Thank you very much, but one question. Why do you not use screws to connect the plate with the miner?

@kahc
Can you please upload the plans. I was already thinking about buying a old miner and use the plates, but did not found one cheap enough.

I mentioned it tonight, the second fan makes the miner a lot louder (removed it tonight for better sleep). I will make another try with a hose and a sonodec.

@imine2
I removed the backplate before to clean the miner, but I do not like to run the miner completly open.

I used rubber screws made for fans.


Maybe I will change all screws later.

QFR1212GHE, about the noise level I can't say anythin because the miners stand next to each other. After one day testing I will change the second one.

I changed for testing  one of my Z9 mini to dual fan.


Maybe later I will cut a big whole in the backplate.


Stats of the dualfan Z9 mini


Stats of the normal Z9 mini


EDIT
Some thoughts, the big advantage is that the miner have now enough power to push the Air out. My problem is that there is no good way to install the hose. Does anybody know where to get a backplate with screws for the other side.

The hose (I'm not sure about the right word in english)

Sounds promising, is the miner louder now?
And did you reverse the fan by turning the connector around?

A lot choices, thank you very much.

I'm thinking about changing my z9 mini to dual fan like the guy on the video:
https://www.youtube.com/watch?v=8pONPwLJMP4

I want to use normal industry fan to pull the Air out of the miner.
My Idea is to do this  to have a airflow which is strong enough to get the air directly out of the window by using a SONODEC. I guess a second fan might althoug be an option for using a slent Box.
But I'm not sure which fan will be compatible (I read about than when the ampere is wrong the antminer won't start).

I want to buy a fan with this specs, hope somebody can tell me if it will work (or if not what is important by choosing the fan).

-- Size: approx. 120*120*38 mm
-- Voltage: 12(V)
-- Blast Capacity: 280.38CFM
-- Current: 5.0A
-- Rotate Speed: 7500CPM(r/min)
-- Noise Level: 64DBA
-- Wind Pressure: 24.60 mmH2O
-- Bearing: High precision double ball bearing
-- Operating Temperature: -10℃ ~ +70℃
-- Storage Temperature: -40℃~ +70℃
-- Power range: Plus or minus 15% of rated power supply
-- Insulation Resistance: More than 500 megohm
-- Fan Frame: Injection molding, PBT+ 30% glass fiber + VO class flame retardant.
-- Fan Blade: Injection molding, PBT+ 30% glass fiber + VO class flame retardant.
-- Suitable for workstation cooling/server CPU cooling.

I'm testing mininspeed for some days, I got although about 13k sol but I get only about 1,3 ZCL per day. And whe I see the Stats of the other Miners whis have the same speed it is same low. I think I will change the pool this evening.

https://zclassic.miningspeed.com/workers/t1VZtF8716JFCfEqVdjKXtNUui8zwiJ7tRG

Had no problem wirth the import, but UPS needed thes time a extra agreement for the customs in which I wrote my EORI number. Bt the hotline told me it shoul work for private persons even without EORI.

My Z9 Mini is on the Way now 
Is Nicehash still working bad and are any mining pools for ZCL available?