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Old 25th March 2010, 08:04 AM   #161
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Quote:
Originally Posted by 40 watt View Post
Is this the little bug for B1, I assume the bridge rectifier:: Little Bug

...60 cents.

...83 cents from another manufacturer.

both at Digikey.

For this I could probably recycle a transformer from an older dead Philips CD player I have, maybe.

Somehow, I have to wrap my head around the idea of 60 cents vs $1.23 X 8 [$9.84] for MUR86O's. The building of many active speaker systems just became more practical.


...looking closer at the traces the AC in are on diagonal corners. Hmmmm....
So much to learn and experience.
The 1A unit may not achieve longevity for active speakers (power amp use); however, BR84 (8 ampers) or KBPC1004 (10 ampers) can be used for active speakers.

These 1 piece bridge rectifiers contain 4 diodes each. If you want to do a similar job to the 8 of MUR860's, it would take 2 of either BR84 or KBPC1004.

Last edited by danielwritesbac; 25th March 2010 at 08:11 AM.
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Old 25th March 2010, 08:46 AM   #162
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Originally Posted by danielwritesbac View Post
The 1A unit may not achieve longevity for active speakers (power amp use); however, BR84 (8 ampers) or KBPC1004 (10 ampers) can be used for active speakers.

These 1 piece bridge rectifiers contain 4 diodes each. If you want to do a similar job to the 8 of MUR860's, it would take 2 of either BR84 or KBPC1004.
I was thinking more along the lines of powering the pre-amp/input buffer and the opamps in the active crossover as well as its output buffers, all line level stuff and not too piggy on power, though they are adding up. I'm debating quad package opamps like the LME49740 for easier positive/negative power routing and grounds for decoupling as well as a little less cost.

Power amps would get their own beefier supplies like the ones you suggest.

Question on opamps: Can a quad package have, say, only 3 of the opamps inside used and the the 4th be left unused...so there is an optional stage available like for an active notch filter, if required, for unruly peaks like those from metal coned drivers? I'm trying to make each individual driver's crossover portion be multi-use for different driver types, though manual tuning would be required for each set-up. Having a readily available single opamp [one of 4 in a quad] with ready power already there would make it easier.

Last edited by 40 watt; 25th March 2010 at 09:14 AM.
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Old 26th March 2010, 01:00 AM   #163
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Quote:
Originally Posted by 40 watt View Post
Question on opamps: Can a quad package have, say, only 3 of the opamps inside used and the the 4th be left unused...
the 4th can be connected as a current buffer.i wlould not leave it alone.


to danielwritesbac,
yes you are right,C1~C4 at 16V for +/-12V using is unsafe.25V is good.
and,this mini power supply was design for light loading.it is up to lm78xx & lm79xx regulator only handle 1A.
may be,just a imagine,this mini psu can work on +/-12VDC lm1875 poweramp.

-z
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Old 26th March 2010, 02:51 AM   #164
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Originally Posted by digi01 View Post
. . . it is up to lm78xx & lm79xx regulator only handle 1A.
may be,just a imagine,this mini psu can work on +/-12VDC lm1875 poweramp.
-z
My imagination does this:

+/-15vdc is workable for drv134 + LM1875//LM1875 (paralleled LM1875 amp) There's 8 regs and 8 LM1875's (for bridge+parallel LM1875).

+/-15vdc is workable for UCP + LM1875 stereo amp.
There's 2 regs and 2 LM1875's.

It seems to work out that there's exactly the same number of regulators as LM1875's. It looks convenient to make boards with 2 regs and 2 LM1875's (per each board).

Just one board can make a cute little stereo amp, or 4 boards + DRV134 can make a more powerful amp, all on nicely regulated power.

This is imagination, so you might want to check the figures. Although, I'm sure that the regs would need heatsinks.

I wouldn't power UCP from the same set of regulators as LM1875 because of the speaker's high amperage return force into the ground plane of the amp, which is a noise into the power circuit that is not easily stopped. Since the regulators allow very small capacitance at the LM1875, that feature (capacitive multiplier effect of a regulator) does reduce the return line noise considerably, and it is a higher class of audio amplifier. If bridging then the problem is avoided; however, LM1875's don't like to be bridged unless they are paralleled, so that's 8 chips for stereo. The highest class of audio amplifier has its pre-drive on separate power source (or regs), so UCP still needs its own regs.

How's that for an imagination spree?
Of course none of this works. . . until it plays, and that is when it works.
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Old 27th March 2010, 01:50 PM   #165
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So, howabout it Digi01? Did that give you any ideas?
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Old 29th March 2010, 06:58 AM   #166
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i like bridging.i have two design for bridging(BLD & BRM).these two has including fixed regulator on the pcb.

this midi psu,i named it as DUAL.it will service on UCP series and universal using.you may have a try with brain's lm1875 amp.
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Old 30th March 2010, 11:27 PM   #167
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Originally Posted by digi01 View Post
i like bridging.i have two design for bridging(BLD & BRM).these two has including fixed regulator on the pcb.
I like bridging too.
The slight loss makes for excellent bass from sealed box speakers, small speakers and small rooms. And it brings easily availability for the clean sound of regulated power, that can be done simply.

Quote:
Originally Posted by digi01 View Post
this mini psu,i named it as DUAL.it will service on UCP series and universal using.you may have a try with brain's lm1875 amp.
1 LM1875, 3 resistors, 2 330uF caps, (per each of 2 channels) will fit for 15-0-15 regulated power supply. So, I might use Daniel's inexpensive sub-miniature LM1875 instead of a bulky kit.

Even more entertaining would be Zang's bridged LM1875 monoblocs with onboard 15v regulators.
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