Hey all!
I was plucking my '97 4003 MG (w/ 7.4K toaster, horseshoe w/ .0047 mfd cap, and v63 guard) the other day and was relishing the diverse sounds that come from these great machines. Having read all past postings about the horseshoe and the volume drop that occurs when both pickups are on, I decided to take out my other Rick, a '98 4001v63 FG w/ .0047 mfd cap to size the two up. As I was comparing them, I noticed that the horseshoe in the 4003 dropped in volume when both pickups were on and returned to full volume when selected solo. The 4001v63 does not exhibit the same anomaly, that is, the horseshoe volume does not decrease when both pickups are selected. (I tested this by using the “pick-click method”: place a pick between the gap in the horseshoe, and tap on the top of the pickup while moving the pickup selector switch.) Having said that, both basses sound neck-pickup dominate with both pickups on. I understand this to be quite normal, correct? The 4003 is understandably more neck-pickup dominate than the 4001v63 simply by virtue of the horseshoe volume drop in the 4003. Anyhow, this led me to study the schematics that are posted on the RIC website. The diagram for the 4003 and other stereo basses shows how the 4003’s wiring is completely "stereo" and that the mono output is really just a 2nd output off of the stereo output. Also notice the "R5" resistor. Unless I completely missed something, my '97 4003 does not have a "R5" (I scoured that control cavity). Mark Arnquist answered this in a previous post by saying that this is the "5th knob" for a 4005 or something. There is, however, a separate diagram for the 4005, 360, and all others that feature stereo wiring and the mixer knob, which is a 250K pot, not a 500k pot as shown in the 4003 diagram. Here is the 4003 schematic. Take special notice of how the outputs are wired...
http://www.rickenbacker.com/us/19507.htm
and the 4001v63...
http://www.rickenbacker.com/us/19501.htm
So could the volume drop in the horseshoe we all notice be due simply to the stereo wiring? If we all look at the wiring of our stereo basses, we notice how much wiring there actually is. The 4001v63, c64, and all other and older non-stereo 4001’s are not as complex (like this post!). Now, I really am not sure, this is just a theory, but unless there is an obstruction (like a resistor on the horseshoe) that becomes active when the mono jack is used, where is it? It's not in the actual wiring and it is only labeled on the diagram, not represented. If it is something else, perhaps the only way to find out, without an electronics expert, is to rewire the bass. What could possibly account for the large volume decrease in the horseshoe in a Stereo bass and no horseshoe volume decrease in a Mono bass? What really scares me is that something is wrong with either, if not both, of my babies... I mean, basses.
Stereo Wiring v. Mono Wiring
Moderators: rickenbrother, ajish4
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jwr2
I had a 1974 Ric that I rewired 2 mono outputs and no cap ... it was louder when one pickup or the other is turned down to 8 or 9 ... my '68 does not have that problem ... and my '73 that I sold to Cooper does not have that problem ...
It is not a stereo mono issue ... it is a pickup phasing problem ...
It is not a stereo mono issue ... it is a pickup phasing problem ...
The cause of "out of phase" is that one pickup's magnet is facing north while the other's is facing south. It's like connecting the left speaker of a hi-fi system with proper + and - terminals while reversing the connection with the right speaker.
When both 2 pickups out of phase with each other are turned full on and combined, the signal drops to about 20%, with weak low frequencies. All strings are affected.
The simplest way to test 2 pickups' phase/polarity is to put them face to face. If they want to kiss each other, out of phase. If they want to avoid each other, say Thank God.
When both 2 pickups out of phase with each other are turned full on and combined, the signal drops to about 20%, with weak low frequencies. All strings are affected.
The simplest way to test 2 pickups' phase/polarity is to put them face to face. If they want to kiss each other, out of phase. If they want to avoid each other, say Thank God.
Well I know my pickups aren't out of phase cause there is serious bass response and no overall volume loss with both pickups firing. My 4003 exhibits the treble volume phenomena that I believe Bob Young mentioned a while ago, simply rolling of the BASS vol. increases the Treble vol. If all pickups on both my modified 4003 and 4001v63 are in phase with one another respectively, please explain why the horseshoe on the 4001v63 doesn't lower in volume like the 4003. The only differences between the two is stereo and mono wiring... I'm nuts...
um....ok.....R1, R2, R3, R4.......yes, what R5?
The email address shown is down, you can email me at septic_bullfrog@yahoo.co.uk
"Me oh my!!!"
Have I actually caused a change to be made to an official Rickenbacker wiring diagram? And they said I would never do anything with my life. John, do you think you could create the position of "Schematic Quality Control" and hire me to fill this new position? I don't want any money, I just want to know anything and everything about the Rickenbacker bass, past and present. Plus, it's too cold in Chicago, I need to get out of here.
"Lucky guy is what I am"
Have I actually caused a change to be made to an official Rickenbacker wiring diagram? And they said I would never do anything with my life. John, do you think you could create the position of "Schematic Quality Control" and hire me to fill this new position? I don't want any money, I just want to know anything and everything about the Rickenbacker bass, past and present. Plus, it's too cold in Chicago, I need to get out of here.
"Lucky guy is what I am"
no one why........????
The email address shown is down, you can email me at septic_bullfrog@yahoo.co.uk
