OTL amps, my pick for the tube used.

I’ve always been interested in these which use the 6C33C but at $22k/pair they are out of my ballpark:

http://www.atma-sphere.com/Products/#Novacronhttp://

Those 6C33s in the OP are too closely spaced for reliable operation. The 6C33 is a very hot running tube on account of its prodigious filament.

We re-introduced the Novacron by popular demand, but its a simple fact that other tubes are a lot easier to live with. 

I know this is a good figure for an OTL, but I have to laugh when I look at the flagship models of my amps (100-amps continuous)

Just to be clear, that's 100 **watts** not amps, per the manufacturer's website. With 150 watts into 4 ohms, that's about 6.2 amps total. Our MA-2 can do more than that.

I have yet to talk with the owner of a product that uses 6C33 tubes that hasnt had to live with much higher than average problems with these tubes during the first 50 or so hours of use. Perhaps this is no longer the case. 

Just to be clear, that’s 100 **watts** not amps, per the manufacturer’s website. With 150 watts into 4 ohms, that’s about 6.2 amps total. Our MA-2 can do more than that.

Hi Ralph,

Before George points it out, the datasheet shown at the second link in his last post does in fact say "output current: 100 amps (continuous)," for the ME 1400/ME 1500 amplifiers referred to in that post (as opposed to the OTL amp referred to in his OP).

However, as best as I can tell from some somewhat blurry rear panel photos I found on the net there is a 5 amp fuse located immediately adjacent to the ME amp’s pendant power cord. Assuming 240 VAC (as is used down under) that would correspond to a maximum AC input of significantly less than 240 x 5 = 1200 watts, assuming reasonable derating of the fuse. Which in addition to calling into question the specified "typical" output power capabilities (e.g., 800 watts per channel into 2 ohms and 1500 watts per channel into 1 ohm, these figures stated to be "continuous and with both channels driven"), would mean that 100 amps could be continuously supplied into a load impedance of no more than 1200/(100 x 100) = 0.12 ohms. And actually much less impedance than that, given reasonable derating of the fuse and reasonable efficiency assumptions, and if two channels are to be driven.

In other words, a usage scenario that would never exist in practice.

Best regards,

-- Al

Beautiful amps, I can't afford the tubes let alone the amps though.