Does adding a preamp change tone (obv the answer is yes).

[Owen]

Everything is fine but I am seeking advice. I am wondering if I have made a mistake. I have a bass with 2 x J pickups, 1 x P pickup and piezo elements in the bridge. I have put a John East pre in the bass to buffer the piezo and that makes a lovely noise. The passive pickups are going through the 5 way switch and then into one side of the preamp. http://www.east-uk.com/index.php/all-products/mpm-01.html

The piezos went in after the magnetic pickups were fully funtioning. In the original pre-piezo set up the magnetic pick-ups were lush beyond. After the piezos were plumbed in along with the preamp I am not sure if I have lost some of the heft of the magnetic pickups. The Piezos sound lovely. I am just not sure if I am experiencing the full lushness of the mag pickups as they were.

Would it be possible to wire the bass Vol/Vol/Vol for the mag pickups (2 x J + 1 x P) + passive tone and then have a plain 2 x way switch so that the output is either passive mag or pre-amped piezo? Would the magnetic pickups load each other (I am not entirely sure what I have just asked) in a negative way, that is - would the P pickup mess with the 2 x J pickups if they all had their own passive volume controls and the P pickup was turned off? Would a 2 way switch create a nasty "click" if I went for it mid song?

I freely admit that I am utterly cluless in these matters. I know enough to get myself into trouble but not enough to get myself out of trouble

[brensabre79]

I used to swear by active basses, but having owned a few decent passive basses more recently I'm convinced that they sound better actually, especially in the 'heft' department. Sure you can boost lots of low frequencies with a pre-amp, but still something gets lost to my ears.

To answer some of your questions...

Yes you can have V/V/V/T - but I would say it'll make it tricky to dial in a sound quickly. Id go for Master (Magnetic) vol, 5 position rotary switch ( N-NM-M-MB-B ), master tone and maybe a blend with the Piezo so you can balance it in well. EDIT: Just to be clear, I'm suggesting you run the magnetic pickups passive, blend with Pre-amped Piezo.

You will always get phasing issues when you combine multiple pickups - for some this is a good thing, the classic Jazz Bass scooped mid sound is caused by the two pickups interacting and cancelling out certain frequencies in the mid range. The further apart (physically) the pickups are, the more noticable the effect.

P - pickups tend to be much meatier and more powerful than J pickups. (because the P is two pickups in series). Making it ticky to volume balance a P with a J - although it is possible with the right pickups, the Js tend to sound thinner side by side with a P.

Having lots of pickups is not necessarily a good thing. The higher the amount of magnets, the more chance they will interfere with the vibration of the string. I wanted 3 pickups on my Lakland Decade, I spoke to Lakland, and Hanson Pickups, and they advised against this as 3 pickups would pull on the strings too much. (Their Chi-sonic pickups are extremely powerful though).

The switch 'click' depends on the type of switch you use. "Break before make" switches disconnect one pole before connecting another and are prone to dropping out momentarily (causing click). "Make before break" switches do the opposite, so you'll momentarily have both circuits in play - depending on the setup this can cause a bit of a click too - but usually less so.

To add my 2p:
I think you have a very complicated sounding setup, and I'd question whether you actually need all those pickups. For example, you can make a passable P-Bass sound by switching the two Jazz bass pickups in-series rather than in-parallel. 2 pickups and a Piezo is much easier to manage. 3 pickups introduces such a number of variables that you'll end up with a confusing array of knobs and switches.

Edited October 27, 2015 by brensabre79

[Woodinblack]

[quote name='owen' timestamp='1445807915' post='2894435']
Would it be possible to wire the bass Vol/Vol/Vol for the mag pickups (2 x J + 1 x P) + passive tone and then have a plain 2 x way switch so that the output is either passive mag or pre-amped piezo?[/quote]

Yes, perfectly possible.

[quote name='owen' timestamp='1445807915' post='2894435']
Would the magnetic pickups load each other (I am not entirely sure what I have just asked) in a negative way, that is - would the P pickup mess with the 2 x J pickups if they all had their own passive volume controls and the P pickup was turned off? Would a 2 way switch create a nasty "click" if I went for it mid song?
[/quote]

It would be the same as switching between two pickups (well, actually maybe not, but if you put a load it would), so not really.

[quote name='owen' timestamp='1445807915' post='2894435']
I freely admit that I am utterly cluless in these matters. I know enough to get myself into trouble but not enough to get myself out of trouble
[/quote]

A preamp in itself, unless there is something actually wrong with it, should make no difference to the sound of your pickups. Any change that you hear in difference is either that the preamp is bad (which shouldn't be the case, there is nothing complicated in a preamp), or what you were originally putting it into presented a higher load on your pickups, or you liked the resistance and capacitance introduced in your lead, which you could get round by taking some of the treble out.
Or that your amplifier doesn't like a low impedance source.

You can have a volume on each mag pickup if you want, there would be a slight loading from the 3 volumes and there would be a change in frequency response at certain volume levels (like you get anyway with a jazz or any 2 pickup device).

Are you sure the pickups sound different or is it just they sound different now you are comparing it to the mag?

You could of course have V/V/V/V

[Owen]

Thanks everyone. It has been suggested that because the preamp is super high impedance for piezo that I could usefully put a 250k resistor across the mag input to lower the load the mags see. Someone else was in exactly this situation and this was done with good results. The bass is wired with a 5 way switch at the moment and that works fine. I had two soapbars made which had one J and half a P in each. Just because I wanted to try. As it happens I tend to stick to the 2xJ option and ignore the P. But you have to try! Again, thanks all for your input.

[Chienmortbb]

On a passive bass the pickups are "loaded" by the pots, cap, your lead and the amplifier input stage. The tone control affects the top end and the volume control affects both volume and tone and the lower you have the bass volume, the more the treble is cut.

[size=4]A good preamp takes out some, or all,of these and lets the pickup sound come [/size]through unaltered.[size=4] Of course the passive sound is what most of us are used to and so the natural sound of [/size]the[size=4] pickup sounds too bright or [/size]zings[size=4]. The biggest load on the pickup on a passive bass is the volume pot and the 250K resistor that is added is the same as having a 250K pot set to max volume. In other words it gives you back (most of) your passive sound.[/size]

[size=4]I understand that some of John East's [/size]preamps also have a preset mid scooped sound pre set. It may be worth chatting with John re your options as few know as much as him about preamps and sound.

Edited November 1, 2015 by Chienmortbb

[Owen]

What has come through from this is that John himself suggests the 250k resistor as an option. If I still get no joy then I will put an either/or switch in and, as Hannah Montanna would say, get the best of both worlds

But thanks everyone for your answers and PMs.