For under a grand I would suggest a Conrad-Johnson MV 52. Usually goes for around $800. Try to get the 52 over the 50. The 52 has all polypropalene caps in the power supply.
BTW, I'm a long term S30 owner. If you can get one for around a thousand dollars, go for it, though I'd be a little cautious about why it's priced that low. Typically. it goes for $1800-2500 used.