Forget about regulators for Power Amplifiers until AFTER you have learned how to apply a regulator to the very complex loading that a speaker+amp is for any regulator !
i actualy responded to this-
so its still valid question, why people say 7xxx series are noisy, they are not.
and why quoted collegue should use separate transformer if he can drop few volts with resistors from amplifier supply- into regulators to power opamps?
so its still valid question, why people say 7xxx series are noisy, they are not.
and why quoted collegue should use separate transformer if he can drop few volts with resistors from amplifier supply- into regulators to power opamps?
Well, for my money, it's hard to beat this power supply combination:
For the preamp supply (Lm317/337):
DIY Kit Adjustable Filtering Power Supply LM317 LM337 Voltage Regulator Module | eBay
For the power amp (LT1083s):
LT1083 Adjustable Regulated Power Supply Module DIY Kit Be | eBay
And for the transformer (2 x 28v + 2 x 15v):
AS-3428 - 300VA 28V Transformer - AnTek Products Corp
I did add larger smoothing capacitors (10,000uF-pre; 22,000uF--pwr) and selected the PCBs based on their ability to accommodate these larger caps.
Total cost including shipping and the larger caps was still under $100.
For the preamp supply (Lm317/337):
DIY Kit Adjustable Filtering Power Supply LM317 LM337 Voltage Regulator Module | eBay
For the power amp (LT1083s):
LT1083 Adjustable Regulated Power Supply Module DIY Kit Be | eBay
And for the transformer (2 x 28v + 2 x 15v):
AS-3428 - 300VA 28V Transformer - AnTek Products Corp
I did add larger smoothing capacitors (10,000uF-pre; 22,000uF--pwr) and selected the PCBs based on their ability to accommodate these larger caps.
Total cost including shipping and the larger caps was still under $100.
I have those power amp regulators, and the transformer I'm grabbing is essentially the same thing- just available locally.
Is it fine to drop ~20V over the LM337? I'm guessing the preamp wouldn't draw much more than 200ma/side but I'm really not familiar with that op amp.
HUH?? If the transformer you're using is "essentially the same thing", you don't need to drop 20V anywhere! The 15 volt secondaries provide ~21v to the LM317/337s to output the +/- 18 volts for the preamp; the 28 volt secondaries provide ~39v to the LT1083s to put put a nice fat, regulated +/-35 volt rails for the power. If your transformer DOESN'T have the additional 15 volt secondaries, Antek will sell you a nice 2 x 15volt transformer for only $11.
Note that the two LT1083s for power require 2 x 28 v, NOT 28-0-28.
The OPA2134s draw about 10 ma per 8-pin opamp (2 amplifiers), so unless you're doing some heavy preamp signal processing, you only need less than 100 ma for each rail.
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Oh man, this is why you don't look at stuff when you're half asleep - I have no idea what I was talking about haha.
I've just ordered the Gainclone PCB/kit, transformer and smaller regulated power supply so it should hopefully be here by the end of the month
While digging around in my parts container, I found a toroid of interest. It's a CT with +/-40 and +/-12 - twin CT wires for each voltage, so I'm guessing I can split them for quad output. It's 300VA. Now this will give me ~55v after regulation - pretty damn high.
Going through the data sheet, the current load limit is 1A @ 25v dropped, and 8A @ 5V dropped - obviously, this voltage is too damn high. Is it worthwhile dicking around with this to get the voltage to something useful, or just keep this for another project?
Going through the data sheet, the current load limit is 1A @ 25v dropped, and 8A @ 5V dropped - obviously, this voltage is too damn high. Is it worthwhile dicking around with this to get the voltage to something useful, or just keep this for another project?
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