Anyne know how low a 9v battery can go in a tube screamer B4 it affects the tone negatively?

[daz]

Wondering how low a 9v battery cab go before it affects tone. I usually have used wall warts with pedals but am using batteries for a certain reason now and just wondering when i should toss them. Running on about 8 volts or less at the moment and i hear no difference, So i'd be interested in knowing how long i can use a battery before tossing it, especially with prices going so high lately.

[pdf64]

If the supply decoupling ecaps are good, they seem to carry on working fine down to 6V or less.
I’ve always used rechargables. Uniross or GP are safe choices and are cost equivalent to brand name alkaline, the Hybrio range come precharged.

[daz]

Thanks. I've had bad luck with all the rechargeables i've tried but i'll take your word on those brands. Unicross doesn't seem to be available in the USA and they say they cannot be shipped here which i suppose must be due to some EPA regulations here with the chemicals in them or whatever. The GP is tho and the best one is 200mah which i think i will get. 2 questions tho....do u have any idea what the actual voltage on this one is... https://international.gpbatteries.co...ttery-200-9v-1
Also, do u have a recommendation on what charger to get? I'd like one that charges AA and AAA to because if these are as good as u say i'd get some of those also for other home uses.

[pdf64]

The nominal loaded voltage is usually noted as 8.4V. But with just the light load of a TS9 etc, I get a full 9V for many, maybe 10-20, hours. And many more before it conks out and needs a recharge.
Digital delays suck the charge out much more quickly though.

I can’t help with charger advice, sorry, I DIYed mine about 30 years ago.

[daz]

I emailed the company so hopefully they will be able to tell me on that particular battery. Most that i see are 7.2v but there are a few like u said that are 8.4 and ever fewer still that charge to the same as a regular battery. Not using them with digi stuff, just boost pedals like the TS. If i get these i guess i'll go for the charger by the same company even tho it's pretty big $. Which 9v do you have? Same one i linked?

[pdf64]

I’ve got several of these https://www.amazon.co.uk/Uniross-Hyb...dp/B005CN25JE/
and this for a digital delay https://www.amazon.co.uk/Extreme-Rec...dp/B002LNLCDI?
which was a gamble that’s paid off.

[The Dude]

I haven't used batteries in pedals for quite some time, but when I used to use rechargeables, I had the best luck with Varta. They charge higher than most rechargeables and seemed to last longer.

[daz]

I did a search for the bets 9v rechargables and found a site that said these are best. When i looked at the specs...holy %$#@ ! Unless it's BS, theres show THREE times the Ma as the others, 600 Mah. If thats true i would think these gotta b the way to go. https://www.amazon.com/Rechargeable-...e-batteries-20

Hmmm..some bad reviews tho and not sure what to think. Most report slightly larger than typical 9v's so they don't fit in some devices.

[pdf64]

Lithium batteries are in a different league, but tend to be much more expensive. And amazon tend to only sell them in multipacks.
Dunno about their charging criteria and self discharge behaviour.

[daz]

Description shows 1200 cycles and 8.4v fully charged so as good as the other at least. And it's a 4 pack so they're actually about 1/2 the price of the one i linked at first. So maybe they ARE too good to be true. I will have to do a bit more research. They also have a combo pack with 4 batteries and charger for $22 !

[nosaj]

How about one of these?

[Mark Hammer]

I regularly recharge/rejuvenate my nonrechargeable 9V batteries. It is safe to do IF YOU OBSERVE PRECAUTIONS. If you do not observe them it IS NOT SAFE TO DO.

Rechargeables can be left in the charger overnight with no harm coming to them. Alkalines and carbon-zinc batteries can explode if they overheat. It's not like having a stick of dynamite go off in your kitchen, but it can be messy and spray chemicals over the charger and wherever you placed the charger. I would not recommend leaving any type of nonrechargeable in the charger. unattended, for more than an hour at a time. You can feel them at that time to see if they are warm-ish, and if they aren't, give 'em another hour. Even if a battery does not explode, overheating can sometimes make the battery expand, such that it doesn't fit in the space for it anymore. So be careful.

NOTE however, that where best practice for many rechargeables is to drain them down fully before recharging, alkaline and carbon-zinc 9V batteries can be easily rejuvenated if they have not dropped below 7V or so, even back up to 9.6V. A 9V that measures 5.7V is unlikely to come back from the dead. That rejuvenation doesn't last as long as a fresh battery since it doesn't pump as much current back in as a fresh battery has. But it does stretch out the lifespan of a battery, and stretches out "good" batteries more than cheap ones.

In the grand scheme of things, attempting to rejuvenate a worn 9V battery is fine for pedals that draw little current, like many fuzzes and distortions. Do not expect to power an analog delay or other current-hungry pedal with a 9V brought back from the "mostly dead" (to quote Billy Crystal in The Princess Bride).

A tip: Many facilities rely on wireless transmitters of one kind or another, and make a point of changing out one Duracell for another on a regular basis, regardless of what it measures on a voltmeter. When I was a cardiac patient, the changed the battery on my portable monitor regularly. And when I was a university lecturer, wearing a wireless mic, the techs would change the 9V in the transmitter regularly, so that the class watching remotely wouldn't suddenly find themselves staring at a guy merely mouthing words. Not all such places will let you come by and score a couple dozen Duracells...but sometimes they might. So get to know someone there. And a Duracell that has only dropped down to 8.5V can easily be rejuvenated to freshness.

[Mick Bailey]

Quite a few years ago there was a charger schematic for non-rechargeables in one of the electronic magazines. The difference was that there was AC superimposed on the DC (a resistor was used to partially bypass the rectifier). The claims were that the recharged cell/battery held a charge for longer, had better current/discharge characteristics, and the recharged voltage was higher than by using DC alone. Some prolonged trials were carried out with the recharged batteries and they held up well.

EDIT: I think the batteries concerned were zinc-carbon and this method may not work with alkaline

[J M Fahey]

A common practice here is to "rejuvenate" zinc-carbon batteries with a pulsing DC charger, meaning transformer+diodes but NO capacitor, so voltage is swinging 0 to peak all the time.
Nominal 9V which is actually 10V (if you fit a cap) because cheap cheesy chargers COUNT on dropping under load.

This crude charger type works better than a conventional wall wart with a series current limiting resistor.

Avoid standard (capacitor input) wall warts as they easily overcharge non rechargeables with bad results, I guess that happened to you.

I remember an old project for a simple but "smart" at the same time "universal" charger.

It charged them with a reasonable current but incorporated a thermistor in the charger cradle, touching battery body.

It measured neither current nor voltage but once body reached 45C or so (so definitely warm but not hand burning) it triggered a small TO92 SCR which turned charger OFF for good.

Very clever.

Missing that, do as recommended above, touch battery often, no longer than 1 hour intervals.

[daz]

Yeah, not gonna go there. Money matters but not when it comes to exploding batteries ! However, i have a question....when using a single battery for 2 low drain pedals like tube screamers, aside from the battery draining faster what are the other considerations? For example, does a battery at 8 volts only allow each pedal half that or 4 volts? Or in some fashion is there any compromise like that which would affect tone ***besides*** quicker drain down to a useless voltage? I have been running 2 screamers off 1 9v and it works exactly like using one battery for each except that i *thought* i noticed some tonal degradation when it got down to about 8 volts, but i'm not sure.