Helicopter noise channel two of Carvin Nomad

[JUSTJOB]

I have a Carvin Nomad and it started making a noise in channel two (dirty channel) only. It sounds kinda like a helicopter in the background, but otherwise plays ok as far as sound goes. It is dead quiet as far as amp noise on channel one (the clean channel) and sounds great. I checked tubes and even swapped with known good ones with no success at eliminating the noise. However, I found that if I set the impedance switch in the back of the amp to 16ohms the noise goes away and the amp plays fine. It has a single Celestion Vintage 30 rated at 8ohms installed in it.
I know it's a long shot, but, can anyone steer me in the general direction as to what may be the cause of this noise? Hasserl?
Thank you!

 

[guitarsnguns04]

sounds like its motorboating

 

[TheAmpNerd]

Sounds like a fire mission to me.

If you hear the words "Repeat" or "Fire for effect"


Get the hell outta there as fast as you can
and find some shelter.

 

[JUSTJOB]

sounds like its motorboating

Sounds like a fire mission to me.

If you hear the words "Repeat" or "Fire for effect"


Get the hell outta there as fast as you can
and find some shelter.

You guys are real funny.

 

[JUSTJOB]

Just wanted to say thanks for all your help.:AOK Today I tore into it to see if I could find out what the matter was. This was the first tube amp (or any amp!) I've been into, but I need the amp so I had to try. I did find a cold solder joint at the power switch that i could easily wiggle the wire in so I resoldered that after I discharged the caps. I fired it up and the noise was still there, although the slight hum that always accompanied the amp when it was on was gone. So I dug a bit further and found that the cause of the helicopter noise was caused by the ribbon cable between the effects loop/footswitch board to the main circuit board. The cable had sagged over the years of lugging it here and there, and was making contact with some power tube wires causing noise to bleed through. I pulled it up and off of the wire, reformed the kink in it so as to prevent it from contact, and problem solved. This time when I fired up the amp it was dead quiet when not playing, I mean quieter than it has ever been! The best part of all is this did not cost me a dime!
Best Regards!

 

[jh45gun]

Congrats on getting it fixed and figureing it out. The first thing I look for is loose connections, Bad solder joints ect. It seems that bad solder joints and loose connections make up for a lot of amp issues. While that did not solve your motorboat problem it did help with some noise issues. Good one!

 

[JUSTJOB]

Congrats on getting it fixed and figureing it out. The first thing I look for is loose connections, Bad solder joints ect. It seems that bad solder joints and loose connections make up for a lot of amp issues. While that did not solve your motorboat problem it did help with some noise issues. Good one!

Thanks! I am absolutely green where it comes to amp repair, although, I have been contemplating and researching on building an amp. I would like to build one in the near future in kit form, but have been kinds undecided on build. I kinda would like to build a 5F2A from Marsh, but would really rather it be with two 6V6's to double the power. I guess I have to reseach more to find out for sure what would give me that tweed Princton sound but with twice the power. So I guess this experience was good to get my feet wet a bit.
Best Regards!

 

[jh45gun]

Why don't you just build a 5e3 delux that seems to be a standard build. I built mine out of a old mono phonograph amp that used the same tubes except for the preamp tube which I changed to a 12ay7 and I gutted the chassis and used the tranformers and chassis and tube sockets to build a 5e3 head. That is a frugal way to do it if you have speaker cabs available already and can find an old chassis to get the iron to work with. My Next build is going to be a 5f4 Tweed Super
5e3 head Yea I know the handle is a bit off you know the old saying measure twice cut once well my buddy measured once and drilled twice and got a bit off and did not notice it until we had it all put together I just have not taken the time to move it and might not if the holes would show afterwards.

 

[JUSTJOB]

Why don't you just build a 5e3 delux that seems to be a standard build. I built mine out of a old mono phonograph amp

Would a 5E3 give me the clean headroom as a double the power Tweed Princton? Or even a Blackface/ Silver Face double the power Champ? I don't want to end up with a "dirty" or overdriven sound only. I am after clean, or at least semi-clean with about the same headroom as a Blues Jr, but with better bass response. Am I after the right animal, so to speak?
Best Regards!

 

[hasserl]

Just seeing this thread right now. Good to see you got it figured out. That is not a "common" problem, but I've seen it two or three times before. Most noise problems with that amp are connected to that darn fx loop ribbon cable or the jacks.

 

[jh45gun]

Well I do not get a dirty sound unless my 5e3 is cranked but then Tweeds do not sound like a BF or SF either, Which is why I am building a Tweed Super 5f4 Next to give me more headroom than the Delux can deliver. I got to say though them 5e3's sound nice With using the back pickup on my Peavey Reactor Tele it stays pretty clean until its dimed. Front pick up it gets over driven faster. A double the power champ would be 12 watts less than the 5e3's 15 watts A Tweed Princeton is lower wattage than the blackface princetons were I am not sure if the Fender Field guide is right as it says the Tweed Princeton is only 4.5 watts????? While the Brown and Blackface are 12 which if you doubled them would give you more wattage. I do not know what a "double kit" would cost maybe you should consider building a larger amp or look for a Fender Blackface or Silverface Delux Reverb that is 22 watts and they stay clean.

 

[JUSTJOB]

Just seeing this thread right now. Good to see you got it figured out. That is not a "common" problem, but I've seen it two or three times before. Most noise problems with that amp are connected to that darn fx loop ribbon cable or the jacks.

Thanks Hasserl! By the way I like your work on these Carvins! You take a great amp and make it even more versatile! I mostly use the clean channel, but have toyed with the idea to remove the diodes on the Soak channel someday. I'll be in touch in the future I'm sure.

Well I do not get a dirty sound unless my 5e3 is cranked but then Tweeds do not sound like a BF or SF either, Which is why I am building a Tweed Super 5f4 Next to give me more headroom than the Delux can deliver. I got to say though them 5e3's sound nice With using the back pickup on my Peavey Reactor Tele it stays pretty clean until its dimed. Front pick up it gets over driven faster. A double the power champ would be 12 watts less than the 5e3's 15 watts A Tweed Princeton is lower wattage than the blackface princetons were I am not sure if the Fender Field guide is right as it says the Tweed Princeton is only 4.5 watts????? While the Brown and Blackface are 12 which if you doubled them would give you more wattage. I do not know what a "double kit" would cost maybe you should consider building a larger amp or look for a Fender Blackface or Silverface Delux Reverb that is 22 watts and they stay clean.

Thanks! Probably your right, the 5E3 may be fine. I was figuring a Champ build at 8watts, or a 5F2A at 9watts. And also yes, the Deluxe Reverb would probably be almost ideal powerwise, but I would like a simpler basic amp without reverb or tremolo. Yea, now that you mention it the Deluxe Reverb tone and headroom are what would be an ideal build.
Best Regards!

 

[jh45gun]

This might do the trick since it does not have reverb or vibrato, a 5F4 (Tweed Super) looks from the layout not much tougher then a 5e3 build a couple more pots ect and the folks on the forums claim that amp has more clean head room. This is going to be my next build.