Tubes may look the same – but test results are NOT.

In the past, most Chinese tubes (including high end tubes) are sold over internet without adequate distribution quality control. Some consumers are confused about the quality grade on the Shuguang Treasure tubes and wonder if all Premium tubes out of factory are the same, and if the factory test readings are accurate.

Below is the sample testing results for Shuguang Treasure tubes that Grant Fidelity receive from factory in 6 months of time (Jan 2009-July 2009). They are self explanatory as you can read all the testing results obtained by Grant Fidelity’s 5-spec test. 1) Listing results are listed in the order of factory matched pair or quad (shaded or unshaded in the spreadsheets). If a tube is listed as single or a quad is not complete, it means the other one(s) have failed in our first test and graded as ‘Rejects”. 2) “Rejects” are not included in the list as those tubes are reported with ‘Short’ in the tester, hence no further results can be reported. 3) KT66-Z and 2A3-Z tubes are not as popular as other models, so they are not included as we don’t have sufficient data to deem the testing results as representative.

Shuguang Treasure 300B-Z: