Amp problem :)

[Andrew Lamprecht]

So I installed the texas heat... awesome sound and I was making some soundclips but after about an hour of playing this crackle-y sound started coming out of it.



Like I said, it was fine for about an hour then this just came up. I turned the bass completely off at the end of the clip and it still crackles. I checked all the connections and they were all fine, the outlets and cables and everything... it seems to be coming from the speaker? there are no holes or rips/tears in it though.... and it doesn't crackle at low volumes... idk. maybe the tubes? Any help would be appreciated for sure.

And I don't play like a robot haha, I was just trying to show the crackling.

 

[Funkfingers]

Re: Amp problem

What amplifier is the new loudspeaker in? What wattage? More importantly, what impedance rating?

Have you done up all of mounting nuts tightly enough? Did you knock the magnet end of the loudspeaker into anything whilst you were installing it?

Whilst the amplifier is running, what colour are the plates inside the valves (tubes)? Gray or orangey-red?

 

[Andrew Lamprecht]

Re: Amp problem

What amplifier is the new loudspeaker in? What wattage? More importantly, what impedance rating?

Have you done up all of mounting nuts tightly enough? Did you knock the magnet end of the loudspeaker into anything whilst you were installing it?

Whilst the amplifier is running, what colour are the plates inside the valves (tubes)? Gray or orangey-red?

Its in a Mesa MkII B, 60 watt amp, 150 watt speaker. Both the amp and speaker require 8 ohms.

I don't believe I knocked the speaker into anything no, and the mounting screws I thought were really tight. I tightened them up as tight as I could but I can go back and see if any of them came loose.

The tubes are an orangey red.

 

[Funkfingers]

Re: Amp problem

The tubes are an orangey red.

This is bad news. Switch your amp off NOW, please.

Something about the new loudspeaker is not loading the power amplifier stage correctly. A weak connection at the positive and negative terminals on the loudspeaker itself could explain the issue. The obvious A/B test to try is reconnecting the previous loudspeaker. (Loose with the cables running out from the cabinet will do.)

EDIT - Needless to say, disconnect the amplifier from the electricity supply and drain the capacitors before you work on anything inside the amp.

 

[Andrew Lamprecht]

Re: Amp problem

This is bad news. Switch your amp off NOW, please.

Something about the new loudspeaker is not loading the power amplifier stage correctly. A weak connection at the positive and negative terminals on the loudspeaker itself could explain the issue. The obvious A/B test to try is reconnecting the previous loudspeaker. (Loose with the cables running out from the cabinet will do.)

EDIT - Needless to say, disconnect the amplifier from the electricity supply and drain the capacitors before you work on anything inside the amp.

Was the tube things a joke?

I guess it could be a bad connection, Ill check it out and get back to the thread.

 

[Funkfingers]

Re: Amp problem

Was the tube thing a joke?

No. Valve amplifier power stages MUST be run into a suitable load at all times. For some operations, a dummy load is acceptable.

If the plates inside your power stage tubes are running bright orange, something is badly wrong. There are several possible reasons. I am not going to attempt to deduce the problem from the other side of the Atlantic Ocean.

 

[GoldenVulture]

Re: Amp problem

It sounds like a shorting or overheated voice coil.

With the amp turned off , pushing up and down evenly on the cone does the voice coil move smoothly and quietly or can you hear noise coming from it ?

I don't believe I knocked the speaker into anything no, and the mounting screws I thought were really tight. I tightened them up as tight as I could but I can go back and see if any of them came loose.

You didn't over do it and bend the frame of the speaker ?

 

[trevorus]

Re: Amp problem

Tubes should only glow from the heater in the center of the tube. The plates should be grey or black. Some blue glow while running is ok. If the plates are glowing AT ALL, turn the amp off immediately, and get it serviced.

That crackle sounds like it COULD bad pre tube, loose connection... any number of things, honestly.

 

[Andrew Lamprecht]

Re: Amp problem

It was just a connection issue. the solder job on the positive terminal was lackluster from me.

The tube thing, I didn't know the different parts of the tube, I thought you meant that any orange light coming from the tube was bad. They are fine.

Anyway, I fixed the issue, it was just a bad connection, thanks everyone.

 

[Adieu]

Re: Amp problem

Man, now you got me all worried too... Especially after pulling two power tubes all undocumented like (but to stable positive results)

WHICH parts arent supposed to glow and where in the tube are they?? Will this be visible on standby or only when pushed hard?

 

[GoldenVulture]

Re: Amp problem

Bad !

 

[Adieu]

Re: Amp problem

Bad !

Is this on standby or driven hard? Also, my JJs seem to have cutouts in that metal thingie - so light coming thru them is ok, but the metal thingie glowing red hot would be way bad, correct?

 

[trevorus]

Re: Amp problem

Is this on standby or driven hard? Also, my JJs seem to have cutouts in that metal thingie - so light coming thru them is ok, but the metal thingie glowing red hot would be way bad, correct?

Wait, is this a topic you don't know about and are actually asking questions? Amazing!

That would be while on and playing. It doesn't have to be driven hard to make it heat up and glow like that. I suppose it could, but setting proper bias should make the amp operate properly under most conditions unless there is something else wrong.

 

[JOLLY]

Re: Amp problem

I have come to the conclusion that you must live on top of an ancient Indian burial ground. you seem to have the worst luck with amps.

 

[Adieu]

Re: Amp problem

Wait, is this a topic you don't know about and are actually asking questions? Amazing!

Who, me? Perish the thought... as you well know, I'm all about giving malicious, uninformed and provocative advice on topics I cannot hope to understand.

More than a hobby, I feel it's a calling of sorts :jester:

 

[Andrew Lamprecht]

Re: Amp problem

I have come to the conclusion that you must live on top of an ancient Indian burial ground. you seem to have the worst luck with amps.

I think thats about right. haha

 

[Adieu]

Re: Amp problem

I think thats about right. haha

Youre probably just not catching issues at first glance as they begin to appear, the way the older generation can with their decades of experience backing them up.... Tubes havent seen many innovations at all in decades, so its very much an old timers home field advantage

I figure us twenty-somethings will figure it out too...eventually. Probably around the time we end up with more chest hair than head hair

 

[Funkfingers]

Re: Amp problem

Experience is the name that we give to our mistakes.