No sound but hum in my mark IV help a tube newb

[metalmike23]

Ijust got my first tube amp in the mail. There happened to be a cracked tube as well as a replacement so I changed the tube and plugged in and I have absolutely no sound but hum. Help me please.
-Mike

 

[musicman10_1]

That stinks. I'll ask the standard question: have you checked all cables, connections, made sure all the tubes are in all the way, speaker cable connected?

Sorry to ask as I would guess you have done all the above but my reaction to a problem like this is to start from square one and check everything.

John

 

[Russ]

What kind of amp is it?

Is there volume on any channel?

Check your preamp tubes too.

Check your guitar and instrument cable. It is always easiest to point at the new thing, especially when you bought it sight unseen.

Do you smell anything odd?

Do your tubes glow?

How long did you let it warm up before taking it off standby? Some amps require more time than others. Some tubes require more time than others.

Are you sure that you know how to use your amp?

 

[musicman10_1]

Mike,

What happened? Did you get the amp working?

 

[metalmike23]

I replaced the power tubes with el34s and still nothing. I get buzzing but it seems like I have no input from the cables. I'm thinking it's either an input problem or a speaker problem. I've tried everythign. The store said it was working perfect before it was shipped out. I'm really frustrated If anyone can help me with this diagnosis please do.
-Mike

 

[metalmike23]

What kind of amp is it?

Is there volume on any channel?

Check your preamp tubes too.

Check your guitar and instrument cable. It is always easiest to point at the new thing, especially when you bought it sight unseen.

Do you smell anything odd?

Do your tubes glow?

How long did you let it warm up before taking it off standby? Some amps require more time than others. Some tubes require more time than others.

Are you sure that you know how to use your amp?

My tubes glow. How long do you think I should let it warm up. I can't see it being more than two minutes. Everything looks like its working yet its not..

 

[Russ]

Have you checked your output knob? Make sure it is pushed in. Make sure that you are not in a silent mode. Try another output jack. Check your fuses. Try switching the power mode. Also try changing the channel on the back. Try both pentode and triode. Try both simul and class A. Is there any change when you try to come out of stanby? Try moving all your knobs. It may be a short in the amp. These things happen from time to time. It is usually caused by getting jarred (shipping can do this as well as riding in a trunk). Check to make sure that your cables are good. Check to make sure that your jacks are making connection when you insert a cable. Look at your chassis' internals and look for any signs of melting or discoloration or broken solder joints. Be careful not to zap yourself though caps can kill. Smell your amp while it is powered up. Your tubes should only take a minute or so to warm up even if they are older though I have seen some old Marshalls take up to a few minutes before they were ready. Check your preamp tubes for any that have white powder inside. Look at your tubes while powered up and look for anything uncommon between them. All tubes should glow slightly. Hit a string and see if it makes them a little brighter.

 

[metalmike23]

Have you checked your output knob? Make sure it is pushed in. Make sure that you are not in a silent mode. Try another output jack. Check your fuses. Try switching the power mode. Also try changing the channel on the back. Try both pentode and triode. Try both simul and class A. Is there any change when you try to come out of stanby? Try moving all your knobs. It may be a short in the amp. These things happen from time to time. It is usually caused by getting jarred (shipping can do this as well as riding in a trunk). Check to make sure that your cables are good. Check to make sure that your jacks are making connection when you insert a cable. Look at your chassis' internals and look for any signs of melting or discoloration or broken solder joints. Be careful not to zap yourself though caps can kill. Smell your amp while it is powered up. Your tubes should only take a minute or so to warm up even if they are older though I have seen some old Marshalls take up to a few minutes before they were ready. Check your preamp tubes for any that have white powder inside. Look at your tubes while powered up and look for anything uncommon between them. All tubes should glow slightly. Hit a string and see if it makes them a little brighter.

I'm getting absolutely no signal. Every cable I've tried makes no sound when it is being plugged in or touched. It is not in silent mode. No white powder or discoloration. Again everything looks fine but the only thing I'm getitng out of the amp is a hum regardless of whetehr or not theres a cable plugged in.

 

[Russ]

Have you taken a look inside yet?

 

[Russ]

try sending from your effects loop. This will tell you if you are getting signal provided your preamp is working.

 

[metalmike23]

yes.. I don't see anything unusual

 

[Russ]

also try sending to your amp via the effects loop.

 

[Russ]

how old is the amp?

 

[metalmike23]

also try sending to your amp via the effects loop.

What should I do just run a pedal through it?

 

[Russ]

If you don't have a preamp yes

 

[metalmike23]

What am I looking for just any type of sound?

 

[Russ]

anything?

 

[Russ]

try another amp with the same guitar and cables

 

[metalmike23]

I did everything is fine in my practice amp.. it sounds to me like a shortage although I'm obviously no expert

 

[Russ]

in your original post you said there was a cracked tube and a replacement. What kind of tube was it and was it in the socket and cracked?