[chgolatin2]

Under the advise from Jolida technician I took all of my tubes to get tested by a local Hi Fi tech guru (recommended by Matt Thanks!)  he ran the following test on the tubes: 

Tonsols 12AX7 (2) 84-91 & 102-86 Pre amp tubes
Mullards 12AT7 (2) 96-90 & 63-81 Driver tubes

JJ KT 77’s 8 power tubes total

All tested between 70 to 77 minus 2 that tested in between 66 & 67

Under the advise from the tech he informed me to changed one of the low testing tubes (1) Mullard that tested  between 63-81 since he didn’t have a Mullard he sold me a Brimar tube (ECC81)  12AT7.  The tech stated that I didn’t need to have the same name matching brand for the driver tubes, don’t know if his statement is true but I would like to know if this is a fact or not? To make my long story short my integrated Jolida 1000RC amp was having problem which it would turn itself off for no apparent reason so I called Jolida and they informed that most likely I have a bad power tube and to run a test on them.  I am currently testing my amp out running her at full steam and to my surprise it hasn’t turn itself off ? so hopefully she is doing ok for now.  Since I am somewhat new to tubes I would like to know if it does make a difference to have the same brand matching tubes or not? 

Thanks!  Robert

[JohnR]

Hi, this might be a Lab thread... anyway, changing the 12AT7 will have no effect on the power tubes. Different tubes will change the sound of the amp slightly, so you may wish to try swapping out the remaining Mullard for another Brimar.

Why changing the 12AT7 would stop your amp from shutting off is a mystery though. I would suggest first checking if your amp has a bias adjustment. Second, check your wall voltage, it may be on the high side.

BTW the test he ran sounds like a transconductance test. This will not show up a bad power tube. Typical tube testers don't stress power tubes the way they are stressed in a power amp.

[SET Man]

Under the advise from Jolida technician I took all of my tubes to get tested by a local Hi Fi tech guru (recommended by Matt Thanks!)  he ran the following test on the tubes: 

Tonsols 12AX7 (2) 84-91 & 102-86 Pre amp tubes
Mullards 12AT7 (2) 96-90 & 63-81 Driver tubes

JJ KT 77’s 8 power tubes total

All tested between 70 to 77 minus 2 that tested in between 66 & 67

 The tech stated that I didn’t need to have the same name matching brand for the driver tubes, don’t know if his statement is true but I would like to know if this is a fact or not?...

 Since I am somewhat new to tubes I would like to know if it does make a difference to have the same brand matching tubes or not? 

Thanks!  Robert

Hey!

    I guess to the tech guy it doesn't matter since they both will measure the same electronically. But! For us they will be sonically different
   
    So, yes like JohnR said I would find a match for the Brimar or Mullard. Of cause if you are an audiolunatic than you will also look for a one with matched date code and made in the same factory.... oh! wait I think that's sounded alot like me

Take care,
Buddy

[chgolatin2]

Good point and I am in the process of just upgrading all of my tubes the new tubes. Since I purchase the amp used I really dont know what the previous owner did or how he ran the tubes how long he left them on etc etc etc.  To make sure I'm just going to replace all the tubes and start out new.  For the moment I re biased my amp and changed the bad at7 tube and the amp is running smoothly however this is a temporary fixs.

Hi, this might be a Lab thread... anyway, changing the 12AT7 will have no effect on the power tubes. Different tubes will change the sound of the amp slightly, so you may wish to try swapping out the remaining Mullard for another Brimar.

Why changing the 12AT7 would stop your amp from shutting off is a mystery though. I would suggest first checking if your amp has a bias adjustment. Second, check your wall voltage, it may be on the high side.

BTW the test he ran sounds like a transconductance test. This will not show up a bad power tube. Typical tube testers don't stress power tubes the way they are stressed in a power amp.

[lonewolfny42]

chgolatin2....Send a PM to Bill Baker......he's very familiar with Jolida products...