Colossus dual-mode power architecture (Stock Mode / Pure Linear Studio Mode) and upgrade
Добавлено: 04 сен 2026, 04:56
Hey Vasili,
Hope all is well.
Colossus RV.2.0 owner here. I want to commission a deep modification of my existing preamp—creating a hybrid, dual-mode power architecture (Stock Mode / Pure Linear Studio Mode) and upgrading the components to minimize the noise floor.
My unit is the early, 100% pure analog revision with no digital board or built-in IR cabsim. The objective is to preserve the stock portability of the unit for travel or rehearsals, while implementing a switchable, stationary Studio Mode that completely cuts off the internal SMPS to eliminate high-frequency switching interference.
I already have a premium external FiiO PL50 linear power supply (12V DC) on hand, which will serve as the foundation for the low-voltage rail in Studio Mode. For the high-voltage anode rail, I plan to source a compact, low-noise regulated linear PSU from AliExpress. To help me perfectly match it to your circuit, could you please provide the exact electrical specs of the preamp: the target high-voltage (Anode B+) rail and the nominal current draw (amperage) requirements for both the plates and the heaters/relays?
Here is the exact technical scope of work for this modification:
1. Dual-Mode Power Infrastructure (Stock/Studio Bypass)
We need to install a single robust, 4-pin GX16 aviation connector on the rear panel along with a high-grade mechanical toggle switch.
* In Stock Mode, the preamp operates exactly as it does now, running off the standard 12V input with the internal SMPS engaged.
* In Studio Mode, the internal SMPS is completely de-energized and isolated. The low-voltage rail (heaters/relays) and high-voltage DC (tube plates) will feed directly through the new GX16 jack. For this setup, I will assemble a custom dual-input DC umbilical cable that combines the 12V output from the FiiO and the high-voltage lines from the AliExpress block into a single 4-pin GX16 plug.
2. Premium Component Overhaul
* Electrolytic Recap: Replace all stock industrial CapXon and Elzet caps with top-shelf, low-ESR Japanese components (Nichicon FW/KW/Muse series or Panasonic FR/FC series) for maximum ripple rejection and long-term thermal durability near the hot tubes.
* Film Capacitors: Replace any standard industrial OEM film caps in the critical coupling and tone-shaping nodes with authentic German WIMA MKS4/MKP4 or equivalent premium film caps to achieve absolute signal transparency and top-end definition.
3. Headroom Optimization & Low-Gain Modification
* Scale back the overall gain matrix to expand the dynamic headroom for precise studio tracking. This must be achieved strictly by optimizing the cathode and feedback resistor values on the tube stages while keeping the stock 12AX7 glass configuration. This will drop the gain structure and secure a totally black background without altering or shifting the core 5150 frequency response curve.
4. PCB Reference Verification
* Out of technical curiosity regarding the board layout: what is the engineering purpose of the unpopulated DIP-6 footprint near the SW_DIO and SW_CLK labels on this early revision? Is it routed for an optional optocoupler/IC for channel switching, or is it just a factory testing interface?
Budget & Logistics:
I understand that this is a highly customized hardware modification project requiring strict engineering precision, custom pathing, and chassis drilling. We can discuss all financial details and pricing strictly via forum private messages (PM) rather than publicly.
I am considering shipping you my existing Colossus V2.0 unit for this upgrade, provided that the total costs of shipping, components, and your bench time remain economically practical for this project.
Please let me know your thoughts on this technical scope, your current availability, your location for shipping logistics, and a rough pricing estimate for the modification via PM so I can evaluate the options.
Best regards,
Sledge
Hope all is well.
Colossus RV.2.0 owner here. I want to commission a deep modification of my existing preamp—creating a hybrid, dual-mode power architecture (Stock Mode / Pure Linear Studio Mode) and upgrading the components to minimize the noise floor.
My unit is the early, 100% pure analog revision with no digital board or built-in IR cabsim. The objective is to preserve the stock portability of the unit for travel or rehearsals, while implementing a switchable, stationary Studio Mode that completely cuts off the internal SMPS to eliminate high-frequency switching interference.
I already have a premium external FiiO PL50 linear power supply (12V DC) on hand, which will serve as the foundation for the low-voltage rail in Studio Mode. For the high-voltage anode rail, I plan to source a compact, low-noise regulated linear PSU from AliExpress. To help me perfectly match it to your circuit, could you please provide the exact electrical specs of the preamp: the target high-voltage (Anode B+) rail and the nominal current draw (amperage) requirements for both the plates and the heaters/relays?
Here is the exact technical scope of work for this modification:
1. Dual-Mode Power Infrastructure (Stock/Studio Bypass)
We need to install a single robust, 4-pin GX16 aviation connector on the rear panel along with a high-grade mechanical toggle switch.
* In Stock Mode, the preamp operates exactly as it does now, running off the standard 12V input with the internal SMPS engaged.
* In Studio Mode, the internal SMPS is completely de-energized and isolated. The low-voltage rail (heaters/relays) and high-voltage DC (tube plates) will feed directly through the new GX16 jack. For this setup, I will assemble a custom dual-input DC umbilical cable that combines the 12V output from the FiiO and the high-voltage lines from the AliExpress block into a single 4-pin GX16 plug.
2. Premium Component Overhaul
* Electrolytic Recap: Replace all stock industrial CapXon and Elzet caps with top-shelf, low-ESR Japanese components (Nichicon FW/KW/Muse series or Panasonic FR/FC series) for maximum ripple rejection and long-term thermal durability near the hot tubes.
* Film Capacitors: Replace any standard industrial OEM film caps in the critical coupling and tone-shaping nodes with authentic German WIMA MKS4/MKP4 or equivalent premium film caps to achieve absolute signal transparency and top-end definition.
3. Headroom Optimization & Low-Gain Modification
* Scale back the overall gain matrix to expand the dynamic headroom for precise studio tracking. This must be achieved strictly by optimizing the cathode and feedback resistor values on the tube stages while keeping the stock 12AX7 glass configuration. This will drop the gain structure and secure a totally black background without altering or shifting the core 5150 frequency response curve.
4. PCB Reference Verification
* Out of technical curiosity regarding the board layout: what is the engineering purpose of the unpopulated DIP-6 footprint near the SW_DIO and SW_CLK labels on this early revision? Is it routed for an optional optocoupler/IC for channel switching, or is it just a factory testing interface?
Budget & Logistics:
I understand that this is a highly customized hardware modification project requiring strict engineering precision, custom pathing, and chassis drilling. We can discuss all financial details and pricing strictly via forum private messages (PM) rather than publicly.
I am considering shipping you my existing Colossus V2.0 unit for this upgrade, provided that the total costs of shipping, components, and your bench time remain economically practical for this project.
Please let me know your thoughts on this technical scope, your current availability, your location for shipping logistics, and a rough pricing estimate for the modification via PM so I can evaluate the options.
Best regards,
Sledge