17-0-17V/5A good for 3886 GC??

Triode · 14th December 2005, 08:12 PM

Hi, i am busy building a LM3886 GC. I have a toroidal transformer 17-0-17V/5A. Is this enough for the GC? Speakers are 4 Ohms, 89dB/1W/1m. Thanks, Hans

lineup · 14th December 2005, 11:20 PM

Will give you power supply of something like 2x27 VDC
and trafo is 170VA/5A
I say you would have a nice supply for two LM3886 = stereo.

I would have only trafo in common for these two channels
and each one LM3886 having its own rectifier ( 4 diodes or rectifier bridge) and supply caps.

madscience · 15th December 2005, 08:10 AM

I think a 17-0-17 transformer should give you about 50 Watts per channel into 4 ohms. This is more than sufficient for 89 dB/W/m speakers. Plus, you don't need to use a big heatsink...Actually, I built a subwofer amp using 17-0-17 with about 160 VA and my sub isn't terribly efficient!

sagarverma · 15th December 2005, 10:19 AM

170VA::good.will suffice for stereo also.
but 17v ac gives approx 23v dc.very low to exploit fully the potential of
3886.

orpheus · 18th December 2005, 05:18 AM

The National Datasheet says that at 23v the 3886 will output around 40 watts into 6
ohms, a little less for 8ohms. That should be enough to drive most speakers.

Google LM3886. The first link is Nationals site for the 3886. Download the datasheet. Go to Typical Performance Charts. There's a graph on page 14 called "Output Power vs. Supply Voltage" that will tell you how much power you need to achieve how many watts.

-Aaron.

14th December 2005, 08:12 PM	#1
Triode diyAudio Member Join Date: Oct 2005	17-0-17V/5A good for 3886 GC?? Hi, i am busy building a LM3886 GC. I have a toroidal transformer 17-0-17V/5A. Is this enough for the GC? Speakers are 4 Ohms, 89dB/1W/1m. Thanks, Hans

15th December 2005, 10:19 AM	#4
sagarverma diyAudio Member Join Date: Feb 2005 Location: NEW DELHI	170VA::good.will suffice for stereo also. but 17v ac gives approx 23v dc.very low to exploit fully the potential of 3886. __________________ Never Underestimate The Bandwidth of A Station Wagon Full Of Magnetic Tapes Hurtling Down The Highway...................Andrew S Tanenbaum

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14th December 2005, 11:20 PM	#2
lineup diyAudio Member Join Date: Dec 2005 Location: the north	Will give you power supply of something like 2x27 VDC and trafo is 170VA/5A I say you would have a nice supply for two LM3886 = stereo. I would have only trafo in common for these two channels and each one LM3886 having its own rectifier ( 4 diodes or rectifier bridge) and supply caps.

15th December 2005, 08:10 AM	#3
madscience diyAudio Member Join Date: Mar 2005 Location: Hergiswil, Switzerland	I think a 17-0-17 transformer should give you about 50 Watts per channel into 4 ohms. This is more than sufficient for 89 dB/W/m speakers. Plus, you don't need to use a big heatsink...Actually, I built a subwofer amp using 17-0-17 with about 160 VA and my sub isn't terribly efficient!

18th December 2005, 05:18 AM	#5
orpheus diyAudio Member Join Date: Jul 2004 Location: NYC	The National Datasheet says that at 23v the 3886 will output around 40 watts into 6 ohms, a little less for 8ohms. That should be enough to drive most speakers. Google LM3886. The first link is Nationals site for the 3886. Download the datasheet. Go to Typical Performance Charts. There's a graph on page 14 called "Output Power vs. Supply Voltage" that will tell you how much power you need to achieve how many watts. -Aaron.

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