Active electronics for guitars...

[RobertD]

Any ideas, I'd like to get your input on putting active electronics in a bass, perhaps involving a uC. I don't need midi, but I can put it in. I'm mostly looking for good onboard sound manipulation capabilities, output directly to the amp. I don't want to buy active electronics already made since I make the basses myself, I want to make the electronics as well.

 

[Nigel Goodwin]

Any ideas, I'd like to get your input on putting active electronics in a bass, perhaps involving a uC. I don't need midi, but I can put it in. I'm mostly looking for good onboard sound manipulation capabilities, output directly to the amp. I don't want to buy active electronics already made since I make the basses myself, I want to make the electronics as well.

Modern effects generally use DSP's, I suspect you would really be struggling to build anything anywhere near as good as commercial offerings.

If you really want to add an effect in a bass, buy an effect you like, strip the insides out, and build it in your bass.

Matthew Bellamy the guitarist from Muse plays custom guitars designed by himself and Hugh Manson, which commonly have various internal effects - have a look at https://en.wikipedia.org/wiki/Matthew_Bellamy

As I see it the biggest problem with internal effects is control, with a footpedal you can turn in ON and OFF, adjust what it does, all by your foot while you're playing flat out with both hands. If the guitar has the effects internally you don't have any where near the same degree of control over it.

Are you sure you actually want effects?, my daughter is an excellent bass player, and she had a multi-effects bass pedal for Christmas a few years back, yet apart from playing with it at first, it's hardly been used - and she's never played a gig with it (although it did get used for the guitarist once or twice).

What sort of effects were you thinking off anyway?

 

[RobertD]

I'm trying to get as close to the URB (UpRight Bass) as possible. I'm all passive right now, and I moved from piezo to homespun pups, and still have a lot to learn about that. Calculating Q's and such. I'm having difficulty getting mids and highs. I also like the crisp sound of modern instruments. I'd ike to experiment with midi and such. As far as foot switches vs on board, I know about the on/off and one degree of liberty. But a 5 position switch can give me all the versatility and tone control I need. 5 sounds is plenty, coupled with treble and volume. That's the set up I have in mind. So I'm looking for a midi/digital signal processor with a driving circuit. The 5 sounds would be something like URB, passive clean, passive distorted, active bright, and active distorted.

 

[RobertD]

First thing I need is a fast A/D converter.

 

[Torben]

I was thinking about this while waiting for my physio appointment today. If I was looking to buy a high-end instrument and my choices were between one which had 5 effects built in, and one which had no effects and cost the same but the money difference went toward better build quality and materials, I'd go for the non-effects one. Just my opinion.

Perhaps the 5 effects would be great, but maybe I only ended up liking (and using) two of them. With outboard effects that's no problem, but if they were built in then that would just be a waste of money and space in the instrument.

If it's intended to be a lower-end instrument, with the effects built in as a money-saving measure for a student or something, that might be a different story.

Not trying to shoot any ideas down; just chipping in my 2 cents for whatever that's worth--probably less than 2 cents .


Torben

P.S. Yes, I am a musician.

 

[RobertD]

Yes I know a lot of this research has been done by every guitar maker out there, but getting there is all the fun. Plus it's a learning process for me. Building pick ups is interesting, and I'm still a beginner at that. As far as the instrument itself, I make a fretless small scale smaller cello type of bass. Classical neck construction, solid body electric. I used piezos and coils, my first few were quite bright, most of them have decent sound, and good action. Most of all, light and comfortable to play. I'm already making my pickups, so I want continue developping this. Even if the result is just passable, it will be worth it. Eventually I will get better at it, and who knows if I can't give it an original twist....?

 

[Nigel Goodwin]

As you're making your own pickups, I would suggest you spend more time getting them to sound how you like, it's going to be difficult to reproduce the sound of an upright particularly well though.

Obviously the first thing is to ensure the bass is fretless (but I presume you're already doing that?), then I would add a proper mixer so you can adjust the levels independently from each PU, followed by a decent three way (or more) active tone control system.

My daughter has an active fretless bass (amongst others) and it sounds pretty impressive, but she's an exceptional player - she mostly plays a five string though, and has never actually gigged the fretless yet.

 

[RobertD]

Fretless is the only bass I make or play. 4 string only to this date. I'm of the school of thought that I am to master one thing and not spread myself too thin by building all sorts of different instruments. I concentrate on this type of bass only. So far progress has been significant, I am producing a very original instrument but I need to learn more on the electronics in order to get the sound I want. It's been hit and miss so far. I have great sounding basses, and some not so hot. Of course, when I change the construction each time I build a new bass It's only normal that I get different results each time.

Active tone control, now that sounds like a plan... Indeed the pups need work, I did not spin enough of them to know what I'm doing. So it's a good advice to continue until I have been able to get the sound I'm looking for. What would you call a proper mixer? I'm using independent volume control for each pup, and for tone just a cap to ground. I am not satisfied with the tone control range. So active tone does have appeal to me. How does active tone control work?

One of the things I'm looking for is a magnetically permeable wax to seal the coils, is there something I could add to verathane to make it more conductive? Something like carbon or iron. The idea is to make the coil all conductive and not just the iron core. Sorta extend the iron core over the coils by making the wax conductive. There is a pick up like that on the market and it is the most responsive out there.

 

[Nigel Goodwin]

Fretless is the only bass I make or play. 4 string only to this date. I'm of the school of thought that I am to master one thing and not spread myself too thin by building all sorts of different instruments. I concentrate on this type of bass only. So far progress has been significant, I am producing a very original instrument but I need to learn more on the electronics in order to get the sound I want. It's been hit and miss so far. I have great sounding basses, and some not so hot. Of course, when I change the construction each time I build a new bass It's only normal that I get different results each time.

Active tone control, now that sounds like a plan... Indeed the pups need work, I did not spin enough of them to know what I'm doing. So it's a good advice to continue until I have been able to get the sound I'm looking for. What would you call a proper mixer? I'm using independent volume control for each pup, and for tone just a cap to ground. I am not satisfied with the tone control range. So active tone does have appeal to me. How does active tone control work?

A proper mixer uses an opamp as a virtual earth mixer, use a TL0xx series opamp, as these have high impedance JFET inputs. By using a dual opamp, you could use one as the mixer, and one as the active tone control after it.

For ideas for the tone controls (and perhaps even using the entire preamp?), here's a popular one off the net

**broken link removed**

You existing passive controls give top cut only, active ones give both cut and lift, at a range of frequencies - and in the case above at a switchable mid frequency.

One of the things I'm looking for is a magnetically permeable wax to seal the coils, is there something I could add to verathane to make it more conductive? Something like carbon or iron. The idea is to make the coil all conductive and not just the iron core. Sorta extend the iron core over the coils by making the wax conductive. There is a pick up like that on the market and it is the most responsive out there.

No idea, sorry.