Repair Audio Amps

Dr.Tube is the specialist in the repair of tube amplifiers, both vintage and new. Contrary to the vast majority of other repair shops, who find it is sufficient to repair to the level of “it works again”, Dr.Tube goes the extra mile to make an amp not only “work again” but also to make it really sound good again. A subtle but huge difference! See the Repair Guitar Amps page for repairs on guitar tube amplifiers.

Dr.Tube has extensive ex­perience repairing, amongst others, the following brands of audio tube amps:
Air Tight, AMC, Audio Innovations, Audio Note, Audio Research, Audiomat, Audion, Beard, Bocama, Cayin, Conrad Johnson, Copland, Croft, Dynaco, Dynavox, EAR, Fatman, Geloso, Grant, Jadis, Jasmine, JJ, Jolida, Kebschull, KR, Leak, Lectron, Lua, Lumley, Marantz, McFarlow, McIntosh, Melody, Ming Da, MOSCode, Music Angel, Musical Fidelity, Papworth, Pathos, Philips, Prima Luna, Pure Sound, Quad, Radford, Sonic Frontiers, Spark, Sun Audio, Synthesis, T+A, Unison Research, Vincent, VTL, Yaqin, Yarland…

Common tube amp repairs at Dr.Tube are:


Retubing is replacing (all) the tubes. Tubes are subject to wear and tear and have a limited lifetime. A tube amp with old and worn tubes can:

  • hummmmm,
  • sound thin and lifeles,
  • hisssss and/or make crackling noises (fried egg noises),
  • distort,
  • have less power.

The wearing out of the tubes is a gradual process which means that you easily get used to the lesser sound.

It’s striking how many audio tube amps come in here for repair that have completely worn out power tubes. Tube amp owners seem to have a tendency to keep on playing with old tubes. This is not a good idea. When a power tube, at the end of its life, finally kicks the bucket, it often damages the amplifier itself. In the worst case scenario the output trans­former can blow. Unnecessary and expensive to fix!.


Recapping is replacing all the electrolytic caps (electro­lytics). Due to the way electrolytics are constructed and the high temperatures present in tube amps, electrolytics also have a limited lifetime. A tube amp with worn and dried up electrolytics can:

  • hummmmm,
  • have less gain,
  • sound dull and thin,
  • lack punch and “oomph”.

Our experience is that electrolytics have a max­imum life time expectancy of around 10 to 15 years. So with a lot of older amps it is high time to replace these electrolytics, even if they look OK. When we recap, we do not replace all the capacitors, just the electro­lytics, as film (plastic), ceramic and mica caps usually can last many tens of years. If, however, one or more of the other caps are not OK, we replace these too of course.

The effect of fresh electro­lytics is usually very pronounced. A lot of people do not realize/know this. We have often heard from customers that they should have had this done years ago.

Dr.Tube is very well stocked in high quality electrolytics for use in tube amps.