Need a big transformer...

On 3ÔÂ23ČŐ, ÉĎÎç4Ęą35ˇÖ, mrdarr...@gmail.com wrote:

So let's say I want to build an LM3886 amplifier.http://www.national.com/mpf/LM/LM3886.html

At 68W RMS, assuming 50% efficiency, I'd need at least, what, a 150W
transformer, right?

And if I build two for stereo, that would be 300W required. 70V
secondary, center-tapped, to get +/- 35V.

Those things are expensive on Mouser ($60+). Especially considering
the LM3886 only costs $7 or so.

Any suggestions where I can get such a large transformer for cheap?

Thanks,

Michael

Do you want access to China's massive pool of electronic
manufacturers... but lack the time to contact suppliers, negotiate
contracts, arrange shipping or monitor product quality? Don't worry -
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service. You can profit by selling hundreds of different products,
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be answered by the seriouswholesale English-speaking customer support
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easier to run than ever before.

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seriouswholesale - Buy from the source, profit without the hassle.

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with no additional fee - Pay by safely by PayPal seriouswholesale
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wholesaler & drop-shipper: seriouswholesale. com

 

On 3ÔÂ23ČŐ, ÉĎÎç6Ęą12ˇÖ, "Bob Eld" <nsmontas...@yahoo.com> wrote:

mrdarr...@gmail.com> wrote in message

news:37c1b825-37ff-4042-8c36-e5a294c4b4bb@s12g2000prg.googlegroups.com...





So let's say I want to build an LM3886 amplifier.
http://www.national.com/mpf/LM/LM3886.html

At 68W RMS, assuming 50% efficiency, I'd need at least, what, a 150W
transformer, right?

And if I build two for stereo, that would be 300W required. 70V
secondary, center-tapped, to get +/- 35V.

Those things are expensive on Mouser ($60+). Especially considering
the LM3886 only costs $7 or so.

Any suggestions where I can get such a large transformer for cheap?

Thanks,

Michael

There is no such thing as an RMS Watt. You mean 68Watts sign wave average.
Depending on the service, you can usually get by with about 1/4 of the
average sign wave power in the transformer which would be about 70 Watts.
100 Watt transformer would be a little better. Remember music reproduction
does not need continuous power. Any transformer can supply four times it's
rated power in short bursts. It's a matter of heating or how hot the
transformer is allowed to get. For your application a 100Watt transformer is
more than sufficient.- Ňţ˛ŘąťŇýÓĂÎÄ×Ö -

- ĎÔĘžŇýÓĂľÄÎÄ×Ö -

Do you want access to China's massive pool of electronic
manufacturers... but lack the time to contact suppliers, negotiate
contracts, arrange shipping or monitor product quality? Don't worry -
Let seriouswholesale deal with all that for you.

*Check out the huge range of Gadgets, MP3 / MP4 Players, Car DVD /
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catalog at seriouswholesale. com You'll have peace of mind thanks to
the seriouswholesale Quality Control, 12-month Warranty on all
products, and easy secure payment by credit card through Paypal.

Selling on eBay or your own online store? Send products direct from
our warehouse to your customers using our unique drop-shipping
service. You can profit by selling hundreds of different products,
without holding any of your own inventory! Any questions you have will
be answered by the seriouswholesale English-speaking customer support
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easier to run than ever before.

Welcome to http://www.seriouswholesale.com.

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- 12 Months Warranty - No minimum order restrictions - Drop-shipping
with no additional fee - Pay by safely by PayPal seriouswholesale
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wholesaler & drop-shipper: seriouswholesale. com

 

[HapticZ]

whers your junk box?

scout the streets for discarded unit of any sort,

plenty of fools throwing tons of copper out every day!


<mrdarrett@gmail.com> wrote in message
news:37c1b825-37ff-4042-8c36-e5a294c4b4bb@s12g2000prg.googlegroups.com...

So let's say I want to build an LM3886 amplifier.
http://www.national.com/mpf/LM/LM3886.html

At 68W RMS, assuming 50% efficiency, I'd need at least, what, a 150W
transformer, right?

And if I build two for stereo, that would be 300W required. 70V
secondary, center-tapped, to get +/- 35V.

Those things are expensive on Mouser ($60+). Especially considering
the LM3886 only costs $7 or so.

Any suggestions where I can get such a large transformer for cheap?

