Carbon Amps / Los Angeles
Three tubes and a circuit that was drawn once in the 1930s and never built again. Reverse‑engineered to the component level, and built again by hand, one at a time.
The circuit
This one is drawn, then built. In a tube amplifier the circuit does not exist only as a schematic. It exists physically, in the routing of each wire, the spacing of each component, the grounding scheme, the relationship between signal, voltage, heat and magnetic field.
Printed circuit boards are efficient. Repeatable. Fast. They make sense for products designed around mass production. The Shetland C6 is not designed around mass production.
Hand‑wiring buys control: short signal paths, careful lead dress, robust component spacing, low noise, serviceability, and the ability to voice each amplifier as an individual instrument. The work is slow and technically demanding. A Shetland C6 takes weeks, not hours.
That is not inefficiency.
That is the point.
The result is a signal path with almost nothing in it, and everything that matters left intact. Instruments don’t just pass through it. They reveal themselves.
The Shetland C6 is not a recreation. The original circuit is honored in full and wired in the traditional manner, with components chosen for the reliability that serious work demands.
| Preamp | 6SF5 single triode |
|---|---|
| Output stage | Single‑ended 6V6, cathode biased |
| Rectification | Type 80 directly heated tube rectifier |
| Filtering | 15H inductor. No solid‑state devices in the signal or supply path |
| Controls | Volume, tone, single input |
| Output | Internal speaker with switched external speaker jack — runs as combo or head |
| Speaker | 8″ driver, arched cabinet |
| Construction | Point‑to‑point hand wiring on a folded aluminium chassis |
| Cabinet | Built from scratch. Curved ply shell over a solid arch former — not a converted radio |
The output
A small amplifier is usually a fixed proposition. Whatever the speaker in the box can do is what you get, and the day the room is bigger than the box, the amplifier stops being useful.
The Shetland C6 is not fixed. There is a jack on the chassis and a switch beside it. Throw the switch, plug in a cabinet, and the internal speaker steps aside. The amplifier becomes a head.
The internal speaker is sized to the cabinet, and the cabinet is sized to a room you can talk across. That is where this amplifier lives most of the time, and it is what it was drawn for.
Then the room changes. A four by twelve, a single fifteen, an open‑back two by ten borrowed from whoever is on before you. Every one of them takes the same amplifier and gives it a different set of lungs. The circuit does not change. The air it moves does.
The whole amplifier
fits under one arm.
This is the argument for a small single‑ended amplifier that people forget. A 6V6 run properly, into real iron, does something no hundred‑watt amplifier can do at a volume anyone in the room will tolerate. The only thing that ever limited it was being welded to one speaker. It is not welded to one speaker.
Assembly
Nothing here is a render or a mock‑up. This is the amplifier going together, in the order it goes together.
Socket spacing, transformer footprints and lead lengths resolved on the drawing board, so they were never discovered halfway through with a step drill. The choke sits under the deck, out of the field of the output transformer.
Aluminium chassis cut to the plan. Fuse holder, power inlet and speaker jack still marked in pencil on the metal, because that is the fastest way to catch a mistake while it is still reversible.
Output transformer, power transformer and three sockets fitted. The iron sets the character of a single‑ended amplifier more than any other choice, and it dictates the whole layout, so it goes on first.
A 15H filter choke mounted under the deck, keeping the supply inductor clear of the output transformer’s field. This is the part of the amplifier nobody sees and everybody hears.
The control panel worked out at full size with the actual parts sitting on the drawing. Power, tone, volume, input. Nothing on the front of this amplifier that does not need to be there.
The first twelve
The first twelve Shetland C6 amplifiers will be numbered, and they will go to this list in the order it was joined. No money changes hands until there is a finished amplifier to photograph, a price, and a date.
Join and you get the build as it happens, first refusal on a number, and the price before anyone else sees it.
Twelve numbers / One builder / No deposit until the amp exists
Questions first? hello@carbonamps.com