| Author | Message | ||
| ajdover
Senior Member Username: ajdover Post Number: 726 Registered: 11-2003 |
I just purchased a '95 Epic off of eBay. It's in very good shape, a few dings here and there, but nothing major. Got it a few days ago, oiled the fingerboard, cleaned it up, polished the brass, put new strings on, made some truss rod adjustments. So far so good. Today I noticed that when I have the pan pot turned all the way forward (neck pickup only) or all the way backwards (bridge pickup only) I pick up (no pun intended) a radio station (Q98 here in Fayetteville, NC). If I back it off a little bit, it goes away/gets quieter. Puzzled, I took it to my guitar tech. We plugged it in at his shop, did the same thing with the pan pot, and low and behold, no RF interference. He suggested I take it to another location to see if maybe it was a location thing, so I did. Did the same drill, no RF interference. Took it home, tried new cables, switching the ground on my F1-X, etc. No difference. At home, I pick up the radio. I don't have this problem with any other bass I own (I own 26) to include my '06 SC Sig Standard, my '04 Dragon's Wing, or my '91 Essence. Before I did any of this I called Tony at Alembic. He told me to look at the connectors going to the pan pot, to see if any were frayed. They're not. He also suggested checking to see if the circuit boards are touching the shielding paint. They're not. Finally, he told me to check the jack for problems. As far as I can tell, it's OK. Tony, God bless 'im, told me I could always send the harness back to be rewired. Don't want to do that if I don't have to, but it's there if I need it (man, Alembic is a great company!). Has anyone else had this problem? I don't want to take out the electronics if I don't have to and create only more work for Tony. If anyone has anything else I can try I'd appreciate it. Thanks in advance, Alan | ||
| dannobasso
Senior Member Username: dannobasso Post Number: 1082 Registered: 3-2004 |
Alan maybe da gubment is listenin' in! | ||
| ajdover
Senior Member Username: ajdover Post Number: 729 Registered: 11-2003 |
God help me if they are! ;-) | ||
| bob
Senior Member Username: bob Post Number: 859 Registered: 11-2002 |
I had a strange radio problem, though I thought it was with my SF-2 rather than a bass, and since yours seems related to control settings, it probably isn't relevant, but anyway... Whenever I played through the SF-2, I picked up some AM sports station (I figured out the frequency, but forget). If I played the same instrument through a different amp, no problem. Since I use the SF-2 as my preamp, it was difficult to truly isolate it, but as I recall I figured out how to use the preamp-out from another amp and narrow it down. I was stumped for ages, discussed it with Alembic, and so forth. Eventually, I accidentally discovered that the problem only occurred when the wall-wart (power supply) from my headphone amp was plugged in. Could have even been on a different circuit, didn't need to be otherwise patched into the system - as long as that little box was in the wall, my SF-2 was going to put out baseball scores, or whatever. I sort of think the SF-2 was jointly responsible, or at least overly sensitive, but I've never had the problem with anything but that one particular wall-wart. Probably won't help, but might be worth thinking about. | ||
| mario_farufyno
Intermediate Member Username: mario_farufyno Post Number: 185 Registered: 9-2008 |
I had this exact problem with my Rogue here in Brazil. I was completely frustrated because Alembic's PUs are shielded and shouldn't have this problem at all. Everything seemed right at harness, but - you know - when you live in a country that doesn't take a real attitude against illegal gospel radios, you can't expect much. But sending the harness to mother ship was tottaly off my reallity, either. Brazilian laws would made me pay (high) taxes just to send it and get it back. It could cost me something as 200% over its declared value! So I was left by my own (only solution seemed to be moving away). I first tried to avoid this problem instaling one ferrite bead per PU, but I don't think it did much about it (Rogue got just one for both PUs). Anyway, you should check it to verify if you have one and if PU's cables are properly wraped around it. I also cleaned the conections. I know you've tried this before, but I finally solved most of my RF issues just when changed all cables in the chain (all cables at pedalboard and the conection to the cabinet, too). I confess still having some problematic places where I prefer not to use it, though. But now they are fewer and signal/noise ratio improved a lot (isn't a thing you could notice when entire band is playing). I don't know how bad your problem is, but since cables change it doesn't bothers me anymore. Have to say I've also changed the way I adjust the Bass, though (never full pan the PUs and don't use the filter wide open, anymore). I know this looks somekind of limiting, but still got all tones I need from it. So, it is working fine now. Hope this brings you ideas... | ||
