I want to make this thread for people who are looking for good guitar amps to buy. Although I am a new member here, I do have a lot of experience with guitar amps.
This is a list of amps you should check out if you want an amp with a good tone.
Just remember, there are LOTS of different amps on the market (tons more than the ones I listed.) I recommend you go to a music store to try out the amps you find there.
*NOTE: The difference between half-stacks and combos is that half-stacks have two parts to them (a head, the main part, and the cab, the big speaker at the bottom.) Combos are "single pieces." You can choose whichever one you want.
Here are some things you should know:
1. "Tube amps" (guitar amps that run with vacuum tubes) give better guitar tones overall. Don't be fooled by those solid states that have "a tube tone in a low budget." Most of them will never sound as good, no matter what they claim. In fact, most professional guitarists use tube amps. Although, most tube amps only achieve their best tones with more volume. If you can't crank it up high, you can buy an attenuator.
2. The used market has a LOT of great deals.
3. Some amps sound better when "boosted" with an overdrive pedal on top of the OD channel. I will note that if I know of amp that sounds better boosted (I will also list a specific pedal that I know works well with it.)
Now, lets begin the list.
Good guitar amps (by price-range)
$0 - $299
Vox Valvetronix 15 ($169) [15 Watts Solid state]
http://tinyurl.com/l96bum
This is a good starter amp for a pretty low price. I only recommend it if you need a first amp that sounds decent.
Peavey Vypyr 30 ($199) [30 Watts Solid state]
http://tinyurl.com/ax5ksh
This is another "starter only" amp, but considering it's "purpose" it is a pretty good amp. Let me just give you one tip: Use the tubescreamer stomp box as a boost to another channel.
Fender FM 25 DSP / Boss MT-2 (Total=about $200)
http://tinyurl.com/2alc2d4 (FM 25)
http://tinyurl.com/6bcmlj (MT-2)
This is an odd combination that surprisingly gets a great tone. Here is the video where I found out about it from:
$300 - $599
Blackstar HT-5 Combo ($499) [5 Watts Tube]
http://tinyurl.com/2d33okv
This is a GREAT bedroom amp. It is 5 watts tube, so you can crank it for a good tone without blowing your ear drums. If you are playing rock/metal/shred, you are going to want to use a boost to get more gain. A half-stack version is also available.
Randall RG50TC Combo ($429) [50 Watts Tube]
http://tinyurl.com/29ztwdp
This is another great amp, especially for the price. It has great metal tones, and has pretty good cleans. It is a great low-budget guitar amp, and it has enough volume for shows.
Line 6 Flextone III Combo ($479) [75 watts Solid sate]
http://tinyurl.com/246y53b
This is a solid-state amp, but it is actually very good. You can only but it used, since it is discontinued. This is a great non-tube bedroom amp (since it does not need to be cranked for a good tone.) I recommend you try it out first though, if you can.
$600 - $999
USED Marshall JCM 2000 DSL401 Combo / BOSS SD-1 (about $600 total) [40 watts Tube]
http://tinyurl.com/dmhjfy (BOSS SD-1 Link only)
You can get some very nice tones out of this, but it needs to be at a high volume (an attenuator can fix that.) Also, you might want a BOSS OD-2 as a boost. I find that the OD-2 gives it the best boosted tone. You have to get the amp used though.
Peavey 6505+ Combo / Ibanez TS-9 (about $700 total) [60 watts Tube]
http://tinyurl.com/299ov3z (6505+)
http://tinyurl.com/2fy6c2q (TS-9)
This amp/pedal work really well as a combo. The amp sounds good on its own, but with a TS-9 in front of the lead channel, it sounds even better. This is a great metal amp, and it is worth the money. This amp is also available as a half-stack.
USED Marshall JCM 900 SLX / BOSS SD-1 (about $800 total) [50 watts Tube]
http://tinyurl.com/dmhjfy (BOSS SD-1 Link only)
This is another good Marshall/boost combo. The cleans sound good on their own, but the overdrive channel sounds better boosted by an SD-1. This amp is only available used though. You can also buy the JCM 900 as a head, and get a cab to go along with it for more money.
Carvin V3 ($999) [100 Watts Tube]
http://www.carvinguitars.com/products/single.php?product=V3212
This amp sounds great on its own, no boost required. I believe it is only available from Carvin's website, but you can check out demos on Youtube. You can even buy it in different colors.
$1000+
There are TONS of amps in this price range that are great, so I will post some of them in list form.
Most of the ones I listed are heads (the top part of a half stack,) but combo versions ARE available for most of them.
I also listed them as the head only, so you can choose the cab yourself.
Mesa Mark V Head ($1900)
Mesa Dual Rectifier Head ($1800)
Marshall JVM 205H Head ($1400)
Soldano Avenger Head ($1960)
Fender Super-Sonic Head ($1200)
Diezel Herbert Head ($4400)
Splawn Nitro Head ($1950)
ENGL Powerball Head ($2000)
Randall RM100C1 ($2100)
Marshall JCM 800 2205 w/ SD-1 (about $1000)
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That's all I need to list right now. Feel free to post any amps you think should be added.