DC-5, how would you further modify that amp to improve it?

[DesolationBlvd]

As a non-amp-technical guy and a Mesa DC-2 owner, this was a fascinating read. Thanks for posting this topic.
I've owned the DC-2 since 2005 and I always found the crunch and contour modes to be not my cup of tea, and subsequently I never use it for its intended purpose. To get distorted tones that are more to my taste, I always used a Boss GT-6 processor as a preamp into the effects return of the DC-2, essentially rendering the DC-2 as just a glorified poweramp.
Would like to use the DC-2 on its own if it had more useful character. Sounds like your presence modification and speaker swap on your 50 Cal+ changed its character for the better. What would you suggest for DC-2 mods to improve it? Now that you partially cannibalized your DC-5, how would you further modify that amp to improve it?

I've actually shelved the DC-5 mod project for now. Moving the tone controls to the first tone stack was only the first part of the mod, I was balancing the gain to prevent oscillation. It was there that things went haywire. Meanwhile, I'm too busy playing through the modded .50 Cal+. The preamp circuit was already there vs. what I was hacking the DC-5 into.

As for the .50 Cal+, it really was almost there stock. The stock Eminence "Vintage Black Shadow" speaker was brighter, but the Celestion Black Shadow had more body.

That said, looking at the DC-2 schematic, I'd snip the 1n cap to ground coming off the lead master. It's a dulling cap similar to the way the stock .50 Cal "presence" worked. Then after the treble pot, there's a 22k resistor to ground followed by a 1n cap. I jumpered it in the DC-5 and got more brightness. The DC-5 also has dulling caps on the phase inverter plate resistors - the DC-2 does not.