I purchased a Silvaweld SWH550 phono stage (the top phono in that now extinct line of product) about 6 months ago, to use as a dedicated MM phono stage. Found it on eBay for surprisingly low cost, probably because few people have ever heard of Silvaweld, let alone do they know that Silvaweld products were designed by the same guy who now designs for Allnic. Brad Morricab gave rave reviews to the lesser SWH450 version, in Positive Feedback and on the internet. The 550 is pretty cool, uses tube rectification, choke-input filter, and separate tube-based voltage regulators for R and L channels. Each tube in the circuit also has its own decoupling capacitors located near the plate pins. However, unlike the top Allnic phono stages, the SWH550 does not use LCR RIAA filtering. I've been enjoying it, but not insanely so. The other day, I replaced the suspect output coupling caps with a pair of Mundorf Silver/Oil caps that I broke in before installation. Holy cow! This simple upgrade vaulted the Silvaweld into the stratosphere. The SWH550 feeds my MP1. I use the built-in MP1 phono stage for MC cartridges. I have not heard a huge variety of very expensive phono stages, but suffice to say that the Silvaweld is terrific, as is of course the MP1. The Silvaweld has MC capability; the needed extra gain is added at the input via the use of what appear to be battery-biased JFETs, rather than the more typical SUTs. Have not auditioned the MC circuit. This should remind us that brand names are secondary; the meat of the matter is the circuit design and the parts implementation.
