I have been Wed to a selection of Pre Amp's' over the years and have had Honeymoon and Estranged Periods with the same devices, fortunately in the order of Bliss followed by Tribulation.
A few years back, I was caught on a DIY Build Thread for a Pass Design Pre Amp', which I was quite encouraging about and as a result was over time introduced to five build guises of it.
I have been impressed beyond the usual and one owner chose the Pre over a selection of Branded Pre's that were demonstrated with an intention to purchase.
One the built models has been used in my system for over 18 Months and has made a extremely good impression to the point I have had two PCB 's produced to enable myself to have a 'commission built' Balanced Version of the design.
The difficult to comprehend part, is that without a Case, these can be produced for very fair money, even if a Commission Build is carried out.
How far a individual is wanting to go with the aesthetic, will add to the end cost.
I have seen one produced with repurposed Black Gate's with a Three Box Design inclusive of Circuitry and Source Selector Module, Standalone VC and Standalone Power Supply for less than £500. It was this model that shone above Branded Pre's during a comparison demonstration. A Basic Build that was also present, at the demonstration, proved that it was very close in comparison to a few quite expensive Pre's.
The Basic Pre Amp' was the one that the individual behind organising the demonstrations opted for, which has over a period of time had an extra couple of hundred extra spent on it, and with the improved parts on board, does punch well above its cost for the sum of parts.
Disclaimer:
1, As for a Transparent Presentation, this Pre' falls into the category of being epitome to this sonic trait.
2, If not a ee savvy individual, the Build is best to be produced/ sourced from a skilled in ee technician.