I've had my head in the budget preamp space for quite a while.
The
Bottlehead Foreplay III stands out as one of the best bangs for the buck, but it's slightly more than $350. A new unit is $449. They're hard to find for less b/c owners usually modify them with better caps, volume attenuators, etc. Building a kit is a great learning experience if you're into that kind of thing. Bottlehead gives great support and there's an active forum to ask questions.
AES (
Audio Electronic Supply) is owned by Cary. They used to offer kits, but don't anymore. I had the standard AE-3 for a while and found it to be bloated. At times, the bass was out of control which muddied the midrange and skewed the whole presentation. I was using RCA Red Base 5692 and Sylvania 6NS7GTB at the time -- neither are known for being muddy, so I can only attribute the bloat to the preamp. You can easily find the AE-3 for $350. It's certainly not a bad preamp. It has a silky midrange, smooth top end and it's very quiet which is hard to beat for $350. If your speakers are bass shy you might find a nice synergy. It might work well with monitors.
There's a big difference between the standard
AE-3, the
DJH and the
AE-3 MkII. Kevin Deal from Upscale Audio had this to say about the three:
With the regular AE-3 and now AE-3 Mk 2 the bass can be a little bloated depending on the application, but the AE-3 DJHs front end topology is slightly different. It is direct-coupled, meaning there are no coupling caps between the input and output stages, which makes the preamp much more dynamic. I think it has incredible bass, great imaging, airy highs.
I now own the DJH and positively confirm what Kevin says. It isn't bloated in the least. It's a completely different beast compared to the standard AE-3. The bass is fast and tight. Overall, it has a nice balance between warmth and detail. IMO, the only drawback is the gain at 20 dB. They sell for roughly $750-800 used.
I had an Audio Experience Symphonies V2R for a brief period of time. I paid a ridiculously small amount for it (something like $300). Unfortunately, my unit had a loud buzz that turned out to be a circuit problem. Despite the noise, it was a surprisingly nice warm sounding preamp when the volume was cranked up. I decided to return it rather than have it fixed. New it's $448 plus shipping from China.
I've heard a lot of praise for old Dynaco Pas preamps. They sell on eBay for $150-300 depending on the condition. There's an active community of folks who restore them. They claim it sounds phenomenal. I haven't heard one to confirm, but if budget and performance are your priorities, you might check it out. The only downside is they look dated.