I honestly don't know where to begin, and I just need to vent. I already know that the solution to whatever my problem is will be expensive, but maybe getting it all out here and reading your responses will help. I'm at my wits end, so grab the popcorn.
Firstly, I'm not a tube-savvy guy. I barely understand what's really happening with the technology. So, I put my trust in information from others, forums, reviews, repair guys, and do the best I can to filter it and determine what might help me achieve the sound I want.
Now that that is out of the way. I was a Mesa Mk IV combo guy for a while. As my tastes and playing evolved, I was drawn to the MP-1. For the first year and a half that I owned it (purchased on eBay April 2020), I used the power section (6l6) of the Mk IV, even bypassed the legendary 5-band EQ, but got the tone I wanted. Seeing that the Mk IV was being wasted, I sold it last October and purchased a Carvin Tube 100. I chose this power amp after reading about it's transparency. I also made the switch from 6l6 to EL34.
Now, I get conflicting information on the following. Everything I read on the internet, from reviews to forums tells me that power tubes do affect tone, not to the degree of pre-amp tubes, but they do influence your sound. However, my amp repair man, and another I recently went to tell me power tubes have no effect on tone, unless I'm playing at very high volumes, and the break up characteristics really shine through, but even then, it's not an affect on tone. However, the internet always seems to tell me differently, and since I have limited knowledge of tubes in general, I don't know what to believe. However, I trust my ears, and lately they're telling me something is way off in my rack.
I recently had the Carvin serviced (by the second repair man) as the entire thing went silent while playing a few weeks ago. I suspected bad power tubes, but as I bought it second hand, I thought it would be a good idea to have the entire unit looked over to establish a baseline as the current owner. It was the power tubes, and I also had the (2) 12ax7s replaced.
The amp was previously tubed with Svetlana, I received it back with re-issue Mullard's and EHX 12ax7s. From what I've read, both are well-defined tubes and pretty neutral. However, my tone is now very honky, with a mid-range boost and flubby bass. I've tried every EQ combination imaginable on the MP-1, boosted bass, scooped mids, spiked treble and presence. It goes from flat to shrill and ice-picky. I've tried EQing with my Rane MPE-28 to no avail. I even tried cranking the power amp, which did bring out some amazing crunch, but the tone was still awful.
I also adjusted both gain stages on the MP-1, achieved a nice tight gain structure, did hear a slight difference in tone when I drove them hard, but couldn't remedy the tone issues. The MP-1 has had 7025 tubes (from Doug's Tubes) for the past year, which I noticed clip when I push the Master Gain past 8. I rolled the JJ's that came with the unit from eBay and it actually sounded better, and the clipping disappeared, but the tone still sucks.
In October, I also had to buy a speaker and cabinet to make up for the Mk IV, which had the Electro-Voice Black Shadow in an open back cabinet. I have a mono rack, so I decided on a Celestion Redback 150w (to accommodate the 100w Carvin) and a MojoTone birch ply 1x12 closed-back cabinet with about 12" of depth. Maybe the Redback is a mid-range speaker? Maybe the cabinet sucks?
Maybe the repair guy cold biased the Carvin? But I don't even know if that affects tone. Maybe the EHX 12ax7s in the Carvin are wrong for the tone I want?
Or, maybe the MP-1 needs service? I've been in extensive talks with MarshallJMP about shipping it from NY to his country.
WILDCARD: I swapped the EMG 81/85 in my Jackson Soloist for a Seymour Duncan Jazz/JB in December. Maybe that's the culprit (but I doubt it).
As you can see, there are way too many variables and the expenses are piling up. Is it the MP-1, the Carvin, the Celestion, the cabinet? I don't have a second speaker, power amp or cabinet to cross check any of this. I'm ready to get rid of it all and just buy a Marshall head and reverb and call it a day.
Thanks for reading through this. Please talk me off the ledge.