May i suggest the CORON DS7 or DS8 clones as showed here :
They are small drum synths with large sonic possibilities and a fat and warm analog sound . It will be hard to design a more simple synth !
They can be controled by any analog Sequencers, MIDI CV/gate interfaces or simply bit hitting the box ( with a piezzo cell inside )
They are low cost devices made of very classic parts so there is really no risk. Assemble them do not require special electronic skills and tools.
Compared to the vintages DS7/8 actual prices on Ebay ( for example) , it is a real bargain to DIY them ! Also you can design the front panel as you feel ( see examples at the end of the DS7 pages) Modify them as you feel, it is quite easy to add more features ( filters,disto boxes... etc...)
You can also combine many of them to build an amazing and unique analog drumbox perfect for most of techno/electro music styles...
Well for a beginner this is probably one of the best solution to get a first positive experience with the synthDIY world, and to learn basis before to try more advanced/complex designs without risk...
Sorry to self promote, this is not my uses, but here i couldn't resist