On-board Pre-amp

[LowB_FTW]

I'm in the process of getting all my ducks in a row for the start of my bass build, and I'm in the process of looking at pre-amps.

I know the pickups I'd like to use - it's gonna be a three pickup system - and I've spoken with the supplier of the pickups and, by way of customer feedback, he recommended me the Aguilar OBP3s.

 

The way I'd like the pickups are a mini toggle switch for on/off for each pickup so I can choose what combinations I'd like to use at any given time.

Individual tone controls with +/- boost and master volume.

Also a switch for active/passive.

 

Now, I won't be doing the soldering work, because that is absolutely outside my wheelhouse, but I'd just like to know if what I'm looking for is technically feasible.

 

Any and all constructive feedback is welcome.

 

Mark

[Chiliwailer]

Definitely do-able 👍

 

A tone control for the passive option may be helpful too.

 

And if you really want to max out your options, depending on the pickups, you could add series/parallel switch, or coil split switch. 

[itu]

I have written a few times about signal path. Please find it if in need.

 

The system that consists of many switches and maybe even ser/par option might be usable, if you make it happen with a rotary switch. Otherwise there will be many options, where the sound is off, or switches are excluded from the line. That would mean that you'd need to learn to walk in the switch jungle.

 

I would start from feasible sounds: what is functional, what is not. After the options are charted, someone familiar with electronics finds the parts you need and puts them together. Otherwise there will be non-usable situations, and you may cut the sound in a band context just by accident.

[Hellzero]

You may also choose the stacked volume and tone per pickup à la early Jazz Bass plus the 3 bands EQ coupled to an active/passive switch.

 

Easy to use and understand.

 

I would avoid the Aguilar OBP-3 for a lot of reasons, the first being its total lack of transparency and the fact that it's too powerful meaning that just touching one control already means too much of anything.

 

But it depends on what your looking for: if it's a take that in your face approach, the OBP-3 is perfect, if it's a very slowly fine tuning EQ, you'll be disappointed.

[tauzero]

I agree with @Hellzero about the OBP-3's being too powerful. I had one in one bass (IIRC it was the Sei 6-string) and it was just too much, it wasn't possible to do delicate adjustment on it. I put a Delano Sonar in instead. I normally have the tone on the bass set flat but it's useful to be able to make a change on the bass rather than the amp.

 

I assume you mean individual tone controls for the whole lot, rather than per pickup? The OBP-3 has treble, bass, and switchable mid - do you want three band EQ?

 

You could also consider toggling between on, off, and out of phase, for those extra sounds. These would do the job: https://www.ebay.co.uk/itm/113926665065

[LowB_FTW]

Thanks all for your replies.

It's tough trying to find a suitable on-board pre-amp for three pickups. Everything seems to be geared towards dual pickup, which is understandable really.

I liked the idea of stacked vol/tone per pickup, this might be making its way into my ideas box now.

I might look at other makes considering there's not much love here for the Aguilar.

 

Mark

[Chiliwailer]

7 hours ago, LowB_FTW said:

Thanks all for your replies.

It's tough trying to find a suitable on-board pre-amp for three pickups. Everything seems to be geared towards dual pickup, which is understandable really.

I liked the idea of stacked vol/tone per pickup, this might be making its way into my ideas box now.

I might look at other makes considering there's not much love here for the Aguilar.

 

Mark

I didn’t think it should matter how many pickups you have, would be surprised if so, but some folk will have better knowledge of that. 

Worth looking at John East preamps, I’ve had a couple of his and they’ve been excellent IMO. You can contact him too for advice, nice guy. 

Edited May 17, 2023 by Chiliwailer

[LeftyJ]

On 14/05/2023 at 12:20, Hellzero said:

I would avoid the Aguilar OBP-3 for a lot of reasons, the first being its total lack of transparency and the fact that it's too powerful meaning that just touching one control already means too much of anything.

 

But it depends on what your looking for: if it's a take that in your face approach, the OBP-3 is perfect, if it's a very slowly fine tuning EQ, you'll be disappointed.

I have to agree here. I have an OBP-3 in one of my basses and "in your face" is fairly accurate. The bass control gets boomy quickly, the treble control is voiced too high to my liking and mostly adds finger noise, and the mid control (with, in my case, a push-pull to switch between 400 or 800 Hz) is all or nothing: at the 400 Hz setting it gives a really ugly and nasal hump which is too much at even the lowest setting. At the 800 Hz setting nothing happens until the pot is maxed, at which point it adds a lot of brightness and a Rickenbacker-ish high mid growl which is just too much and leaves nothing of the original character of the bass. I run it at 18V, I don't know if it makes a difference in the boost level versus 9V. It was wired like that when I got it. 