Thanks,

Michael

 

[Paul E. Schoen]

<mrdarrett@gmail.com> wrote in message
news:757a6ecf-7bdb-4573-91bb-da2bbafe75bd@s19g2000prg.googlegroups.com...

If I tie the secondaries to get +/-24V, two of these might actually do
the trick.
http://www.mpja.com/prodinfo.asp?number=7846+TR

If I only wanted to power one LM3886, two of the smaller ones could
work:
http://www.mpja.com/prodinfo.asp?number=7845+TR

Pretty cheap. Cheaper than Mouser, at least...

Michael

You can get +/- 28 VDC from a 24VCT transformer by using a doubler circuit
(actually more of a tripler) on each leg, consisting of two capacitors and
two diodes.

I made an LTSpice circuit that shows how to generate +/- 28VDC into dual 24
ohm loads (for about 76 watts), from a 24VCT transformer with a current
draw of 7.2 amps RMS. It has 10V P-P of ripple, so you might need to add
more capacitance or an inductor filter or a regulator. So you could use
just one of the 7846 transformers (24VCT, 10A). Not bad for $18, but
shipping it might be expensive. And you will need to add the diodes,
capacitors, and other components.

The switching supplies would be smaller, lighter, regulated, well filtered,
and would not require any extra components.

Paul

=================================================================================

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pn="UPL1J122MRH" type="Al electrolytic" ppPkg=1
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SYMATTR InstName C2
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SYMATTR Type cap
SYMATTR SpiceLine V=63 Irms=2.51 Rser=0.025 MTBF=5000 Lser=0 mfg="Nichicon"
pn="UPL1J122MRH" type="Al electrolytic" ppPkg=1
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SYMATTR Type cap
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pn="UPL1J122MRH" type="Al electrolytic" ppPkg=1
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SYMATTR Type cap
SYMATTR SpiceLine V=63 Irms=2.51 Rser=0.025 MTBF=5000 Lser=0 mfg="Nichicon"
pn="UPL1J122MRH" type="Al electrolytic" ppPkg=1
SYMBOL diode 368 496 M270
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SYMATTR Value MUR460
SYMBOL diode 240 416 M180
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SYMATTR Value MUR460
SYMBOL res 544 320 R0
SYMATTR InstName R2
SYMATTR Value 24
TEXT -104 464 Left 0 !K1 L1 L2 1
TEXT -130 506 Left 0 !.tran 1

 

[Phil Allison]

"Bob Eld Shithead "

There is no such thing as an RMS Watt.

** Really ?

You mean 68Watts sign wave average.


** Which is precisely what the term " watts rms " means in audio
amplifier specs.

Yes I know, a bull shit term invented by uneducated technicians


** That is an entirely false comment.

The term " watts rms" = watts derived from continuous sine wave test.

It is a simply a verbal shorthand.

Idiotic shorthand for saying "sine wave"?

** No, you fucking moron.

It is shorthand for using the rms value of a sine wave instead of the peak
value.

The term " watts peak" was once in wide use ( mainly in the US and Japan )
and referred to a sine wave test where the maximum value was used and gave a
number double the value of the rms one.

BTW notice than nobody in the commercial or industrial world uses the
term.

** It is commonly used in the world of audio amplifiers, pro and consumer
and of all the output power specs around it is the most conservative.

Only smartarse, know nothing, autistic fuckwits like YOU are confused
about the meaning.

Piss off - fuckhead.



........ Phil

 

[Phil Allison]

"Paul E. Schoen Autistic MORON "

You can get +/- 28 VDC from a 24VCT transformer by using a doubler circuit
(actually more of a tripler) on each leg, consisting of two capacitors and
two diodes.

** But only a dumb, autistic ASS like Schoen would use it to power an
amplfier.

With a 24 volt secondary, only TWO diodes and TWO filter caps you get +/-
34 vots DC.

Its called a full wave voltage doubler.



........ Phil

 

[Don Klipstein]

In <37c1b825-37ff-4042-8c36-e5a294c4b4bb@s12g2000prg.googlegroups.com>,
mrdarrett@gmail.com wrote:

So let's say I want to build an LM3886 amplifier.
http://www.national.com/mpf/LM/LM3886.html

At 68W RMS, assuming 50% efficiency, I'd need at least, what, a 150W
transformer, right?

And if I build two for stereo, that would be 300W required. 70V
secondary, center-tapped, to get +/- 35V.

Those things are expensive on Mouser ($60+). Especially considering
the LM3886 only costs $7 or so.

