small preamp design for a bass guitar

[Minion]

Ive built the Tillman pre , and yes the J201 is very available , it"s a very common fet ... the problem with the tillman pre that I built is it is just basicly a fet buffer , there isn"t any real amplification going on , just 3db if you get the fet biased properly , you might have to try a few fets to get one that is optimumly biased useing the Values in the schematic .....

The real advantage to useing the fet pre amp or any onboard preamp there is less signal loss and coloring of the signal due to cable capacitance because your instrument is now has a low impedance output .......

Ive been useing a very simple single opamp based pre in my guitar for years and I love the sound , mine has quite a bit of gain to give my preamp tubes that extra kick ......

Cheers

[tinitus]

Hmm, good insight
Wonder what its supposed to be good fore then
do you know what kind of preamp is needed fore piezo pickups

btw, as I understand it many preamp/tops have two inputs, one fore passive pickups, and one fore active
Its also my understanding that many active systems tend to be more noisy
I suppose that relates to higher gain
Or is also related to impedance issues

Any opinions about those variables would be nice

[Minion]

Hi , I don"t find onboard preamps or active electronics noisy , then again I only have experience with mine and my friends Les Paul with Zack Wyld active pickups which are dead qiet , I guess if the Pickups are noisy it will just get amplified , I actually find it lowers the noise cuz you don"t have to crank the amp as loud and you don"t get nearly the interferance when running a 20 foot patch cord .......

For a piezo you would need an amp with a very high input impedance , Like 10m ohm ...
You could use the Tillman circuit for a Piezo but change the 3m resistor to a 10m resistor , but you will need a lot more gain for a piezo so you can put a simple opamp curcuit after it with adjustable gain or have the gain set and use a Pot between the fet stage and the opamp stage ......


Cheers

[tinitus]

Minion, I can tell from your answer you know a lot of what its about
I trust your experience
And your suggested mods fore using Tillman pre with piezos are no doubt useful

Yet, Im not really sure about the need fore another gain module
At least not if one doesnt need any controls on instrument
I would expect any good linedriver would be enough
Ofcourse we would need the gain from the preamp/top instead

But most people would like to have controls on instrument, thus optimally need more than a simple buffer
And most instruments are built with two pickups, and the blend between them changes sound

I dont want any controls, thus our goal doesnt seem alike

[Gene_Johnson]

My focus on onboard controls is to provide a means to further refine the sound; not to be a means onto itself.

For example, if you hold the physical features of the guitar constant (these physical features are also major contributors of tonal characteristics) and look at bass, treble, mids, gain etc. something like 81 different options become available. The amp controls are then used to further refine the sound.

Granted in some respects, I’m opening a can of worms, because I’m suggesting the variability generally reserved for the guys at the studio control console.

I’m also know not everyone can be a session musician, but perhaps it would be nice to give those guys, like me for instance, the opportunity to shape and blend the sound they want when studio equipment is not available.

[tinitus]

Originally Posted by Gene_Johnson

My focus on onboard controls is to provide a means to further refine the sound

Wouldnt any of these be better, or other ?
Bass Guitar Preamps | Traditional Floor And Desktop

[Gene_Johnson]

It depends how much variability you want to "shape" the sound.

Or more importantly, how much you want to spend to "shape" sound.

Yes, a really good high-end amp will work. But in truth, those high-end amps don't dominate the market.

[tinitus]

What I see very often lately, when a bass player needs a different sound fore a certain piece of music or part of a session/concert, he change instrument
I have even seen it done in the middle of a piece, and back again

Im looking into bass guitar building, and it seems its mostly the different pickup types and brands that make a difference, and the blending of neck and bridge pickup
Also various woods, and their combination and whole instrument design matters
And speaker design, amp combination etc

Thats my approach
I will buy a preamp, but build my own speaker and poweramp
I hope to get a distinct sound from a clean setup
I dont like the idea of shaping the sound electronically too much, and maybe loose the natural sound
But realise I may be on my own with that one
And so far my experience with electrical bass is zero
Its all just in my head
I have played acoustic bass a while ago

[Troy]

Originally Posted by tinitus

Im looking into bass guitar building, and it seems its mostly the different pickup types and brands that make a difference, and the blending of neck and bridge pickup
Also various woods, and their combination and whole instrument design matters
And speaker design, amp combination etc

Thats my approach
I will buy a preamp, but build my own speaker and poweramp
I hope to get a distinct sound from a clean setup
I dont like the idea of shaping the sound electronically too much, and maybe loose the natural sound
But realise I may be on my own with that one
And so far my experience with electrical bass is zero
Its all just in my head
I have played acoustic bass a while ago

I have building my own archtop electric guitars for over 20 years now. I have been playing the guitar for over 40 years. All of my guitars have active onboard preamps and yet retain a good portion of their natural sound. But let's be clear; if we truly wanted a more natural sound we would be using piezo pickups not magnetic ones. However such a bassist would limit his or herself inregards to being called for work.

The truth is if if you are using magnetic pickups you have already chosen a more electronic sound than a natural. My guitars with preamps are very clean, very low distortion but very dynamic and punchy.

I used to have to switch from one of my full size archtops when playing traditional jazz to one of my smaller ones when playing comtemporary or pop jazz. I no longer have to do so because my preamp allows me to get the more midrangy sound for the comtemporay and fusion tunes we play.

Since you already admitted that you are considering different pickup types and brands, blending of neck and bridge pickups, buying a preamp and building your own speakers and pwr amp. Well all of these things are electronic ways of shaping your sound anyway.

Bypass your amplifier's preamp and see how you like the sound and you will see my point which is that without the amp's preamp your guitar's natural sound would be terrible.

[tinitus]

Originally Posted by Troy

Since you already admitted that you are considering different pickup types and brands, blending of neck and bridge pickups

Nice to hear from a pro

Might be a misunderstanding
Im interested in new ABM piezo bridges, I have said that
The post you quote, was only to speculate on why my needs with a piezo may be different from most others, with active pickups

Or I would consider passive pickup
I suppose Tillman pre/buffer would work with those

And it was my intension to have a pre/top with equaliser
I just dont want controls on instrument, if possible
But I dont know how the piezos work