I recently made (for me) a useful discovery. I don't often use the Ehrlund, since the Full Circle is so easy, dependable and feedback resistant. But, using the Ehrlund preamp with the Full Circle gives me a volume control "on board", and a phase switch. Sounds (to me) transparent with the Walter Woods. Took me a long time to realize how useful the volume control is, particularly if there is enough pause time between arco and pizz to turn it.