Any suggestions where I can get such a large transformer for cheap?

Transformers are normally rated for VA rather than watts.

You need to consider RMS current feeding the DC power supply circuitry
following the transformer.

There is a power supply circuit that minimizes ratio of transformer VA
requirement to DC output watts:

(Also consider a "linear" amplifier having efficiency at best about 78%)

1. Fullwave rectify, and have filter capacitors somewhat on the small
side - to have ripple maybe 15-20% at "full load". (I forget the exact
percentage by now.)

2. Have this ripply DC feed an RC filter to make smooth DC at the average
DC voltage of this ripply DC.

3. Feed the output of that to a voltage divider to have a voltage of
smooth DC that is of voltage less than all points of the ripply DC waveform.

4. That feeds an "emitter follower" that feeds a nice big
filter/smoothing/energy-storage capacitor, and that is the output of this
DC power supply circuit.

Output DC voltage will be close to the input AC RMS voltage. I forget
what the ratio is ideally in the best case, but IIRC it is not far from
unity. Ratio of RMS AC amps from transformer to average DC amps from the
final DC output is well above unity, though I have faint memory traces of
this being optimistically 1.3-something.

Keep in mind that a "retail audio amp", according to a 25-whatever/plus
year old regulation, merely has to be able to deliver a 1/3 power sinewave
on a long term basis - which has current about 58% of "full". I do see
the above circuit having power factor decreasing at reduced power - so I
suspect the transformer needs amp rating significantly more than
1.3/whatever times .58 times ratio of nominal output watt rating to
nominal DC supply rail voltage. I think 1.6-1.75 is good for this ratio.

So for 68 watt nominal output, and at the "ideal" 78% efficiency does
this with about 87 watts filtered DC, and that times .58 times 1.6-1.75
means about 81-88 volt-amps transformer requirement - amd that is in
"average to gentler" applications. I would go for more for DJ and band
duty amplifiers - as in not much less than 1.3/.78 times full power, or
about 110 VA, preferably a little more rather than a little less. More
still if capacitor values are not optimized to minimize VA requirement
from the transformer, so maybe 120-150 VA or so, and I give warranty of
refund of what you paid me so far to post this that this is adequate.

As for where to get: Sorry, these are expensive through electronics
distributors, with price per pound in/near the filet mignon range.

My first approach is to see if such a transformer can be found from any
of the surplus/hobbyist outfits. My second approach would be to make a
SMPS (switchmode power supply) - if you are new at this, be prepared for
dozens of hours of homework, as well as a fair chance of parts or quite a
few parts failing - sometimes spectacularly - be prepared to have several
power transistors (or MOSFETs or IGBTs) to fail and maybe even explode.
Also be prepared for exploding components to explode after whatever
malfunction burns out some nearby semiconductors, so that exploding
components do not protect everything around them by acting as fuses.

My experience is that such SMPS blowups tend to have compound
failures limited to semiconductor components, and that "magnetic
components" (inductors and transformers) have a high rate of being
protected by failing semiconduictors acting as fuses. Magnetic
components that suffer the much-less-common fate of also getting burned
out in compound failures tend to smell burnt/smoky, and also usually
produce visible smoke and/or other similarly noticeable signs of being
severely cooked during the few compound failures that go that way!

- Don Klipstein (don@misty.com)

 

[Don Klipstein]

In article <slrnfueb3m.7ah.don@manx.misty.com>, I, Don Klipstein wrote:

In <37c1b825-37ff-4042-8c36-e5a294c4b4bb@s12g2000prg.googlegroups.com>,
mrdarrett@gmail.com wrote:

(In short transformer for DC power supply for 68 watt audio amplifier)

VA ratings that I said there need to be increased by 41% if you make any
use of transformer windings working in halfwave mode.

I suspect more likely your transformer candidates have every secondary
winding portion working from both halves of the AC cycle to power your
amplifier...

- Don Klipstein (don@misty.com)

 

[Paul E. Schoen]

"Phil Allison" <philallison@tpg.com.au> wrote in message
news:64o6a2F2ckobuU1@mid.individual.net...

(after his usual and expected outburst)

With a 24 volt secondary, only TWO diodes and TWO filter caps you get
+/- 34 vots DC.

Its called a full wave voltage doubler.

