maybe a randall or cube. Im in the same boat mate and going used for 500 won't get you far. There is the ashton vp 30 a all tube combo that can do metal but i haven't heard the quality of it.
I got my Cube 60 for around about 500, is excellent.
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if you want tubes, there is the randall RG 50 TC, It should be under 500 bucks as well.
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if you want tubes, there is the randall RG 50 TC, It should be under 500 bucks as well.

the rg50 tc is around the 1000 mark in aus.
you can get a Laney LV100 for 550 off bmusic.com

ive never played it myself but all the other laneys ive played were great, certainly far better than randalls anyway.

peavey bandits arent too bad either but i think they cost more
drum power.

they sell randall stuff cheap as. Go on ebay, search randall. Heaps of the entries are from them.

Or, 80 watt Ashton combo with a Metal Muff.
Hey man, your best bet is ebay. Over here in Australia the only "NEW" valve amp your going to get are the ashtons, and even then they arent anything awesome.

For 500 you might be able to get a second hand tiny terror, but I dont know if you'll be able to get a cab , or maybe a marshall JCM 900, 40 watter.

However, I would go for a Peavey Transtube series amp. I used to own a Peavey Studio pro 112, and they were bloody loud for a ss, and could easily do metal (the newer ones anyway) depending on where you live I would give ausband.com.au a go,
they sometimes have great deals!!

cheers ,man.
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