[stevesolo]

What can I expect for battery life on a Meta-42 with a single 9V and Opamp 8620?

Regular 9V battery vs Rechgargable Plainview 9.6V 170Ma?

Must I buy the Plainview 9V recharger to fully charge their 9.6V battery?

Is the performance of the Plainview 9.6V battery and its recharger worth the money?

 

[gswpete]

Mine: AD823A, dual 9V Plainview batteries. Probably lasts for about a few hours (6-7 I guess).

 

[lextek]

I have a single 9V JMT META portable. I'm guessing my first battery lasted around 20 hours. Never really timed it. Seemed to last quite a while. It was a standard Duracell.

 

[charlesb]

I have a KurtW-built META, single 8620 amp, dual 2001 buffers. Kurt measured the current draw at ~12 mA. Plainview 9V batteries are rated 170 mah, so that's a theoretical time of about 14 hours. I haven't really had enough time with the Plainview to say if that is what I really get.

 

[Fuse]

I just ordered a used META42 from KurtW that is similar to yours, charlesb, and I wanted to know, what's the battery life like with regular batteries? Also, does anyone know where you can get these Plainview rechargeables? I hear alot of people talking about them, but I've never really seen them in stores. Thanks in advance.

J.F.

 

[lextek]

The Plainviews are available from Thomas Distributors. I can't remember the website right now.

 

[KurtW]

Here's the source for the batteries and chargers: http://www.thomas-distributing.com/9...s-chargers.htm

Regular alkaline batteries usually have 2 or 3 times the mAH rating. However the problem is that much of their output will be at lower voltages as the voltage gradually drops. How much a problem this will be for you will depend on your headphones and how loud you want them; high impedance headphones usually will require higher voltages.

The nice thing about the Plainview is that it puts out around 10v when fully charged and maintains a fairly high voltage until it's almost depleated. Thus the useful life of the Plainview can be longer than a regular alkaline.

Most other rechargable batteries are only 8.4v, so the chargers made for them may not charge the Plainview battery fully. The downside of the Plainview charger is that it is a dumb charger designed to take 8 to 10 hours, at which time you have to unplug it.

I have two Plainviews so that one is always charged. One problem with rechargables is they will slowly loose their charge with time even if not used. To solve this problem I've made a simple trickle charger so the spare battery is always fully charged. It can also slowly charge the battery if it didn't get quite a full charge. Plainview recommends 1.7 to 5.1mA trickle current. I used a 2N5484 FET as a current source powered by a small walwart. You can also use the walwart as a charger but you'll want 15 to 35mA.

 

[charlesb]

Quote:

Originally posted by Fuse I just ordered a used META42 from KurtW that is similar to yours, charlesb, and I wanted to know, what's the battery life like with regular batteries? J.F.

I like the slight extra voltage that I get from the Plainview battery. I found that I would end up changing the alkaline batteries when they still had plenty of current (mah) left, but sometimes I would hear clipping on difficult piano passages once the alkaline batteries had dropped to ~7.5 V. Using the Plainview at 10.5+ V seemed to make an audible difference.

Others have said they find the 8620 just fine down to even lower voltages, so YMMV