My 6922 Tubes Are Too Bright!

   Hi , I have a SEP low power amp that takes a single driver tube of your requirement 6DJ8 . So I purchased the following -  NOS E88CC Telefunken, Tesla, CCa Siemens , Phillips SQ, Mullard , JAN Phillips ECG, Russian 6N1P. So now at about $1000 dollars later I put them all in for evaluation . I run Zu speakers which are bright . I avoid silver Interconnects and speaker cables to avoid added brightness . So the results are exactly what you’re asking . Number 1 is the Telefunken ( absolutely ) . Not too bright , flat response and Very Musical . Number 2 is the NOS Tesla E88CC Red Tip ( just like the Telefunken , but more liquid ). Number 3 is the Siemens CCa ( like the Telefunken , but a pinch more brightness ( I run this with KT120 power tubes)  . Number 4 is the Russian Rocket ( the good one ). After that it’s a mixed bag . The Holland Phillips is Too Bright . The American JAN Phillips is good, but plain . And the Mullard is my least favorite ( it’s like a blanket over my speakers ( Sorry To The Mullard Guys ). However the Mullard is good in multi driver tube amps as the phase splitter . My music source is digital with a Schiit Yiggy , a Rogue Pre with NOS Tektronix Telefunkens . My power tubes are NOS GEC KT88 and NOS GEC KT66 smoked glass ( yes the real stuff ). Rectifier is a NOS WE 422a or a NOS RCA 5U4G Black plate or a NOS Mullard GZ34 double getter . So my advise is to go NOS Telefunken E88CC . Also if you read the Tone Descriptions on the Brent Jesse site , you will find they are spot on . If I may offer any additional input , please ask . Best Wishes and Happy Listening , Mike.