Nomad 55 4x10 - help needed

[TMB]

Hi,

I am owner of a above mentioned combo and was very satisfied untill last rehearsal . I noticed a slight distortion in my clean channel.

The whole story:

I connected my Boss GT-10 per 4CM with my Nomad and found this weired noise in my clean channel.
After playing a chord loud (strumming once strongly) and let fading out the tone I heard a slight distortion at the point when the tone fell down a specific volume (at the end of the fade-out) - the tone "dies" in distortion.
Same could be heard when (at same setting of the amp) strumming very gently to reach the same decreased volume from the beginning.

First of all I thought that the 4CM was responsible for the noise, so I unplugged everything and tried again. The same effect occurred.

I got a lot of headache thinking about the problem and I found out that I did not try one thing which maybe could be the reason....when trying to find out the difference between 4CM and no-4CM I did not turn the S/R knob on the rear to zero. Could this be the problem? And if yes..do I need another potentiometer? If no...do I need new tubes?

And another one: Our drummer told me that he (he is a headphone player and the Nomad is connected with his small mixing desk via the Nomad's recording out) noticed distortion in all channels since the beginning - is that normal or do I just have a second problem?

My settings on Channel one is the factory preset called "Twang"

Thanks in advance for your help and sorry for my English..I'm not a native speaker

Cheers,

Mark

 

[nomad100hd]

well the record/headphone out is pretty hot and could easily over drive most mixer boards if not careful. I also know that the parallel FX loop is not friendly with anything that has latency. I had a problem with my clean channel and it turn out to be in the switching matrix, bad relays! Relays fixed all good for a while, not i sometimes get a distortion on my clean channel but i bet it's a bad solder joint. However next i'll send it to mesa and have them check it out, and it's cheaper than the local guys.

 

[TMB]

Hi,

I finally managed to find out where and what my actual problem with the amp is:

As described in the beginning of the thread I have this slight distortion an the fade out of my clean channel and / or when playing very quietly.

I first changed the preamp tubes (e.g. from 1 to 3) but no change occurred. Then my fellow band member said again it sounds like bleeding from the crunch channel. So I reduced the gain from channel 2 (it was up to over 80% :mrgreen: ) to 50% and then the distortion in the clean channel was gone completely!!

As >I really love the sound of the crunch channel with gain that high I have to get the problem solved.

I'd really appreciate any advice on that issue.

As I told before, the recording out produces only distorted sounds....I put an DI box with damping -40db in between and the sound is much better now. Not good enough for recording but at least good enough for our drummer.

thanks,

Mark

 

[nomad100hd]

your switching matrix needs repaired. I don't think anyone really records with the line out for anything high quality.

 

[TMB]

your switching matrix needs repaired. I don't think anyone really records with the line out for anything high quality.

thanks!

could you please explain me what is switching matrix? does that mean that optocoupler's or potentiometers are damaged?

 

[nomad100hd]

i think the nomad is all relays, it some part of the channel switching system is broke.

 

[TMB]

today I got my Nomad back - I had it at the Boogie Tech and he had two good news for me:

first: the problem with channel bleeding was due to defective FET and repair cost 40€
second: he said that my boogie (which I bought used recently) was in an excellent condition (like new..even the tubes)

happy happy happy

cheers

mark