Hi all,
I want to replace the power-supply in TEAC A-L700P, to a battery. I'm not a experienced diyer, so all I want to do is connect the battery to the mainboard, just like current PS does. I guess I need to cut out the connector on the other side of the power cable which is going from the mainboard and connect it to switch in the front, which will be connected to the battery terminals. Where can I buy a battery for this and how exactly do I connect it to the mainboard? What is the easy to mod way to charge that battery?
Here is a picture of the Teac.
I want to replace the power-supply in TEAC A-L700P, to a battery. I'm not a experienced diyer, so all I want to do is connect the battery to the mainboard, just like current PS does. I guess I need to cut out the connector on the other side of the power cable which is going from the mainboard and connect it to switch in the front, which will be connected to the battery terminals. Where can I buy a battery for this and how exactly do I connect it to the mainboard? What is the easy to mod way to charge that battery?
Here is a picture of the Teac.
An externally hosted image should be here but it was not working when we last tested it.
Why do want to do that ? It looks like it has a switch mode power supply which they have probably selected as being a good match for the Class D chips.
What does make you think that the regulated switching mode power supply is the weak component there?
Unless your looking to make something thats portable, I see no advantage of replacing the switching supply with a battery.
One diyer, RedWineAudio, made that mod in addition to many others, and there were dozens of users that could hear a great improvement in powering the Teac by battery.
For more info, see here:
http://www.redwineaudio.com/Teac_AL700P_mods.html
For more info, see here:
http://www.redwineaudio.com/Teac_AL700P_mods.html
SLAs are cool, but they aren't that much quieter than a SMPS - when the amp is running. The switch mode amps kick back tons of noise onto the power rail. An SLA battery doesn't do any better at handling this noise than a good linear supply or a filtered SMPS. It can be better at some frequencies, worse at others.
Batteries are very quiet with no load. Small loads like preamps are well suited to batteries.
I have a lot of PSU measurements to post and will do so as soon as I clear my amp work backlog. Maybe this week.
Batteries are very quiet with no load. Small loads like preamps are well suited to batteries.
I have a lot of PSU measurements to post and will do so as soon as I clear my amp work backlog. Maybe this week.
The thing about a battery supply that puts me off is the constantly fluctuating and decreasing voltage, not to mention the hassle of a charging system, limited runtime, size, etc. etc..
Besides, what better way to complement a switching amp than with a switching supply.
Maybe theres something about the supply in the TEAC thats not up to par, but its not the fact that its a switching supply.
Besides, what better way to complement a switching amp than with a switching supply.
Maybe theres something about the supply in the TEAC thats not up to par, but its not the fact that its a switching supply.
gevorg said:
Not likely!
A good low ESR cap will do wonders for cleaning up the noise of a SMPS. The Panasonic FM series are what I use and like. An LC filter (inductor-cap) will work wonders, but you may need to check the stability of the PSU with an inductive load.
Adding more good quality capacitance won't hurt, either. Getting some good caps close the amp board will help reduce the noise that the amp generates, and being a switching amp, it generates plenty!
Well, but the point that gevorg has to understand is that the own amplifier module is a switching mode power supply, and not particularly well engineered as usual. The main switching power supply is probably quieter than the own switching amplifier in terms of EMI and supply rail "pollution".
I added a 6,800 cap(between output and amp) to the SMPS I have and it dropped the volts from 12v to 11.6v, so I removed it.
Eva said:
My understanding of SMPS in general, is that they collapse dramatically when the wattage rating is exceeded. In equipment that has a linear draw such as a computer, they are fine as the demand is known & constant and the supply can be sized accordingly.
In a system that taxes the supply with non-linear demand (such as music) they can perform unsatisfactorily unless they are upsized. On peaks, you might be able to detect audible differences as the supply sags. So, a 300W SMPS might perform better on a 100W amplifier than a 100W SMPS would in this regard.
It would be interesting to see if the supply is adequate on the TEAC and if changing to a beefier supply is audible or merely psychological in effect.
speaker said:
I have not seen that exactly, but believe it may be so. Most I have worked with will shut down briefly if too much current is drawn. AKA, short circuit protection! Typical linear supplies will try a little harder before shutting down.
This isn't a problem if the SMPS is of adequate size. For example, a 3A "line lump" SMPS is just fine for a Sonic Impact type amp.
All the supplies I have tested -SMPS, linear & battery, benefited from added capacitors near the amp. Lower noise, better regulation.
panomaniac said:
I've yet to hotrod my SI-5066 which runs off an IBM laptop switcher. It performs adequately in its current role as my portable music system when I am in a hotel. My laptop & Boston Micro 110's round out the package. Your rec intrigues me though as it is simple to implement.
How much capacitance would you add onto the +DC feed?
speaker said:
Easy answer - as much as possible!
But in your case, possible needs to be portable, too.
Adding 1800-2200uF to the rail will help noise, especially if you use good caps like the Panasonic FM series. It will do a lot to clean up noise on the power rails. These caps are small enough that you should be able to solder right to the points where the onboard electrolytic is already soldered.
Adding 10-20000uF will stabilize the power supply quite a bit. You should be able to find 10000uF caps of decent quality that are not too big.
Is your amp in its original case? If so, you can stuff the battery compartments with caps.
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