# 1991 peavey classic chours 2x12 scorpion speakers one speaker makes a buzz noise only on a high e note only sometimes -if i want to replace the speaker do the front grill come off to remove spekaer

There are a lot of possible problem areas it could be. I would first check that the speaker is working correctly. If so, I'd clean all jacks and pots. If that doesn't do it, it'll be time to take it to the shop.

... do you, by any chance, have non humbucking pick ups on your guitar? Just curious...

There is something resonating with that note frquency. Often the grille or wiring inside will rattle at certain frequencies. You need a sustained source of these frequencies to find what is causing the noise.

The voice coil on the cube speakers must be scraping against the magnet.Or the speaker cone must be damaged causing it to flutter at low frequency where there will be large cone movement. Try removing the phono jack from your musical instrument/ guitar and touch the tip of the jack with your finger. You will hear a hum, now turn down the volume and listen to the speakers very closely and see if you can identify the flutter. All the same you will have to fix the speaker or replace it. Have you ever dropped the speakers, if so the speaker frame could have warped causing the scraping noise.

The voice coil is probably damaged. You can get replacement basket that has the cone, basket, and voice coil for under $100 and put the old magnet on it. Reconing costs as much... you can change the basket in 5 minutes. Sometimes the voice coil partially separates from the cone or you can see it has overheated when you take the magnet off. Be careful not to get contamination in the magnet asembly. The basket is part number SP12825 RB for a 12 inch 8 ohm type..

Peavey uses a protection network and sometimes it gets blown when too much power is sent to the speaker. The speaker may be blown however. Peak power for this is 800 Watts and 400 Program... That is NOT RMS power. Make sure your amp is no bigger than 300 Watts RMS driving this. If you are REAL lucky, maybe a lead has fallen off the speaker... Open the unit inspect and test the components.

Testing the driver with an ohmmeter is incomplete test. Sometimes the magnets break off the drivers rendering no sound. Sometimes the voice coil shorts and if you don't interpret the ohmmeter readings correctly you can overlook a faulty driver. Remove the horn and look for damage such as lost magnet from the back. Also the peavey cabs have a protection circuit so if you did not try another speaker to the same wores going to the driver, it may be the Polyfuse on the protection circuit or other components.

There MAY be a circuit trace on a board that is cracked OR a poor soldered connection. It is vibration sensitive as you have found. Changing a switch vibrates the unit.

Depending on what you have connected, this could even ba a bad input jack.

The unit needs to be serviced. You could open it and see if there is something obvious.

http://www.tubesandmore.com/

Horn and speaker combo cabinets have an electronic component called a "crossover". The horn and speaker both work off different electrical signal frequencies. If you can take off the back, or get inside by pulling the speaker, check for a small circuit board mounted inside the box or on the speaker or horn. Check for a broken wire or loose connection of the crimp connectors.

A common problem with speakers, often the cone, or paper part of the speaker will come un-glued or separated from the magnet "voice coil". This happens when played too loud, when it's commected to the wrong impedance, or if the signal was shorted and "overdriven" (usually sounds like an awful buzz that's really loud).

Always make sure your output impedance matches the impedance of the speaker. Most auto stereos are 4 Ohms. Older home stereos are typically 8 Ohms. Musical PA gear varies between 4, 8, and 16 Ohms. Peavey gear is typicall 4 Ohms, but some older models are different. The Ohm rating is the amount of the resistance in the circuit. If your speaker is 4 Ohms and you plug it into an 8 Ohm circuit, you can destroy the speaker and sometimes the crossover circuit board.

Good Luck.

Jim
[email protected]
Phoenix, Az