Hey Everyone I took my V847 wah and did a true bypass mod to it via the fulltone website and I also added an indicator light and a 9volt adapter jack to it the wah sounds great except when driven I get a high pitched squeal as the gain goes up. The squeal is more pronounced when I am using the power supply as opposed to the battery.
Can anyone help? let me know if you need pics and I'll try and post them I'm tempted to buy a fulltone wah but am trying to avoid spending the money also let me know what I should replace on the wah like inductor etc.
Thanks
At a guess, have you tried swapping in some lower gain transistors (particularly Q1)? Maybe try some BC109B or BC109C? The chances are that your Vox came with MPSA18's, which are pretty high gain for a wah. I'm pretty sure swapping these out will at least improve the sound of your wah and may well cure the problem you describe. You might want to socket the transistors and try out some different combinations.
Wahs are very simple circuits and can be modded easily to achieve the sound of pretty much any commercially available inductor-based wah out there - save your money.
If you are itching to swap the inductor, I can highly recommend the 'Whipple' - available on e-bay for peanuts.
Andy.
youll get oscillation with higher gain, theres no doubt about it. a happy medium is around 400ohms, beit 330 or 470, 400ohms seems to sound good. im referring to the bass/gain resistor.
good ol wahs...funtimes...
Yeah - the inductor is crucial to the tone and feel. The ArielFX Halo inductor that found it's way into my V847 has done wonders and really helps me to bring out that WHAAAACKA WHAAAACK :icon_biggrin:
S.
Thanks for the replies I'll give them a shot and keep you posted.
with that wah, it's CRUCIAL to run it off a well regulated power supply also... maybe that's why they never gave you the option from factory.
Quote from: darron on October 13, 2007, 10:24:01 AM...with that wah, it's CRUCIAL to run it off a well regulated power supply...
Huuuh? can you elaborate on what that's about? having never experienced a problem with my V847 's power supply (battery) or my Thomas Cry Baby, both of which have no regulated supply input, that
CRUCIAL thing has really got me curious.
Hey
Stoneham11, when you say "
when driven I get a high pitched squeal" do you mean you're driving the wah with another gain device, or do you mean the guitar's volume ctrl is full-on? if you are driving the wah with another gain device you will likely experience squealing and other peak-resonance issues, it's the nature of a resonant circuit like the wah, it really needs to be first in the chain with any high-gain chain.
try running your wah on, say, 3 volts. it wont sound too crispy. run it at 10 volts, 18 if you want even more girth, and youll hear a great difference.
Quote from: thebattleofmidway on October 13, 2007, 10:55:26 AM
try running your wah on, say, 3 volts. it wont sound too crispy. run it at 10 volts, 18 if you want even more girth, and youll hear a great difference.
Although beware...there may be components in the way that are not rated beyond 16v
ah yes, sorry i forgot to mention that :D ;) the electrolytic capacitor is your main concern, there. up it to say 24 volts or something like that.
Quote from: RedHouse on October 13, 2007, 10:51:40 AM
Quote from: darron on October 13, 2007, 10:24:01 AM...with that wah, it's CRUCIAL to run it off a well regulated power supply...
Huuuh? can you elaborate on what that's about? having never experienced a problem with my V847 's power supply (battery) or my Thomas Cry Baby, both of which have no regulated supply input, that CRUCIAL thing has really got me curious.
Hey Stoneham11, when you say "when driven I get a high pitched squeal" do you mean you're driving the wah with another gain device, or do you mean the guitar's volume ctrl is full-on? if you are driving the wah with another gain device you will likely experience squealing and other peak-resonance issues, it's the nature of a resonant circuit like the wah, it really needs to be first in the chain with any high-gain chain.
he was saying that it didn't sound so bad running off battery, which made me think that he's installed a power jack. i installed a power jack in my v847 and while testing it out for the first time without running off a battery it sounded crap. a little while later i swapped to my regulated power supply and it sounded normal. some pedals don't work well without a regulated supply, and i think that why some pedals don't even have the option of a DC jack
batteries last forever in my wahs, i think its amazing 8)
Quote from: thebattleofmidway on October 13, 2007, 09:03:41 PM
batteries last forever in my wahs, i think its amazing 8)
you'll find a lot of pedals are like that until you add an LED :D
I did add a power supply. I did not add any filtering or anything like that. could that be a problem?
is there any other mods that you would suggest? I'm going to get a replacement inductor either whipple or arielfx
proper filtering is a plus...
Quote from: Stoneham11 on October 16, 2007, 12:04:21 AM
I did add a power supply. I did not add any filtering or anything like that. could that be a problem?
is there any other mods that you would suggest? I'm going to get a replacement inductor either whipple or arielfx
mine works alright without filtering. the fact that you get more noise off the power supply gives a little bit of questioning about its quality. if you are concerned about it try chucking a 1000μF or so capacitor on the power rails from positive to negative with the respective poles of the capacitor matching. this isn't a full substitute for battery power, but it certainly won't hurt. still... shouldn't cause a 'squeal'.
Quote from: darron on October 13, 2007, 08:09:43 PM
Quote from: RedHouse on October 13, 2007, 10:51:40 AM
Quote from: darron on October 13, 2007, 10:24:01 AM...with that wah, it's CRUCIAL to run it off a well regulated power supply...
Huuuh? can you elaborate on what that's about? having never experienced a problem with my V847 's power supply (battery) or my Thomas Cry Baby, both of which have no regulated supply input, that CRUCIAL thing has really got me curious.
Hey Stoneham11, when you say "when driven I get a high pitched squeal" do you mean you're driving the wah with another gain device, or do you mean the guitar's volume ctrl is full-on? if you are driving the wah with another gain device you will likely experience squealing and other peak-resonance issues, it's the nature of a resonant circuit like the wah, it really needs to be first in the chain with any high-gain chain.
he was saying that it didn't sound so bad running off battery, which made me think that he's installed a power jack. i installed a power jack in my v847 and while testing it out for the first time without running off a battery it sounded crap. a little while later i swapped to my regulated power supply and it sounded normal. some pedals don't work well without a regulated supply, and i think that why some pedals don't even have the option of a DC jack
Ahhh, got it now.