Nomad transformer hum (I think) - help!

[MusicManJP6]

I am 'test driving' a Nomad 45 2x12 and it has an audible hum that starts when I flip the amp on out of standby. It does not get louder with volume, and remains the same across all channels. Is this transformer hum? What does this mean?

The amp sounds great otherwise! I didn't realize there was any other amp besides the RoV combo that has a 3/4 back design. Love these cabs!

 

[jaquetapus]

My Nomad 100 head has an unnerving hum when flipped on too, coming from the chassis. It always sounded like the transformer to me, so I never looked into it.

-dave

 

[Monsta-Tone]

Both my DC-10 & my Heartbreaker have this hum. On mine, it comes from the power transformer.
I've noticed this on all of the DC-10's & Heartbreakers I've owned and had in my shop. I bet that the transformer could be isolated a little better from the chassis and this would stop.


On a side not Adam,
If you decide you don't like the Nomad, maybe we can work out some sort of trade for the mods on your DC-3 and some cash! :mrgreen: I've been interested in a Nomad 45 for a long time, but haven't had the scratch to pick one up!


Just a thought!

 

[MusicManJP6]

Both my DC-10 & my Heartbreaker have this hum. On mine, it comes from the power transformer.
I've noticed this on all of the DC-10's & Heartbreakers I've owned and had in my shop. I bet that the transformer could be isolated a little better from the chassis and this would stop.


On a side not Adam,
If you decide you don't like the Nomad, maybe we can work out some sort of trade for the mods on your DC-3 and some cash! :mrgreen: I've been interested in a Nomad 45 for a long time, but haven't had the scratch to pick one up!


Just a thought!

It's a very cool amp! I had never heard one until this weekend. I'm trading those two recto cabs I have for it. I think that's a pretty fair trade, don't you? The tone is very much like my DC-3, but a little looser and not as focused. And, I don't feel like it needs a GEQ to get a modern tone. The EQ is very effective. It doesn't have the mids the DC does so it's base tone seems to be a little darker. They both have a very similar vibe and feel due to the 4xEL84s though. If I decide I don't like it then we might see what we can work out. I played the DC last week and really tried to listen to it and think of what I would want to make better/improve and I couldn't really put my finger on anything in particular...

OK, so if it is indeed the transformer then the hum will actually emanate from the transformer itself, correct? Is there any easy way to isolate the transformer from the chassis? I have some copper foil tape if that might help!

 

[MusicManJP6]

Just listened to the noise again and it is audible when in standby if you put your ear to the top of the combo. The sound is coming from the speakers when you the amp is on (out of standby). It's more like a buzz mixed with hum than just a hum really.

 

[Monsta-Tone]

Well shoot. I don't know then.

My amps have a distinct hum, but it doesn't come through the speakers. It's basically from the transformer mounting screws transmitting vibrations through the amp's chassis.

I've been thinking about removing the bolts and using fiber or rubber washers to see if that gets rid of it.

 

[MusicManJP6]

Well shoot. I don't know then.

My amps have a distinct hum, but it doesn't come through the speakers. It's basically from the transformer mounting screws transmitting vibrations through the amp's chassis.

I've been thinking about removing the bolts and using fiber or rubber washers to see if that gets rid of it.

I pulled the chassis last night and noticed what looked like cardboard between both transformers and the chassis. ?? Kind of strange - I've never seen that before. I replaced all the tubes with some spares I had and the noise is unaltered - still the same...

Don't tell me I have stumped the mighty Monsta!!!

 

[Monsta-Tone]

:lol: :lol: :lol: It's not that hard to do on a Monday!

The cardboard is to keep the vibrations from transferring into a hum through the chassis. It probably worked for the 1st few years!

You might try a piece of high temp rubber and see if that helps.

 

[MusicManJP6]

Played it again on my lunch break after swapping the JJs from my DC-3 into the Nomad. It sounds great with JJs! The hum/buzz is still there consistently, but when I sit back a few feet and actually play it is not all that noticeable or irritating even. I'd love to know what it is, but, hell, for now i'll just play the **** thing! If you have any other ideas to try then let me know...

 

[MusicManJP6]

Just got a response from Marcus at Mesa. He also said it sounds like power transformer vibration. Where can I get some high temp rubber? Does it really need to be high temp? I would think cardboard is not exactly high temp!!

EDIT: Marcus just emailed me back and said they don't recommend using any other material. The cardboard has been working for them for years he said. I'll see what I can do with it tonight... I've got lots of cardboard boxes laying around for shipping stuff.

 

[MusicManJP6]

Replaced the cardboard... no dice. Techie friend of mine told me to pull the power tubes and turn the amp on - it's dead quiet when I do this. He says this rules out any induced hum. He thinks it may be a bad power supply cap or something?

 

[KozMcCharlie]

I get the same hum on my Nomad 45... I've had a tech go over it 3 times and there's nothing that will take it out. It doesn't make the amp unusable, and it really isn't audible when recording. It becomes almost inaudible when I switch out of extreme mode and I don't think that I've ever had a tube amp that didn't have just a little hum so I can live with it... Although if anyone finds a way to eliminate it I'd be game for trying.

 

[nomad100hd]

mine does it to, it's just the PT only real fix i know would be to put a new pt on it. Not worth it to me.

 

[Monsta-Tone]

Well, if they're not worried about temperature, I guess I wouldn't be either.

You could probably just loosen the screws and use some weatherstripping. I have some that's about 1/8" thick and sticky on one side. I bet that would get rid of most of it.