Roadster owners, please take the time to read this and reply

[budlovesaly]

I am sure some of you read my thread on here detailing my issues. I have alas one final question, and I need as much input as possible. With the amp on and the effects either engaged or disengaged, if you turn down the gain and the channel volume, are you left with a noticeable hum/noise coming from your speakers? Also, if you are getting that hum, is it still there when you disconnect your instrument cable from your guitar?

I get alot of hum when I turn down the gain and the channel volume, even with the loop disengaged.

 

[fjk1138]

Generally speaking, no, it should be extremely quiet or as relatively quiet as possible. I experience very very slight hum on when the loop is engaged.

But we need more detail in order to diagnose correctly:

a. Does it do it on all channels or certain ones?
b. Does it happen on Spongy, Bold, or Both?
c. What kind of pickups are you using?
d. How close is the guitar to the amp?
e. Is there anything else on the AC line that might cause the noise?

etc.

 

[budlovesaly]

Generally speaking, no, it should be extremely quiet or as relatively quiet as possible. I experience very very slight hum on when the loop is engaged.

But we need more detail in order to diagnose correctly:

a. Does it do it on all channels or certain ones?
b. Does it happen on Spongy, Bold, or Both?
c. What kind of pickups are you using?
d. How close is the guitar to the amp?
e. Is there anything else on the AC line that might cause the noise?

etc.

There is hum in all the channels when I turn down the volume and the gain, and disconnect the instrument cable from the guitar with the volume and gain down -- fx loop or no loop. It happens on both settings. I use Fender Samarium Cobalt noiseless pickups on a Fender American Deluxe HSS, my guitar is about 6-10 ft from the amp in a given time, there is nothing else connected, and it happens with the lights on or off.

 

[b0nkersx]

Maybe your house is poorly wired. It sounds like this problem is not a major design flaw type thing.

Have you tried a power conditioner? How low are the volume and gain when this happens? You shouldn't disconnect the instrument cable from the guitar, but from the amp instead. If there's noise with the cable disconnected from the amp, it's a problem with the amp or power supply. Have you tried a new power cord? Also, does it happen on every speaker output?

 

[budlovesaly]

Yes, I have tried disconnecting from my amp too. And if you read my previous thread, it happens with NO VOLUME AND NO GAIN, IN ANY CHANNEL!

And yes, it happened at my tech's office too. That is why he initially said that he has never seen an amp do that, and after troubleshooting the usual, he was stumped. He called Mesa (as I did days before bringing the amp to him, after their tech diagnosed my amp over a cell phone!) and they told him that the amp was behaving normally. So of course I told him that there has to be something wrong, if not tubes (which I switched all of them a month ago, and haven't gigged with them) then it must be the output transformer or something. He said the tech said that this was normal. Normal my ***! Again today, my reverb isn't working -- second time in two months. I know there is something happening to my amp, and it's clear that it is unusual.

 

[pinhedgtr]

Hey bud,
I just tried this out for you and my amp (roadster 2X12 combo) was dead quiet. However with the loop on I did have a noticeable hum once the output volume was past 9:00 the hum gets louder from that point as I turn up the output volume. Hope this helps you bro.

 

[davidfloyd]

Sounds like the problem could either in your power supply stage of the amp or possibly a bad output tube. I would've guessed it could have possibly have been interference with the transformers with something outside, but since you've tried the amp at other locations, I think that's been ruled out.

The rectifiers are part of your power supply stage. Have you tried turning off the tube rectification in each channel to see what results? On that note, I'd also play with the other switches on the rear just to see if anything can be eliminated as a possible culprit. If one of your output tubes is bad, it is possible that one of the bad ones is also one of the pair that gets "turned off" when you go to 50 watt mode, so you could try that just in case. Shotgunning your 6L6's with another good tube if you have an extra one available could help as you can try rotating it through each of the 4 positions.

 

[davidfloyd]

Oh, if your reverb is out too, that could be a whole different issue. You mentioned you changed tubes recently, but did you keep the old ones? Some additional shot-gunning with your older preamp positions may not be a bad idea though you'd think the tech would've done that, but sometimes obvious stuff can be missed if someone's having a busy day. You can try disconnecting from the reverb tank directly and see if there's anything related to the hum when you do that.

Good luck!!

 

[iceman]

I had some hum in my Roadster from the start at medium volume level on channels 3 and 4. I've since went through several preamp tubes and the last one I replaced was in v6 position. Since then I've noticed that its actually less noisy. So its possible its tubes. I also notice that if my pickups are facing the amp I pickup some hum from the amp it self.