Possibly Dumb Question re:Battery as a power supply

I think that you made a good decision. DIY is possible, but it has its costs in time, uncertainty, and risk.

Enjoy!

Like a wealthy friend of mine often says, it's easiest to write the check.

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.

@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.

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.

@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.

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

Phoenix, agree with what you say, but let me add that 19VDC is the voltage at which the part is known to meet spec. With obvious consequences - which, to an engineer such as yourself, pose no issues.

Battery noise was measured by someone in Germany some years back. I think they were looking at powering phono stages. He found that all technologies made a fair bit of noise, except NiCd, which measured at the noise floor of his HP instrumentation.

Anyway, I'm in the process of designing a new phono power supply based on NiCd's for listening and a linear PS for warming, and the unexpected issue is charging. Seems that no-one does it right - i.e. warning at 1.1VDC per cell to avoid memory effect and separate current source for each cell.

Expect to start building in a couple of weeks, will let you know if it makes a perceptible improvement over alkaline with LC filter.

@terry9-

ELECTRICAL CHARACTERISTICS (Vin = 19 V, IO = 500 mA, TJ = Tlow to 125°C (Note 17), unless otherwise noted)

That is the standard disclaimer at the top of the chart of parameters. It is the operating point used in all of the measurements below it. One of those parameters is DROP OUT VOLTAGE which was listed as 2.0VDC (assuming 500mA load) on the datasheet I found on-line. The disclaimer does not mean the device has to be operated at those parameters, only that the published specifications were measured at that operating point.

Agree with your point about noise not being an issue. I don’t know that I’ve ever seen a measurement for this on a battery, but the internal resistance of a fully charged battery is extremely low so the equivalent noise resistance should be microscopic.

I would think a Sealed Lead Acid battery would be better (and cheaper) than a NiCad. SLAs tend to last longer and don’t suffer from memory effect if they are not fully cycled between charge and discharge as NiCads do. YMMV.

@lubachl 
I actually have an Amazon Model One - it's a superb motor unit - I think that is a great buy because the Amazon motor is actually not your usual DC motor - I think the UK importer at the time advised me it was from a nautical clock. It is exceptionally smooth and quiet.
@kingharold - why more people don't rug up a car battery is beyond me - they can easily be tucked away. Lithium Ion is particularly good as the voltage drop is very consistent. Be careful though not to discharge them too much as they become unstable and in fact volatile. I know all of this from Radio Control car racing. Not all lithium ions are created equally and I am more than happy to recommend those used in RC racing that are of a good quality. 

Thank you, @imhififan  for new information. This shows that a 12V battery should be fine. Still, 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.

Phoenix, from the MC7812 data sheet:
ELECTRICAL CHARACTERISTICS (Vin = 19 V, IO = 500 mA, TJ = Tlow to 125°C (Note 17), unless otherwise noted)

One last thing: different battery technologies have different noise levels. It's probably not an issue; but if that Clearaudio pack uses NiCds, maybe it's for a reason, and $1200 for NiCds is not excessive.

millercarbon: Never misunderestimate the ability of the forum to overthink even the simplest things. Full disclosure: I converted AC to DC battery, did none of that, and it was audibly quite a bit better. Just not that hard. Unless you make it so.

Truer words were never written. If the Clearaudio table uses a DC motor, it is not driven directly from the wall wart power supply. At 33 RPM, it is most likely driven by 3-4VDC and from an internal controller which not only regulates the voltage but has active current feedback (negative output impedance) to compensate for the motor’s negative-slope torque/speed curve, without which, the motor will slow under load.

Regulating an AC-to-DC supply is done to remove any AC ripple from the output. The turntable should work just fine from an unregulated battery supply as there will be no AC ripple present. Regulating a battery supply in this case would do nothing other than complicate the application and waste heat and power. The rest of this discussion is just noise.

FYI, MC7812 regulators have a dropout voltage between 2.1 and 2.4V, depending on the device, so you would need 14.4VDC or greater for proper regulation. LDO regulators (Low Drop Out) exist with dropout voltages as low as 200-300mV, but they can become unstable and oscillate without careful layout and compensation.

Advice to the OP: As millercarbon alluded to, don’t over think it.

