Ormagoden

Ormagöden is a custom-engineered, flagship 220-Watt cathode-biased tube monster bass amplifier head in the Thermionic Studios fleet. It is built explicitly for absolute volume worship. It will be available for rental for rehearsal, recording, and performance, within the Southern California area.

Technical Specifications & Architecture

Parameter	Specification	Engineering Notes
Topology	Quad Class AB Cathode-Biased Beam Power Tetrode	Optimized for dynamic, touch-sensitive sag, musical even-order harmonics, and a dense mid-range bloom.
Power Output	220 Watts RMS Clean / 240+ Watts Saturated Peak	Continuous clean floor up to 1% THD; pushes past into a soft, square-wave power tube distortion.
Power Tubes	4x Tung-Sol KT-120 Reissue	Massive 60-Watt plate dissipation rating per bottle, engineered to withstand continuous stage punishment.
Phase Inverter	1x Vintage 12BH7 Double Triode	Estate-sale vintage television vertical deflection tube running a Long-Tailed Pair layout. Low internal resistance ($ pprox$ 5,500 $\Omega$).
Driver Stage	2x 12AT7 Dual Triodes (Dedicated Quad-Triode Driver Deck)	Post-Phase Inverter Differential Gain Block. Each of the four triodes is independently dedicated to driving its own KT-120 grid, establishing an un-loaded 24:1 impedance leverage ratio.
Rectification	Solid-State Silicon Diode Bridge (4x 1N5408 / UF5408)	3-Amp / 1000V high-current gates providing zero rectifier sag. Keeps the B+ rail completely rigid to balance out the compression of the cathode furnace.
Cathode Bias Network	150 $\Omega$ Shared / 200W Top-Deck Gold Aluminum Array	Four 50-Watt gold-jacketed chassis-mount power resistors wired in parallel on the top exterior deck of the chassis plate.
Bypass Capacitance	470µF / 100V Electrolytic + MLCC Array	Massive low-frequency reservoir running parallel to the gold resistors to preserve deep, un-attenuated sub-bass transients.
Grid Leak Constraints	240,000 $\Omega$ Maximum Per Tube ($R_{g1}$)	Cathode-bias architecture safely expands the fixed-bias 51k$\Omega$ limit, preventing thermal runaway or grid-loading signal collapse.
Coupling Capacitors	Sprague 715P/716P Orange Drops (600V Polypropylene)	0.1µF off the 12BH7 phase inverter; 0.22µF off the 12AT7 driver plates to maximize low-frequency fundamental transmission.

Headshell

• The 304 Stainless Steel Battleship Chassis: A thick 12-gauge or 10-gauge structural 304 Austenitic Stainless Steel deck pan built to support colossal transformer weight without any physical deflection, twisting, or mechanical warping.
• Top-Side Exposed Exoskeleton Bracing: Structural stainless steel angle reinforcing trusses are TIG-welded directly onto the outside top deck of the chassis sheet. The welding process leaves a raw, exposed, multi-colored titanium-like chromatic oxide "rainbow" patina (heat tinting) along the structural weld beads as an intentional aesthetic flex.
• The Quad-Tube Thermal Furnace Layout: Four KT-120 envelopes radiating up to 482°F (250°C) each are positioned adjacent to top-deck chassis ventilation slots to initiate a natural convective draft, pulling cool air through the bottom deck and dumping infrared energy straight out of the box.
• The Dual-Engine Iron Core Platform:
  • The Plate Engine: Standalone, high-current Ampeg SVT-class replacement power transformer delivering a continuous 1.0 Amp (1000mA) DC current rail.
  • The Filament Furnace: Dedicated 6.3V AC / 10-Amp auxiliary heater transformer oriented at an exact 90-degree perpendicular phase offset relative to the plate iron core laminations to cross-cancel electromagnetic stray fields and eliminate 60Hz inductive hum.
• The Enclosure Vault: A solid Baltic birch plywood floor and side-panel base fully upholstered in menacing, deeply embossed Red Croc Faux Leather. The front, back, and roof are wrapped in an unbroken, heavy-duty black steel expanded metal cage grate.
• Ergonomic Road Armor: Dual Reliable Hardware RH-6630 16-gauge Recessed Edge Handles are mechanically anchored across the top corner seams using structural steel backing washers and pop rivets, allowing a transport dolly or road crew to lift the monolith securely.

