Loss of Gain Roadster

[Holy Diver]

Hi all,

Quick Q for you:

Last night at rehearsal I experienced a progressive loss of gain over the course of a couple of hours. Even at the start it sounded pretty weak to me. Ended up with a v tinny bass/gain lacking ch4 tone and almost inaudible clean tone - similar to rolling back volume on guitar almost all the way. Ch3 seemed to hold up marginally better than ch4 although probable down to the eq'ing of the channel.

I am assuming it is down to some failing tubes? There isn't much hours on the tubes i have in at the moment though - although I went 9 months without playing due to a smashed arm...

I will swap out the tubes tomorrow and see how that goes.

Strange thing is i had an amazing tone last week... Stranger still is that the the exact same symptoms occured about a month ago with a different guitar but that turned out to be a pickup problem on the guitar. Just found it really strange that it sounded like the exact same thing last night with a different guitar - I checked out the guitar afterwards and it's output is perfect.

 

[screamingdaisy]

What brand of preamp tubes are in it?

 

[Holy Diver]

What brand of preamp tubes are in it?

Off-hand not sure. Did a full retube from Dougstubes last year but can't recall exact specs now

 

[Ramon]

Guitar cable maybe? I know it's stupid, but it's the first thing you should always check, if you haven't done it already

 

[Holy Diver]

Guitar cable maybe? I know it's stupid, but it's the first thing you should always check, if you haven't done it already

Cables are grand as far as I know. I'll have to strip rig back to basics and systematically swap out the tubes and see how I get on.

 

[Ramon]

I'd check the power amp tubes too. Good luck!

 

[Holy Diver]

I'd check the power amp tubes too. Good luck!

Well - I went to the rehearsal room last night with a box of tubes in hand ready to do some investigating. And...

Everything sounded spot on. Wtf like? Pretty annoying

Have a full band practice tonight so will see how things go. I am now considering whether there is too much equipment drawing power from the same source and I'm some how getting less power than I need to. Does this sound feasible?

 

[screamingdaisy]

I am now considering whether there is too much equipment drawing power from the same source and I'm some how getting less power than I need to. Does this sound feasible?

Yes, but unlikely. I've run a lot of kit off one outlet (my rack used to dim the lights when I hit the main power switch) and never had an issue with a lack of juice while playing.

 

[boss4]

It was a warning! Probably a tube failure, keep the spares next to you!

 

[Norseman]

I experienced something like this too (actually from time to time) with my Roadster. I re-seated all the tubes and fired it back up and it was punchy again. It's happened a few times. The last couple times, I just put it in standby, turn it off for 30 seconds, turn it on for 30 seconds ...take it out of standby and it's back in business. I just chalked it up to another strange thing with this amp.

 

[KH Guitar Freak]

Might be a preamp valve problem. In my case, channel 3 worked fine, but channel 4 was stuffed. Turns out it was a faulty treble pot. What luck. Brought a brand new unit out of the box, and never played it much, but especially on channel 4. Cost me AUD 145.20 to send to a tech to diagnose and replace said faulty pot...