Sanei Lab 2A3 Single-Ended Tube Amplifier
Archived listing from the original vintage-amplifier.com. Prices, seller details and purchase links have been removed; this page is a reference record, and nothing here is for sale. About this archive.
Tube power amp use RCA 2A3 manufactured by SANEI Laboratory. Saneimusen is very famous handmade tube amp manufacture in Japan, all their tube amp has the simple circuits but using high grade part all part was selected one by one for matching all of them in one amplifier.
Some people spell their name is Sa-nei but in the Japanese, it was spell as SAN-EI. All transformer is top class of HIRATA TANGO (not ISO )which is very very rare and hard to find nowaday. Output transformer is XE-20S and BLACK GATE condenser is unable to be found nowaday . You can see in picture to see which part was used in this amp. Output 2A3 tube is China made but driver tube is USA and Telefunken made.
I took detail picture inside of amp, you can see which part was used in it. All of them are high grade ones with professional wiring. 100% handmade, no board was used in this amp. The sound is very natural, especially middle range is great.
Amplifier of age is over 20 years, I did test it in my system and there is no problem, sound is perfect, you can easily change 2A3 to 300B tube but need some modified. You can connect this amp directly with CD player because it has volume adjustment. Amplifier was manufactured for Japan so its AC electric volt is 100-110V 50/60Hz.
About this model
A single-ended 2A3 amplifier from Sanei Laboratory, a Japanese builder of hand-made tube amplifiers, with Hirata Tango transformers including XE-20S output transformers and Black Gate capacitors. The seller dated it to over twenty years old, with Chinese 2A3 output tubes and American and Telefunken drivers, and a volume control so it can be fed straight from a CD player.
A 2A3 gives around 3 watts single-ended, so an amplifier like this needs efficient speakers. The seller's note that it can take a 300B "with some modification" is true in principle, but the two tubes need different filament voltages and operating points.
| Builder | Sanei Laboratory, Japan (listing) |
|---|---|
| Type | Single-ended triode amplifier |
| Output tubes | 2A3 (listing) |
| Output transformers | Hirata Tango XE-20S (listing) |
| Output | About 3 W per channel (typical for 2A3) |
| Mains | 100–110 V (listing) |
Questions collectors ask
How much power does a 2A3 amplifier make?
About 3 watts in a single-ended circuit.
Can I put a 300B in a 2A3 amplifier?
Not directly. The 300B needs a 5-volt filament supply and a different operating point; the conversion is a rebuild, not a tube swap.
Sources: Wikipedia: Single-ended triode; Wikipedia: 300B.
