The Last Bass Outpost
Gear Discussion Forums => Bill's Shop: Projects, Mods & Repairs => Topic started by: Johnbob on June 29, 2010, 04:18:09 PM
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So, I have some questions about changing the pots on a Bachbird TH-1. I know the stock pots are pretty crappy but I was wondering what I would gain from upgrading to better pots and a new jack? Obviously I'm assuming it will improve the sound but what would be the difference? Would it be give the bass more bottom end, etc.? I was wondering if changing the pots would affect the output of the pickups? Right now it still has the one pickup but I bought a second artec pickup that I will be installing soon. The output seems pretty low and the pickup sounds kind of muddy too. Will changing the pots help this stuff?
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Yes, changing the pots, jack and cap with high quality ones would help the sound a little bit, also you will gain better control when you are using the pots and most of all reliability. Those crappy electronics could broke anytime and leave you with a dead bass!
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Don't forget to upgrade the cap too. That'll make a bigger difference than the pots. It'll open up the sound.
If you change the pots to CTS; you'll have a better range from 0 to 10, instead of the on/off effect of the cheap ones.
About the Artec. it doesn't sound muddy at all to my ears.
And about the output. It may not be the hottest pickup around, but it is not weak if you ask me.
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I don't know much about this stuff so I was wondering if you guys could help me pick the right ones because I'm not sure which ones to get, there seems to be a few options.
So I know I need USA CTS Pots but do I want 500K or 250K? It seems like most of you guys are getting the 500K pots. Also, do I get long shafts or the regular ones? I also see some that say +10% and some that say +20%, which ones do I get? Is CTS the brand name or is that just a type of pot that a bunch of different manufacturers make? If so, what brand do I get? If you guys could send me a link to any of this stuff that would be great.
Also, if you guys could help recommend or post links regarding caps and jacks that would be great too since I know even less about that stuff. I always here the words CTS, Switchcraft, etc. thrown around but I have never had to buy any of that stuff so I'm a little clueless about that stuff.
I'm also going to be converting my bass to a 2 pickup model so do I need 3 pots that are the same and one cap? I want to wire it up just like an original NR Thunderbird because the goal is to make it as close to the original as possible. I know that I have different pickups and it won't be the same but hopefully I will get Lulls one day and make it sound closer to the real thing. Thanks.
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I agree with Rob, I'd say the Artec is a medium-hot pickup, not hot as hell but hot enough to make your ears bleed! :P
Humbuckers usually sound better with 500k pots, and single coils with 250k.
You will need normal shaft pots, the long ones are for guitars with thick/carved tops, like Les Pauls.
Also you will need AUDIO (or LOGARITHMIC) pots and not LINEAR ones. Audio pots have better suited "taper" for use in guitars.
Caps are very important, especially if you use your tone pot alot, and not use it like an on-off switch.
Most people use 0.022uF or 0.047uF or even 0.1uF caps. The bigger the cap, the more the cut of highs and the "feel" of more bass when you put your tone cap on "0".
There are two types of caps that you can use, film caps and ceramic. Most instruments use ceramic, they are cheap and gets the job done. But if you want something better (that's just my opinion) use a film cap. I like Mallory 150 series caps. They are well made and not expensive.
I usually get my stuff from Banzai, here are some recomendations:
pots
http://www.banzaimusic.com/CTS-Potentiometer-500k-log.html
jack
http://www.banzaimusic.com/Switchcraft-SC-11.html
cap (ceramic)
http://www.banzaimusic.com/22nF-Ceramic-Cap-5mm.html
http://www.banzaimusic.com/47nF-Ceramic-Cap-5mm.html
http://www.banzaimusic.com/0-1uF-Ceramic-Cap-5mm.html
cap (film)
http://www.banzaimusic.com/Mallory-150-0-022uF.html
http://www.banzaimusic.com/Mallory-150-0-047uF.html
http://www.banzaimusic.com/Mallory-150-0-1uF.html <------ my favourite
There you are, I hope I helped a little bit to clear things up for you!