The OEM wall wart is a 12V 600mA regulated switching power supply, so long as a battery can supply a regulated 12V with min. 600mA it should be find. Since the Performance DC feathered fine speed adjustment on the back of the turntable to compensate variability in voltage difference, I think using a 7812 regulator shouldn't cause any problem.

https://hifiheaven.net/shop/image/cache/catalog/Clearaudio/12V1-750x750.JPG

I should have mentioned another issue: variability in parts. For example, the MC7812 is specced to regulate +/- 4% or so; which means that if you buy 5 of them, one should be within 1%. That’s 33 RPM to 33.6 RPM. Assuming you need it. Maybe you don't.

Like I said, it’s a project. You might have the time and inclination for it, or you just might want to listen to music.

Drop out due to VR is usually dependent upon many factors including current draw most importantly. I built a PS for my Klyne 6LX which has regulators on board the audio chassis. The PS needed to put out not more than 4-6V above the needed regulated V. I am sure an 18V battery or a 24V one at most would work for the clearaudio. We don’t have enough info even to guess.

@lewm , just so. An MC7812 requires 19VDC if I remember correctly. And it's hard to know the characteristics of any internal regulation or the motor, and it may not even be obvious about how motor speed relates to platter speed.

Doable, sure. How much of a project? Depends on your luck and how much test equipment you have lying around. If you don't have any test equipment, it'll take some pretty dumb luck not to void the warrantee.

Only way around it I can see is to measure (or otherwise determine) the voltage on the manufacturer's battery pack. Then replicate with a comparable rechargeable pack of your own. And don't forget to protect the pack with a diode and protect the motor with a fuse!

Never misunderestimate the ability of the forum to overthink even the simplest things. Full disclosure: I converted AC to DC battery, did none of that, and it was audibly quite a bit better. Just not that hard. Unless you make it so.

Terry, you make some very good points, which make me wonder what is the voltage rating of the battery in the Clearaudio kit. You can’t add regulation, which is needed to hold V constant, to an unregulated 12V output and still have 12V downstream from the regulator, assuming the motor requires all of 12V. All regulators consume some V. So either they use a battery that puts out >12V or the motor runs on less than 12V.

I salute you, Harold, and your attitude towards what awaits us all. Condolences for Mary.

About that battery supply, it’s not hard to engineer something like that, but it does have to be engineered. A DC motor’s speed depends on the supply voltage, and when a battery discharges, well, it discharges, and the voltage declines. That means the TT’s speed will be far from constant unless it is precisely regulated, and that means more than just an MC7812 regulator chip.

Unless you want to take it on as a DIY project, I’d buy the power supply, pricey as it is. To DIY, a good place to start is "Art of Electronics" by Horowitz and Hill. More I think about it, I’d buy that battery power supply if I were you.

Full disclosure: I built the power supply for my AC motor TT, full quadrature, silent. But it was a project, and it would have taken real time if I hadn’t been retired with the equipment to hand.

@kingharold
High end audio greatly benefits from clean power, and battery power may be the cleanest- don’t have to share a dirty AC line shared by devices, appliances, and neighbors. But as per the reasons mentioned by other posters, batteries have safety, space, and logistical problems to solve.
FYI- Some audiophiles use this as a battery power supply for their audio systems:
https://stromtank.com

Also, a heartfelt condolence on your loss.

Harold I wanted to add my condolences for your loss.

Yeah, I know just what you mean.  There's something about Mary. https://www.youtube.com/watch?v=mbFx0CbaIlY

I married a girl like your Mary too, and I love to hear someone give their wife due credit. So very sadden by your loss. Maybe an idea for a new thread, " Great wives/partners in audio". Surely some wonderful memories/stories. 

Use a 18V power tool battery connect to a regulator board bring down the voltage to 12V for the turntable power supply. Total cost included a spare battery and charger can be less than $200. 

Dear Mijostyn and anyone else, Did you not read my response to Noromance’s warning about noxious gases? Optima batteries are sealed, have no vents, and do not emit anything, let alone noxious gases. From the website:

"Sealed absorbent glass mat (AGM) batteries like OPTIMA® Batteries do not spill, sulfate or degrade like flooded batteries do. AGM design holds the electrolyte in suspension while keeping it in constant contact with the active lead material on the plates. This results in higher efficiency when both discharging and recharging.

AGM design offers lower internal resistance and greater plate area, which provides superior starting power, the ability to recharge much faster and higher voltage characteristics during discharge."

