Clever design with two ADC, where you still have 2 GSa/s with two channels and 1 GSa/s with four channels.
Not so !
5k AFAIK uses a homespun ASIC, it's different !
SDS2000, SDS2000X, SDS2000X Plus, SDS2000X HD and SDS5000X for all their 4ch models use dual ADC's.
So does the $499 SDS1104X-E.
SDS6000A uses 1 for each channel like many now old scopes did but they never had the memory depth anything like the modern DSO.
Can't offer further info on other Asian brands as may be incorrect.
Indeed, I've checked. Quartation of sampling rate on four channel is more common on Rigol scopes (HDO1k,4K, MSO5K, 7K, 8K) while Siglent has many models that keep sampling at half on four channels.
My intention was to say something good about this scope along with my complain about it, but if the vendor does not come with a solution for noise I think I will return it.
Big difference compared to TO1152 whose noise was barely audible.
Also the battery is draining fast with two fans at full speed all time.