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Dolphin Reversion Project

Discussion in 'Hardware, Setup & Repair [BG]' started by James Collins, Jan 25, 2019.


  1. James Collins

    James Collins

    Mar 25, 2017
    Augusta, GA
    I do like reading about other people and their self made or repair projects. About a year ago, I purchased a 1991 Warwick Dolphin. Anyone that knows me knows that I am a bit of a Warwick fenatic.

    It is my second Dolphin. The other I have is a 1992 after they switched to gold hardware but with the original electronics. I love how that bass sounds so much that I own two of the same bass for the first time in my life with one caveat.

    That caveat is the electronics are not original. Someone replaced the electronics with Bartolini pickups and a Bartolini preamp. I know originally, that is how they came, so was interested to try one. After setting up the bass, I just never enjoyed the sound of the pickups or preamp. They sound too brittle no matter what I do. So I decided to go back to the original electronics.

    Those original electronics were sent with the bass. Here is where you can learn from some of my mistakes and oversights. I thought I could just swap them back, but nothing is that simple.

    First I noticed even before I decided to do this that the route was expanded at the bridge pickup for the different shaped Bartolini. It isn't all that noticeable if your not looking. There is no going back from it. The route was never shieled. It should have shielding paint. Fortunately I have plenty of this type of paint wishing it had a use.
    Screenshot_2019-01-25-22-21-48~3.png
    Now for the real things I did not pay careful attention to:
    The Bartolini uses 3 mounting screws and the MEC uses 4. The fourth screw is no where to be found and the metal insert for the screw is missing. The screw I could find a replacement for at a hardware store. The metal insert I cannot.

    The original chrome control knobs were replaced with black.

    The body was drilled to accommodate a 3 band EQ with volume, balance, mid, and stacked bass treble. The original circuit is just two stacked push pull pots. One is volume and balance with push pull active/passive. The other is a stacked bass/treble control with a coil split push pull for the bridge pickup.

    So I have some replacement parts and revised circuitry to work out. I don't know why I didn't pay closer attention, but I like the bass and have just a little bit to invest in it to bring it back to a sound I prefer. Screenshot_2019-01-25-22-21-56~2.png
     
    Hoggles and Matt Liebenau like this.
  2. James Collins

    James Collins

    Mar 25, 2017
    Augusta, GA
    Screenshot_2019-01-25-22-55-52.png
    This is the wiring diagram for a Dolphin of the era. Turns out none of the pots I have match the ones needed for the circuit. Also, I have to come up with a way to use the extra holes.

    I considered a lot of schemes. I could not come up with any additional functions I wanted. About the only "extra" switch I could think of was a kill switch. What I have decided to do is a layout with:
    1) DPDT switch nearest the bridge for coil splitting.
    2) Volume B500k mono push/pull pot with active passive switch
    3) Balance a25k/c25k stereo pot
    4) Bass/Treble stacked B100k pot

    This layout will have the benefit of keeping me from inadvertently changing volume or balance when adjusting the other. The layout will also be similar enough to make swapping between basses easy enough. It wasn't terrible, but the old layout somehow had me constantly reaching for volume and manipulating the balance.

    I would also like to say the Warwick shop website has a great supply of parts and good customer support to help find the correct pieces large or small. Shipping is expensive, but the overall price still ended up about the same as if I ordered from other websites with better guarantee that it is a genuine part.

    My hope is to get it wired early next week. This is my first active bass to wire. Should be exciting, but at least I understand the diagram. I will post new pictures as I do the electronics.
     
    Hoggles, Warhawk and Matt Liebenau like this.
  3. James Collins

    James Collins

    Mar 25, 2017
    Augusta, GA
    Finally got around to it today. It took way more time than it should have and I didn't take as many pictures as I meant to.

    First off, least week I used shielding paint on the cavities. The routed bridge pickup cavity was never shielded. Today, I replaced the threaded insert for the pickup mounting screws. Then I reamed the balance knob hole because the hole was too small. Deep breath! This tool was helpful, I've never used one before, but much cleaner than a drill.

    20190210_235354.jpg

    For soldering, I made a template to match the control layout with scrap cardboard. That way I could minimize extra wires. I used copper wires for a sprinkler. They are low resistance and rigid so they won't let the pots move much. This using a template. The downside to them, is they are relatively thick so they take a minute to heat up.