Grounding

Because 304 stainless steel carries a significantly higher internal electrical resistance than standard aluminum, traditional chassis-grounding points are strictly forbidden to eliminate ground loops:

• Grounding Scheme: A heavy-gauge, continuous piece of bare copper wire runs entirely across the tube sockets to act as an isolated ground rail. Every single preamp, driver, filter, and cathode ground links directly to this copper bus.
• The Chassis Ground Anchor: The solid copper grounding rail connects to the stainless steel chassis frame at exactly one single, dedicated brass bolt right next to the main AC power entry.
• High-Voltage Lead Dress: High-temperature, heavy-gauge Teflon-insulated hookup wires pass through rubber wiring grommets bored via cobalt/carbide tools to prevent the sharp edges of the stainless steel from chafing insulation.
• Post-Phase Inverter Master Volume (PPIMV):** Dual-ganged 100k=ohm audio-taper potentiometers are positioned between the 12BH7 phase inverter and the 12AT7 driver grids, allowing full preamp saturation while managing live stage monitoring limits.

• Rectifier: Pure silicon rectification combined with the un-sagging 1A plate engine ensures that when real-world venue voltage grids sag during live sets, the B+ rail stays rigid. The amplifier preserves a razor-sharp transient note attack while pushing dense, squared even-order musical harmonics straight through the room.

Preamp

Unlike conventional high-power bass platforms that rely on complex, interactive tone networks that introduce severe signal insertion loss, Ormagöden utilizes an un-cluttered, high-current, two-tube preamplifier topology optimized to pass high-amplitude transients straight to the power section without clipping the front end.

• V1 (12AX7 Dual-Stage Input Furnace): Your input gate cascades directly across both triode halves of a single 12AX7. Triode A acts as an instantaneous voltage accelerator, while Triode B injects a rich layer of touch-sensitive, even-order harmonic grit.
• V2 (12AT7 Low-Impedance Cathode Follower): The hot output of V1 is routed straight into V2 configured as a Cathode Follower (Cathode Out). This drops the internal output impedance of the preamp below 1,000 Ohms, providing the raw current leverage needed to drive the single-pot tone architecture without frequency choking.

Controls

To eliminate choice paralysis, the front panel layout is minimal.

1. GAIN: Dictates the input saturation of the dual-stage V1 12AX7 furnace. Sweeps from a fat, high-fidelity clean baseline into a dense, singing harmonic distortion that pre-shapes the low-mid fundamentals.
2. TONE: A single-pot Passive Tilt/Pivot Network driven by the low-Z V2 cathode follower. Turning Left rolls off top-end single-coil hiss while boosting massive, clean subterranean tracking. Turning Right pulls out sub-bass mud, aggressively sweeping a focused, vocal-like midrange bark (250Hz - 400Hz Hump) straight into the core mix to perfectly match the 33nF sweet-spot capsule of Doubly.
3. BOOST/MASTER (The Post-PI Sledgehammer Control): A heavy-duty, dual-gang potentiometer wired directly after the V3 12BH7 Phase Inverter phase splits. Turning this control up does not choke down preamp signal; it allows the full, un-attenuated voltage halves exiting the phase inverter to dump into the dedicated post-PI 12AT7 driver triodes, forcefully slamming the four KT-120 grids past their bias thresholds into hard power-tube squaring.
4. PRESENCE: Wired directly into the global negative feedback loop coming off the secondary tap of the 25-pound interleaved output iron. Directly controls power-section dynamics, un-clamping upper high-frequency transients to give the speaker cabinets an immediate stage edge.

Tube Contingent

The internal glass architecture reveals a total of nine vacuum tubes configured in a high-current, zero-cross-talk matrix:

Stage Designation	Tube Quantity / Type	Functional Role in the Circuit
V1 Preamp	1x 12AX7 Dual-Triode	Input Voltage Gain & Primary Harmonic Distortion
V2 Driver	1x 12AT7 Dual-Triode	Low-Impedance Cathode Follower Tonestack Line Driver
V3 Phase Inverter	1x 12BH7 Double Triode	Long-Tailed Pair Phase Inverter (Phase Splitter)
V4 - V5 Driver Deck	2x 12AT7 Dual-Triodes	Quad-Triode Dedicated Driver Matrix (1 Triode per Power Grid)
V6 - V9 Output Stage	4x Tung-Sol KT-120	Beam Power Tetrode Quad (Push-Pull Class AB Cathode-Biased)

Considerations

Ormagöden has been designed to sound unlike any tube-powered high wattage bass amp. Because the input preamp and the quad-triode 12AT7 driver deck maintain a 24:1 impedance leverage ratio over the circuit, the pluck of a bassist's pick or finger never gets squished or compressed by the front end. Attack is lightning-fast and punchy.

The millisecond after that percussive string-snap cuts through the room, the current hits the 150-Ohm resistor cathode network. The power section is designed to sag and bloom. It's been designed to not only offer wooly bass tones, but to make sure that those tones do not get lost in a band's mix.

For or purposes, Ormagöden is a piece of basic research. We want to hear what happens when high-powered power tubes are pushed into distortion by a previous gain stage's output. This is why we have an additional gain stage after the phase inverter. The phase inverter isn't pushing the power tubes. An separate gain stage is built-in to push the power tubes so the phase inverter doesn't have to.