This thread:
http://www.diyaudio.com/forums/showthread.php?s=&postid=187556&highlight=#post187556
and the discussion of regulators at TNT which included batteries:
http://www.tnt-audio.com/clinica/regulators_noise4_e.html
has got me wondering about their effectivness as clean power supplies.
I'm about to start Thorsten's 'El Cheapo' phono pre and started wondering about regulated supplies (I know he doesn't like them) since it's actually for a friend who would prefer no batteries. I know the general consensus around here is that regulated is great for chip preamps but batteries are better for delicate signals such as this RIAA preamp.
Anyway, wondering if there have been other discussions and data presented on this topic since then?
certain batteries quieter than others? (within their own category, ie lead acid vs lead acid) what about lithium batteries?
Thanks,
Rob
http://www.diyaudio.com/forums/showthread.php?s=&postid=187556&highlight=#post187556
and the discussion of regulators at TNT which included batteries:
http://www.tnt-audio.com/clinica/regulators_noise4_e.html
has got me wondering about their effectivness as clean power supplies.
I'm about to start Thorsten's 'El Cheapo' phono pre and started wondering about regulated supplies (I know he doesn't like them) since it's actually for a friend who would prefer no batteries. I know the general consensus around here is that regulated is great for chip preamps but batteries are better for delicate signals such as this RIAA preamp.
Anyway, wondering if there have been other discussions and data presented on this topic since then?
certain batteries quieter than others? (within their own category, ie lead acid vs lead acid) what about lithium batteries?
Thanks,
Rob
robselina said:
Unfortunately Andy Weekes never seemed to answer the queries over his battery measurements, so the odd spikes etc. remain a mystery. I would suggest though that an opamp based pre would only draw a few milliamps, so any noise would be nearer the noload condition , hence more like the lowest curve on his graph, especially with a cap included.
I'm currently getting surprisingly good sound from a simple opa627 set-up powered by 2 12v leadacids with a resistor rail splitter and two crappy 2200uF caps. If you use big 10 or 12 Ah batteries you might go 6 months or so between charges, thus saving most of the hassle of a battery set-up.
I can't tell you that batts are better than mains though; I used them 'cos it was the easiest way to test my pre. The mains PS will hopefully be built soon, and that wonderful joy that is AB testing can start.
hi rob
i can't make comparison between various batteries, for I am using only one type, that is lead 12 volt, from ups battery power backups
i use one for mosfet buffer and two for phono preamp
sounds quiet to me
every couple of month i notice my system does not sound right, like an old solid state amp with high crossover distortion, even i am using tube amp, that means batteries need to be recharged
there are many commercial phono preamps which use batteries, nothing new about it, but i like the idea of having front end of phono preamp powered by photodiode as a source of dc, with a bulb as light source......quiet, very quiet
i can't make comparison between various batteries, for I am using only one type, that is lead 12 volt, from ups battery power backups
i use one for mosfet buffer and two for phono preamp
sounds quiet to me
every couple of month i notice my system does not sound right, like an old solid state amp with high crossover distortion, even i am using tube amp, that means batteries need to be recharged
there are many commercial phono preamps which use batteries, nothing new about it, but i like the idea of having front end of phono preamp powered by photodiode as a source of dc, with a bulb as light source......quiet, very quiet
Batteries
I have only used SLA type. And then used a lot of capacitance close to circuit.
The sound is never warm and smooth. For some reason an active power supply sounds more wholesome and full. Maybe the diode switching noise is improving the sound somehow.
I have tried batteries with a class D switching amp, a nos dac, and a class a fet buffer. All sounded better with a simple active power supply.
Many report all would sound even better with a simple filtered switching power supply. Cannot comment, only used the SMPS for the digital amp. It was better than batteries, but not the linear supply.
My experiance with batteries has not been great.
George
I have only used SLA type. And then used a lot of capacitance close to circuit.
The sound is never warm and smooth. For some reason an active power supply sounds more wholesome and full. Maybe the diode switching noise is improving the sound somehow.
I have tried batteries with a class D switching amp, a nos dac, and a class a fet buffer. All sounded better with a simple active power supply.
Many report all would sound even better with a simple filtered switching power supply. Cannot comment, only used the SMPS for the digital amp. It was better than batteries, but not the linear supply.
My experiance with batteries has not been great.
