Page 1 of 1

New (To Me) Class 5 And A Question About Noise

Posted: 16 Dec 2015, 00:56
by colchar
Since this section of the forum seems to be somewhat dormant I am not sure if anyone will see this post, especially with the holidays coming up, but I figured I would give it a try.

I recently purchased a Class 5 (C5-01 model) from a friend of mine. This is my second Class 5. The first was one of the originals (one of the green ones) and had major rattling issues that could not be resolved. Because of the rattling I got rid of that amp.

My new Class 5 sounds good but I have noticed that it is noisy when in 5 watt mode, even with the volume turned down (and by turned down I mean almost off). The noise is noticeable but does not increase as the volume is turned up, at least not until I hit about 3 o'clock and then the noise becomes significantly louder. I am not so concerned with that as I doubt I will ever be using the amp when turned up that high. It is the noise at low levels that are the issue.

Is this noise normal for this amp? It has been quite a while since I owned my first Class 5 so I cannot remember if that one was noisy or not. When in low power mode the amp is dead silent - this is only happening on the normal 5 watt mode.

Just curious if anyone else has noticed this with theirs and am wondering if anyone might have an idea what could be causing this?

Re: New (To Me) Class 5 And A Question About Noise

Posted: 16 Dec 2015, 06:13
by GuitarBuilder
The noise is not normal; mine is very quiet.

Is it noisy without the guitar cable plugged in? Can you describe it? Hissing or hum?

Re: New (To Me) Class 5 And A Question About Noise

Posted: 16 Dec 2015, 09:15
by colchar
I just checked and yes, the sound is there without a guitar cable plugged in.

The sound is tough to describe - it is the sound of an electronic device being on but with nothing playing through it. For example, if you have your TV turned on and the sound turned up but do not have your PVR turned on so no program is playing. Or a radio that is on but is not tuned to a station. Not sure if those examples make sense.

And again, it is dead silent when in low power mode.

Re: New (To Me) Class 5 And A Question About Noise

Posted: 16 Dec 2015, 10:08
by Mike_LA
You might try a chopstick.
My 6101 was noisy in a similar way and when I took the chassis out and move some the wires around (WITH A CHOPSTICK and One Hand Behind my Back) I was able to quiet it down significantly when I pushed a wire closer to the wall of the chassis.
Best of luck

Re: New (To Me) Class 5 And A Question About Noise

Posted: 16 Dec 2015, 14:21
by colchar
Below is an audio file of the noise that I am hearing. I hope the upload to the forum works as I've never used SoundCloud before.

For the first 15 seconds the volume of the amp is on '2', for the next 15 seconds it is on '8', and for the final 15 seconds it is back down to '2'. The volume of the sound might be a bit exaggerated as I didn't realize until after I had ripped the audio file from the video file that I had the media volume on my phone turned all the way up. By that point I couldn't be arsed to record and rip it again. This was recorded with the phone an inch or two away from the front of the amp.

https://soundcloud.com/colchar/class-5

Re: New (To Me) Class 5 And A Question About Noise

Posted: 16 Dec 2015, 17:34
by Leddyman
Possibilities off the top of my head: Tubes, try a different tube in each position one at a time and see if it changes. The chopstick test is a go for me in this situation. Be very careful. Also check the power source. Take it somewhere else and plug it in and see if it still makes the noise. It could be the circuit, lights etc. If none of that reveals the problem I'm headed to a tech.

My bet is a tube going bad. Good luck.

Re: New (To Me) Class 5 And A Question About Noise

Posted: 16 Dec 2015, 20:33
by colchar
Sorry, tried to respond earlier but am having computer issues tonight.

Thanks for the info. The friend who had the amp before me works at a guitar store. He returned it there and I bought it from them. Because of that, it is under warranty. From past experience that warranty will include tubes.

And if it has to go to a tech they can either send it to a Marshall service center or one of their company's own people can deal with it as they are owned by the same company as Traynor Amps and the retail chain's head office is in the same building as Traynor (Traynor was started in the back room of this chain's first store in Toronto back in the '60s).

Re: New (To Me) Class 5 And A Question About Noise

Posted: 17 Dec 2015, 06:17
by GuitarBuilder
Sounds like white noise; since it's affected by volume I would guess it's in the preamp section. Have you tried replacing V1?

Re: New (To Me) Class 5 And A Question About Noise

Posted: 17 Dec 2015, 08:36
by colchar
I don't have tubes here. I will get some in the next few days and will replace them then.

Re: New (To Me) Class 5 And A Question About Noise

Posted: 20 Dec 2015, 15:09
by colchar
Turns out it was the preamp tubes (or one of them at least).

My buddy at the store offered me tubes yesterday and I took the amp in today. It still made the noise in the store so it definitely wasn't the electricity in my house that had been causing the problem.

We put new preamp tubes in and tested it to see if that had worked or if we would have to replace the power tube as well. With the new preamp tubes it quieted right down. We couldn't hear anything until the amp was turned up to its maximum output, and it is to be expected that you would hear something at that volume.

It has been a while since I owned my first generation Class 5 so I had forgotten how this model sounds. Actually, because that one had rattle issues I don't think I ever got to experience it at its best. Now that I have with this C5-01 I do have to say that I am really impressed with how good it sounds - especially when turned up!!!

Now I just have to figure out the best overdrive pedal to use to give the amp a kick without significantly increasing overall volume. But that is a search that can wait until after the holidays as I have no reason, and even less desire, to hit a store of any kind until after Christmas.

Re: New (To Me) Class 5 And A Question About Noise

Posted: 22 Dec 2015, 15:52
by Leddyman
Try a clean boost. I use an Ibanez tube screamer. Sounds huge!