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Electric Guitars/has anyone ever played this noisy vox amp ?

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QUESTION: howdy , Iím an acoustic player and Iíve just bought a vox-ac4tv to play my first electric guitar through it . but I have a problem . as Iím not familiar with all tube amps ( particularly small ones ) , I need to ask before returning the amp . hereís the situation :
- itís a tube amp with 12AX7 & EL84
- there are vol & ton knobs and wattage control ( 4w , 1w , 1/4w )
- my guitar is a stratocaster with high output single coils
- I can play only in my room , where there are some electronics , wifi transmitter , cell phones , pcs , Ö
now the problem :
1) when I turn on the amp , without the guitar plugged in , and with the volume at zero ( all the way down ) ; I could hear a noticeable hum . it doesnít increase or decrease , but if I turn down the OP mode to 1w , the hum decreases ; and at the 1/4w , itís not as loud as before , but itís still there . now , tell me , is it normal with all tube amps ( especially small tube amps with 10Ē speaker and small cabinet ) ? itís not a high end amp , you know , there are quality control issues and blah blah , but I need to know if itís ok with tube amps or not ?
2) then , when I plugged my strat in , some weird sound starts , like buzz problem but continuously , like Ď zzzzzzzzzzzzzzzzzzzzzzzzz Ď sound . unlike the hum sound , it depends on the volume , the tone and the output wattage . turning up each one  makes the Ďzí sound higher and higher . do the electronics or room or Ö cause the problem ? what's that ?
3) do the solid state amps have the same problem ? shall I order a ss amp instead of a tube amp ?

ANSWER: Hi David I had that noise with several different tube amps, all caused by different things.
I will not tell you it is normal, your Strat single coil pick up will have a normal nose but
that is the price of the cool sound!
First your computer and TV and all will not cause the problem.The power line should be plugged in a grounded outlet.When it is on  lift and shake the power line to see if that is the problem, ya too simple?
I guess this is a used amp and you need to find out the history the hard way.I buy all used stuff, you save 50% to 70% off new. I had one of these little Vox amps and they are good or the best little tube amps.
I think a good cleaning will fit it up. Take the tubes out and make sure the same people made them both.
The only cleaner I use is Radio Shack 64-4315 cleaner. It is safe on plastic.
First clean the pins on the tubes, then the sockets, dirt in here can cause that bacon frying sound. Next the pots
they are the round controls behind the control knobs. Look at all solder joints for graying and if they are loose.
Check the speaker wires, loose ones can do odd stuff with sound.
The guitar inputs also get dirty and loose. The hex nut on the out side of face will tighten it.Your Vox should be
unplugged several hours before you work on it. These things hold enough power to kill a man.
David I truly hope I was of help, if you still have this trouble let me know. Not being there with you I am giving
you the most common repairs with out getting in to Volt/ Ohm meters and running line tests and parts all over.
I do not think you want that! Thanks David and I will be here so get back to me for help, better tell it is fixed!


---------- FOLLOW-UP ----------

QUESTION: first things first :
- the amp is a new vox-ac4tv ! 250 $
- the guitar is a stratocaster with custom high output single coils , I'm not sure about shielding or ... ; it's not a high-end model , you know !
- I tried different places at home and nothing's changed . same noises , every where I played !
- I couldn't try a Gibson or any other guitar with humbuckers !
now , I know a little more , here we go :
a) hum & hiss problem :
it comes from the amp , for sure . when I turn it on , the hum starts . even with the volume at zero and no guitar plugged in . but as I checked , if I turn up the tone knob , some hiss adds to the hum ! and if I turn up the volume , both increase ! more hum and more hiss . it's the same for each wattage level ( more hum & hiss with more volume or brighter tone ) , but the hum & hiss at 1/4w , is less than 1w , and at 1w is less than 4w . some say it's normal with Class A , tube amps ?!
b) buzz ( or 'z' sound ) problem :
I guess it must be the guitar ! as they said 60 cycle or single coil issue . when I plugged the guitar directly in to the amp , it starts . if I turn down the guitar volume , it decreases , and with the volume all the way down , there is no more 'zzz' ! also if I mute the strings , the noise fades away ( almost ! ) .

what shall I do ?

Answer
Hi David I still do not have much to work with, like what make are the pick ups? Stock, active, or a custom made set? I will give you a few things to look at and hope we get lucky. I do not like to use  that word but at this point I feel I need it. They sell many guitars that Look like a Fender Stratocasters. I am going with a stock Fender. The real Fender Strats have two grounds, it is one of the few that do that. If the bridge ground is not connected or loose you will get some very bad sounds.You can get a wiring diagram from Google. Just type in Fender Stratocaster wiring diagram, and you will have several come up.
To look at the wires you need to remove the pick guard. Eleven screws pulse the switch and pick ups. Look for bad
joints wires that are connected to the wrong place.The diagram will be of great help to put all in order.
The term you use "custom high out put single coils", makes me think that if they are in fact after market pick ups.You problem is there and a proper inspection and repair is called for. The lower end Strats are great guitars
but they are modified more than not. The Bullet model is the one that is a great guitar to make in to a Super Strat! Two last things, The cable between the guitar and amp can have loose ends and can be tightened with your fingers. Last, take it to a guitar shop and try the guitar on one of the amps on display.I have rebuilt many Fenders for people and my self. They are easy to work on and great guitars to play.
If this goes on I would have it looked at in a shop. A new Vox amp I would rule out, but if it is return it.
David sorry you are having a bad go of it with your first electric guitar I know how it feels my first car was
a 14 year old Ramble! Let me know how it goes!  

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DR Kevin P Moore

Expertise

Guitars and cats make life so much better. Playing the guitar is a wonderful thing, fixing you guitar is not that hard. I have played since I was a kid and started to fix guitars and the other things that needed repair. I still repair guitars for friends and myself and do enjoy it. I rebuild old guitars to their former condition, all amps and music gear. That the mystery out of where and when a guitar was made. The value of it and the difference between junk and a guitar you can grow old with. Ask me things and have some fun.

Experience

The fascination with electric guitars is the top for me. I fix amps, wiring and put the things that fall off back on. The way to really set a guitar up and make it a player. Buying a guitar is an art, and good amps that will get out that tone we all look for, Zen guitar and amplifier is a way to approach it. Better is no worry ask an expert.

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Linkin Professional Org

Publications
Library of congress, five patients. I write on several guitar forums and many essays on guitar health.

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PhD, MS, BA and a BS all from CMU. I have a BA from Mercyhurst College.

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