For the 3rd time I rebuilt my ST35 with a custom layout. The previous version used a large box which I needed to fit the big Clarity TC film caps for the power supply. It worked well but took up a lot of space.
This year my older brother asked me to build him a tube amp for his office. He wanted a small footprint and every connection and control mounted on top so he can drop the amp into a fancy wood box he's going to build for it.
I went with the Hammond 12x10x2" box and designed a new layout which incorporated Shannon Parks' driver circuit which uses a 12AX7 voltage amp and 12AU7 for phase splitter for both channels. I also used Dave Gillespie's EFB circuit for improved power and lower distortion, a single bias point for each channel, fuses on the EL84 cathodes, that stepped attenuator everyone here likes and finally 2 inputs with 1 pair of RCA and one 1/8" jack. Everything is wired point to point.
I initially had some trouble due to a missed wire and higher voltages than expected. I think it was a bad regulator in the EFB along with feedback not being properly set. It's all good now. With inputs shorted it is dead quiet. I was surprised by how good it sounded with my cheap test speakers. Pretty cheap to put together too although there was quite a bit of labor.
This year my older brother asked me to build him a tube amp for his office. He wanted a small footprint and every connection and control mounted on top so he can drop the amp into a fancy wood box he's going to build for it.
I went with the Hammond 12x10x2" box and designed a new layout which incorporated Shannon Parks' driver circuit which uses a 12AX7 voltage amp and 12AU7 for phase splitter for both channels. I also used Dave Gillespie's EFB circuit for improved power and lower distortion, a single bias point for each channel, fuses on the EL84 cathodes, that stepped attenuator everyone here likes and finally 2 inputs with 1 pair of RCA and one 1/8" jack. Everything is wired point to point.
I initially had some trouble due to a missed wire and higher voltages than expected. I think it was a bad regulator in the EFB along with feedback not being properly set. It's all good now. With inputs shorted it is dead quiet. I was surprised by how good it sounded with my cheap test speakers. Pretty cheap to put together too although there was quite a bit of labor.