    I also have a helping hand and some fine forceps which are so helpful.
    20190210_212348.jpg
    This is the soldering iron I use which makes things so much easier. It heats up immediately with really good temperature control. I'm not really sure what is too hot for guitar electronics. I always do the work around 600-700F. Lower takes too long to heat up. Hotter is smoky.

    What ended up taking a while was how cramped the cavity was. It was supposed to be two stacked push pull pots with a preamp and a battery. The extra two pots made it difficult to fit everything. You can see the yellow foam that used to be on the bottom of the preamp years ago. It is in a new location now. Also, there was no room for a battery retainer, which was part of my original plan.

    20190210_234819.jpg
    I had to rewire it to make it fit. In addition, I broke the terribly small bridge ground wire and had to replace it. In all the layout changes, I messed up the wiring. Fortunately, that fix just required swapping three wires. I had swapped the neck pickup and the volume input wires. The last modifications I could fix in situ. There is still so much extra pickup wire, but I don't know about cutting it back. I mean, I know I can, but I won't.

    20190210_212156.jpg

    In the end I'm pretty happy. It is definitely a unique layout. The switch splits the bridge pickup--it is a SPDT. In the up position, it is a Humbucker. In the down position, it is single coil. The first pot is a volume push/pull--linear 500k. The next is a balance pot that is a 25k stereo audio taper. The most caudal is the stacked 2 band EQ using a linear 100k pot.

    The MEC sounds more growly with better miss to my ear. The chrome matches much better than the misplaced black potsp Wish I had some recording tools to have recorded the before and after.
     

    Attached Files:

    Matt Liebenau likes this.
  4. James Collins

    James Collins

    Mar 25, 2017
    Augusta, GA
    I plan to come back and explain the wiring diagram sometime when I have time this week. This is my first active wiring. Everything I've done before has been done variation of: volume and tone with or without a selector switch.
     
  5. James Collins

    James Collins

    Mar 25, 2017
    Augusta, GA
    upload_2019-2-12_12-24-49.png
    I'm going to refer to the diagrams a bit, but essentially these are what each of the parts of the potentiometers are doing. I will say that I believe the way that the volume is below the balance on the left is unusual. My experience with stacked pots is that the way that the control knobs are arranged is mirrored in the internal lugs; meaning that the control knob that is on top on the outside and furthest from the body will be on top inside and closest to the body. The original potentiometer is wired like this, so I suspect that this is not an error.

    Also, note the preamp did not label the colors of the different wires to the EQ controls listed. I was fortunate that the original was still wired up and I could just duplicate the setup on the new potentiometer. Here is a color coded diagram of this in case someone needs it for their project.

    upload_2019-2-12_12-30-3.png

    This will be very basic for people learning how to do the wiring like myself. I apologize if it gets too simple for others.

    First part to understand are the switches. A push/pull pot is a switch. Switches are often called names like double or single pole. In the case of both switches in this wiring diagram, they are Double Pole/Double Throw or DPDT. The "pole" refers to the number of independent parts of the switch. A double pole switch could be wired like two switches that have to both be flipped the same direction every time. "Throw" refers to the number of toggles the switch has. Double Throw means there are two position--Pushed or Pulled in this example:

    upload_2019-2-12_12-34-53.png

    Most switches and potentiometers will have a common lug surrounded by two other lugs. A switch is easy to understand, in position one the first lug is connected to common and the second is not. In position two, the opposite is true.

    upload_2019-2-12_12-36-46.png

    The push/pull switch to turn off the preamp is simple to understand. The common connection is attached to the output jack. The pushed position is connected to the output from the preamp. When pushed, the preamp signal is sent to the output jack. In the pulled position, this connection is broken. The common lug connected to the output jack is now connected to the output from the pickups after being blended and volume adjusted.

    upload_2019-2-12_12-40-23.png

    The push/pull switch to split the pickups is only slightly more complex. The pickups are active, so connected to the 9 volt battery positive lead. Also, they use a shielded ground wire around the hot wire. They look something like this:

    upload_2019-2-12_13-39-10.png

    The humbucker is two jazz pickups wired to a double throw switch. The switch works to either send both pickups to the balance pot in parallel or to send the bridge half of the pickup by itself to the balance pot. The lug accepting the bridge half of the pickup is also wired directly to the balance pot. In the down position the two pickups are linked together in parallel. In the pulled position, the neck pickup is grounded out and only the bridge half of the pickup is heard.

