Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: 67polara on January 21, 2011, 09:36:45 pm

Title: Rattle in my speakers
Post by: 67polara on January 21, 2011, 09:36:45 pm

I posted about this a while back and thought it was fixed but it is not.  Certain note on certain strings make a rattle sound.  I have used several different speaks and they all do it.  It is very irritating.  It gets louder as I turn the amp up but is always in the same places.

bass E  Frets                          0,3,6.7.8,11,12,
No rattles on 5 th string
D string Frets                         9,20,21,22
G string Frets                         3,4,15,16,17
B string frets                          11,12
no rattles on high E

Any thoughts?  Oh yea this is a TOS that is somewhat modified and we thought is was due to wrong resistors at the PI.  I changed them and it got a lot better but it is still there.

Tony

Title: Re: Rattle in my speakers
Post by: 67polara on January 21, 2011, 09:46:48 pm

Oh yea I thought of something else.  When I first get ready to use my amp I heat up the filaments when I take the head out of standby, It is OK for about 30 seconds then the noises start.  This might be an important fact.

Tony

Title: Re: Rattle in my speakers
Post by: Frankenamp on January 22, 2011, 02:07:23 am

I had rattles on my new geetar- and thought it was my P*** poor playing, but it turned out that the neck PU was loose. 5 minutes with a small combo screwdriver and my ___ poor playing improved to merely embarrassing. (Hear my father's spectre still grumping about 'no sense of rhythm' or 'no sense at all') :wink:

Title: Re: Rattle in my speakers
Post by: jeff on January 22, 2011, 08:06:45 am

Do the rattles get worse as the volume increases?
Is the amp a combo or a head and a speaker cab?
Try it with the amp not on/in the speaker cab.
I built a little combo and had the same thing. I thought it was a rattley tube but I tried 4 different tubes with no luck. When the amp was out of the cab, no problem.
Your noise may be comming from the vibrations and not the circuit.

Title: Re: Rattle in my speakers
Post by: 67polara on January 22, 2011, 09:31:30 am

It is a Head and it is not sitting on the speaker cab.  It gets louder with the volume so it is an amplified noise.  I have used 3 different speaker cabs and they all do it.  I will check it with another guitar or try my guitar in another amp and see if it is OK.

Tony

Title: Re: Rattle in my speakers
Post by: 67polara on January 22, 2011, 10:03:10 pm

Found it!  Feedback resistor problems all better now.

Tony

Title: Re: Rattle in my speakers
Post by: jeff on January 22, 2011, 11:46:29 pm

 Could you explain what was wrong. wrong value? wired wrong?

Title: Re: Rattle in my speakers
Post by: 67polara on January 23, 2011, 12:18:15 am

The resistor that was supposed to be a 4.7K was coded correctly with yellow violet red but actually measured 47 ohms.  Someone must have had a bad day LOL.

Tony

Title: Re: Rattle in my speakers
Post by: nateflanigan on January 23, 2011, 08:13:28 am

Wow you really can't assume anything with this stuff.  Good sleuthing!