| mario_farufyno
Intermediate Member Username: mario_farufyno Post Number: 187 Registered: 9-2008 |
sorry, doubled post (Message edited by Mario Farufyno on August 06, 2009) | ||
| mario_farufyno
Intermediate Member Username: mario_farufyno Post Number: 188 Registered: 9-2008 |
I forgot that also reduced gain at trim pots a bit... Check these old threads: http://alembic.com/club/messages/393/17271.html?1111351599 http://alembic.com/club/messages/393/23914.html?1136555070#post52108 http://alembic.com/club/messages/394/25558.html?1141081839#post56057 It seems the beads should be the answer... (Message edited by Mario Farufyno on August 06, 2009) | ||
| jack
Advanced Member Username: jack Post Number: 218 Registered: 11-2005 |
I've never had a problem on my 95 Epic, I'm no help at all, but you have my sympathy- just going by the website, that seems like a real nightmare: http://www.q98fm.com/ | ||
| ajdover
Senior Member Username: ajdover Post Number: 732 Registered: 11-2003 |
I've taken my Epic to a couple of other locations, and there is no problem at all with RF interference. So now I'm a bit confused - is it my location, the preamp, or what? As I said, I can always send it back, but nothing I'm doing is working (I've tried different cables, too). Any suggestions? Alan | ||
| davehouck
Moderator Username: davehouck Post Number: 8550 Registered: 5-2002 |
Alan; I may be way off base here as I can't remember what control cavities look like for the different models, but is it possible to switch pan pots with another one of your Alembics? | ||
| ajdover
Senior Member Username: ajdover Post Number: 733 Registered: 11-2003 |
Dave, I have no idea. I'd have to defer to Tony Stouffer on this one. Al | ||
| keith_h
Senior Member Username: keith_h Post Number: 1349 Registered: 2-2005 |
Al, As I said in a note I had the same situation when I first received my Orion. I would pick up a station in Fuquay-Varina but only when I faced that direction and only when I was upstairs in my bonus room. If I'd move downstairs or was at someone elses house it went away. While I am not close to the transmitter all I can figure is the direction of the hills and valleys concentrate the signal and my bonus room happens to be in the beams path. Once I received a new preamp from Alembic I no longer had the problem. Keith | ||
| mario_farufyno
Advanced Member Username: mario_farufyno Post Number: 205 Registered: 9-2008 |
RF interference always has to do with your placement. As said Keith, you can control it by changing your position in the room. In some degree, at least. The question is to learn where the RF is finding its way into your signal path. People at Alembic claims their PUs are shielded by their own faraday cage. Alongside the use of the ferrite bead we shouldn't expect it could pick up any eletromagnetic noise. So, if its PUs and Harness are properly shielded we couldn't solely blame the Bass for it. But this also only happend to me with the Rogue, so if it is not the source, it certainly make things worst. I believe this got more to do with capacitance issues on Cable, Pedals or Amp that turns them into a big antena when connected to Alembic Eltronics (or indutance, I'm not eletronic expertise). Remember that a Capacitor (or Condenser, if in a Mic) can charge one plate just being near it. So you don't really need to have the circuit touching something, just near enough. It seems it can happen even if the wiring inside a cable isn't uniform (if too stepped or bended during use) or if the plug conectors are hurted. After doing the Bead thing I've tried it at a problematic spot I knew. It was then I noticed the problem was still there (although considerably lower in volume). I took everything off my signal chain (Effects, Eqs and PreAmp), just Bass+Cable+Amp, but it persisted.* That Cable was fairly new and looked okay, but I couldn't say if it wasn't stepped in the stage some other night. Then I took the Bass off and noticed the RF still was interfering. It was almost nothing, but you could hear it at background (and it changed its character if I bent the Cable). So, the Bass seemed to be just amplifying something that was already there due to the Cable. That night I've had to play standing still in a position where it wasn't too anoying and also took the pedalboard off, since all that conections seemed to get things worst. My suggestion is pass both PU cables trough the Bead with one turn if possible - thats why I got a second bead, it was difficult to pass both cables twice around it - and test your Bass again with just one (good) Cable and a Combo (skip the F1 or any rig with lots of conections). | ||
| mario_farufyno
Advanced Member Username: mario_farufyno Post Number: 213 Registered: 9-2008 |