    upload_2019-2-12_13-40-8.png

    Potentiometers are only slightly more difficult to understand. They act like a switch that lets a variable amount of current across the connections depending on where the control knob is turned. The resistance value is drawn from the perspective of the left lug or the output lug to make it more understandable. The resistance would be mirrored for the opposite side.

    upload_2019-2-12_13-47-3.png

    Turned all the way clockwise will connect the common terminal to the terminal #1 or left terminal with the most resistance between the common and right terminal. This is reversed when you turn counter clockwise.

    The volume pot in this wiring diagram works like every volume pot I've used. The potentiometer is rated as B500k. So it is a linear (B) pot with 500 k(ohms) of resistance. "A" denotes logarithmic. "C" would denote anti-logarithmic. The connections can be reversed for the input and output with no difference in sound or signal. This setup makes clockwise turning the volume up and counterclockwise turning it down.

    upload_2019-2-12_13-52-59.png

    As a side note, wiring a tone pot works sort of in the opposite direction. The tone pot passes the signal across a capacitor to ground. The capacitor only lets higher frequencies through, so it cuts out the brightness. It is wired to the opposite half of the potentiometer. This lets a counter clockwise turn increase the amount of signal sent to ground.

    The balance control is a bit more complicated. This is the first time I wired one of these. Additionally, it is a stacked 25k A/C pot. This means that the half wired to the neck pickup is logarithmic and the half connected to the bridge pickup is reverse logarithmic.

    upload_2019-2-12_14-2-43.png

    If you think of them as volume pots and ignore the connections between them. The neck pickup will be loudest when the control knob is all the way clockwise. The bridge pickup will be loudest when all the way counterclockwise. The two halfs of the circuit are linked together to share a ground and to link both outputs in parallel. This particular potentiometer has a detente or a notch you can feel at the midway point when both pickups are mixed 50/50. Additionally, the taper is designed such that there really isn't a perceptible change in volume as the control knob is turned.

    On another side note, you cannot reverse the wiring with a logarithmic pot the same way you can with a linear pot. A linear pot will look the same from the perspective of either lug. A logarithmic potentiometer will look like a logarithmic change in resistance from the left lug and an anti-logarithmic change from the right lug. I made a mistake of wiring it up like this at first. It made it so that to clockwise was the neck pickup, counterclockwise was the bridge pickup, and in between was a noticeable decline in volume.

    upload_2019-2-12_14-14-41.png

    The EQ controls are easy to understand at this point I hope. Just two stacked linear pots.
    upload_2019-2-12_14-15-55.png

    I don't really want to pretend like I understand what the preamp circuitry is doing--it is a bit of a mystery. The wiring of this one, I do understand how it connects. There is a red wire that goes to the 9V battery. This powers the device. The battery is wired to the pickups and the preamp in parallel. That means the voltage across each is 9 volts, but that the current would be 1/3 of what the battery can produce. There are the three wires that control the bass EQ and the three wires that control the treble EQ. I believe the preamp must measure the resistance across the wires and that determines to cut or boost the frequency. There is a black ground wire. The white wire is the output from the preamp. The grey wire is the input wire. Note: I couldn't draw a white line. So the funny looking outlined white line is supposed to be white.

    upload_2019-2-12_14-26-18.png

    The grey input wire is connected at the same lug as the output from the volume pot on the active/passive switch. In the pushed position, the connection goes from the volume pot to the preamp and to the output after processing. In the pulled position, the pickups are still connected to the preamp, but the preamp output is disconnected. Instead, the volume pot output is connected to the output jack.

    I know that is relatively long. Maybe it will help someone in the future. I just dove into wiring it myself. I think if I had understood this all at the onset, it would have been much faster and I wouldn't have needed to redo anything. If I hadn't have made so many mistakes, maybe I wouldn't have learned as much as I did though. Thanks
     

    Attached Files:

    Barticus and Haroldo like this.
  6. Barticus

    Barticus Supporting Member

    Sep 16, 2017
    NEOhio
    Thank you @James Collins this was a great explanation and extremely beneficial. I'll use it as a reference to assist with some rewiring and troubleshooting I'm doing on a come different basses.

    Thanks!
     

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