The blurb goes on to mention the Optima digital trickle charger, which I also own and which I recommended to the OP. I have used Optima batteries in all my collector cars since the early 90s with zero problems. I have also run 12V tube filaments with a huge Optima battery sitting in my living room, for several years, with no problem. Shame on you for not having one in your Porsche. After a conventional 6V battery, chosen because it was an accurate reproduction of the OEM Porsche 6V battery in my 550RS Spyder, puked acid into the forward area of the car, I replaced it with an Optima 6V battery, which you can even mount lying on its side, as I did to make it fit into the Spyder. (Early Spyders were 6V.)

Clearthinker, The question asked by the OP was not "whether" he should use a battery to run his turntable.  The question was whether he should spend $1200 on the Clearaudio battery and charger vs using some other battery. I don't disagree that maybe the OP would be best off with an outboard linear regulated 12VDC power supply, but I certainly do think the Clearaudio battery and charger are overpriced and could be replaced by excellent much less expensive equivalents.  (Actually, now I think of it, there may be a voltage regulator built into the turntable, which is why it can be run by a simple external battery.  So maybe the outboard linear supply need not be regulated.)

I use what I call ''German artillery'' consisting of ASR Emitter II
amp and Basis Exclusive phono-pre . Together + 120 kg. Both
have battery power supply consisting of 2 x 6 X 6 Volt batteries.
One for  pre -amp in the amp the other for the phono pre. Their
''life'' duration is +/- 7 years. 

clearthinker, please don't get them started.

I don't see much likely benefit in powering a TT by battery.  After all, the TT just goes round and round.  Wow and flutter figures on current good TTs are vanishingly low.  I have seen no evidence that battery power lowers them further.

But powering amps by battery seems much more likely to pay dividends by abolishing at a stroke all the grunge coming in from the power company.

Any benefit of coloured fuses when using battery power would be an interesting topic for discussion by those who believe fuses can have an effect on a mains powered amp.

My deepest condolences. I can’t imagine how difficult that is for you. I met my partner 35 years ago in graduate school. She had just done a marketing project on high end audio and knew someone that had purchased two Threshold S500 amplifiers! I couldn’t believe she actually ever heard of the company… what was she, one of three in the USA? I had purchased one ($5,000 in 1982), I took out my first bank loan to buy it. She had also just purchased what would be a very respectable budget high end system. Obviously I was enthralled. We have been together ever since. She has understood and at times encouraged my obsession in being an audiophile. However, I  learned about SAF… spousal acceptance factor. One thing most of us can be sure of is that car batteries in the house would not be within the house would ever be a possibility. She must have been an amazing woman. I can’t imagine how I would cope.

No problem, charge away! Just make sure the battery is well ventilated. Lead acid batteries make hydrogen gas which is explosive. Enclosing it in a cabinet is a terrible idea.

There is a complete battery operated turntable motor and power supply on US Audiomart https://www.usaudiomart.com/details/649783098-turntable-motor-with-battery-power-supply/

That might work well for you.

First, my condolences to you, Kingharold. So sorry to learn of your recent bereavement.  Sounds like your wife was a wonderful person.

Second, having been the first to recommend substitution of an Optima auto battery for the $1200 Clearaudio battery supply, I would point out that Optima batteries are sealed and do not vent any noxious gases, ever. Noromance makes a valid point that an unloaded car battery will make up to 14V when fully charged.  Whether that would damage the DC motor or not is definitely worth worrying about, but I don't think the danger would be much ameliorated by an in-line fuse.  A fuse senses current, not over-voltage. One would have to determine whether the load presented by the motor will pull down the voltage to an acceptable range around 12V, and if not, and if one were really determined to go this route, one could calculate the current draw necessary to bring down the voltage to the desired range and insert an appropriate resistor in series.  (I really doubt it would be necessary but worth evaluating.) Optima make a sophisticated trickle charger specifically designed for use with their batteries.  I recommend that too.  I have been using Optima batteries for 20-25 years on one or another classic car in my closed garage, with nary a problem.  I am sure some of the smaller size batteries discussed here would also work, but there you would have to worry about its maintaining output voltage over the course of a long listening session, because in my experience battery-powered audio gear does not sound good with charger in operation.  Smaller batteries tend to have less capacity to store current. And finally, I did find that capacitance in parallel with the battery output did audibly improve sonics, for whatever reason, in my one long term experience with battery power.  I used a couple thousand microfarads in the form of 16V electrolytics wired in parallel.

But third, I also like what Bill said about using a regulated linear power supply.  I am sure you can buy a good one off the shelf for less than half of $1200.