I forgot one thing: You must always be aware to not let Cable rolled up, this turns it into a coil. You can control these RF interference at some point changing the direction it is laying. | ||
| slawie
Member Username: slawie Post Number: 96 Registered: 8-2002 |
The human body is a wonderful thing. Try this. Do it again while holding the strings with your left hand. Slowly turn around with your right hand in the air. If the signal gets louder in any particular direction. Viola you are an antenna! It might not get rid of the problem but it does cause some slight amusement to those who walk in on the scene. Check your grounding. slawie | ||
| mario_farufyno
Advanced Member Username: mario_farufyno Post Number: 226 Registered: 9-2008 |
This is something I've found at Shure FAQ: "How does Radio Frequency Interference (RFI) occur?" Q.: - Please provide a basic (non-technical) explanation of how RFI gets into a microphone or sound system and why I hear it? Answer - This explanation provides the general concept. (If you are an RF expert, please forgive the generalizations employed.) Radio Frequency Interference (RFI) in a sound system can be defined as an unwanted audible signal that invades the sound system via a radio frequency (RF) signal. Typical sources of RF signals: FM radio station, AM radio station, walkie-talkie, cell phone, Blackberry PDA. If the RFI is audible, it can take many forms: buzz, noise bursts, speech, or music. The common element is that these sounds are not desired in the sound system. A modulated RF signal (i.e., carrying information like an audio signal or digital data) travels through the “air” looking for a receiving antenna. Any piece of metal that has the appropriate length can be an antenna: a piece of wire, a metal beam, a sheet of aluminum foil, a trace on a printed circuit board, or a nail. Most of the time these metal items are not connected to a circuit that can “detect” the radio signal. Detection means converting the signal from RF into audio. A detector can be very simple: a diode, a transistor, an integrated circuit, even a slightly imperfect (“cold”) solder joint, all are potential detectors. Let’s look at a microphone and its cable as seen by an RF signal. The microphone cable has a long length of metal, called the “cable shield”, just under the outer plastic jacket. The cable shield protects the cable’s inner conductors from outside interference (such as electrostatic buzz/hum) and also is part of the phantom power circuit for condenser microphones. However, the RF signal sees the cable shield as an antenna. One end of the cable shield goes to the microphone; and if the microphone is a condenser, the cable shield eventually connects to the printed circuit board inside of the microphone. The other end of the cable shield goes to the microphone mixer or to a wireless transmitter; both have a printed circuit board. These boards are covered with diodes, transistors, integrated circuits and many, many solder joints…and all can be detectors. So the cable shield intercepts the RF signal, carries the RF signal to a printed circuit board where the signal is detected, transformed into an audio signal, and heard in the audio system as unwanted noise. There are multiple reasons why RFI is not always a problem. The microphone may have a dynamic element and thus no printed circuit board. The mixer might handle the cable shield in a way that sheds the RF signal before it can reach the mixer’s circuit board. The RF signal might be so weak that the detected audio signal is too quiet to hear, though moving closer to the interfering RF signal transmitter will increase the RF signal level and the RFI could become audible. A cell phone or Blackberry PDA is an RF transmitter - - a local source of RFI that can be extremely strong. Audible RFI is quite likely when an active cell phone or Blackberry PDA is located close to a microphone or its cable." | ||
| mario_farufyno
Advanced Member Username: mario_farufyno Post Number: 227 Registered: 9-2008 |
This where I got it: link The explanation above shows even a bad soldering plug can pick up RFI. When they say about Condenser Mikes, remember the back cover can act as one condenser if near enough to the circuit board. Even the shielding of a Cable can behave like one if its wires are not uniformely wraped around the core. And this can happen if you step over it, hard bend it or even if you just wind it up always to the same side ading tension on the wires. Let me know if I'm being bothering or helpfull insisting in this key... (Message edited by davehouck on August 18, 2009) | ||
| ajdover
Senior Member Username: ajdover Post Number: 734 Registered: 11-2003 |
Mario and all, Everything is appreciated, believe me. I've yet to try all the suggestions, but I'll keep everyone posted. Mario, You're not bothering me at all. Keep it coming! Thanks, Alan |
