Battery powered clock circuit.

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#21
Yes, rfbrw, skin effect at DC would not seem to be a factor. I have just gotten in the habit of making most all DIY audio pwr, IC & speaker wire from multistrands of 24awg copper or silver pulled thru natural cotton sleeves. In this application you just need high-quality, thick-gauge wire. I did observe that the multiple strands of Audio Consulting copper wire I used with the batteries sounded much better than the cheap 12awg solid copper I started out with on the bench.
 
#23
Re: Battery Powered Clock

David Garretson said:

1) I have had fantastic results powering an Audiocom SC3 in my Sony SCD-1 with batteries, as well as all other circuits in the CDP.
A well-designed battery implementation beat the best I could design with AC/DC discrete regulation stages by a significant margin.
2) The keys are low impedance batteries (e.g. 2 milliohm Optima Yellow Top spiral cell or Enersys Odyssey PC2150 thin-plate), decoupling the battery from the application with a parallel array of fast filtering caps located inside the CDP(e.g. Rubycon ZA), DC trunks of quality wire, short length, and adequate gauge (3' or so max length and 20-25 strands of 24 AWG poly-coated magnet wire to minimize skin effect), and where possible, running the application unregulated directly off the battery.
The results are astonishing.
Click to expand...

Dear Mr. Garretson,
thank you very much for your very interesting message.
1) I saw your creation. Very impressive indeed. Congratulations!
Actually it is well known that batteries do have an internal impedance that, as you well did , must be lowered with a suitable caps pack.
I played some times ago with a simple op-amp (AD797) powered
with a dual power supply +/-12V made out two SLABs.
With two 2200uF caps close to the op-amp the sound was much better and powerful too.
I do not know the effect with a class A circuit (i.e. with a constant current draw). Maybe the caps are mandatory only with AB circuits where caps can act as a reservoir of energy.
Then I saw those measurements on the TNT AUDIO site that made me dizzy (please excuse my "macaroni English").
Maybe that noise can be related to a lack of decoupling.
But I really do not know.
I will read better the test conditions.
2) could you provide any link about those special "batteries".

Thank you very much for disclosing your very interesting experience.
Kind regards.

beppe
 
#24
Here are a few references to batteries with great characteristics for audio. The 55AH Optima Yellow Top and the 100AH Odyssey both have very low internal resistance in the 2-3 milliohm range. They are also deep-cycle, thin plate technology that is well above conventional SLA batteries in performance and price. Though both are very good indeed, one can actually hear the difference between the two and the Odyssey is a bit better. Unfortunately it takes large batteries to get the low impedance characteristics necessary for the hi-end audio application, despite the slight MA loads of the CDP application. If you are just powering the clock, consider at least a battery with 7 milliohms or less resistance, such as the smaller Odysseys.

Regardless of the battery used, I would put some fast capacitance close to the application. I find it always improves the sound, though less capacitance is necessary with a better battery.

I modified my Merlin speaker line-level bass equalizer (BBAM), replacing the stock arrangement of four 9V NiMH batteries and 3-pin regulators with an unregulated +/-12V supply of two 55AH Optima Yellow Tops. The four AD op amps in the BBAM woke up and the speakers now sound at least 50% better with the 55AH Optimas than with the NiMH. So there are big differences between batteries.


Enersys Odyssey PC2150 100AH 2.2 mOhm internal resistance, and also other smaller Odysseys with resistance below 5 mOhms.

http://www.odysseyfactory.com/specs.htm

http://www.batterymart.com/battery.mv?p=ODY-PC2150

Optima Yellow Top D34 55AH 2.8 mOhm internal resistance:

http://www.optimabatteries.com/publ...fo/automotive/deep_cycle/technical_specs.html

Good luck & regards,

Dave
 
#25
I add that I am also using the Optima +/-12V supply to run BB BUF634s in the Sony SCD-1 modded analog stage. On good battery power these monolithic devices are in my opinion right up there with the best tube buffers in terms of smooth, grainless sound. I was never happy with their hard treble using any AC/DC regulated source.

Dave
 
#26
David Garretson said:

Here are a few references to batteries with great characteristics for audio.
The 55AH Optima Yellow Top and the 100AH Odyssey both have very low internal resistance in the 2-3 milliohm range.
They are also deep-cycle, thin plate technology that is well above conventional SLA batteries in performance and price. Though both are very good indeed, one can actually hear the difference between the two and the Odyssey is a bit better. Unfortunately it takes large batteries to get the low impedance characteristics necessary for the hi-end audio application, despite the slight MA loads of the CDP application.
If you are just powering the clock, consider at least a battery with 7 milliohms or less resistance, such as the smaller Odysseys.
Regardless of the battery used, I would put some fast capacitance close to the application.
I find it always improves the sound, though less capacitance is necessary with a better battery.
I modified my Merlin speaker line-level bass equalizer (BBAM), replacing the stock arrangement of four 9V NiMH batteries and 3-pin regulators with an unregulated +/-12V supply of two 55AH Optima Yellow Tops.
The four AD op amps in the BBAM woke up and the speakers now sound at least 50% better with the 55AH Optimas than with the NiMH. So there are big differences between batteries.
Enersys Odyssey PC2150 100AH 2.2 mOhm internal resistance, and also other smaller Odysseys with resistance below 5 mOhms.
http://www.odysseyfactory.com/specs.htm
http://www.batterymart.com/battery.mv?p=ODY-PC2150
Optima Yellow Top D34 55AH 2.8 mOhm internal resistance:
http://www.optimabatteries.com/publ...fo/automotive/deep_cycle/technical_specs.html
Good luck & regards,
Dave
Click to expand...

Thank you very much indeed Mr. Garretson for the extremely kind and valuable advice.
I understand they are truly exceptional products (55 and 100 Ah, wow).
I played with off-the-shelf SLABs of 7Ah each.
I will study deeply the info in the links you mention.
Speaking of caps I had nice results with PANASONIC's caps of the FA series (105°C).
I found them very good indeed and with a "sane" price.

Thank you very much again.
Kind regards,

beppe
 
#27
David Garretson said:

I add that I am also using the Optima +/-12V supply to run BB BUF634s in the Sony SCD-1 modded analog stage.
On good battery power these monolithic devices are in my opinion right up there with the best tube buffers in terms of smooth, grainless sound.
I was never happy with their hard treble using any AC/DC regulated source.
Dave
Click to expand...

Dear Mr. Garretson,

I have looked at your system showed in the link.
My sincere congratulations.
The interiors of your Sony look indeed very impressive.
Many times I read that the "magic" sound of the best audio units comes from their power supplies.

Thanks for the very precious advice.
Kind regards,

beppe
 
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