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I want to wire it up just like an original NR Thunderbird
You will want 500K pots for the volumes, and a 250K for the tone with a .047 uf cap.
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Cool, thanks for the responses/help. I wonder now if I should still go for the vintage specs or if I should get the 0.1uF Film caps? The price isn't a factor since they are obviously so cheap. Also, I should have asked this in my original post but which wiring should I use? I also know little about that but I do hear a lot about cloth wiring but I don't know what gauge, brand, colors (if that matters) or how much I will need. Any links or advice about that stuff would also be appreciated. Thanks again for the links and help.
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You will want 500K pots for the volumes, and a 250K for the tone with a .047 uf cap.
I believe the original was a Sprague 'Orange Drop' cap. Still available. Less than 2 USD. definitely has the vintage look.
http://www.google.com/search?q=sprague+orange+drop+capacitors&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a
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This is a really handy thread. I have a Bronco and another bass needing some pots and a cap, and having parts ID'd is a great convenience......
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Lot easier in the old days when pots meant CTS and caps meant Sprague.
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Great another option...ha..ha. But seriously, does anyone know if the Sprague 'Orange Drop' caps are 0.022uF, 0.047uF or 0.1uF caps? I'm assuming that the Sprague is a 0.047uF cap since some people claim that the originals had 0.047uF caps and then some people claim that they came with Sprague's. Are they film or ceramic? Should I get the Sprague or the Mallory-150-0-1uF.html film cap? I know it's all a matter of taste but I have no idea. I wanted the bass to be modeled after the original NR bird because I have played one and I loved it but maybe they have come a long way with caps since the 60's. And also since I am using Altec pickups it won't sound that way anyway. Someone please make a decision for me..ha..ha.
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There are Spragues on most usual capacitances, 0.022uF 0.047uF 0.1uF and so on. Spragues are film caps, just like Mallorys. Some people find Orange Drops kinda "hi-fi" but the differences are almost inaudible. I prefer Mallorys for some reason, but Banzai has Orange Drops too, he also has some real expensive caps made of Unobtainium, don't buy those because Alien monsters will eat you alive when they will invade Earth.
You can use this wiring diagram, its for a jazz bass so you have to replace 250k pots for 500k ones.
http://www.seymourduncan.com/images/support/schematics/std_jazz_bass.jpg
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I wanted the bass to be modeled after the original NR bird because I have played one and I loved it but maybe they have come a long way with caps since the 60's. And also since I am using Altec pickups it won't sound that way anyway. Someone please make a decision for me..ha..ha.
It comes down to whether you want to get as close to original as possible. That would be an .047 Sprague "orange drop', 500k CTS pots and Switchcraft jack.
If not, just about anything would be an improvement over the Bach stuff.
Whether or not "improvements" have been made to electronics since the 60's is subjective. Tubes vs SS, vinyl vs MP3, analog vs digital, etc.
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It comes down to whether you want to get as close to original as possible. That would be an .047 Sprague "orange drop', 500k CTS pots and Switchcraft jack.
If not, just about anything would be an improvement over the Bach stuff.
Whether or not "improvements" have been made to electronics since the 60's is subjective. Tubes vs SS, vinyl vs MP3, analog vs digital, etc.
I use CTS and Sprague for most applications and I think things sound better.
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Ok, so we've determined that the original's used a .047 Sprague "orange drop', 500k CTS pots and Switchcraft jack. Some of you claim that a 250k pot for the tone but others claim that they used 500k pots for both the volume and tone pot. Does anyone know for sure? Also if I could get some recommendations for which wire to buy, gauge, color, brand, and how much I will need that would be great. Thanks again to everyone for the super helpful advice and info, I definitely appreciate it. And thanks for the link to the wiring diagram, that was going to be my next question.
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Some people like that slightly treble roll off that 250k pots do to humbuckers, it's up to you really. If you want maximum treble from your bass, then 500k everywhere is the way to go. Again, the difference is minor.
