I won't ask where you sourced your SUT from but can you tell us why this particular one for the VP4 Silver?
We focused on manufacturers who already made such parts. We understood that they require proper knowledge and experience, hence we can't expect a local workshop to make them for us. Also, the most famous Japanese manufacturers like Tango and Tamura started to downscale portfolios. Particularly during Covid-19, they downsized because they couldn't sustain manufacturing dozens even hundreds of models. So naturally they focused on their bestsellers. This wasn't necessarily a safe option for us. We did buy SUT models from several reliable manufacturers and listened to all. First we selected the brand that sounded best to us, then listened to all their models suitable for phono. Ultimately silver was the better choice not because it is a precious metal or cooler. It simply offers another level of musical experience. Once we heard the silver SUT, we couldn't really go back to copper. Considering how tiny the signals from MC cartridges are, we think that the 'silverness' of the SUT and other connections and solder points is crucial

Where did the idea of developing the Silver version originate? Did it start with a silver SUT or did you want a silver version then found the means to make it?
The SUT manufacturer told us that he had a silver part 10 x more expensive than those we had listened to before. It was clear from the start that if we used it, we couldn't just replace the copper one 'for free' so had to design another more expensive version of the VP4. Once we tested the silver SUT, it was so much better that I even considered giving up on copper altogether even though it would have to be significantly more expensive. In this way I could be sure that our customers get the best sound we can offer. We have always focused on sound quality even if it came at greater expense.

Are you even planning on offering a balanced version?
We designed the PCB so it can be used both single-ended and balanced so the latter version could be built. I'm just not sure that we will ever promote it or if there's even a need for it. When it comes to DACs, people often use them to drive power amplifiers direct. If the latter are balanced, so must be the DAC. Not so for phono stages. Also, a DAC's balanced outputs offer sonic benefits but with phono stages it is quite the opposite. Still, we have the option on board so to speak and await orders and inquiries that will tell us whether there is any significant interest in a balanced version. For now we have the regular copper and silver models.

Can owners of regular/copper VP4 upgrade to silver in the future?
An upgrade to the Silver version is physically impossible. If someone wants to upgrade a copper VP4 to silver, we will accept a trade-in for the difference.

Is the upgrade impossible because it also involves silver hookup wiring?
There are more differences. Some parts in the Silver version differ from those in the copper version like capacitors we selected after long listening sessions. It is not so much about using more expensive components but rather about the copper SUT sounding so different that to match its character took different parts around it. Some work better with the copper SUT, some with the silver. The choice is not based on price. We do upgrade to WBT connectors but they are not silver. We use WBT for all inputs because we realize how small the signal entering is to really suffer from a poor conductor in a cheap socket. Let me get back to silver transformers. Let's forget the fact that they feature very hard-to-make hence very expensive amorphous cores and focus on silver wire. Few people realize that in audio where silver appears in crossover coils, capacitors leads, high-quality relays like ours or amplifier output transformers and in this particular case small-signal transformers, the silver wire itself is the challenge. The global industry is focused on huge quantities of copper winding wire covered in insulating enamel. The manufacturing process is very difficult and only huge factories can do it. You can't do it in your garage. We need the same process for silver wire but it is not a product used by the industry as such. It is not really needed so demand is minimal. You can't really convince a manufacturer of copper winding wire to switch over to silver because the process of re-purposing production is complex and for it to even be profitable would need kilometers worth of silver wire. Any high-end product will also need several cross sections of such wire. You'd have to to order kilometers for each needed cross section. That's more than the entire industry of silver coils will consume in the next 1'000 years. What's more, the silver would likely get contaminated by copper because the whole production line is filled with copper waste and fumes. All that by way of stressing that obtaining high-quality silver winding wire is incredibly difficult. I believe that only two or three companies manage it. That's why there aren't dozens of small boutique manufacturers who offer silver transformers. It just can't be done. It is one of our industry's secrets, one of its barriers of entry. If you don't have access to such wire, you won't be able to get it no matter how much you're prepared to spend. We're lucky to know a manufacturer of silver SUT and amorphous cores.