Rickresource Rickenbacker Forum

I have a 1979 4001 with a toaster in the neck position and the original high-gain in the bridge position. I always leave my V/T full on and control my V/T with my effects, volume pedals and amp tone circuit.

Does the circuit cut out some frequencies and gain?

Is it possible to wire the pickups directly to the output jacks without the V/T circuit?

I have on my 79, both pup's wired directly to high quality ALP's pot's and straight to separate output jacks, no stereo jack, just two jacks and two leads from the bass, one for each pup, effectively like having two separate basses, the difference in clarity and output is quite noticeable. It works well for me as I never used the tone controls, but volume pot's on the bass in a stereo scenario is important if you don't have two amps.

In theory, the volume and tone circuit affects the tone and signal level from the pickups even if the controls are turned up all the way. A pickup is a combination of inductance, capacitance, and resistance. As such, it tends to have a resonant frequency. Both the frequency and the bandwidth of the peak are affected by any attached resistance (like the volume pot).

Generally speaking, a lower resistance volume pot will tend to decrease the amount of high frequencies you get. A higher resistance (or removing it completely) will tend towards a brighter sound, and possibly a sharper resonance at a different frequency.

Also, keep in mind that whatever you plug into will affect the pickup as well. This may become more noticeable without the volume pot in the circuit.

That's theory. In practice, what you will hear is hard to predict. The brighter tone might be welcome, or a peaky resonance might be annoying. The only way to know whether you will like the result is to try it. If you're handy with a soldering iron, it should be an easy and very reversible mod.

One more thing you might want to consider is the effect of using the volume controls to change the blending of the two pickups. I don't notice this so much on my 4001 - I have a reissue horseshoe (a pretty hot pickup) and an old toaster, and their signal levels and tone colors are pretty different. But it's dramatic on my Fender Jazz, where backing off the bridge pickup just slightly gives a whole spectrum of different tone colors. You might want to experiment with this before ripping the volume controls out entirely.

Thanks! Sean and Bill.

Sean, what k ohm pots did you use and why? Also, what brand/style jacks did you use?

Bill, if I wire it like Sean's, will 500k pots be rated high enough to avoid most of the loss?

A less dramatic alternative than removing the tone and volume controls completely:

With the standard wiring both volume pots are in-circuit even when playing a pickup solo. A little bit of rewiring and you can at least get the opposite volume pot out of the circuit when soloing a pickup. It basically involves changing the wires so that the pickup cables goes to the volume pots, then output from the pot goes to the switch, and from the switch to the output jack.

Use a no-load pot for tone control. A no-load pot cuts connection to ground, and effectively takes the pot and cap out, when the tone is full up. Either get at readymade Fender no-load tone pot, or you can modify a CTS pot. It’s quite simple to modify the pot yourself. Just bent up the tabs to open the housing, cut over the resistive track at the right place, and put it together again.

I can put up some drawings if wanted.

Just FYI, I have done a lot of experiments such as you are hinting at (I even made a zero-load harness for my 4003FL once), and honestly I prefer the sound of the bass with the pots in the circuit. Without them the signal develops a harshness I do not like.

Joshua, Please describe the "harshness" you refer to.

Were you not able to reduce that harshness with your effects and amp tone controls?

MichaelStewart wrote:Bill, if I wire it like Sean's, will 500k pots be rated high enough to avoid most of the loss?

I've read some comments elsewhere here that 500k pots made an audible difference. I haven't tried this on my bass, so I can't claim to be an authority.

I've also gotten the impression from others' posts that the older instruments had much more of an individual personality. Pickups were wound differently, and sometimes pots are way out of tolerance. So putting a good 500k pot into one bass might make a big difference, on another bass not so much. And of course players have individual personalities too! What one hears as a "brighter" sound another may consider "harsh"; what is "dull" to one is "warm" to another.

Temporarily rewiring your bass so the pickups are isolated from the controls and directly connected to the output jacks would let you experiment with various volume and tone circuits externally. That way, you'll quickly find out which combination sounds best to you.

MichaelStewart wrote:Joshua, Please describe the "harshness" you refer to.

Extreme amounts of treble and string artifacts that were not very musical sounding.

Were you not able to reduce that harshness with your effects and amp tone controls?

Well sure, you could do that, but why not start with something you like and do small tweaks at the amp? That's my approach. I'm not telling you you shouldn't try this but when you think about it, we've spent the last 60 years listening to passive basses that are loaded down by 250K or less (a Ric is more like 125-165K) on both volume and tone, and those are the conditions under which bass legends like James Jamerson, Jaco Pastorius, and the Ric-wielding Chris Squire were operating. Trying to unlock yet more treble and grind in a passive circuit is going to often lead to something that sounds brittle and "unnatural" or harsh, as I first put it. Will you like it? Maybe, different strokes. But I think most people who go down this road find it's better to focus on a good direct inject with an impedance buffer, and then a good preamp, and then a good amp, and then a good speaker...

My zero-load harness was this: 1 meg-ohm volumes for each pickup (final load: 500K) and a Fender No-Load for each tone pot with fairly small caps. I ended up finding I had to turn all the controls down just a little, like 10%, to get the bass to sound "right" to me--in other words I was moving all the pots closer to the specs that have traditionally been used in passive guitars.

You'll find yet another issue here: the less impedance loading in a passive harness, the more critical the capacitance of your instrument cable, i.e., a bad cable is "less bad" working with a circuit that already has some loading. (And all cables are bad cables, in that they have capacitance and longer runs mean more tone suckage, unless you have an active buffer to get your signal into the truly low impedance range of less than 1,000 ohms.)

MichaelStewart wrote:Thanks! Sean and Bill.

Sean, what k ohm pots did you use and why? Also, what brand/style jacks did you use?

Bill, if I wire it like Sean's, will 500k pots be rated high enough to avoid most of the loss?

I used the same value pot's as original and gold switchcraft jacks (these are quite rare, ones with gold contacts, not just a gold face and nut). I just wanted to keep the same value and not change the sound to much, just make the signal better, I think that the switch is probably the biggest sap in signal. Oh and I used HiFi quality cable inside too.

As for the sound It's def brighter, but the lows are lower too, in fact the whole signal is wider and more full, it's a little more difficult to Eq as the amp controls have more of an effect on the sound, because the bass is sending more frequencies.

songdog wrote:....what you will hear is hard to predict. The brighter tone might be welcome, or a peaky resonance might be annoying.

Personal experience with that. I had 500K pots in the tone position for some tests, and I noticed a ringing or a 'metalic zorny resonance' at 300~400hz that I had to use my parametric to knock out.

cassius987 wrote:Just FYI, I have done a lot of experiments such as you are hinting at (I even made a zero-load harness for my 4003FL once), and honestly I prefer the sound of the bass with the pots in the circuit. Without them the signal develops a harshness I do not like.

Could that be the same issue- is a no load pot approaching infinite resistance? I don't know.

Anyway, I have had some of the guys say the tone circuit loop is the most sensitive part, and prefer to use the best pots there, something like a 250 audio taper CTS. Since the push/pull pots are all 500K, you put it in the volume circuit. Any issues with putting 500K pots in the vol circuit? I was considering putting another 500K in the other vol position to make both volume pots 500K, balance them out so to speak. Is that circuit safe from any of the annoying resonances discussed?

Is it possible to create a wiring harness that has no pots, but has a "minimal" circuit that filters out those "'metallic zorny resonance' at 300~400hz" without limiting the highs and lows that are lost with a normal tone circuit?

"'metallic zorny resonance' at 300~400hz"

I don't think there's much that can sound "metallic" at those frequencies. 300-400 Hz is what I usually scoop to get rid of "mud" from bad bass rigs that are not reproducing fundementals accurately. If its truly metallic sounding, it's far more likley to be at 3000-4000Hz. That said, the desirability of the change in sound caused by increasing the impedence that the pickups are feeding into is all very much in the ear of the beholder. Modern bass rigs do a much better job of projecting high/mid and high frequencies, and modern strings are aften very bright. Consequently, the effect is perhaps a litttle les desirable than, say 35 years ago, when I fitted FET transistor buffers between the pickups of my 4001 and the pots. The FET's had a theorical infinite input impedence, and buffered the pickups from the input impedence of the amp. I personally loved the sound, although the very things I liked, the enhanced "growl" and top end, which sounded good through my rumbling Carlsbro 2X18, migh be irritating on a more modern rig. I would always caution, however, against judging the sound of a bass by listening to it "solo." The "harsh" frequencies that may show up with a high impedence circuit may be just what's needed to cut through when your guitarist has a Marshall turned to 11. Several times I've been complimented on the mixed sound of a bass track that sounds like razor wire if you solo it.

Are the pickups you all tested toasters, hi-gains or hb-1s? It seems like this would also make a difference.

I have both a toaster and a h-gain in my 4001. I am also toying with the idea of using at least one hb-1.

It took me a while to remember where I'd misplaced this information... here's a link to some good information about pickups and the effect of resistive (volume pot) and capacitive (cable, mainly) loading:

http://buildyourguitar.com/resources/lemme/

One really important point in this article is that the pickup alone doesn't determine the tone; it's the combination of the pickup and whatever load is attached to it.