Battery as Component

[WGTP]

I'm slower than most, but in my ongoing dual op-amp distortion experiments (bread board sitting on amp) I have come to see the battery as a component effecting the tone more significantly than the op-amp.  

IMHO batteries don't get enough respect.  It's probably the voltage level (I know various debates occur concerning alkiline,etc.), but I just tried an OP275(slightly more aggresive sounding, OPA2604(slightly more smooth sounding) and TL052 (just fine for cheap) and they didn't sound tremendously different.  

But changing from a 7.2v battery to a 9.2v made a significant noticeble difference (the OPA2604 started squeeling with the lower voltage).  An 8.2v probably would have been very noticible as well.

Recognizing that different ears are sensitive to different things and I'm not playing at 110db:

Previous lesson - the DIODES make way more difference than the op-amps (diodes aren't even necessary for a different/good tone).

Intermediate lesson - he Resistor/Cap to ground from the feedback loop is another very important area for tone shaping.

New lesson -  the BATTERIES make more difference than the op-amps

As much as I like the Thought of tweeking with op-amps, it is less important than other components effecting the overall sound.  I know some of you have been trying to tell the rest of us, so you can say I told you so.  

Batteries are problematic, in that they MORPH as they are used and various perameters change as they mature, unlike other things that become Vintage.  Maybe this is why they get less respect.  

[JimRayden]

Yes, the changing of supply voltage tends to change the tone. But batteries with different manufacturers don't.

It'd be a cool idea to make a supply voltage regulator pot to give another dimension to the sound controlling.

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Jimbo

[WGTP]

Forgot to mention that I prefer the lower voltage sound, less edgey and smoother.

I going to find an alkiline and regular with the same voltage and check it out.  

[Peter Snowberg]

The battery will absolutely make a difference in sound in any circuit where you let it.


First off you have the voltage. That's pretty straight forward.

Next you have the constant current availability or how much power you can draw all the time...

Next you have the instantaneous current availability and the recovery time. These are where the "sag" characteristic of tube amps come from...

Then you have the equivalent series resistance or ESR.


Over time all of these numbers change and the response of the circuit will change with them.

If you want something more consistent, tie a 100uF and a .1uf cap across the power rails. That will greatly reduce the impedance of the power supply. A voltage regulator (LM317) and current regulator (made from JFET) will allow you to shape the voltage and current supply to taste. From there it's a matter of at least one stage of RC filtering, not so much for filtering, but to add some dynamics to the current supply after the current regulator.

It all matters.

[JimRayden]

Oh... so I should start using those expensive last-forever ones instead of the 50-cent cheapos to get a decent sound?

Ok ok I believe ya.

-------------
Jimbo

[Paul Perry (Frostwave)]

There is, of course, a flat battery emulating power supply at Geofex.
http://www.geofex.com/

[WGTP]

OK, I tried a 7.2v Duracell - Alkaline and the same voltage Cheapy.  About as much difference as most of the op-amps I compare.  The Duacell might be slightly warmer or mushier and I might be getting lucky tonight.  

I guess I need to identify the distortions that sound best at various voltages and cycle the batteries thru them as the "AGE".   :twisted: