Ok, I'm looking at these two all tube amp heads. Other than the massive difference in price, I don't see any other differences!



Either way, I'm changing out tubes.
Go to www.harmony-central.com and see what the user reviews say about them. I've never played either one but hear good things.

BTW I wouldn't consider $100 to be a massive price difference.
It's a fine line between clever and stupid.
Based on specs alon e(since I've never seen / head a B-52 amp), I'd say it would be worthwhile popping the extra $100 for the AT-100. You get a whole lot more bang for not a whole lot more buck...
Guitars: Custom Lado Earth 2000-3, Custom ESP Explorer, BC Rich KKV, Gibson LP Studio, Greco SG, El Degas Stratocaster, Agile AL-3000, LTD EX-351

Rig:Marshall JVM410H + Marshall 1960A, Boss Noise Suppressor
I just bought the AT-100 head and it is amazing for the price. Definetly get the AT. Gain of a Recto and cleans of a fender (not exact, but pretty good.)
I have never played the ST-100.

However, the reviews on HC seem to be greatly in favor of the AT-100.

From owning the AT-100 I can say that I enjoy what the amp brings to the table. Good gain, though the two gain channels are kind of similiar.

However, I recommend a tube swap; it does wonders for the amp.