|
Dirty-South Blues Harp forum: wail on! >
Annoying
Annoying
Page:
1
Martin
1488 posts
Jul 30, 2018
3:24 PM
|
One of my amps, a Vox (I think it´s called AV60 -- cheap stuff and most of you guys wouldn´t even look at it) gave me a certain loudness that I was looking for and therefore I bought it, a while back
It didn´t give me a whole lot else, though (like "good sound") until I discovered (erh, I was told ...) that I should perhaps try to use use a "power level" switch that it has as a master volume, and thus firstly maximize the ordinary volume switch, and then push up the power level as high as it goes. (The power level is supposed to change the amount of Watts that the amp puts out, I think.)
Now when I do this, I find that the amp is not so bad after all. (Cost me roughly $100.) But there´s a problem: when I hit the sweetest spot on the settings, the amp gives out a sort of scream when I start to play.
It then dies down, but returns when I´ve left some space between notes.
No good.
My guess is that this is just feedback and it goes away when I reduce volume, but the annoying thing is that when the scream has died down, the amp sounds really good.
This is probably a no brainer, but I wonder if anyone of you has dealt with something like this, and found a way the get by without lowering the volume?
I use a Harp Octave, with "blend" and "volume" almost to the max; I own a Boss parametric EQ as well as some other gadgets (like a Joyo "American Sound"), but I´m very un-technical and never really learn how to use things.
Buying a Harp Shield or something of that kind is not an option right now, unfortunately.
|
jbone
2650 posts
Jul 30, 2018
3:54 PM
|
I wonder if the amp has some kind of anti feedback circuit? What mic are you using? Your sweet spot is pushing frequencies that cause a feedback loop it sounds like.
I had a similar issue with more than one amp, usually tube amps but also a Denelectro Dirty 30 solid state. I had no real answer except use a gain cutting tube in the pre amp section on a tube amp. The Dirty Thirty did not as bad with an SM57 mic rather than a cm or crystal mic. It was still never going to be a big stage amp.
I much prefer a tube amp and a smaller stage with the duo format, that's part of my ultimate solution.
----------
Reverbnation
Facebook
Youtube
|
Martin
1490 posts
Jul 31, 2018
5:05 AM
|
"Anti-feedback circuit?" Sorry haven´t a clue.
I use various mics (no crystals) but same result -- when I get it to sound good I have to back down some crucial steps on the volume.
The amp has some tubes in a preamp section, or whatever it´s called, but I´m afraid I don´t know enough about gain cutting tubes and such to undertake any changes there.
This amp is not used in a duo format but rather with a very loud band with two guitars, therefore any volume gains is very much sought for.
|
Dragonbreath
103 posts
Jul 31, 2018
1:36 PM
|
Looking at specs, your amp, the vox av60, has a 12ax7 preamp tube. A possible solution to your problem is switching this tube. 12ax7 is a very usual tube that produces gain but often also is a source of feedback for harp mics. A very common first mod to many many amps is to change this tube to a lower gain version; the 12at7 or the 12au7. This usually makes it possible to have slightly higher volume before screaming feedback. Theres probably lots of discussions about these tubes, heres one with some info about the difference between the tubes.
http://m.modernbluesharmonica.com/board/board_topic/5560960/457204.htm
And dont worry the tubes are pretty cheap and really easy to switch out, not much different to changing a regular light bulb, check some youtube videos and youll see how easy it is.
|
Barley Nectar
1363 posts
Jul 31, 2018
4:24 PM
|
I would roll that Harp Octave back and seee what happens. I don't know how much gain the HO has but you may be hitting the amp with too much signal. IMO you are best to not use any pedals for a while so you can get a feel for the amp, mic combinations you can try. Body position or more correctly, mic position in respect to the amp, can make a huge difference in volume before feedback. Also a volume control on the mic lets you cut back during those feedback prone moments, when you have left some space between the notes. It is good that you are listening to what is going on and thinking. Yes, tube amps liked to be pushed, played on the edge of feedback, if that is the sound you want. Yes it is risky territory but this will help you learn. Roll your volume back some for clean harmonica sounds. That is a powerful amp and needs a big space to fill with sound. Small spaces will give you fits of feedback. Also room acoustics enter into the FB game. Soft, sound absorbent rooms, will be less prone to FB whereas Hard, sound reflecting rooms, are more prone to FB. Good Luck and keep listening.
Last Edited by Barley Nectar on Jul 31, 2018 4:27 PM
|
Martin
1491 posts
Aug 08, 2018
8:30 AM
|
@Dragon Breath: Actually, I´m one of those guys who can mess up even when changing a light bulb, but I will certainly look into this idea. They way you put it, it does not sound too drastic ...
@Barley Nectar: Will try to run through some alternate settings, according to your suggestions. There´s a big disadvantage here, living in an apartment I mostly try to work out how to make an amp sound good while at rehearsals.
It´s interesting that when I was whining about feedback from a small tube amp, I was told to drop the Harp Octave and use it with bigger amps; now you suggest I should put it away even here ... Question is, when/why to use a HO?
What it has done for me is dirtying up the sound a bit, and reducing feedback. But I will certainly try to pull it back.
Yes, that amp can be loud -- but the loudness comes with a prize, a rather harsh sound. That changed when I was told to push the Master volume, but then I didn´t get the same output in terms of shear moving-air-power.
Unfortunately the only mic I own with a volume control is a bullet type and then feedback occurs at even lower volumes.
I have a gig coming up this Saturday and soundcheck will hopefully allow me a minute or to to fiddle with the settings according to your instructions.
Many thanks to the both of you for interesting pointers!
|
jbone
2658 posts
Aug 08, 2018
9:03 PM
|
Find tone first. Acoustic first of all, then with a mic/amp. The if possible at a gig get your amp miced to the p.a. and let the p.a. boost your volume with tone.
----------
Reverbnation
Facebook
Youtube
|
Thievin' Heathen
1037 posts
Aug 08, 2018
9:27 PM
|
For years, back before all this harp knowledge was so readily available to all on the iSuperHwy, I controlled feedback with an ON/OFF switch on my mic cable. Jbone may remember my Shure 58 through a Peavey Heritage rig. It Screamed. The good 'ole days at The Prairie House out on 380.
|
Martin
1492 posts
Aug 09, 2018
6:19 AM
|
@jbone: Tone is an important factor in playing, surely -- but not here. I´ve been playing a while and can say with some certainty that in this particular context those howling screams from my amp is not related to my tone, neither acoustic nor electric.
@Thievin´: I own a Shure SD545 with on/off switch but unfortunately it does not provide the sound or volume that some of my other (cheaper!) mics does. I mainly use it for micing the amp.
|
Post a Message
|
