#1
Someone the other day told me to put a CD centered over my speakers and tape it to the tolex on my amp. Im rocking a 6505 combo and theres this really weird high pitched noise that is coming out of it when I play, it's hard to pick out but it's piercing and sounds like poop. Has anyone ever heard of this as a cure for my problem?
#2
I was getting alot of really high end harmonics with my old rig.. Tried every setting and my ten band it would dull it but not get rid of it. So I had to get a parametric eq to fully cure the issue.

Other then that I dont know.. Could be a number of issues.. Can you make a recording of it..
Last edited by IbanezPsycho at Aug 28, 2009,
#3
Quote by SloppyJoseph
Someone the other day told me to put a CD centered over my speakers and tape it to the tolex on my amp. Im rocking a 6505 combo and theres this really weird high pitched noise that is coming out of it when I play, it's hard to pick out but it's piercing and sounds like poop. Has anyone ever heard of this as a cure for my problem?

Wait, wat?
I'm confused. I have the 6505 combo too. This doesn't sound normal. Are your pups wired correctly? What about cable(s)? Tried new ones?
If neither of those, I'd do a retube. Also, new speakers do WONDERS for this combo.
#4
First, turn down the treble and presence if thats an option. Then roll back the volume on your guitar just slightly (or lower your pickups, most people set them too high anyway).

The suggestion to putting a CD over the center of your speaker is in theory correct (although a CD is WAY too big, try something the size of a baseball). The highest frequency sounds come from the center of your speaker cone. However, by blocking the center you are not removing these higher sounds, instead you are better distributing them with the rest of the tone. In other words somebody who stands in front or your amp would normally hear much more high end, but somebody standing at an angle hears more bass and mid. So this solution makes the amp sound more consistent throughout the room.

If your problem is that the amp is just producing a crappy high pitched noise, this wont help. The source is then something else; the amp itself, your pedals, your guitar, etc. We need more information to diagnose the problem then. Is it constant? What if nothing is plugged into the amp, still there? Is it there on clean tones as well?
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#5
Sorry to kind of butt in here, but what does the presence knob do on amps? I've had one on my amp and never figured out what it does.
#6
Quote by Bobinedefil
Sorry to kind of butt in here, but what does the presence knob do on amps? I've had one on my amp and never figured out what it does.

Short answer: Kind of like a treble/brightness boost after the preamp but before the poweramp. I'm sure someone will chime in soon with a MUCH better explaination. But in a nutshell, I'm close.
Last edited by TheEsupremacy at Aug 28, 2009,
#7
Quote by TheEsupremacy
Short answer: Kind of like a treble/brightness boost after the preamp but before the poweramp. I'm sure someone will chime in soon with a MUCH better explaination. But in a nutshell, I'm close.


+1

Presence, generally is the frequencies above the Treble control. Some touch on just treble some touch on the high mids.. It really depends on the amp on what function it actually holds. It basically changes the way high freq's are sent back an forth in the amp.
#8
My guess is your problem is tube-related.

A cd over the speaker is a ghetto solution to avoid 'beaming', where the speaker sounds overly harsh and bright when you're standing at a 90-degree angle to the centre of the speaker,directly in front of the amp. It makes an amp sound more even wherever you stand, though if your amp is sounding really harsh and trebly all the time it's probably to do with the amp itself.

Incidentally, a CD is a really ineffective choice for beam blocking; you need something with a smoother/softer texture (like rubber or cardboard) and without a hole in the middle.

There are loads of reasons for an amp to go fizzy and harsh, poor mains power being a major one. I think you should be looking at your preamp tubes first.
#9
Quote by kyle62
My guess is your problem is tube-related.

A cd over the speaker is a ghetto solution to avoid 'beaming', where the speaker sounds overly harsh and bright when you're standing at a 90-degree angle to the centre of the speaker,directly in front of the amp. It makes an amp sound more even wherever you stand, though if your amp is sounding really harsh and trebly all the time it's probably to do with the amp itself.

Incidentally, a CD is a really ineffective choice for beam blocking; you need something with a smoother/softer texture (like rubber or cardboard) and without a hole in the middle.

There are loads of reasons for an amp to go fizzy and harsh, poor mains power being a major one. I think you should be looking at your preamp tubes first.

I agree. I'd start with a retube too, but I like to waste money. Lulz.
Here's what I have in my 6505 combo and I LOVE the tone.
2 Black Sable SED (Winged C's) 6L6's. Overpriced but sound amazing. You can skip the cryo treatment and get them MUCH cheaper.
V1 Use a Tung-sol 12ax7 RI if you like brightness, or use a Mullard 12ax7 RI if you don't.
Then just buy the cheap Chinese 9th gen Shuguang 12ax7B's the rest of the way V2-V5.
It WILL sound killer. I promise. I'm willing to bet this will solve your noise issue(s) too.
#11
Quote by TheEsupremacy
Short answer: Kind of like a treble/brightness boost after the preamp but before the poweramp. I'm sure someone will chime in soon with a MUCH better explaination. But in a nutshell, I'm close.
Presence dials are high end freq controls for the poweramp. Resonance dials are low end freq controls for the poweramp.

For the OP, I would bet swapping a few key preamp tubes would help alter and smooth out some of those harsh highs. Probably just a few tubes, like the gain spot and input preamp tube.
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