Hello, I just bought a 230VAC/15VAC transformator and just cant figure out how get the 15V down to 13V...
Its going through a rectifier and some 20000uF to feed a small Class D amp...
So, I can only test it without load... 🙂 I dont want to hook up the amp before I know what will feed in to the amp...
Any suggestions?
Its going through a rectifier and some 20000uF to feed a small Class D amp...
So, I can only test it without load... 🙂 I dont want to hook up the amp before I know what will feed in to the amp...
Any suggestions?
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15V AC, rectified are about 20VDC. For a Class D amp I would use a buck regulator like L4970 series, and synchronized to the amp to minimize noise and EMI.
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Thanks for your reply! But I must say that I used a switching regulator and had bad interfearances in my analog radio through the amp...
Tried also a 12V lead gel battery and all was good... 🙂
Dont know what to do...
Is there a old school methode without useing a switching regulator?
Tried also a 12V lead gel battery and all was good... 🙂
Dont know what to do...
Is there a old school methode without useing a switching regulator?
Do you have more details on the specs of this class-D amp?
min/max power voltage (no seperated plus and minus supply needed?)
max current
Its a SMSL SA-S3... with the TA2021b chip...
Specific:
T-Amp IC Tripath TA2021B
Output Power 2 x 25W @ 4ohm, 2 x 13.5W @ 8ohm
Dynamic Range 100dB
Power Efficiency 81% @ 25W, 4ohm, 88% @ 13.5W, 8ohm
Audio input: RCA x 1
Power socket (5.5mm/2.5mm) x 1
Circuit board : 1.6mm thick, full-fiber, deep golden
Specific:
T-Amp IC Tripath TA2021B
Output Power 2 x 25W @ 4ohm, 2 x 13.5W @ 8ohm
Dynamic Range 100dB
Power Efficiency 81% @ 25W, 4ohm, 88% @ 13.5W, 8ohm
Audio input: RCA x 1
Power socket (5.5mm/2.5mm) x 1
Circuit board : 1.6mm thick, full-fiber, deep golden
The chip's data sheet says absolute maximum 16V and 14V typ., so a regulator must be used. Any linear approach will loose (20 - 14) / 14 = 0.42, so the net efficiency will be only 0.58. Again, a PWM reg will enhance it to more than 85%.
Then, a Class AB amplifier is also a must. Why do you think that a Class D amp has no interference into radio and a PWM regulator does?
I can only say, that with my 12V battery the sound was great without audible interferences...
So I conclude that a decent made linear power supply could do it also...
Or am I wrong?
So I conclude that a decent made linear power supply could do it also...
Or am I wrong?
How long are the cables between battery and amp? How long will be the wires from the amp to linear reg?
would do something like thisbut with only one 3055:
(and smaller caps, 4700uF should do it)
An externally hosted image should be here but it was not working when we last tested it.
Making the mat, the chip says 25W @ 4Ω, does not say if is only one or both channels simultaneously. Lets suppose that is single channel only (Worst case). Then, I = √(25W/4Ω) * 2ch * √2 = 4√3 = 6.9Amper peak. So U will need a power supply capable of deliver about 10Amper. A couple of TIP36 plus a LM317 may do the job.
With music, 6.9A peak will translate to maybe 2A average, tops ...
An LT1085 followed with a hefty cap will do.
The xformer wouldn't support more anyway.
Jan
An LT1085 followed with a hefty cap will do.
The xformer wouldn't support more anyway.
Jan
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Thats okay... I am not very skilled into electronics...
hanks for your concern and ideas!
Christoph
hanks for your concern and ideas!
Christoph
In this case, search for a regulator board capable of 10 amper peak, and 14V output. You must think in a large heat sink for it. There must be some kit of this kind available in your town. Also, think of buying a small trafo output, say, one of about 10VAC @6-7Amps.-
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(13.5V * √2 ) - 2 * 0.7V = 17.7V, it is still over maximum ratings. You will destroy the amp. Search for a 12V transformer, it is rather common.