The 'Vintage Tone' cap - experimenting with different values

[espidog]

My 4003 dates from 2004, so came without the pull-switch and 'Vintage Tone' cap on the bridge pup. Recently I got busy with the soldering iron and installed the requisite 4n7 cap, curious to see what the effect would be.

Now, given that we're dealing with passive circuitry here, obviously the end result is going to be affected by the input impedance of whatever amp you're plugged into, so my experience may not necessarily be similar to yours, and of course we all have our own preferences. Here's what I found, anyway, FYI:

I found that the 4n7 was a bit extreme for my tastes. It left me with pretty much nothing but top end twang, and the signal was so weak in comparison with the hi-gain neck pup that - even with the bridge pup cranked right up close to the strings - dialing it in made no useful difference to the tone of the bass.

So, I experimented with a couple of alternative values. First, a 6n8: slightly better, but still a bit 'strangled' IMHO.

I ended up with an 8n2, and for me, this seems to provide the best compromise. It blocks the very bottom end, but leaves me with a nice mix of midrange and top, and a signal with enough poke to blend usefully with the neck pup.

Has anyone else tried altering the value of the VT cap in this way?

[rickaddict]

I found that the 4n7 was a bit extreme for my tastes. It left me with pretty much nothing but top end twang, and the signal was so weak in comparison with the hi-gain neck pup that - even with the bridge pup cranked right up close to the strings - dialing it in made no useful difference to the tone of the bass.

Sounds like my 20-year frustration with my otherwise beloved 4001. And man did I do the "happy dance" when this forum taught me how to get rid of that thing. You put the cap back IN? I'd rather lick a salt block all night long than listen to that!

Okay...rant over! I realize that different players have different styles and what works for me might not necessarily be ideal for you. I know that some people like their basses to have less bass and variety is the spice of life and blah, blah, blah....

I think at least one forumite had the cap on an adjustable pot so that he could dial in the amount of cap. Was it Bob Young, perhaps?

[jwr2]

These days with 3 and 4 band preamps you can get all the treble you need without cut off the bass frequencies to a pickup.

[jps]

I found that the 4n7 was a bit extreme for my tastes. It left me with pretty much nothing but top end twang, and the signal was so weak in comparison with the hi-gain neck pup...

What was the input impedance of the device you tried this with? I have found you need I fairly high input impedance to get it to sound right. If I plug my '08 4003 straight into the line input of a channel on my Allen&Heath PA12 I will get exactly the same tone you describe. If I plug into one of my bass amps or use my Radial DI into the A&H then the tone is what I would normally expect from the .0047 cap in circuit.

[headbanger]

I've tested various and the best is 0.0uf

[espidog]

What was the input impedance of the device you tried this with?

Interestingly, it's pretty high. I work mostly into a valve pre-amp stage with an input impedance of 1Meg

[johnallg]

I've tested various and the best is 0.0uf

An open circuit??!!



I realize you're saying no cap just a wire.

Ken, a 1M input impedance should be sufficient. I have put the tone circuit into 2 of my basses, but always come back to the no cap position. On my V63 I got from Kevin Teed, there was no cap as was standard, but the treble pickup's tone circuit cap was changed from a .047uF to a .1uF cap, and the RIHS pickup is fuller and a bit darker than usual. An idea for those who want to go the other way!

[wints]

I've tested various and the best is 0.0uf

Yes, we understand Gerry!

I'm right with you....that cap is an all round tone killer! Get rid of 'em....

[weemac]

Just put a 102 treble bleed cap inbetween the in and out of the treble volume pot, if you wind the volume back a bit some of the treble will remain, and it is variable. you can get some real sweetspots in the sound.
I have done this mod to all my passive basses (apart from my RM1999 which already has enough losses from the treble pickup)
Eden.

[espidog]

Just put a 102 treble bleed cap inbetween the in and out of the treble volume pot...
Eden.

"102" - we're talking 1000pF, yes?

[weemac]

"102" - we're talking 1000pF, yes?

I think that is the one. It has "102" stamped on it anyway....
Eden.

[johnallg]

"102" - we're talking 1000pF, yes?

I think that is the one. It has "102" stamped on it anyway....
Eden.

That indeed would be 1000 puff. Or would that be 1000 uuF?

[woodyng]

john allgaier wrote "On my V63 I got from Kevin Teed, there was no cap as was standard" ....is that right? i did not realize that. sounds like yet another good reason to get a v63. it has been 30 some years since i had a 4001,and i remember thinking how weak and pitiful sounding the bridge pickup was by itself,although it did add some nice top end clarity when both pups were on.

[henry5]

One thing worth noting here is that the cap doesn't have the same effect on every bass. My old 76 sounding thin and weak with the cap; took it out and it was much improved, like night and day. Tried it with my CS and preferred it without, though not by a great margin; it had nothing like the same degree of effect. My 72 however sounds better with the cap in; fullness wise it makes a difference but not much of one, and I actually prefer the tone with the cap in. I suspect that someone with non-too discerning an ear would struggle to tell the difference between in and out in that bass, whereas it's a massive difference in the 76.

[rickcrazy]

Nah! Leave the capacitor in, but get rid of the original pickup and replace it with a hot, hothot one! The result? An earth-shattering Rickenbacker experience hehehehe! Cheers!