[autoteleology]

I need something much more powerful than my Magni 2 Uber (1.8W @ 16Ω) to drive my JVC HA-SZ2000 EQ'd for massive bass impact.
 
Basically all I want is some recommendations for headphone amps or receivers/speaker amps (I plan on using an adapter to tap the speaker outputs) that are inexpensive (the cheaper the better), have tons of gain and don't look bad sitting on my desk. Solid state is preferred. If it's a receiver, the simpler (less unnecessary features I'll never use) the better.

 

[Music Alchemist]

Did you test the M2U with the SZ2K and verify that it clipped when you boosted the bass to extreme levels? Because I don't see how it could. It outputs up to 1.8 watts at 16 ohms, which is the impedance of that headphone. Many (if not most) SZ2K users use portable amps that aren't nearly as powerful. As I'm sure you know, the massive bass impact comes primarily from boosting the bass with EQ, and if the amp can handle it without clipping, I dunno what else you want.

 

[autoteleology]

  Did you test the M2U with the SZ2K and verify that it clipped when you boosted the bass to extreme levels? Because I don't see how it could. It outputs up to 1.8 watts at 16 ohms, which is the impedance of that headphone. Many (if not most) SZ2K users use portable amps that aren't nearly as powerful. As I'm sure you know, the massive bass impact comes primarily from boosting the bass with EQ, and if the amp can handle it without clipping, I dunno what else you want.

 
I have the Magni 2 Uber on high gain, 100% volume and it's hissy, and also not loud enough. I just need more power.
 
I also don't "boost" the bass, because I EQ subtractively. As you can see below, I have some parts EQ'd to -40dB. In avoiding the quality reduction that comes with positive EQ, I have volume issues. 
 

 

[Muinarc]

Maybe try a cheap yard-sale speaker amp/receiver with resistors? It's hard to get high power for low money.

 

[Music Alchemist]

  I have the Magni 2 Uber on high gain, 100% volume and it's hissy, and also not loud enough. I just need more power.
 
I also don't "boost" the bass, because I EQ subtractively. As you can see below, I have some parts EQ'd to -40dB. In avoiding the quality reduction that comes with positive EQ, I have volume issues. 

 
I see. That must really reduce the volume dramatically, since the SZ2K is a very sensitive (108 dB/mW) headphone. The only headphone I had to crank the M2U with was an exotic piezoelectric.
 
I wonder how much of an improvement reductive EQ makes in the context of extreme bass. I mean, the bass is a lot stronger either way, and you generally have to mess with the rest of the frequencies to get things to sound better when there's so much extra bass. I'm assuming you've done this comparison already and concluded that the more difficult method was better.
 
Anyway, there are plenty of speaker amps under $200 that could suit your needs, especially on the used market. I don't specialize in speakers, though, so the only thing I can recommend is to research speaker amps in that price range.

 

[Noah Marchais]

Try buying a speaker or home theater amp with a Headphone output. with mine i drive my Hifiman HE400S at 20 volume and there about 32 ohms