This Post Has Been Edited by the Author
company background : Sun Valley Co., Ltd. [100% subsidiary of Toyota Industries Corporation]
Some initial impressions....
The Sun Valley 211/845 amp is an elegant and beautifully designed audio component.
There are many things which are immediately apparent:
The materials are excellent, the finish of the Chassis is perfect and the coating is unusual, refined and almost indestructible. Very Nice.
This is s kit which has clearly gone through years of refinement and focus to obtain the highest level of performance. The circuits are designed with elegance and performance with dozens of notable features:
1. All of the passive components are very well specified and uniquely employed to provide the highest performance and durability. For example, the power supply employs very closely matched metal resistors for precis voltages while the audio path specifies carbon resistors, favored by manty including myself, for the audio path.
2. Extremely high quality multi strand internally tinned wire is supplied at various gauges optimized for the power and audio circuits.
3. The power transformer and filament filter/power supply design is VERY robust and can supply any 211/845 with stable well filtered power.
4. The main power supply board is designed to provide exceptional stability and filtration and separately address Blow voltage standby, and fixed bias reference voltages...very nice.
This build will be very different from anyone solely familiar with pre-printed circuit boards and step by step check box style instructions. The documentation is quite adequate, very precise and compact delivering all of the required information and guidelines BUT it is very important that the builder has noted all of the specifications and subcomponent relationships prior to the build... i.e. Know what the designers intended, why the approach the construction as they do and pay attention to the details.
Going through the instruction for the first few pages I made a few illustrative notes.
1. Note the sequence for construction and you will begin to get a feel for the relationship among the sub-assemblies and why, in many cases the parts specification is very specific.
2. The Parts list on page 6, describes not only the individual parts, but the subassemblies for which they were provided. Unlike many manufactures, Sun Valley does not package their components separately for each sub-assembly but has grouped them by component type. Thus for the Bias board the circuit board, potentiometers, connection block and resistors are all packaged in different locations but carefully packaged and verified by quality control (you will find an inspection sheet in the packaging to assure you receive all that is required. .
3. Note that you must know how components are coded, where they go or carefully follow the specifications on the parts index (pages 5-6) Sun valley does not print component values on the circuit boards (but does specify part designation relative to the parts list and schematic) and you need to attend to assuring that you employ the correct value, capacity and type of component. Resistor packs for example contain the resistors for several sub-assemblies in various wattages).
4. Mechanical assembly employs very high quality hardware with the capacity to make small adjustments to account for manufacturing variability in parts so you can obtain a perfect and symmetrical build. For example, there is just enough play in the M3 securing hardware for the tube sockets and bias boards to allow alignment of these assemblies in the exact center of the chassis holes for a perfect build and very attractive final product.
You are correct, the sound is incredible. Very beautiful design, excellent quality components; I made a few upgrades and small changes but basically and Very Well Designed.
Great and very specific guidelines for initial check and all measurements were within 3% of the reference voltages.
The sound is incredible and the power supply design, allowing a full warm up prior to applying B+ is exceptional.
I would love to comment on the noise floor... but I could not find any noise!!
This is a very quiet and refined component.
This was an interesting build. Best built from the schematic with reference to the diagrams for component locations and wire routing suggestions ( modified many of these to minimize hum). This map has an awesome powers supply and with high quality components offers great flexibility for refinement.
Edits: 05/10/17 05/11/17 05/11/17 05/11/17 05/16/17 05/18/17 05/18/17 05/18/17 05/19/17 05/19/17 07/01/17Follow Ups: