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Re-capped my Warwick Corvette FNA--yuuge improvement!

Discussion in 'Pickups & Electronics [BG]' started by Walking, Apr 17, 2017.


  1. Walking

    Walking

    Apr 5, 2010
    Minnesota
    I have two Warwick Corvette FNA basses, a fretless and fretted. I really love the way they feel with that ovangkol neck. Well, I was preparing to do some recording in my home studio and I tried them out, and was a bit disappointed with the sound. I was expecting more bass, as they have that giant single pickup. Also, I noticed a significant high frequency hiss.

    Now obviously, its easy to use eq to take hiss out of a bass track, but I wondered if these basses were operating at full potential. Well, to cut to the chase, I decided that the preamps on these basses contained electrolytics that were 20 years old (I can narrow down the mfg date to 1989-2000. I have always guessed mid 90s.) So, before getting some sort of aguilar replacement and engaging in some nerve-wracking soldering of more than a dozen fine wires, I decided to do what I have been doing on tube amps for years--replace the electrolytics. The only potential downside to this was that they might sound worse, or I might wreck some traces on the circuit board while soldering tiny parts. Or simply wasted time and effort.

    My philosophy is to try the inexpensive thing first and failing that, look to more expensive alternatives. So, caps it was.

    They each had 3 10 uf, and 1 4.7 uf 50 volt caps. There are diameter constraints due to their close proximity on the circuit board. So I got on the digi-key parts finder and based on what they had available, settled on some 25 volt caps--I ordered the more expensive of the caps--they are about 25 cents each--maybe under $20 for the order including shipping--I really like working with digi-key. Its got a 9 volt battery, so I felt that would be plenty. The caps just came today, and I have a hakko soldering unit with a fine tip.

    I took some photos in case I got lost during the project--the main thing being to properly orient the polarity of the electrolytics. The board has two multi prong plugs and one wire soldered to the guitar guts. So I unsoldered that wire and had access to the circuit board unimpeded by the bass. Also had to remove the adhesive Velcro strip which holds it down. After I took the adhesive off, I cleaned the capacitor solder areas with solder resin remover.

    As always, de-soldering the existing parts is the most difficult, as there is danger of over-heating and lifting circuit board traces. Well, it was a hassle, but I got the caps out and cleaned up the board with de-soldering braid and some solder resin cleaner. Put the new caps in, soldered the one wire, and plugged it back in to the ton pots--and I couldn't be more pleased with the result.

    I got lots of full and growly bass, that I like in a warwick, and the hiss was no longer audible. And this was with the tone controls all at center-notch. I did also put in new batteries, so maybe that helped a bit as well.

    I noted that on the bottom of the circuit board it said 'Seymour Duncan 412125 r 1'. I sent an email to the mfgr to see if they will send me any doc on the unit. Well, no more thoughts of upgrading the pickups or active electronics. I can post photos if anyone is interested. It was pretty straightforward.

    Next project--use the fret-dressing tool I just bought from ebay to clean up the fret edges of the burl-wood eye-candy Ibanez that I just couldn't stop myself from buying--but that's another story....
     
    Axstar likes this.
  2. 74hc

    74hc

    Nov 19, 2015
    California
    Those capacitors had the easy life inside the bass compared to their ratings. There are many types of electrolytic capacitors... solid-based, semi-solid, wet, water-based just to name one category.

    Around the turn of the century, the water based caps had quality issues. Bulging, bursting, and exploding were common problems. The PC motherboard industry turned to solid caps which they like to advertise as solid-state and/or high durable caps. Notice they used high-durable because of marketing images of "HD" that consumers denote as being good.

    You probably should inspect the old capacitors, and measure them. This way you'd know if those caps were truely bad, or you inadvertently switched to a different type that you like better. If the tone improvement was due to switching to a different type of electrolytic capacitor, you would benefit in knowing that for future reference/bass mods.

    At least inspect those, and compare the datasheets between the old and new.
     
    Walking likes this.
  3. Walking

    Walking

    Apr 5, 2010
    Minnesota
    Thanks for commenting. I recall the 'capacitor cancer' that impacted dell retail computers, whereby some Asian capacitor company stole the process for making caps from another company, but got it wrong somehow and created caps that failed fairly quickly. I had never thought about that impacting my Seymour Duncan preamp, and it would be complete speculation as to whether that was the case, but who knows...

    I do notice when caps are swelled, as I look for that as a good indicator of failure, the caps I took out here were not physically distorted. As to 'solid state' caps, maybe I should have spent more time on the digi key cap finder, as I went right to the aluminum capacitor category. I will take another look at my order to see what I can learn about the new caps I put in. My theory at this point is that the electrical characteristics of the caps migrated over time, but just a theory. My thought was that if they lost capacitance, they may pass low frequencies less effectively and not filter out hiss, as was the case. Again, thanks for the ideas, I will look into this a bit more.
     
  4. Axstar

    Axstar

    Jul 8, 2016
    East of Eden.
    Reflowing a bunch of solder joints probably didn't hurt either!
     
    Walking likes this.
  5. two fingers

    two fingers Opinionated blowhard. But not mad about it. Gold Supporting Member

    Feb 7, 2005
    Eastern NC USA
    How bout some pics?
     
    Walking likes this.
  6. Walking

    Walking

    Apr 5, 2010
    Minnesota
    New to photobucket, so let's see how this goes...The macro lens has great detail but narrow range of focus.

    Overview:
    after_overview_zpsqpw1leqo.

    Before photo with original caps. Note cap stripe indicates polarity.
    before_zpsm7joytky.

    Circuit board, before replacement. Note the battery plus wire in the lower right corner. If you follow the trace to the top, that is where the wire was soldered on my other warwick.
    back_zpsukf1vjgx.

    After--note caps are smaller physically.
    after_zpsdrtplhxe.

    I don't see this as detracting from Seymour Duncan in any way. Wet electrolytics have a limited life span, and these were about 20 years old. I will observe that whatever they paid to get that circuit board set up for manufacturing, looks like they have had some years to re-coup the investment--as it is their STC-3P board, still available in current catalog (with potentiometers) for $135. In my opinion, this bass sounds great--topic for another time, but I think these warwicks with the ovangkol necks, wenge fretboards, and bronze fret wires are very underappreciated as far as used prices go. Good for me, as I will pick up the next one I see on local craigslist if the price is right, knowing that I can give it a mid-life electronics upgrade. I just love the feel of the neck on that beast--baseball bat sawn in half that it is, and I have two of these single pickup FNAs, fretted and fretless (ebony fingerboard). ;)

    Digi-key order with parts numbers:
    caps_zpsuhmpxzj1.
     
    Last edited: Apr 25, 2017
  7. BassLife77

    BassLife77

    Nov 13, 2009
    San Diego
    since its only milliamps going through the caps using solid state won't make much of difference. good quality electrolytics will last decades. the stock caps must have been crap and just dry rotted
     
    Walking likes this.

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