Regarding amplifiers, if you are the owner of an original Leben CS-600, I think the Sophia Electric EL34-ST was the best match for the CS-600's voicing. The new Leben CS-600X is considerably different in its voicing, and I found the Sophia Electric KT88-ST to be the best match for the CS-600X.
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500W ±45V-±70V Digital Power Amplifier Board Mono Channel Class D HiFi Sound Amplifier for 4-8 ohm Car Home Speaker Subwoofer
Aliexpress UK
Arrived early. Good trader.
eBay
AK55-Lite Sound Amplifier Max Power 90Wx2 Channel 2.0Hifi Bluetooth 5.0 with FM USB Digital Power Amplifier for Home Car Karaoke
Aliexpress UK
Power Output: 40W per channel (8Ω stereo), 80W (8Ω mono). Damping Factor: 16. Good used condition. Cage is a little dinged up. Semiconductors: 4 Silicon Diodes, 1 Selenium Diode. Speaker Impedance: 4Ω to 32Ω.
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6N1 push 6P1 tube amplifier kit tube amplifier DIY board include transformer （not include the tubes）
Aliexpress UK
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Nobsound NS-06G HiFi TPA3116 Digital Amplifier Home Desk Power Amp 60W×2 with Power Adapter
Aliexpress UK
Tested and matched!
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BRZHIFI A1S Reference music fax A1 line 20W pure Class A power amplifier household hifi fever level power amplifier
Aliexpress UK
EL34 quad factory matched to within 1mA anode current. “I find the Shuguang EL34-B to be a very warm sounding tube with a magic midrange. Highs are excellent, but not to sharp. They are much louder and CLEARER then the other tubes I've tried.
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JOYO Mini Amp Portable Electric Bass Headphone Amplifier 3.5mm Plug
Aliexpress UK
Here’s a bundle of tubes/valves that have come out of various amps of mine over the years. I’m not sure whether they were replaced because they had failed, or just due to having my amps serviced. I think the two boxed ones were brand new tbh. Electro harmonix 12ax7eh Groove tubes gt12ax7 Electro harmonix 12au7a/ecc82eh 2x unbranded ecc83 Sovtek el34c Unbranded el34 (i think) Untested. I believe most will be ok.
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Fosi Audio ZK1002D 100W x2 Bluetooth Power Amplifier Mini Wireless Stereo Receiver 2 Channel HiFi Digital Power Amp
Aliexpress UK
Model: Statesman Dual EL34. Power Tubes: 2 × EL34. Power Output: 50W. Type: Tube Head Amplifier. Important Point. Channels: Clean + Twang, Overdrive + Boost.
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Gustard HIFI Audio FUSE 1.6A 3.15A 5A 8A 12A For DAC AMPs Power Amplifier
Aliexpress UK