First Watt J2

@Kalali, yes, it is certainly understandable that the maximum power ratings of the two amps into 4 and 8 ohms would be misleading as to which is the current source amp and which is the voltage source amp, since **usually** doubled maximum power capability into halved load impedances signifies a voltage source amp. But as long as an amp is operated within the limits of its maximum voltage, current, power, and thermal capabilities, how its power delivery varies as a function of load impedance will depend on its output impedance, not on its maximum capabilities.

Also, it’s interesting to note that as indicated in its manual the power capability specs of the F2 are based on total harmonic distortions of a very high 4% for 5 watts into 8 ohms, and an even higher 9% (!!) for the 10 watts into 4 ohms. While the J2’s specs are based on 1% in both cases.

Best regards,
-- Al

I’ve had several back loaded horns: CarderSound, Horning, Lamhorns, and Lowthers. Through trial and error, I’ve found they’re a much different animal than my front loaded horns, transmission lines, and conventional box loudspeakers. Like me, you may find a lot of what you thought you knew or how things look on paper quite different from how things work with these.

Although I’m not the biggest fan of the SET built around the bigger 211 and 845, they more than proved the best match with this type of loudspeaker, with the smaller SETs coming in next. The 211 and 845 simply put power into them in much better way, and came across as having much more seat of the pants power and better drive them than my push-pull tube, OTL, and solid state amplifiers

I had a J2 in my system for two weeks (borrowed from a friend).  It ran 99 db/w efficient system easily (I also don't play music that loudly).  I thought it was a very good solid state amp.  Unlike a lot of solid state gear, it did not sound lifeless and lacking in that indescribable "something" that keeps my attention; my mind tends to wander more when listening to solid state and I am just not as engaged.  It was also pretty decent with dynamics when listening at lower volume level (another strength of tube gear).  It was not as warm (bumped up in the upper bass) as some tube gear, but, then again it wasn't thin and harmonically bleached as some solid state and high-powered tube gear can be.  The only thing that really gave it away as being solid state is that it had a slight bit of an artificial edge or hardness to the initial attack of the note that I hear with most solid state amps.  I could easily live with the J2 and I am a committed fan of low-powered tube gear (I don't like most higher powered tube amps, with the exception of certain OTL amps).

I also heard a home built version of one of the First Watt SIT amps in the system of a friend (same person that loaned me the J2 built this amp).  It sounded really good driving a 105 db/w horn system.

kalali,I have 1.3 W SE EL11 Telefunken /in triod/ & EBF11 Telefunken /in triod/ & AZ1. This is my project. Im very glad. It drives my Fullrange 8 inch with added 12 inch bass speakers. If You are interesting, I can give You my amp for a few days to try with Your speakers and tell me Your opinion. I had projects 1 W amps, SEs 6P15P, 4P1L, 6CH6, 6LR8, 6BL7, 6N30P, 5687....I love 1 W SE!