I still think go for the Two-Rock Studio 35,
you have a bonus in that its already branded.
Plus you might make sound even better than the original. :-)
what Gemini says about the four suggestions is an interesting read:
" Each amplifier—the Matchless Spitfire, Two-Rock Studio 35, vintage Valco, and Magnatone—offers a distinct tonal philosophy shaped by its design, history, and target user. The "best" choice is subjective and depends on a player's desired tone, playing style, and budget.
Matchless Spitfire
The Matchless Spitfire is a hand-wired, boutique amp with a reputation for dynamic, touch-sensitive, and chimey clean tones. Powered by a pair of EL84 tubes, it offers a distinct British-inspired sound that is often compared to a Vox AC15, but with more tightness and low-end punch.
Best for: Players who love classic British tones with sparkling highs and responsive dynamics. The Spitfire is a great "pedal platform" but offers its own distinct character, unlike the more transparent Two-Rock. It is a favorite for studio and smaller gigs due to its reasonable volume.
Tone Profile: Sparkly, chimey, and harmonically rich. It delivers creamy, smooth tones at lower gain and a touch-sensitive breakup when pushed.
Considerations: Like other Matchless amps, it is a high-quality build, but it comes at a premium boutique price.
Two-Rock Studio 35
The Two-Rock Studio 35 is a modern, high-end amp known for its massive, pristine clean headroom and its ability to act as an exceptional "pedal platform". With a tonal character inspired by Dumble amps, it provides a warm, fat tone with rich low-end and clear highs.
Best for: Guitarists who build their sound primarily with effects pedals and need an ultra-clean, transparent canvas to do so. It's also an excellent choice for jazz, fusion, and blues players who want a powerful, articulate clean sound.
Tone Profile: Transparent, articulate, with rich low-end and crystal-clear high-end response. The overdrive is smooth and has a mid-forward character.
Considerations: These are expensive, high-quality amps. The tone is far more refined and polished than a vintage Valco.
Valco amplifiers
Vintage Valco amps (under names like Supro, National, Airline) are prized for their raw, unrefined, and gritty vintage character. Unlike the precision of modern boutique amps, Valcos offer a thick, crunchy overdrive at lower volumes due to their simpler, era-appropriate construction.
Best for: Players seeking authentic, low-wattage vintage blues and raw rock and roll tones. They are highly valued for their unique, raunchy character in studio recordings.
Tone Profile: Warm, thick, and compressed with a lot of natural breakup at lower volumes.
Considerations: Being vintage gear, these amps can be inconsistent and require upkeep. They are not known for high headroom or modern features.
Magnatone amplifiers
Magnatone's signature feature is its true pitch-shifting vibrato, a distinct effect that is different from the volume-based tremolo in other amps. Modern Magnatone amps are high-quality, boutique builds that offer excellent clean and overdriven tones with a classic American voice.
Best for: Musicians who want the classic, lush, pitch-shifting vibrato effect. A modern Magnatone offers this vintage sound with contemporary reliability.
Tone Profile: Classic American tones, with some models offering high-headroom cleans and others focusing on breakup. The vibrato is the main attraction, adding a unique shimmer to the sound.
Considerations: The price is comparable to other boutique brands, but you're paying for the specialized vibrato circuit as a key feature.
Summary: Choosing the right amp
For pristine cleans and a pedal platform: The Two-Rock Studio 35 is the top choice.
For classic, chimey British tone and responsiveness: The Matchless Spitfire excels at dynamics and touch sensitivity.
For raw, low-wattage vintage blues and rock: A vintage Valco offers a thick, unrefined tone, but requires patience and upkeep.
For lush, true pitch-shifting vibrato: The Magnatone is the clear choice for this unique effect."