I lost the cable to connect the guitar the the amp

your gonna prob have to replace knob but try and re sodder the connections. if that doesn't fix it then its your knob that needs to be replaced

... do you, by any chance, have non humbucking pick ups on your guitar? Just curious...

Many try to use poor quality guitar cables and have the problem. The sleeve of the guitar cable plug turns on the battery in the guitar. Always loop the guitar cable through your belt or the guitar strap to avoid the cable wisting the plug in the guitar causing noise and WEAR that wears the plug sleeve to the point it no longer will activate the guitar.

If it is new then something is a bit strange to say the least. Turn all the knobs to midpoint. If it is going to click/pop then you will definitely hear it. Switch to standby, then power to on for a minute then standby to on. You should then see the 6l6 and the 3x 12AX7's all glowing. Plug into each channel. Don;t use a pedal to try any of this. If you get a pop on on ch then it can be one side of the preamp either a tube or one of the op amps on the board.

Make sure you try out the cable/guitar on a different amp to make sure it is working. Could be a cable or plug that is the problem.

Honestly if this is new I'd haul it back to the store and return it. It should just work with no hassles. Once you know your guitar/cable is not the cause then I would take it back and get them to either set it up or replace it. Something is just not right here for a brand new amp.

I suspect there is bad soldering on the circuit board in the vicinity of that button. The movement causes the connection to re-establish. It isn't necessarily one of the button leads. Look for a little grey line around the menicus of one of the soldered leads.

Maybe your room is wired without an earth connection. Try it in other rooms or a friends house. If it works OK elsewhere, you need an electrician to check out your house, it may be dangerous. If it still does not work, look at your settings, and use low gain for testing.

Sounds like a problem with the channel itself, if the clean channel works then its not the lead, input, guitar or the drivers. You have to be careful when opening up amps as some can hold a residual charge and there can be danger of electrocution.

I would recommend getting it looked at by a pro, it doesn't sound like an expensive fix.

Yes, there are several possibilities. First thing is to disconnect your guitar and then plug in the cord to the amp. Expect a bit of hum. If it screeches, then problem is not feedback via the guitar. If it doesn't MAYBE your guitar is "hearing the amp" which the guitar is then a microphone and can feedback. Moving the cable generates electrical noise which can trigger the feedback to start.
If you get the screech without the guitar connected, then TRY a new guitar cable. Make sure it is an INSTRUMENT cable... I have seen some try to use speaker cables or junky 1/4 inch cables intended for home stereo... these will NOT work and can cause the feedback. The next possibility is a broken jack on the amp. This would require repair. The common cause of this is to fail to run the cord through the handle of the amp... one trip on the cord or step on it pulling the plug sideways in the amp and the jack is broken and it is a trip to the shop as well. While on the subject ALWAYS run the cord at the guitar end either through the strap or your belt loop. Cords left dangling keep rotating and soon wear out the plug and also the jack in the guitar and then that has to go to the shop.

Most of the pedals are daisy chained right from the guitar. The output of the daisy chain goes into the DI box set to ground lift. An XLR to XLR cable goes from the DI box to the amp or mixer. Do NOT try to loop the sends and receives of the amp through PEDALS! The sends and receives are LINE LEVEL which is too high for pedals. The sends and receives are for external effects MODULES and EQ's that take line level. Some of those effect units have a foot switch to turn them on and off.

Hi, i 'll suggest you use the manual to verify if you connected it the right way. And also you can test it with another amplifier to be sure it's working properly.

You can also test for the cable you used to connect the pedal to the amplifier if it 's working properly i guess that would do..

After checking, If it does not work, i guess you could take it back to where you bought it from if it has a guarantee...

Thanks for using fixya........