Tube preamp topologies and music

If you want to start with tube amps my recommendation is a nicely restored Dynaco ST70. A proven design (250,000 sold!) with adequate power (35wpc) for most speakers. If more power is desired adding a second one and paralleling the outputs on both will yield 70wpc. The ST70 has stood the test of time. Prices are reasonable, well under $1K. Output tubes are readily available (EL34's). I have two - one with a triode input board. The second one is a custom-build from a friend with the stock output transformers and a much larger power transformer.

I do not recommend single-end (one output tube per channel) amps because they typically have low power and high distortion/noise with high output impedances. The last means that the amp will track the impedance curve of the speaker, meaning it will yield a non-flat response, acting like a tone control. Something to be avoided!

A nice thing about the ST70 is the availability of various tube options for the input stage using different dual triodes to replace the stock pentode/triode. Mine uses three dual triode 6922's along with higher-quality capacitors. Plus you can try different brands of EL34's for different sonic "flavors".

An 8 watt single-end 300B amp would be strained to drive a Klipschorn to adequate levels for hard rock/metal because past 2 watts distortion skyrockets to 5 - 10%. Add the inability to provide enough current for the typical 10 - 12 inch woofer and you have an amp with very limited usability.

 All single-end tube amps are best used when power levels don’t exceed 25% of maximum wattage. Otherwise distortion climbs rapidly. Plus signal-to-noise (SNR) ratios are poor due to lack of common-mode noise rejection available in push-pull designs.