As for cable, I have bought a spool of this, and still have some. That reminds me to go buy some cable too!
http://store.guitarfetish.com/guhoupwi22ga.html
The king of guitar wiring cables is cloth covered cable, like this one here:
http://www.banzaimusic.com/Cloth-covered-wire-RED-50ft.html
Not a big difference soundwise, but more practical, you push back the cloth, make your solderwork and then let the cloth come back again.
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... Some of you claim that a 250k pot for the tone but others claim that they used 500k pots for both the volume and tone pot. Does anyone know for sure? ...
I have some Gibson schematics dated 10-22-74 that show 500k volume and 250k tone, similar to but drawn a little different than this:
(http://img.photobucket.com/albums/v245/Johnny_Crab/thunderbird_wiringFx.jpg)
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Oh my Bach I have expermented with pots, pickups and caps. I didn't like the Artec with a .1 cap. I do like the .1 cap with the Seymour Duncan pickup that I currently have installed.
(http://www.mojohobo.com/images/body.jpg)
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I always used 500k pots for tone controls on humbuckers until last year (or the year before, I can't remember!). I tried a 250k pot on my 60's NR TB restoration and I loved the treble roll off it achieved. Now, I only use 250k pots for tone controls with humbuckers. It's all a matter of taste. Gibson, I believe, may have used 300k pots for tone (available thru Bass Parts Resources).
It's not absolute. You have choices and decisions to make.
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That schematic posted above labeled "Thunderbird IV (or III?) 1974" is how I've wired my BaCH w/TB+ pickups. I've been very happy with it. Doesn't hurt to buy some different value parts and experiment, though!
(http://i87.photobucket.com/albums/k125/0chromium0/forums/thunderbird/refin/DSCF0304.jpg)
Stew-mac sells the braided push-back cloth insulated wire. I love that stuff for these types of projects, since you can shield a lot of the circuit by soldering the braid to the pot enclosures. I've rewired my EB-2D, EB-0, Ampeg AEB-1, the BaCH, and Guild JS-II in this manner and never had any noise problems.
It may be hard to justify if this is just a one-time project, but a good soldering station makes such a huge difference. Something like a Weller WTCPT or Hakko 936 would be a great investment (I have the latter, and there are plenty of other options). They pop up used on Ebay - saves ya a few bucks. For solder, I've been using a spool of Kester 44 rosin core. Take the money you save paying for a tech's labor, and put it into some tools, bulk wire, etc... and the next time you have a project like this it'll cost you next to nothing. You can also build your own instrument/patch cables with these tools and save a bundle (I built a mother-lode of Canare/Neutrik cables for my home studio setup at an average cost of $4/ea.)
Also, another excellent vendor for parts is Small Bear Electronics in Brooklyn - http://www.smallbearelec.com/StoreFront.bok They don't stock the CTS brand, unfortunately, but have all the other components that you'd need. I've dealt with Banzai before too, and they're great.
Good luck!!
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Doesn't hurt to buy some different value parts and experiment, though!
I agree to that! I've experimented a lot, and it differs a lot per bass.
For example, I ended up wiring my:
* Jazz with ChiSonics (single coils) with 500 K pots for Volume and 300 K for Tone;
* the same Jazz with ChiSonic Humbuckers with 250 K pots for Volume and Tone;
* Darkstar Precision with 500 K pots for Volume and 250 K for Tone.
It's also nice to experiment with the values of capacitors: I've used the traditional .047, but also .033 and 0.1 values.
But as for Orange Drops: not all of them sound good in a bass I found out:
* the 715/400V are THE Orange Drops to use (available in different values), and;
* the 715/200V sound like crap!
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But as for Orange Drops: not all of them sound good in a bass I found out:
* the 715/400V are THE Orange Drops to use (available in different values), and;
* the 715/200V sound like crap!
Why would the voltage capacity make a difference? The actual voltage in the circuit is a small fraction of that.
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Maybe even if they are the same series )715) they are built different? Seems strange to me too. I have never used orange caps with lower voltage than 400v so I don't know about that.
off-topic: I think it is more useful to install a rotary switch on your bass to choose between some different cap values, than to have a cap and a pot, especially if you are an "on-off" tone user.
