Possibly Dumb Question re:Battery as a power supply

Previous experience with improving power has shown a worthwhile improvement in sound. This manifests as smoother with no shrill overtones or sibilance (dare I say 'more musical') as well as quieter. 

1. Isolation transformers
2. Brute force DC rails for amps: 200kg inductors and a Farad of capacitance
3. Alkaline battery with LC filter for phono/pre
4. Quadrature AC adjusted to AC motor

My experience. YMMV

@phoenixengr, glad to see you join in this discussion, your expertise is greatly appreciated!
BTW, I’ve been using the Teres battery power supply on my turntable for more than 15 years without any problem and only replaced the SLA battery about 5 years ago. The SLA battery will charge up to 13.8V if not in use.

I found an internal image on the Hifitest.de review of Clearaudio smart power 12V.

https://www.hifitest.de/images/testbilder/big/clearaudio-smart-power-12v-hifi-sonstiges-57224.jpg

I can clearly see a LM317T regulator chip in the circuit, I could be wrong, but I think the LM317T is to regulate the output voltage while the 19V wall wart charging the NiMh battery and at the same time supply power to the turntable. In pure battery mode, I not sure if the regulator chip is in circuit or not. Without a schematic, just take a wild guess.
The user manual also warn that if connect the 19V wall wart directly to the turntable instead of the OEM 12V wall wart can seriously damage the turntable!
Since we don’t know what is the highest voltage the turntable can safely take, and OP also concerned if 14V will be too high for his turntable, that’s why I came out the " overthinking " dumb idea of install a simple voltage regulator between the battery and turntable.

The LM317 has a drop out voltage of ~3V, so I doubt it regulates the battery output to the table. NiMH batteries need to be charged at 1C and negative delta V slope detection, thus the higher voltage input, the PIC processor and complex charging circuitry (another argument in favor of SLA batteries which are simpler to charge).

If the input of the table is designed for 12VDC, then 2 possible problems occur if you provide a higher voltage: Power dissipation and exceeding maximum voltage ratings on the input devices. Regulators (even low voltage output devices) typically have 18-26VDC input ratings. CMOS logic is usually rated to 15VDC (some CMOS devices are rated to 12V, but it would be bad practice to operate those at 12V so I doubt you find any devices with a max Vcc of 12VDC in a 12V table). Tantalum caps have standard voltage ratings of 6V, 10V, 16V, 25V or higher (6 & 10V devices couldn’t be used safely with 12V input so we can eliminate those). Power dissipation at 13.6 would only be ~13% higher than at 12V but 58% higher at 19V.

If the OP really wants to regulate the battery supply, then look at the LT3080 (or similar devices i.e. Micrel MIC29150 series which have fixed or adjustable outputs); the LT3080 is a LDO regulator (350mV) and 1.1A current rating. The output cap is critical for stable operation and should be a low ESR ceramic type located close to the output pin and ground.

@terry9

... I would never recommend connecting an expensive component to an unfused battery. And while doing that, why not protect the battery too? I mean, diodes don’t cost much ... But then again, I wouldn’t want to be accused of overthinking the OP’s investment.

I totally agree with you! I believe the Clearaudio smart power 12V is using a 1.6A slow blow fuse in line with the output for protection.
BTW, the goal of using battery as power supply is to improve sound quality and not for mobility or to save power, seems like adding a LDO regulator MIC29150-12 recommended by phoenixengr for over-voltage and over-current protection is not an bad idea after all.

Well......I almost feel that I got weak and wimped out, but after playing twenty-five or thirty LPs on the new Clearaudio Performance DC
Wood turntable with the Clearaudio Tracer tone arm and finding them to sound damned wonderful I decided to stick with a winner and go all Clearaudio.  A little while ago I ordered the Clearaudio 12V Smart battery power supply.  As I wrote on a previous thread on this forum the tt, tone arm and an Ortofon Cadenza bronze cartridge is a birthday gift to myself to celebrate my 72nd birthday, my first birthday without my Mary since 1967.  I didn't want to cheap out.