Jadis JP200 and Marantz 7 clones from Hong Kong

I see real great comments and feedbacks in here. I really apppreciate that.

Althought I still know nothing about other's experience with those "re-eningeered" designs, I see an interesting point here. Would any decent implementation of those "re-engineered" designs amount to anything?

If you happen to look at those listings in eBay, you'd see the parts are actually not so bad. Of course, like Kw6 said, the quality transformers could not be reproduced in those budget-minded imitations. So it's expected to be (several) cuts below the real thing, but could it compare favorably with, say, any decent $2000 preamps out there, simply because it's still fundamentally a great design?

I think the reliability of these units would be good enough. Tube audio gear is inherently simple stuff. If you buy a kit, and are handy enough to put it together, you can probably also fix a fair amount of what may go wrong down the line.

However, like kw6 states, you'll never get the Jadis transformers. Transformers are by far the most critical piece of a tube component, what one should put their money into, and among the biggest reasons a Jadis is a Jadis. I'll also note that the passive parts appear to be different (the Jadis capacitors, which like the transformers, you'll never get), and I have had enough bad experiences to now understand what a good friend told me, "Jadis voices their equipment, and most people look at some of the cheap parts used, and figure they can make things better via modding it. Not so easy." Indeed. I've paid a pretty penny setting my amp back to stock, and the improvement was more than worth it. The unit using a PCB instead of being hardwired is another thing. I never understood Shelby Cobra and Mustang clones, but they sure are popular with others.

If your only goal is to copy the circuit, it seems like a good deal. I could think of worse things to copy than a Jadis. Why not start there?

Then again, you may have issues with someone blatantly disregarding intellectual property, as it's out and out plagiarism - or, maybe you don't...

Guys Jadis and other gear is pretty overpriced for what you are getting in return.
Check Goldmund super transport costing 9000USd and when you open it you will find unmodified Pioneer player costing 60USD.
Those kits are really inexpensive for what you are getting.
I have Art Audio preamp which retails for 3500USD and when you check what's inside you could probably buy all parts for around 200-300USD.
Preamp sounds really good and even better after modifications that I've done like replacing inexpensive volume controll pot with DACT and rewiring everything with Mundorf wires etc.
All so called High End COs are looking for profit so don't let them fool you.
IU modified my Rega Apollo cd player to the point when it plays really nice and I compare it to Saturn and some other more expensive gear and it looks like I have a winner.
Modifications did not cost me more than 200USD in parts.
When you sale 10 000 players and you have to get parts you will try to save money on everything, few cents here and there will matter.

Desiring to get a decent sound for decent money (aka bang for the buck)I built two of the preamp units from analogmetric.com. I would say they embody the essence of the originals without being direct knockoffs. First I built their version of the Grounded Grid preamp. It had a nice quality sound but lacked a certain richness and low end for my taste. Perhaps nicer for orchestra and some vocals.

I sold the GG board on ebay and started again with the JP200 kit. I have no way to compare to the original, but I am VERY VERY happy with the sound. What impresses me is the richness of the sound and the dimension and detail across the soundstage. A definite upgrade IMO from the GG amp and another manufactured tube preamp from HK that I had been using. It's like my system stepped up to the audio quality I was wanting, and for a minimal investment. I didn't have need to try the Marantz 7 board so I can't comment about that one.

I can't imagine anyone could gripe about the audio results of the JP200, especially after spending less than $400 to give it a try. My two cents.