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Why would the voltage capacity make a difference? The actual voltage in the circuit is a small fraction of that.
Well, I can't give the technical explanation, but my ears are the judge. Really a difference. :-\
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Why would the voltage capacity make a difference?
iirc, purely down to physical material differences - were bound to have some electronic techies (ie PBG) to explain in detail...
I don't use tone controls, excluding the amp, so I can't be objective here...
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Wow, a bunch of great information here. Thanks. I think I am going to get the 500k's for the volume and the 250K for the tone but I can't decide which cap to buy. I might go for the orange like the original's but I might also go for the Mallory-150-0-1uF.html film cap. Good thing they are so cheap, I can try one and if I don't like it I could switch it out. I think I am also going to go for the braided wire too. Thanks again everyone.
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Found a link to this interesting article on another board:
http://www.aqdi.com/tonecap.htm
"Our conclusion is that two tone capacitors with the same measured capacitance value and low leakage yield the same tone, regardless of rated voltage, size, dielectric, or price! "
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OK, so I am finally getting ready to buy my new pots, jack, cap and wire for my Bachbird project. Thanks to everyone that threw in their advice and suggestions. I made a list below of everything I am ordering. Please take a look and check it out and let me know if something looks horribly wrong since I really don't know crap about this stuff. I do have a question about the pots though. Should I be getting split or solid shafts?
I am ordering all this stuff from Bass Parts Resource and I have also listed the prices of everything I am ordering and I was wondering if these prices seem good or if anyone out there has a better suggestion of where to order this stuff from. Keep in mind that I am in the U.S. so obviously it would make sense for me to order from the U.S. Although this stuff seems pretty cheap so I can't imagine it could be much cheaper anywhere else but you never know. Oh, one last thing, I am going to be getting the Seymour Duncun SSB4 pickups just to give you guys an idea of what I will be using.
- 1 SWITCHCRAFT USA 1/4" MONO JACK - $2.49
- 1 SPRAGUE .047mfd ORANGE DROP CAP - $1.99
- 2 500K CTS SOLID SHAFT AUDIO TAPER POTS - $4.69 X2
- 1 250K CTS SOLID SHAFT AUDIO TAPER POT - $4.69
- 1 BRAIDED METAL WIRE (8' Long) Vintage Gibson® style. 22awg - $7.79
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Split shaft would be best, as most of the gibby-style knobs are made to fit those knurled split shafts, press-fit style. For solid shaft, you'd typically need knobs with a set-screw to hold them in place. Functionally, the pots are no different.
Good luck with it!
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Yep, go with split shaft for Gibson knobs. And you're probably not going to find much difference in price elsewhere unless you're buying in bulk.
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I'm digging the Duncan SS4s. Duncan specifies 250K pots for both volume and tone. That's what I got since that's what they were designed to use. Braided wire not necessary IMO.
Usually you use a 500k for tone and 250k for volume if you're going to use 500k at all.
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I went 500k for both vol and tone with the Lull pup. I thought about the 250 but why give up any treble if only one pup version... I would not change a thing as it sounds huge.....
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500 vs 250 for the tone pot - If you run it wide open, does it make a difference, or does pot value only effect the amount of roll off?
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Stewmac has a good article on which tone pot to use. Reading it, it does seem to make sense to use 500K for vol and tone on a humbucker. I'm going to give them a try. Says it does make a diff, wide open or not.
http://www.stewmac.com/freeinfo/w101-controlpots.html
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Good article!
No harm in erring on the side of a high value tone pot. You can still sweep the 0-250K range, and with it set in the higher resistance values >250K, it just means that less high frequencies are being bled off thru the cap to ground.
Unless you use a switch to bypass the pot, or one of those "no load" pots (takes itself out of the circuit when its full "open"), there will always be some signal (high frequencies) getting bled off. Whether or not its perceptible depends on the ears involved :)
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Thanks guys. I knew I would probably get something wrong. Spilt shafts it is.