I am new to tube amplifiers and purchased the Badlander 25 combo a few months ago. I noticed that turning up the master (even when nothing is plugged in) produces a wind/white noise that gets significantly louder the more the pot is turned up. It is substantially more noticeable when the EQ pots are used, but still present when everything, including gain, is at 0. Before I go any further with this- is this normal/acceptable or is this something I should look into? I have attached a video for reference.
Wind/white noise coming from amp
- Thread starter ajfavale
- Start date
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That sounds like a bad 12AX7 tube. Do you have a spare?
Swap a good 12AX7 into each tube position until you find the bad tube. Be sure to turn off the power before changing tubes. Be careful, tubes can get pretty hot.
Dom
Swap a good 12AX7 into each tube position until you find the bad tube. Be sure to turn off the power before changing tubes. Be careful, tubes can get pretty hot.
Dom
Thanks, I will have to order a spare and I will try that.
clutch71
Well-known member
Remove all preamp tube shields (if applicable) and tap the tubes gently with a pencil's eraser. That should identify the bad tube.
Both channels
Thanks, I bought a set of power tubes when I bought the amp but didn’t get any preamp tubes. I bought the amp in November but was in an apartment, so I only played with the direct out into my interface with headphones. Now that we’ve moved into our home I’ve been able to play with the speaker connected so this is the first time I really noticed the noise with higher volume settings. I just bought 2 preamp tubes this morning so I’ll give that a shot.
Welcome to the forums.
I have the BAD 100 so I doubt there is much difference in the preamp design. I briefly looked at the manual for the 25 and the task chart is much the same. Perhaps some voltage may be different and some minor things. Anyways I was curious to see if I did the same thing with the BAD 100.
Yep, I get a similar result. It sounds more like fan noise to me on the BAD100. That sound did not change much with the gain control either. At the volume level where it becomes most apparent, I probably would not be in the room if I played the amp at that setting. It is not a silent preamp, but it is not that bad to require a noise gate either. I would assume you may be able to reduce some of that noise but doubt you can eliminate it.
If the noise is excessive though, best to try rolling in a preamp or two. Since you had it in the clean mode, that bypasses the drive circuits V1B and V3A. The usual suspects for noise in a Rectifier amp are the tone stack driver or the FX loop circuit as they make use of cathode follower circuits. More so due to the wear characteristic on the tubes. V2 is the tone stack driver and V4 is the FX loop.
Try playing through the amp with a normal volume setting with the speaker connected. Does the noise floor compete with the guitar signal? If that is the case, you may need to explore swapping a few preamp tubes to see if that changes anything.
I have the BAD 100 so I doubt there is much difference in the preamp design. I briefly looked at the manual for the 25 and the task chart is much the same. Perhaps some voltage may be different and some minor things. Anyways I was curious to see if I did the same thing with the BAD 100.
Yep, I get a similar result. It sounds more like fan noise to me on the BAD100. That sound did not change much with the gain control either. At the volume level where it becomes most apparent, I probably would not be in the room if I played the amp at that setting. It is not a silent preamp, but it is not that bad to require a noise gate either. I would assume you may be able to reduce some of that noise but doubt you can eliminate it.
If the noise is excessive though, best to try rolling in a preamp or two. Since you had it in the clean mode, that bypasses the drive circuits V1B and V3A. The usual suspects for noise in a Rectifier amp are the tone stack driver or the FX loop circuit as they make use of cathode follower circuits. More so due to the wear characteristic on the tubes. V2 is the tone stack driver and V4 is the FX loop.
Try playing through the amp with a normal volume setting with the speaker connected. Does the noise floor compete with the guitar signal? If that is the case, you may need to explore swapping a few preamp tubes to see if that changes anything.
