[Dexdexter]

So now that I've gotten a taste of what the Go-Vibe is capable of with a 24V external power supply, I'd like to take that same magic on the road, as it were.

I've noticed that most common rechargeable 9V batteries actually measure 8.4V. So I was wondering if making a battery pack of 3 such rechargeables in series (25.2V) would be a workable solution

or an invitation to certain amp-failure disaster.

Thanks in advance for your help!

Dex

 

[tigger]

Quote:

Originally Posted by Dexdexter /img/forum/go_quote.gif So now that I've gotten a taste of what the Go-Vibe is capable of with a 24V external power supply, I'd like to take that same magic on the road, as it were. I've noticed that most common rechargeable 9V batteries actually measure 8.4V. So I was wondering if making a battery pack of 3 such rechargeables in series (25.2V) would be a workable solution or an invitation to certain amp-failure disaster. Thanks in advance for your help! Dex

Actually, if you go for the true 9.6v NiMH batteries, such as Maha they measure close to 11v when fully charged, and don't drop much below 9v before running out.
If you feel the need to construct an outboard battery pack, then two x 9.6v NiMH batteries in series would be ideal.
Your 3 x 8.4v NiMH batteries would likley measure more like 27v. This is OK for the LM6172/71 op-amps, but not for some of the other op-amps now offered with the V5, and not for the 25v power supply cap.
The AD8397/AD825 version is restricted to a maximum of 12v DC so one single 9.6v NiMH is about it.

Be very careful of polarity when you hook this battery pack up to the amp, presumably via the DC jack. There is a reverse polarity diode in there, but it is designed to protect the amp against wrong polarity for external DC power supplies. Two 9v batteries put out a huge amount of current and will destroy this diode very quickly. The result will be catastrophic for the amp.

So, when you construct this battery pack, make sure to measure the voltage and polarity with a meter before connecting it to the amp.
24vDC maximum voltage and centre pin positive polarity.

 

[Dexdexter]

Thank you for your speedy reply, Norm, and also for your precautionary advice. I think I'll just give 2 regular 9Vs a go and then try to source some 9.6V rechargeables if the results are as good as I expect they will be.

Cheers, Dex

 

[Dexdexter]

Just put together my 18V battery pack and it is indeed a nice improvement over the single 9V. And with my easier-to-drive portable headphones (Ultrasone HFI-650, PX-100, and KSC-75), the difference between the battery pack and the 24V external power supply is negligible.

So I'm looking forward to locating some of those 9.6V rechargeables that will ultimately give me 19.2V on the go(vibe)!

It is only with my better home cans (Ultrasone PROline 750, 2500, and HFI-2200 ULE) that the superiority of the 24V xps shines through.

Thanks again, Norm!

 

[wlai]

Has anyone tried the same voltage boost tweak with the GoVibe v3? I can modify the battery leads to hook it up to a larger battery pack.

I'm assuming that as long as the voltage is ok by the Cap, as well as for the OpAmp in use, then all is fine? Polarity being correct, of course.

 

[tigger]

Quote:

Originally Posted by wlai /img/forum/go_quote.gif Has anyone tried the same voltage boost tweak with the GoVibe v3? I can modify the battery leads to hook it up to a larger battery pack. I'm assuming that as long as the voltage is ok by the Cap, as well as for the OpAmp in use, then all is fine? Polarity being correct, of course.

Some of the V3s had 10v power supply caps, so check this first. You could swap them for lower value 25v caps if this is the case.
Then read the op-amp data sheet to verify it's maximum safe voltage.

Quote:

So I'm looking forward to locating some of those 9.6V rechargeables that will ultimately give me 19.2V on the go(vibe)!

Remember, when you hook up two x 9.6v NiMH batteries in series, you're going to get 22v when they're fully charged.

 

[Dexdexter]

Quote:

Originally Posted by tigger /img/forum/go_quote.gif Remember, when you hook up two x 9.6v NiMH batteries in series, you're going to get 22v when they're fully charged.

Oops, forgot about that. Approximately how long will they play at 22v?