@kingharold Thanks for relating the stories about your wife. That is a rare occurence I would say! Though my wife doesn't share my same enthusiasm she gives me a lot of leeway; but if she didn't I would take it! I know we have to compromise but I worked for it, I earned it and I can think of a lot of other things worse than enjoying music. WAF be damned!

" I assume you are not married? " 
I was married up until July first of this year when Mary, my wife of fifty-one years, passed away.  Even before that I could get away with many things other audiophiles can't because my wife was a true audiophile and reproduced music lover herself.  At her funeral a long time friend (40 years +) who has been a audio professional all his adult life commented about how unusual Mary was that she understood the technical terms of sound reproduction and could intelligently discuss them.   When I told Mary I wanted to add two eighteen cubic foot sub woofers (Bill Fitzmaurice designed 25 Hz quarter wave corner horns) to the system in our den she just said, "OK, but let's make sure they look good."  She spent hours helping my apply blonde Burmese Teak veneer to the Baltic birch cabinets.

Sheeeesh, it's not rocket science to build a tightly regulated power supply. Why get ripped off by the manufacture when there are so many much cheaper alternatives. You really think that Clearaudio has something special going on aside from the price tag? Hell, you can find laboratory grade used power supplies on ebay for a few hundred dollars that can regulate voltage within fractions of a millivolt or even to microvolt levels with no noise or drift.
Companies like Hewlett Packard know tons more about regulated power supplies than some engineer at Clearaudio. But, hey, if you think that because it's sold by an audio company it's got special JuJu in it, go waste your money.


Billwojo

I would also only use the power supply sold by the company. They would have put a significant effort into making sure it sounds good and perform well. Unless, you are and electrical engineer and reverse engineer it… or actually, I have known many scores of electrical engineers… I would definitely not believe anything they say… unless they worked for the company. Good audio is all about nuance, I wouldn’t take a chance… unless you want to buy and test a bunch of them. 

Use the battery power supply sold by the company $1200.00 is not much if you can get a break on the price that's even better.Enjoy!!

Lots of folks making good aftermarket linear power supplies that cost much less than $1200 Sbooster is another brand to consider.

TeddyPardo has good rep. Clearaudio 12v ps only supplies 1.4amps, pretty minimal, that's crazy price for 12v 1.4a lps.

Thanks for the responses.  I hadn't considered that a fully charged 12V battery can provide 13.5 volts.  Perhaps a bit more research is needed.  I sure wouldn't want to mess up my first new turntable since I bought my VPI HW19 thirty or so years ago.Does anyone have opinions about TeddyPardo linear power supplies? That is another possibility

I have a Performance DC I use a linar power supply made by McRU
in the UK when I first got the TT I used the wall wart and using
Clearaudio stroboscope test record it showed a slight drift in speed after switching to the linear supply speed is spot on I do use a battery power phono stage Musical Surrounding Nova II  you can check out my system in Virtual Systems

Enjoy the Music
Tom

The smaller battery is the way to go. My Teres turntable was DC powered just like this, with a charger on a relay to automatically disconnect it from AC while playing. It is better that the charger be disconnected. The difference is slight, but there.  

Mine was an ordinary lead acid motorcycle battery, but that was decades ago. Today I would look for Li-Ion, ideally one small enough to fit right into the unit. 

Great advice Jim. Battery vapors are very toxic.

You should be able to get by with a much smaller battery.  Thales tables are battery powered with a pack that looks like 4 or 5 AA batteries. This is their description: The outstanding feature of the TTT-Slim II is the battery based power supply with Li-Ion
accumulators. The peak capacity is higher than 100 W while using not one single vibrating element. Therefore it is possible to integrate the power-supply into the main chassis, keep the signal-path short and skip any connection to the power plant. The battery service life is 20 hours

get a battery that will not vent !!!! charging in living space..

I just thought that I have a small 12V 1.25Amp Battery Tender Plus charger I used to keep my motorcycle battery topped up during the heat of Georgia summers when I didn't ride much.  I could just hook it up when I wasn't listening.  That obviates the need to lug the battery to my work shop and also makes a much smaller battery feasible. I am becoming enthusiastic about this.

You shouldn't need any capacitors; a lead acid has very low output impedence. 

Don't forget an in-line fuse to the motor.
A fully charged lead acid battery will have 13.5volts on it.

What lewm said.

U