 

I never gave it much thought, but now this thread made me want to experiment more with that bass! 

I've found that I like my controls simple. Of all my basses, my Jazz Bass has the control layout that suits me best: volume, volume, passive tone and a rotary switch that adds a 6dB active bass boost. It just works, and that bass control gives it a solid but subtle kick. Especially when you're using the bridge pickup soloed.

Edited May 17, 2023 by LeftyJ

[three]

I’d tend to concur with most of the above re: the OBP-3, though it’s certainly one of my favourite conventional on-board pres! A little goes a long way and I tend to just cut the mids slightly at 800. Not for everybody of course, but much depends on your goals. For me, the OBP-3 is glorious with EMG humbuckers (in a Spector). Lots of different configurations of the pre too so should be able to accommodate 3 pickups

[TimR]

Sounds very complicated. Does each pickup need a separate tone control and then a 3 band EQ on the lot? Presumably you also need an overall volume as well.

 

That's 10 knobs in total! 

[itu]

20 hours ago, LowB_FTW said:

It's tough trying to find a suitable on-board pre-amp for three pickups. Everything seems to be geared towards dual pickup, which is understandable really.

What? There are only very, very few preamps for two pickups only.

 

Most of the preamps are after simple blend and vol, or vol and vol. In a three pickup version you could have three volumes. If you want to put an active tone stack after every pickup, you just need more space.

 

It seems that you have not checked my simple drawings of the bass signal path, once more:

 

pickups - blend (or vol) - vol - tone stack - output

 

In your case you just exclude the blend and put in there three volumes. The tone stack is up to you: a battery operated preamp, or a capacitor based, simple passive tone x 1 - 3.

[itu]

A g-word type of approach might work, too: the 5 pos switch, maybe?

[Lfalex v1.1]

Hmm. I've taken a moment.

 

Personally, I think I'd  have a switch for each pick-up, a master volume and a 3band with a sweepable mid. Hopefully, that's only a single control plus 2 stacks (B/T and Mid/freq)

If there's room in the cavity, I'd have a trim-pot for each pickup to set their respective levels so that switching them in/out delivers the pickup balance you want without any nasty jumps in output.

You could even have the cavity cover drilled to allow screwdriver access without taking the cover off (an idea nicked from my Hohner B2A, in which the trim pot allows passive/active level matching)

 

This keeps the front face uncluttered,  yet allows maximum flexibility. You can experiment with each individual switch to see  what options you like best;

 

All off (not sure about this one!)

All on

1

2

3

1&2

1&3

2&3

 

Apologies if I missed any...

[itu]

On 18/05/2023 at 13:31, Lfalex v1.1 said:

Apologies if I missed any...

Ser/par? Then there's a good chance to have switches at hand which do nothing. That was the reason I suggested a rotary switch.

[SteveXFR]

I've had a couple Darkglass Tone Capsules. I'd fir them in any active bass. The feature I really like is instead of bass, mid & treble controls they have bass, low mid and high mid which just seemed so much more useful. They're solder free fitting as well.

[lidl e]

I recently built a three pickup bass and wired it like a strat but with a knob instead of a switch.

[LowB_FTW]

On 17/05/2023 at 06:07, Chiliwailer said:

Worth looking at John East preamps, I’ve had a couple of his and they’ve been excellent IMO. You can contact him too for advice, nice guy. 

I mailed a week ago and I've heard nothing back, which is disappointing as I had a look around that site and saw some interesting stuff.

 

Mark

[la bam]

23 hours ago, LowB_FTW said:

I mailed a week ago and I've heard nothing back, which is disappointing as I had a look around that site and saw some interesting stuff.

 

Mark

 

I emailed them through their site about a month ago and heard nothing back. I think you have to physically ring them for a response.

[Dazed]

Following this looking to pickup (no pun) tips for another 3 pickup bass. 

[Boodang]

I’ve had several Aguilar OBPs and I’ve always found them to be too much, as others have said. Also I’ve always thought the bass was too wide and ended up being a bit woolly. 
Best onboard preamp I’ve had so far is the Audere. They have lots of control options as well. 

[Boodang]

Are the pickups active or passive? If they’re passive check out the Audere pro-z module which has some great impedance options. 

[Dazed]

Thanks @Boodang

Passive in this current one. Still looking at pickup options. I think I have an Audere Pro pre amp somewhere albeit it’s on a jazz plate. I’ll have to dig it out.