Hissing, only from lead channel? This normal?

[mercilessdeath86]

Turn on my 6100LM. Clean channel sounds great. Switch to the Crunch channel. Sounds great. Switch to lead, and I get this hissing noise. When I switch it back onto the other two channels it goes away... Can anyone give me an idea as to what might be going on? Before bringing it in to a tech and paying a bunch of money I can't really afford I'd like to see if there's maybe anything I can do on my own.

 

[BrotherJ]

Hey,

Sorry gotta ask the question, are you running the gain flat out on the lead channel? Is it a very loud audible hiss or is it quite low in the background?

I don't have the schematics handy to see which preamp tube is used where, but possibly the 12ax7 used by the lead channel is starting to go...

P.S The crunch channel of the 6100 is such a great sound, I had the pleasure of playing one a while back

 

[mercilessdeath86]

Usually on that channel I will run the gain at about 5 or 6. The hiss isn;t very loud, if I play you can;t hear it. It's just in the background. Is it safe to play with the other channels if this is happening?

 

[Gain Man]

Usually on that channel I will run the gain at about 5 or 6. The hiss isn;t very loud, if I play you can;t hear it. It's just in the background. Is it safe to play with the other channels if this is happening?

Yes, it is safe. The 6100's preamp is designed with separate gain stages for each channel, so each tube is only dedicated to one channel (this is why it has the insane number of 7 preamp tubes).

Since I don't own a 6100 I couldn't tell you how noisy the Lead Channel usually is, so it is hard to say if there is some issue or not. Assuming your hiss is out of the norm, as stated before, it might very well be that one of the tubes for the Lead Channel is on its way out. So if you interchange the tubes and the hiss happens to move from one channel to the next you might identify the faulty tube(s) and can replace it/them.

 

[steelhorse]

Usually on that channel I will run the gain at about 5 or 6. The hiss isn;t very loud, if I play you can;t hear it. It's just in the background. Is it safe to play with the other channels if this is happening?

Sounds normal to me.

 

[solarburn]

Sounds normal to me.

Yeah I think so too.

 

[mercilessdeath86]

Well, the hiss wasn't there before, it had the same amount of noise as the other channels. Thanks for the help guys, I will switch my tubes around and see what's up.

 

[steelhorse]

Well, the hiss wasn't there before, it had the same amount of noise as the other channels. Thanks for the help guys, I will switch my tubes around and see what's up.

You didn't mention this before (that it wasn't there before) but the lead channel always has a bit of noise.

Sounds like a tube issue so you're on the right track.

A good idea would be to use some contact cleaner when you swap tubes out and spray them on the tube pins and run the tube in and out of each socket to clean the sockets out.

You may also need to check the bias as well.

 

[rockinr0ll]

Try switching out the preamp tubes with new ones and see if that helps. I get hiss if I have too much gain also.