300B amp options

Check out the Bottlehead website.

A variation on TWL's suggestion is a 2A3 amp and using Sophia Meshplate 300B tubes with 2.5 V filaments. I have a pair in my Bottlehead parafeed 2A3 amps and they are very nice. That gives you the option to explore 2A3 tubes but does limit you to this specific 300B.

Tube:

Here are some reasonably priced 300B mono block kits (note that additional shipping is $185US).

http://www.diyhifisupply.com/diy_kits/the_billie.html

These kits can also be ordered in the USA through diycable.com (overseas shipping still applies).

Bottlehead's 300B kits (bottlehead.com) are a bit more money. I own Bottlehead amps myself (Paramour 2A3's along with their Foreplay preamp), but have never heard their 300B models (nor have I listened to the Billies).

My previous amp was a 300B Audion Silver Night (sold along with other gear due to finances) and I am looking forward to owning a nice 300B amp again.

If you are planning on using efficient speakers with an easy load, then you might also look into the Bottlehead 2A3 amps. I am waiting for an iron upgrade to be offered, by Bottlehead, for the Paramours and depending on the price may try this out in the interum. I think that the Paramour 2A3 kits are around $550 now, plus domestic shipping. I am fortunate in that I purchased assembled kits (both the mono blocks and the preamp) on the used market for very little money (just what I needed @ the time) and the young gent that assembled them did a first rate job.

Anyway, the most important thing is to not talk yourself out of a directly heated SET amp (easy enough to do) as the sound from a decent one really has to be heard to be believed.

On a side note you may find the following site interesting in regard to speakers that will mate well with SET amps (both commercial and DIY models in all budget ranges are discussed). There is also a link to a sister site @ the top of the page.

http://f18.parsimony.net/forum31999/

I picked up some inexpensive Japanese Triaxial drivers myself (thrift shop find) that I hope to be using more over the next year (need to build better cabinets) with the 2A3 amps as they are approx. 97 db @ 16 ohms. Even with quality DIY cabinets and cap upgrades they should come in @ well under $200/pr and I have a feeling that they may end up replacing my more expensive speakers (my wife liked the trial run anyway:-).

I'd check out border patrol amps. The finest 300b's I have heard and thats including the pricey Ongaku. They have a massively overbuilt triple choke power supply. If you go the kit route I highly recommend purchasing their power supply. I've read some threads on audio asylum where some DIY's had built this supply so that is a possibility as well.
borderpatrol.net