....... Phil

Here's a full wave voltage doubler that gets 400 volts from 200 volts peak
to peak.

http://www.tpub.com/neets/book7/27m.htm

I made an LTSpice model with the same load. With 2400 uF capacitors, it
produces +/- 30 VDC into the 24 ohm loads.

My circuit gets about the same output, but the transformer current is 7.3
amps RMS compared to 5.6 amps RMS for the FWVD. So it is a little more
efficient.

But there are advantages as well as disadvantages to using the circuit I
posted. You can add a FWCT supply for nominal 15 VDC if you need it. Also,
my original circuit provides some current limiting at the expense of
regulation. It produces +/- 52 VDC at light loads, while the FWVD maxes out
at +/-34 VDC.

So, choose whatever circuit works better for your purposes.

Phil, if you were not such an arrogant hothead I would thank you for
pointing out and posting what might be a better circuit for the OP, if he
chooses to use a transformer supply. But I still recommend the switching
supplies. The LTSpice circuit follows:

Paul

============================================================================

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TEXT 184 528 Left 0 !.tran 1

 

[Paul E. Schoen]

"Eeyore" <rabbitsfriendsandrelations@hotmail.com> wrote in message
news:47E5CDE9.16907172@hotmail.com...

"Paul E. Schoen" wrote:

Why do you need a transformer?

To run it from a mains supply of cousre !

Are you really that silly ?

Graham

Switching supplies run very nicely on mains supply. Of course, they have a
transformer inside, but it's a single component solution.

What's silly about saving weight and the trouble of adding extra
components?

Paul

 

On 3ÔÂ23ČŐ, ÉĎÎç4Ęą35ˇÖ, mrdarr...@gmail.com wrote:

So let's say I want to build an LM3886 amplifier.http://www.national.com/mpf/LM/LM3886.html

At 68W RMS, assuming 50% efficiency, I'd need at least, what, a 150W
transformer, right?

And if I build two for stereo, that would be 300W required. 70V
secondary, center-tapped, to get +/- 35V.

Those things are expensive on Mouser ($60+). Especially considering
the LM3886 only costs $7 or so.

Any suggestions where I can get such a large transformer for cheap?

Thanks,

Michael

Do you want access to China's massive pool of electronic
manufacturers... but lack the time to contact suppliers, negotiate
contracts, arrange shipping or monitor product quality? Don't worry -
Let seriouswholesale deal with all that for you.

*Check out the huge range of Gadgets, MP3 / MP4 Players, Car DVD /
Audio, and Computer Accessories now by visiting the online wholesale
catalog at seriouswholesale. com You'll have peace of mind thanks to
the seriouswholesale Quality Control, 12-month Warranty on all
products, and easy secure payment by credit card through Paypal.

Selling on eBay or your own online store? Send products direct from
our warehouse to your customers using our unique drop-shipping
service. You can profit by selling hundreds of different products,
without holding any of your own inventory! Any questions you have will
be answered by the seriouswholesale English-speaking customer support
team... Their aim is to make your China electronics importing business
easier to run than ever before.

Welcome to http://www.seriouswholesale.com.

seriouswholesale - Buy from the source, profit without the hassle.

- 12 Months Warranty - No minimum order restrictions - Drop-shipping
with no additional fee - Pay by safely by PayPal seriouswholesale
Wholesale Co., Ltd.: Chinas original and best online electronics
wholesaler & drop-shipper: seriouswholesale. com

 

[Phil Allison]

" Paul E. Schoen Autistic Fuckwit "

"Phil Allison"

(after his usual and expected outburst)

With a 24 volt secondary, only TWO diodes and TWO filter caps you get
+/- 34 volts DC.

Its called a full wave voltage doubler.

....... Phil


Here's a full wave voltage doubler that gets 400 volts from 200 volts peak
to peak.

http://www.tpub.com/neets/book7/27m.htm

I made an LTSpice model with the same load. With 2400 uF capacitors, it
produces +/- 30 VDC into the 24 ohm loads.

** Useless piece of shit.

It has CRAP regulation - YOU DUMBFUCK ADS FUCKED ASS !!

Phil, if you were not such an arrogant hothead ....

** Yaaaaawnnnnnnn.........................


The arrogant HOTHEAD is YOU - Paul


You CONSTANTLY jump to WILD conclusions and you post emotional hunches
instead of good advice.

You been doing this for 5 years at least now.

So, it is impossible to believe you are anything other than another
autistic mental defective.


SO FUCK OFF !!!!!!!!!!!!