George
i used batts on my gainclone (2 x 12v sla), with 47uF caps on the rails.
sound is great and it is very very quiet. no complains from me. my speakers are 93db/6ohm. so not much wattage required.
play time is around 40hours or so. i have not really run them till dead as 12v sla should not be left to drain too much as it would harm the batts.
i implemented the 2 x l200cv charging circuit as shown at vt52 and it works like a charm.
sound is great and it is very very quiet. no complains from me. my speakers are 93db/6ohm. so not much wattage required.
play time is around 40hours or so. i have not really run them till dead as 12v sla should not be left to drain too much as it would harm the batts.
i implemented the 2 x l200cv charging circuit as shown at vt52 and it works like a charm.
Depends how you define better i guess. Lead batteries don't do it for me. There is something wrong with the timing, dynamics and bass. The rest is spectacular. NiCds seem to sound faster but again there is something strange and lightweight about the entire presentation. It may be the specific types i've used - they seem to differ as much as caps.
analog_sa said:
That's what concerns me. I'm wondering if there are some tried and true brands that maybe use a slightly different electrolyte or electrode specification/configuration that would result in increased performance (not just Ah, but noise floor and current output capacity, etc)....
robselina said:
A british company called LFD made a reference phono stage about 10 years ago using about a dozen Hawker Cyclon single 2v cells. I read once that these are considered very good lead acids, tho I cant recall why (current,capacity,noise etc.). Not cheap either. I also remember reading that nicads were very noisy.
I think if batts are good for phono stages noise cant be an issue. Lead acids can deliver tons of current, so I cant see a problem here either, esp. for preamps.
I suspect the reservoir caps used have a strong influence in the final result; size being particularly critical.
I used batteries on my pre-amp. My friend looked on
the scope and found batteries to be much cleaner
then AC. However, I got into troubles when the
batteries discharges assymetrically. I found one
battery to be at 2V while the other one still was at 11V.
This could be solved by charging etc.
I found that the sound of AC was very similar to batteries
after I've added 68,000 uF filtering to the AC. I've
also installed a line filter before the Transformer.
I think the sound is pretty much the same so the batteries
are no longer worth the hassle for me.
Harry
the scope and found batteries to be much cleaner
then AC. However, I got into troubles when the
batteries discharges assymetrically. I found one
battery to be at 2V while the other one still was at 11V.
This could be solved by charging etc.
I found that the sound of AC was very similar to batteries
after I've added 68,000 uF filtering to the AC. I've
also installed a line filter before the Transformer.
I think the sound is pretty much the same so the batteries
are no longer worth the hassle for me.
Harry
Re: Re: A discussion about batteries on preamps...
Or bigger loop area by bigger batteries and sloppy test wiring practices.
Just did quick "measurement" with +60db preamp attached to aureal2 line-in. OH boy what noise generator my display is!
With 65k points FFT lower measurement limit is around -170db referred to 1V(rms) line-input sensitivity. Just placing 12cm of wire to form a 5cm diameter loop on the end of preamp input coaxial kicks in LOADS of noise, highest peak at 85hz, +50db above measurement limit when loop is placed about half meter from 21" monitor. Changing refresh rate changes peak accordingly, there is also at least 30+ harmonics of refresh rate visible....
Ground loops are also evil at this level...
On positive side layout of just finished instrumentation preamp seems ok, as placing it input shorted even directly on top of my 21" monitor causes only about 10db noise peaks shown above -170db level.
mzzj said:
Just remember to read that page to end, those measurements by ALW are useless. Ignore that. Possibly some sort of capacitive coupling, PC in ungrounded power outlet or something funny as battery is generating loads of 50hz.
Or bigger loop area by bigger batteries and sloppy test wiring practices.
Just did quick "measurement" with +60db preamp attached to aureal2 line-in. OH boy what noise generator my display is!
With 65k points FFT lower measurement limit is around -170db referred to 1V(rms) line-input sensitivity. Just placing 12cm of wire to form a 5cm diameter loop on the end of preamp input coaxial kicks in LOADS of noise, highest peak at 85hz, +50db above measurement limit when loop is placed about half meter from 21" monitor. Changing refresh rate changes peak accordingly, there is also at least 30+ harmonics of refresh rate visible....
Ground loops are also evil at this level...
On positive side layout of just finished instrumentation preamp seems ok, as placing it input shorted even directly on top of my 21" monitor causes only about 10db noise peaks shown above -170db level.
mzzj said:
solar cells should be more familiar name to everyone
IE put a solar cell and a lightbulb in a box and run lightbulb with DC (not AC). Dont be fooled to use ambient light for free power as it is more or less flickering.
Thanks. That makes it clear enough. Any suggestions for good sources for appropriate solar cells? And, how good a DC does one need for powering the bulb (i.e. is this a chicken or egg type of problem)?
Paul
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.