January 17th, 2012, 02:29 PM
For those of you that use a AC4, I was wandering what the best settings are for a Pro Jet.
My friends daughter got a Pro Jet for her birthday and has never played any electric guitar before. She is using an AC4 and said that she was getting feedback.
I've used the amp with the DSW and never got any feedback.
So, what are your ideal settings for the Vox?
January 17th, 2012, 02:45 PM
It's very likely a proximity or position problem with an ac4, they can howl in a small room if the speaker is pointing towards the guitar or reflected to the guitar. Try repositioning the amp a bit to point in a different direction, that may do it.
January 17th, 2012, 02:57 PM
Thanks Hud, hope thats it. Even so, because I've been out of town a lot I haven't had any time to play with my AC4. Are there any favorite settings y'all have. Do you crank the amp and control volume with the guitar?
January 17th, 2012, 03:09 PM
replace the 12ax7 with a lower gain preamp tube, and there will be more play in the volume control before it starts to distort. The amp will be a little quiter overall, but it will take it longer to get to feedback stage provided she doesn't sit in front of the amp pointing the guitar at it.
January 18th, 2012, 05:01 AM
No problem, hope that's all it takes. I use mine mainly at home and at my last job for jams in the office after work with colleagues. At home I have a slanted ceiling in my office and at work one wall was glass and the others had whiteboards etc.. so lots of reflective surfaces in fairly small spaces, required a bit of amp positioning to avoid feedback.
Settings? well there are not that many options on an ac4 :D, depends on the type of music - for a Vox cleanish (4w) or dirty (1w or .25w, the latter usually only late at night) tone. Usually just adjust the tone for the guitar and pickups used, usually 75% or more no matter which, and the amp volume/attenuator and guitar volume to suit the room and type of music. Sorry probably not a lot of help. A couple of years ago, while my car was in the shop, I tried using it with the band for a practice session.. my band mate's Mashall stack and the drummer left me at the restaurant at the end of the universe... but they are fun at home for practice.
When the preamp tube starts to get noisy (Vox often uses pretty poor 12ax7/ecc83s in these), it's worth replacing it with a decent tube, smooths things out a bit and removes the harshness they can have. You can also use a 12ay7 or 5751 as WhoJamFan above suggests, will change the taper/reaction of the volume a bit and usually (some new prod 12ax7/ecc83s are *very* low gain) reduce the max volume a bit. Opening the amp is a bit of a bugger though, (have to remove the 7 outside wood screws on the back and the two machine screws at the top, pull out very *carefully*, the speaker wire is not very long). Not wild about JJ tubes in general, but their EL84s (the power tube in the ac4) are pretty robust and sound good. Single NOS EL84s can be found for not too much, does not make a very big difference in this amp imho though.
A great resource for all things Vox is here: http://vintageamps.com/plexiboard/viewforum.php?f=2
Despite the forum name, lots of info on modern Voxes including on the newer AC4s.
January 18th, 2012, 05:17 AM
It probably wont really help answer your question but I usually leave everything turned up all the way and use the guitars volume knob to help control the tone dirty/clean. I also turn the wattage down to 1/4 for bedroom use and I'm playing a 5120 with stock pups. I'm also very conscious of where I'm standing or I make sure I have everything muted with my hand.
January 18th, 2012, 08:53 AM
Thanks for the responses. She was just standing right next to the amp.