Series basses and onboard batteries

[paujones]

I have a few series basses and always wondered if the two batteries that power the active pickups when using the 1/4” output jack have any other effect on the tone or operation when plugged into the 5-pin connector.  2 of my basses seem to have more “overdrive/fuzz”… which made me think I might need to change the batteries.  But I just about never use the 1/4” output.  Nearly always use the 5 pin. 


I could have my Radial JDV gain and monitor mixes gain setup.   Could be my channel is just too hot so I’m overdriving it.   


Just wondered about the 9V batteries. 


Thank you!

[sonicus]

I have removed the batteries from my Series instruments as to avert damage from leakage. I always only just use the 5 pin power source. I only use batteries in my non series Alembic instruments but I have given some thought to getting them modded by Alembic to be able to use the 5 pin as well .

[JimmyJ]

I think of the battery power in Series instruments as only meant for temporary use - sitting in on somebody else's rig or maybe for tuning (with my old-school plug-in style tuners) or in case your main 5-pin cable suddenly falls apart.  The batteries are only good for a few hours so that adds to my "temporary" idea..

The Series preamp package is amazingly flexible in its power requirements.  The 5534 chips can run off anything from +/-3VDC to +/-20VDC  The DS-5 provides around +/-18VDC or a 36V "swing".  The two 9V batteries obviously provide +/-9VDC so that's an 18V "swing" or about 1/2 that of the DS-5. (I'm not sore about the FET's power requirements.)

That could certainly translate into less "headroom" when running batteries vs 5-pin power.  So if you run the preamp outputs cranked it's possible the audio would clip or distort sooner when operating on battery power.

Some of us in here have been trying to get Alembic to build a distortion box with that fading battery crunch sound.  It's pretty great - but only lasts for about 30 seconds.   

Jimmy J

[hammer]

However, those 30 seconds are quite frightening when you are not aware that this is to be "expected." The first time it happened, I don't remember thinking, "Wow that's a nice fuzz tone, but rather, OMG how did I break another piece of electronic gear.

[FC Bass]

I use 4 batteries live, does that mean I could get 60 seconds of fuzz? :-)
(four 9V batteries in a "portable" power supply)

I use the side LEDs as indicator for when to change batteries, when I see a black dot in the center of the LEDs it's time for a fresh set.  (of batteries, I hope the LEDs will last many years) :-)

[hieronymous]

Ah, here it is:

http://hieronymous.us/music/fizonly1.mp3

And for context - I was using my Series I doubleneck, and it seemingly died, with more impressive sounds than above. I decided to see if it would work after a few minutes, and recorded it. So you can hear - it was a clean sound, then the horrifically beautiful sound, though only a fraction of the first blast! Here is the complete clip:

http://hieronymous.us/music/fizzle2.mp3

[flavofive]

hieronymous, that's awesome you caught that.  I love the little note that it finally dies on in the 1st sample, ha 

Jimmy J is absolutely right.  Tone-wise, the only difference that should ever happen between power supply vs batteries is when the voltage isn't high enough, which causes overdrive/distortion.  Could be for 2 reasons:
- Even when the batteries are "full"/not dying, they still can only provide about half of the voltage headroom as the DS-5.  But that's only a problem if you have the internal gain trimpots turned up too high for the batteries.  I set mine just below the level where it starts to distort on battery power.  That way it works fine on either batteries or DS-5.
- When the batteries are dying, the voltage level goes way down, which causes the same effect.

[jazzyvee]

Can I ask a question about something that came to my mind after a conversation about my series I with a bass player last night. In the conversation I mentioned that my bass ran on 36v and not 9v as on most standard active basses but could not explain why that was an improvement over a 9v supply.

On the way home I got thinking that if an active bass was designed to run on a 9v circuit then as long as you didn't over load it, you only need to be concerned about the headroom available on your bass rig before clipping. Conversely if you had circuit designed to run on 36v (+/-18vdc) circuit, is the output of the bass higher or lower than that of a 9v or passive circuit?  I think I recall jimmy mentioned that a series bass can be almost line level so my presumption here is that less amplification is required from your rig to reach the same gigging volume.
So, assuming you have the same bass rig with it's output set for the same volume for a 9v and 36v bass what extra is the 36v giving me?

I'm sure my assumptions are way too simplistic and that there are reasons more than just the output levels and preamp voltages in Ron's design. So why 36v and not a higher current capacity/quality 9v DS-5 power supply?

Please fill the gaps in my grasp of this, or point me to some threads to read if they are available as I couldn't find this.


Enjoy your weekend.

[FC Bass]

In this vid Mica explains the need for the Series electronics higher voltage:

(start 42:58)

[gtrguy]

Don't forget to use the hum canceling trimpot procedure listed on the Alembic site too if needed.

[JimmyJ]

While I was composing this reply I realized I'd already said most of what I know earlier in the thread.   

I believe most "active" instruments only have one or two opamp chips in them which is enough to boost the pickup's output slightly and change the instruments output impedance making it easier to get a bigger sound down the guitar cable.  (I'm mostly making this up so bear with me).  A setup like that is probably happy with the power supplied by a single 9V battery, and with pretty good battery life.  Think of it like a "buffer" pedal for a pedalboard.

But the preamp board on our Series instruments has 5 opamp chips and 3 FETs which all need power.  As I said earlier, the 5534s can operate in wide range of power supply voltage anything from +/-2V to +/-22V.  Our double-9V batteries provide +/-9 and the DS-5 is closer to +/-18.

Now consider playing through a small 40W amplifier.  It would sound great up to a certain level of volume and then it would start to suffer, likely "clipping" off the transients or biggest peaks of the audio waveforms.  But achieving the same volume using a 100W amp would likely reproduce a clean sound.  Playing through a poweramp rated at 400W which is just cruising along would yield better results than playing through a 100W amp that is maxed out and nearing it's limits.  If we scale down that idea, I believe our Series boards can provide their cleanest and most powerful output when powered with the higher supply voltage.

I'm sure I'm oversimplifying it but if anybody asks you that question again, the simple answer is "Headroom". 

Jimmy J

[hammer]

Makes total sense to me and when the topic is electronics, that is not typical. I've never played a Series Bass that was not plugged into a DS-5 and never really thought about why one would want to do that. The best "attempted" use of the battery cavity on a series bass is what the builder or former owner the the shop night scroll Series I bass I own did. He filled the battery cavity with lead in an attempted to reduce neck dive. Unfortunately, it only partially works and makes the bass quite heavy.   

[Songdog]

One other consideration regarding "headroom" - Alembic pickups have a much wider range of high-frequency response than (most?) other pickups. High frequencies mean that note attacks are faster and have higher peaks.

That full-range pickup signal is buffered through an op amp before another op amp for the filter (that may cut some of the highs). You don't want that high peak to be clipped in an op amp, it tends to sound harsh even though it's very brief. Having a higher-voltage power supply means higher peaks can be accommodated without clipping in both the initial buffer and filter op amps.

If the bass passes those quick, high peaks (even after the filtering) to the amp, a good bass amp is designed to clip in a more musical way. This kind of comes naturally with tube preamps, but designers have learned that they have to account for this even in solid state designs. And it gives the player better control over whether and where the clipping occurs. Some players (like me) love a little tube saturation (warmth, thickness, compression); others may choose to run their amplification clean all the way through and let those sweet, clear attack transients turn to undistorted sound at the speakers.

The bass just needs to "speak the truth" from the string (with a little filtering) and pass it undistorted to the amp, which can then interpret it.