I’m impressed the direct connection hit a very "reasonable" volume level - props to your Math skills! That said I would not consider a 0-gain passive or buffer stage, in your shoes. You’ll need some extra gain on tap for the occasional softly cut recordings, for times when you want to "rock out", or for adjustments if you make a change to your cartridge / loading / settings / tubes.
A modern, highly regarded tube preamp in the ~ 10dB gain range (8 - 14) is what I’d shoot for. That’s high enough to help out when needed (without having to throttle the volume knob to MAX), and low enough not to cause noise issues and other discernible sonic artifacts. It’s the "sweet" spot for an analog-focused system. Passives and low gains are for folks with hot-output digital sources. Your Conrad Johnson, though probably still nice - is a (perhaps) dated, high-gain tube preamp, so no wonder it sounds a bit soft in contrast to the modern Herron. A 12ax7 in the V1/V2 slot is really not what you want for "pristine" tube preamp sound; too much gain - these tubes belong in RIAA phono stages, not line-stage. Older tube line-stage designs would use 12ax7 like this, in order to "add on" to the phono section for handling medium output MC cartridges - and that appears to be exactly what your CJ does. NOT necessary now with your Herron! I'm also not a big fan of 12au7, though having them on outputs here is an appropriate use of them. The BelCanto is solid state - and who on Earth wants a solid state preamp? (lol)
The Herron 360 preamp looks like a good play. Two gain choices: 4dB, 14dB which should actually be perfect - 4 for digital sources, 14 for analog - but don’t let that stop you from looking around a bit more before investing. A 360 would look sweet in a rack next to the Herron phono stage, to be sure!
A modern, highly regarded tube preamp in the ~ 10dB gain range (8 - 14) is what I’d shoot for. That’s high enough to help out when needed (without having to throttle the volume knob to MAX), and low enough not to cause noise issues and other discernible sonic artifacts. It’s the "sweet" spot for an analog-focused system. Passives and low gains are for folks with hot-output digital sources. Your Conrad Johnson, though probably still nice - is a (perhaps) dated, high-gain tube preamp, so no wonder it sounds a bit soft in contrast to the modern Herron. A 12ax7 in the V1/V2 slot is really not what you want for "pristine" tube preamp sound; too much gain - these tubes belong in RIAA phono stages, not line-stage. Older tube line-stage designs would use 12ax7 like this, in order to "add on" to the phono section for handling medium output MC cartridges - and that appears to be exactly what your CJ does. NOT necessary now with your Herron! I'm also not a big fan of 12au7, though having them on outputs here is an appropriate use of them. The BelCanto is solid state - and who on Earth wants a solid state preamp? (lol)
The Herron 360 preamp looks like a good play. Two gain choices: 4dB, 14dB which should actually be perfect - 4 for digital sources, 14 for analog - but don’t let that stop you from looking around a bit more before investing. A 360 would look sweet in a rack next to the Herron phono stage, to be sure!