Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Rockranger on June 07, 2018, 05:14:37 pm
-
Hey,
I started building amps a couple of years ago because the house that I moved to was very noisy for guitar gear( rf noise that was unbearable). It took forever for me to figure out that I couldn’t fix the noise problem and when I did I began researching building low noise amps. So now I finally have 2 great amps that I love ( fender 5E3 and matchless spitfire clones) with every noise reducing feature I could find. The problem is that I am running these amps with the tone control pretty much all the way off which is a sound that I really like but I would like to use the tone a little bit more especially in the spitfire. Does anyone have any ideas for killing the noise the tone control creates, any little improvement would be greatly appreciated?
http://www.ceriatone.com/ceriatone/wp-content/uploads/2016/08/SpitFireCeriatone.jpg
http://el34world.com/Hoffman/files/Hoffman_5E3.pdf
Thanks
-
ideas for killing the noise the tone control creates
from
rf noise
?
If so,
I've done this on the last 5 builds, it's a "signature", but the added side benefit, knocks the RF down well, IF you line a bottom plate also.
-
Yes I am talking about the rf noise created by the tone control, I do have a bottom plate on the amp, could you explain everything you did with the amp in the pic. Thanks for the response!
-
rf noise created by the tone control
like when you touch it?
TS's in general do not make it to RF.
I copper clad the chassis, copper is somewhat better than aluminum for rf shielding. I didn't figure what wave-link the holes are, but most are filled with grounded parts.
-
Thanks shooter I will give the copper a try!
-
like when you touch it?
before you jump off the deep ends, what's the answer?
-
I guess what I’m saying is the tone doesn’t create rf noise, it’s like in this house the rf noise is always there and the tone knob increases it more than anything else. It’s really easy to hear with the bottom plate off of coarse but after the noise reducing methods used (metal film resistors in the input, shielding wire on everything that makes sense, short low voltage wires etc. etc. etc.) the volume and master which use to create tonnes of noise have quieted right down but the tone has not. It’s bad enough that you wouldn’t want to put the tone over a 1/4 of the way up on both the fender and the matchless style amps.
-
Take your amp to another location and evaluate.
-
All my amps are fine everywhere else just getting ideas for noise reduction in my noisy house.
-
You should be working on your house, not your amp.
-
House is fine had electrician, power company engineer, amp tech guy and everything else you can imagine done when I moved here. Live very close to a large hospital, but no one has any real good ideas where the noise comes from.!
-
Might give ferrite beads a try.
-
Not much you can do about outside interference. Try to identify exactly what kind of interference you have. Is it continuous, ie, 24/7? Does it come and go at regular or irregular intervals? Is it really RF interference, such as radio, tv, or radar transmitter? Or is it just some radiated electrical noise such as a neighbors noisy A/C motor or pool pump? Don't call it RF interference unless you know it is radiating thru the air. Or it could be noise on the incoming power line. Identifying the type of interference is the first step. Then locating the source is the next step. Maybe you can find a band aid fix once you know what it really is and where it's coming from. Probably not.
Do you have any other audio/visual devices in your home that are affected? Are your other amps affected in your home? If this one amp is the only device that is affected then your chances of finding a band aid cure are pretty good. However, if you have multiple devices affected, your chances of finding a reasonable cost solution are greatly diminished.
-
If your cell phone is on turn it off. Get a am radio and see if it does it.
-
Live very close to a large hospital
they can be a great noise source!! I serviced mobile MRI units that hospitals would lease and more times than I can count I tracked down their "noise problems" that were causing me grief :cussing: :BangHead:
the best one was actually a fixed site, arcing relay contacts for the freight elevator, took me a month!!!!