8] Tuning (top)
This tuning chapter was done in much same fashion as in the A821 review.
To get the voltage offset value working, we need to put it as a Cgminer command
in the 'More Options' field found in the Cgminer configuration page.
Here is an example: "--avalon8-voltage-level-offset -2".
See more details in screenshot images below.
Testing made earlier in this review was done with the default setting for the voltage offset, which is 0.
Now the miner will be tested with every available voltage offset value.
The miner will be run for at least one hour before looking at the results.
Just like with the previous AvalonMiner generation, it is possible to choose a value from -2 to +1 for the voltage offset.
Instead of changing the hash board frequency setting, AvalonMiner performance can only be controlled by changing the voltage offset value.
In the Controller Dashboard, what does the Voltage Offset option do?
We added a Voltage Offset option for users because each AvalonMiner is different with each other because of the inclusion of so many high performance chips. The AvalonMiners are very sensitive with voltage, so the Voltage Offset option is used for tweaking the AvalonMiners voltage. If the miner works well, we suggest to not change the voltage.
And, the lower voltage offset, the lower power. So if the miner works well with -2, it just means the miner has better health.
Source: https://canaan.io/question/in-the-controller-dashboard-what-does-the-voltage-offset-option-do/
This time I was able to see difference in performance and power consumption value, when testing each different voltage offset value.
Power consumption was moving in 1330 - 1400W area, and the hash rate was in 13.3 - 13.7Th/s area.
Please notice that these power consumption results are measured power at wall,
so the power supply power efficiency also has an effect in the result.
Voltage offset value | Hash rate (Th/s) | Power consumption (W) | Power efficiency (J per Gh/s) |
-2 | 13.35 | 1332 | 0.0998 |
-1 | 13.54 | 1365 | 0.1008 |
0 | 13.52 | 1400 | 0.1036 |
+1 | 13.65 | 1395 | 0.1022 |

Cgminer status page view and Cgminer configuration page view, when the voltage offset value is -2. Click for a bigger version.

Cgminer status page view and Cgminer configuration page view, when the voltage offset value is -1. Click for a bigger version.

Cgminer status page view and Cgminer configuration page view, when the voltage offset value is 0. Click for a bigger version.

Cgminer status page view and Cgminer configuration page view, when the voltage offset value is +1. Click for a bigger version.

Power consumption measurement, when the voltage offset value is -2. Click for a bigger version.

Power consumption measurement, when the voltage offset value is -1. Click for a bigger version.

Power consumption measurement, when the voltage offset value is 0. Click for a bigger version.

Power consumption measurement, when the voltage offset value is +1. Click for a bigger version.
9) Conclusion (top)
Canaan keeps developing new AvalonMiner models, and while the power efficiency is time after
time improved, the miner design still remains also solid and stable.
According to Steven Mosher, the expected failure rate in the field for AvalonMiners is close 1%.
Looking at this unit closely and disassembling once again convinced me
about the robustness in the miner design.
While the price tag is little higher than competition,
the reduced need for repair, reduced repair costs and reduced down time
most likely result in lower total costs during the miner lifetime.
I would like to thank Canaan Creative for sending this nice piece of gear.
Special thanks to Steven and Lily for inviting me to Beijing
and once again for all the efforts to make this A841 review possible!
If you got any questions or comments about this review/guide,
feel free to drop them here in this thread. 
10) How to order (top)
60 units or more:
If you want to buy 60 units or more, you can buy them directly from the manufacturer Canaan Creative.
https://canaan.io/shop/
Less than 60 (1 - 59) units:
If you want to buy less than 60 units, you will need to order from your local official Canaan hardware distributor.

List of Official Canaan Distributors in March 24, 2018.
Click here to find out the up-to-date official distributor list.
Canaan Creative:
www.canaan.io