Douk Audio. Any experience with any of their products?

I got the "6j1 Valve tube pre-amp preamplifier bass on music fidelity X10-D"
the ad exactly. For $13 bucks. It was an easy kit to build, tiny but I have to admit it held up.
I first put it in between a emotiva DAC and threadhold stasis amp. First my Maggie’s, wasn’t impressed. Laughed cause $12 I’m glad it made sound. But.. it started to warm up and sure I can hear that tube sound. Hooked up a pair of speakers with ribbons. It continued to open up. 
My preamp is a audible illusions modulus 1 tube and This little plastic pretty blue light toy sounded pretty good. damn well worth the $13 I spent. Perhaps,
Improving the cheap components like caps and resistors would make a serious difference. Tubes of course would make a serious deference.
The little engine that could. It's a fun hobby. 

Any particular tubes work with this size tube? These are smaller them 

Jaynewt- which seller did you buy your Dartzeel clone from? Prices are from 800 shipped to maybe $1600 shipped

thank you!!

@jaynewt I'd be interested to know too. Douk sell for $1600ish, but others sell for around 1/2 that. Are they the same clones?

Ref . Douk audio and Amy . I have purchased the Hi-Fi 2.0 Channel Stereo Amp Board Kit/Set_UK and it was the biggest mistake I have ever made. Before I started the build I checked the contents and found that a number of components were missing so I made contact with Douk through Ebay and received a prompt reply from Amy saying would I purchase the missing parts in my country and they would pay .From that I assumed the reply was coming from China even though it was supplied from UK stock , I replied that I was not in a position to do that and if they could not supply the missing items I would complain to Ebay through the appropiate channels . I received a quick reply as follows.... hello dear customer wish you a very nice day OK will resend it the tracking number is JV093944637GB best regards Doukaudio-Amy")..... What they are sending I have no idea.  I am no pro. at building circuit boards and at the age of 91 I thought it would give me an interest having built a number of Heathkit items in the past but I am now in trouble reading the resister coding as no instructions are provided in the kit , just a bag of bits and two heat sinks , HELP. Albert Bennett.

@englebert
Albert,  In "My Ebay"  go to "Purchased" on this transaction,  look to the right side, where it says "Leave Feedback", click the drop down and choose "Return this Item".... Tell them the item "Is not as Described"  request a refund... Do it right away.  Ebay will get involved and you'll get taken care of.