detlevski

You definitely need to bias even with matched pairs, it is important to let them cook for some time before biassing. I usually take one hour to do that and when I have used the amp intensively for a week I check the bias again. A service tech would not do that, you would have to come again to have him do that. There are plenty people I would recommend bringing it to an official tech. Only you can decide if you are capable enough. If it was my company I would also recommend not doing it yourself.

You are asking for how to replace tubes to the wrong person, this is a Line 6 support forum. Of course psarkissian has to tell you to bring it to an official repair tech. Line 6 could be sued if he told you you can easily do it yourself and you got hurt or even died. If you have some common sense and a good multimeter and know the procedure(!), which can be found on YouTube or even this forum, you can do it yourself. But that does not mean anybody can replace the tubes themselves, some people are clumsy or not informed well enough to do it themselves. I had to replaced tubes twice (in not even 1 year!) myself and biassing was a piece of cake. But I have some experience in working with electronics. After I did replace the tubes the last time I sold the DT25. I have never used a tube amp that needed new tubes that fast. Fenders and Marshalls. And yes I did use the right tubes, Sovteks EL84's and EHX 12AX7. I didn't find the DT25 reliable enough so I switched back to an all tube amp Marshall. Read for example Marshall and/or Fender forums, heavy users all replace and bias their gear themselves.

I want a volume pedal in the FX loop of my DT25. After hours of reading articles I think I will need the low impedance version of Boss FV-500(L). Am I right and where can I find information about the impedance of the FX loop of the DT25. I find the information in the Pilot's Guide pretty cumbersome. Even on the support pages I cannot find the answer to my question. I hope someone can give me some more information about this set-up. I just want to use the volume pedal to behave as a master volume.

Last week i replaced all tubes for the first time. But before doing that I measured the current bias. On V3 I measured 31mv and on V2 i measured 26mv. The 12AX7 was indeed a Chinese generic one and the two EL84 were the (probably) original Electro Harmonix ones. I swapped them out for an Electro Harmonix 12AX7 en two (matched pair) Sovteks. I could not believe my eyes when I measured 23mv on V2 and V3. The original pair looked like the picture, one looked a bit "burned". Is this normal that there is such a difference?

I am not that sure it is just a matter of changing tubes. In my case the hum (and noise) was caused bij the HyperGravity Compressor. In the default profiles all the 3 different settings use Auto Gain. Obviously a high gain mode setting of the DT25 is more susceptible for noise that is amplified by the Auto Gain feauture. Using TonePrint I have created a setting with Auto Gain off and reduced the noise and hum.

I also have a big difference in hum in mode 4 and the rest, disabling the compressor fixes it. Not really an option.

Thanks, after posting this question I found that there is indeed a service center. So, we are good to go! Next week the DT25 will arrive in the store. Can't wait!

I want to buy a DT25 combo, but I want to be shure I can get official support here in the Netherlands. I live in Amsterdam. Are there people here that have positive experiences with support. Line6 is very well known here and support can be necessary. Thanks