Major problem with Brand nw mark V Please Help

[joe187]

i I was demoing my new Mark V for a couple of friends tonight. I had used it for all of an hour up to this point and everything was fine. I had all three channels on 10watt mode, showing how loud 10 watts can be, and I heard a small pop in the amp, an i lost virtually all of the output. I figured something was configured wrong, I checked the footswitch connections and everything else, everything s OK. I am not getting anything louder than the 10 watt channel on 2 or 3, regardless of what settings I have selected. If I disconnect the footswitch and put the switch control in bypass mode I get a slight increase in volume, but even on channel 3 in Extreme mode set at 90 watts with the gain and master spiked its not as loud as my 15 watt Blues Jr on 5. Something is seriously wrong. or I have screwed something up and I just don't understand how it all works. However every channel on every mode is the same, whether I have the footswitch engaged or not, whether the overall volume and Solo are enabled by engaging the footswitch, etc.

Anybody have any idea or has anyone seen this before? i believe I got a unit witha problem, but before I go back to GC and make a lot of noise I wanted to pass it by you all.

Thanks

Joe

 

[MusicManJP6]

Sounds like a tube might have popped. Check your power tubes in the dark and make sure they are all lit and none of them are glowing really bright. Next, if you have a good preamp tube, start swapping it out one by one in the amp.

 

[kekam35]

Sounds like a tube might have popped. Check your power tubes in the dark and make sure they are all lit and none of them are glowing really bright. Next, if you have a good preamp tube, start swapping it out one by one in the amp.

If its a pre-amp tube it would most likely be the phase inverter as that is the one that drives the power tubes
and is the only one that runs in all modes so try that first.
After you try new power tubes.

 

[MusicManJP6]

Sounds like a tube might have popped. Check your power tubes in the dark and make sure they are all lit and none of them are glowing really bright. Next, if you have a good preamp tube, start swapping it out one by one in the amp.

If its a pre-amp tube it would most likely be the phase inverter as that is the one that drives the power tubes
and is the only one that runs in all modes so try that first.
After you try new power tubes.

good point.

 

[LPJunky]

If you slave the mute output (tuner output at the back activated when you pull the solo know or engage the mute footswitch) )to an other amp or PA or mixer and they all seems to sound about right, balanced, etc. than you saved yourself a lot of swapping since it would point likely to the power section.

 

[MusicManJP6]

If you slave the mute output (tuner output at the back activated when you pull the solo know or engage the mute footswitch) )to an other amp or PA or mixer and they all seems to sound about right, balanced, etc. than you saved yourself a lot of swapping since it would point likely to the power section.

Another good point.

 

[joe187]

Hey Guys,

I guess I dodged a bullet. I had connected a 4 ohm cab to the amp and left the 8 ohm speaker attacfhed. This resulter in a 2.something ohm load, which was way too low. I was lucky in all that I did was blow the inverter tube. I went through the amp, replacing one tube at a time, and then testing. It ended up being #7, the phase inverter. When I replaced that the amp camback alive. Wll. all but channel 2 did. That turned out to be me breasking the top of the tube off [utting the shield back on. I replaced all 7 tubes with JJ's. I happened to have enough extra JJs pre amp tubes laying around to do it. It is all perfect now, and I am so psyched.

Thanks for your advice. I know not to connect an 8 and a 4 ohm load tgether now - I actually did know it, but it just didn't dawn on me that what what I was doiing.

I am going to run in stereo for a while with my Roadster - be intersting to see what it sounds like. I eventually have to sell the Roadster (and roadcase) but I am going to screw around with it until it sells.

Thanks for all your suggestions. You guys were right on the monry.

Joe

 

[phyrexia]

Connecting cabinets in the way you describe could not have blown your phase inverter tube. You just got unlucky and that tube blew.