Hi all. I'm new to DIY Audio but I'm an avid handyman (with a decently-equipped workshop!) always looking for my next fun challenge.
I randomly came across an Ali store with a selection of bootleggy PCBs and kits for amps, power supplies, etc. I'm into headphones and the Cavalli-Kan Kumisa III caught my eye, so I decided to order the PCB and kit it out with hand-selected components. Board arrived today and the quality actually looks really solid, though it appears to deviate slightly from the original design.
Just thought I'd drop in here, say hi, and see if anyone else has built up one of these boards.
I randomly came across an Ali store with a selection of bootleggy PCBs and kits for amps, power supplies, etc. I'm into headphones and the Cavalli-Kan Kumisa III caught my eye, so I decided to order the PCB and kit it out with hand-selected components. Board arrived today and the quality actually looks really solid, though it appears to deviate slightly from the original design.
Just thought I'd drop in here, say hi, and see if anyone else has built up one of these boards.
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I recently bought the Ali Express Cavalli-Kan Kumisa III kit. It is 90% done, I still need to pick up an enclosure, ganged volume pot and 1/4 jack socket from the electronics store in the city. Great old school hobbyist store. A blast from the past and always fun to visit.
This kit is different from the Cavalli-Kan Kumisa III. I studied the original CK2III schematic and the obvious differences with this kit are that the input stage transistors are BJT and not FET as in the CK2III design and the 2SC4883A & 2SA1859A power transistors. I did find a schematic for the earlier Kumisa III design which has an BJT input section.
I'm eager to listen to this amp with my Hifiman HE400se phones.
@trohricht please keep this thread alive and post your opinions. I'll post an update when I'm done.
This kit is different from the Cavalli-Kan Kumisa III. I studied the original CK2III schematic and the obvious differences with this kit are that the input stage transistors are BJT and not FET as in the CK2III design and the 2SC4883A & 2SA1859A power transistors. I did find a schematic for the earlier Kumisa III design which has an BJT input section.
I'm eager to listen to this amp with my Hifiman HE400se phones.
@trohricht please keep this thread alive and post your opinions. I'll post an update when I'm done.
Nice. Glad you're enjoying your build. I've been busy with work and haven't had a chance to work on my kit yet, but soon. I've also fallen down the rabbit hole a bit and ended up ordering other kits and/or bare PCBs from the same store. My immediate goal is to build my own chassis (found some awesome looking figured birch at a specialty lumber mill) and set it up so it can house two of these amplifiers at any given time (e.g. a CK2III plus a Beyerdynamic A1, or a Lehmann Linear plus a Dynalo) complete with dedicated RCA inputs, volume pot, and output jack for each one. My longer-term goal is to use these kit builds to complement the book-learning I'm doing around transistor fundamentals and amplifier design.
I've already made a few newbie mistakes. E.g. I bought a pair of Burson op-amps before realizing the TL081 op-amps in the Kumisa are just there for the DC offset servo circuit. I've also learned just how rampant counterfeit components are on AliExpress. I'll be sticking to Mouser, Digikey etc. moving forward.
All part of the journey.
I've already made a few newbie mistakes. E.g. I bought a pair of Burson op-amps before realizing the TL081 op-amps in the Kumisa are just there for the DC offset servo circuit. I've also learned just how rampant counterfeit components are on AliExpress. I'll be sticking to Mouser, Digikey etc. moving forward.
All part of the journey.
@trohricht: I've had a Beyerdynamic A1 clone headphone amp for many years. It's a nice sounding amp with plenty of power, but the 100ohm output impedance is not ideal for my new 25ohm planar headphones. My research led me to the CK2III and the kit was hard to resist for the price. The semiconductors look legit, but I do not have the means to confirm their authenticity. The 2SC4883A & 2SA1859A power transistors are marked as Sanken. I'll admit to being skeptical about the authenticity of this complementary pair that have been out of production for several years and remaining stock tend to be pricey nowadays. The measured hFE and Vf values are within the Sanken data sheet specs. The small signal transistors marked as Fairchild also measure to spec.
I'll let my ears decide when I've completed this project.
I'll let my ears decide when I've completed this project.