300b lovers

One of the nice things about working with Cinemag is their custom design service. This gets us away from the many limitations of standard off-the-shelf transformers from other vendors. We specify source impedance, the range of loads (including capacitance), DC current flow, and expected DC imbalance. They show us what their computer model tells them, we test the physical prototype, see how it works on the bench and in-circuit, and go back and forth a few times until everyone is happy. Off the shelf, it's take it or leave it.

This is what made both the Raven and Blackbird possible. I didn't think a transformer using the 6SN7 in balanced mode could be realized because of the quite high impedances involved. To my surprise, Cinemag showed me otherwise ... very clean square waves at 10 kHz with minimal overshoot. This is not an off-the-shelf part ... it's been designed for us.

When we say the Raven and Blackbird use custom parts we aren't joking. Without them, they aren't practical. We use standard tube types because we want our customers to enjoy them for a long time, and we expect the 6SN7, KT88/6550, and 300B to be around a long time. Under the chassis, though, we use custom parts for critical functions.

Ralph, I see you introduced a PP 300B amplifier at one of the recent hifi shows. How do you think it compares to your Class D amplifier, in subjective terms? Since you designed both, you're the best qualified to assess the differences.

@donsachs 

I tried to post a new link but it gets blocked. You have to Google Soundstage SOUTHWEST Texas audio show. Not sure why the link gets blocked, weird. Use atmaspehere 300b prototype in search string. 

@lynn_olson 

“Ralph, I see you introduced a PP 300B amplifier at one of the recent hifi shows. How do you think it compares to your Class D amplifier, in subjective terms? Since you designed both, you're the best qualified to assess the differences.”

There are a few of us curious audio geeks interested in learning more. John Wolf of  Classic Audio Loudspeakers used them with his field coil speakers and he said that the bass was incredible. Perhaps time to ditch the Novacrons he uses a lot for the new 300. 

That is the first thing you notice when you hear our 300b PP. The bass is amazing. It is not over emphasized at all, but if there is bass energy on the recording you hear it all. Most importantly, it is the quality of the bass, not the quantity. When I built the prototype I had never heard anything like it. The resonance in the body of instruments, the attack and decay of bass notes. Then we spent over two years improving the amps by eliminating cap coupling, improving power supply designs, working with Dave Geren through several iterations of custom interstage transformers, moving to Monolith output transformers, etc... Now the bass is otherworldly. So I can imagine a well designed PP 300b is going to have those qualities with a good field coil speaker and make people take notice.