........ Phil

 

On 3ÔÂ23ČŐ, ÉĎÎç4Ęą35ˇÖ, mrdarr...@gmail.com wrote:

So let's say I want to build an LM3886 amplifier.http://www.national.com/mpf/LM/LM3886.html

At 68W RMS, assuming 50% efficiency, I'd need at least, what, a 150W
transformer, right?

And if I build two for stereo, that would be 300W required. 70V
secondary, center-tapped, to get +/- 35V.

Those things are expensive on Mouser ($60+). Especially considering
the LM3886 only costs $7 or so.

Any suggestions where I can get such a large transformer for cheap?

Thanks,

Michael

Do you want access to China's massive pool of electronic
manufacturers... but lack the time to contact suppliers, negotiate
contracts, arrange shipping or monitor product quality? Don't worry -
Let seriouswholesale deal with all that for you.

*Check out the huge range of Gadgets, MP3 / MP4 Players, Car DVD /
Audio, and Computer Accessories now by visiting the online wholesale
catalog at seriouswholesale. com You'll have peace of mind thanks to
the seriouswholesale Quality Control, 12-month Warranty on all
products, and easy secure payment by credit card through Paypal.

Selling on eBay or your own online store? Send products direct from
our warehouse to your customers using our unique drop-shipping
service. You can profit by selling hundreds of different products,
without holding any of your own inventory! Any questions you have will
be answered by the seriouswholesale English-speaking customer support
team... Their aim is to make your China electronics importing business
easier to run than ever before.

Welcome to http://www.seriouswholesale.com.

seriouswholesale - Buy from the source, profit without the hassle.

- 12 Months Warranty - No minimum order restrictions - Drop-shipping
with no additional fee - Pay by safely by PayPal seriouswholesale
Wholesale Co., Ltd.: Chinas original and best online electronics
wholesaler & drop-shipper: seriouswholesale. com

 

[Joerg]

mrdarrett@gmail.com wrote:

On Mar 22, 3:34 pm, "Paul E. Schoen" <pst...@smart.net> wrote:
mrdarr...@gmail.com> wrote in message

news:37c1b825-37ff-4042-8c36-e5a294c4b4bb@s12g2000prg.googlegroups.com...



So let's say I want to build an LM3886 amplifier.
http://www.national.com/mpf/LM/LM3886.html
At 68W RMS, assuming 50% efficiency, I'd need at least, what, a 150W
transformer, right?
And if I build two for stereo, that would be 300W required. 70V
secondary, center-tapped, to get +/- 35V.
Those things are expensive on Mouser ($60+). Especially considering
the LM3886 only costs $7 or so.
Any suggestions where I can get such a large transformer for cheap?
Thanks,
Michael
Why do you need a transformer? The amplifier has direct output drive with
+/- 28 VDC supplies. You can use two inexpensive 100 watt switchers, and
add a little series inductor and a really big capacitor on each, to take
care of HF switching noise and short burst peak power requirements. You
could even use 24 VDC supplies, which might be more common, and available
very cheap surplus or used.

Paul


24VDC supplies are commonly used for...?

Mostly for industrial gear. Meaning that 12V supplies at a scrap yard
that sells to hobbyists cost a whole lot more than 24V supplies of which
they often have a lot. 48V is also popular, can be found in scrapped
telco gear.

I just don't know where such a place would be near Sacramento, I don't
think the guys at Kiefer Blvd run such sales. The Bay Area should be
better, I guess John Larkin would know a place or two.

Or do you mean regular computer ATX supplies, -12-0-12?

Could I take two ATX supplies, and tie them like this to get -24-0-24?

---------- ----------
| ATX | | ATX |
| Supply 1 | | Supply 2 |
| | | |
---------- ----------
| | | |
-12V +12V -12V +12V
| |___________| |
| | |
| | |
-24V 0 +24V

That can get noisy, their -12V is too weak and often they misbehave when
going underneath their minimum load. You'd have to keep listening to
AC-DC or Meat Loaf where the audio will be at max all the time ;-)

Another source would be, you guessed it, a big old stereo amp.

--
Regards, Joerg

http://www.analogconsultants.com/

 

[Joerg]

mrdarrett@gmail.com wrote:

On Mar 24, 1:29 pm, Joerg <notthisjoerg...@removethispacbell.net
wrote:

[...]

I just don't know where such a place would be near Sacramento, I don't
think the guys at Kiefer Blvd run such sales. The Bay Area should be
better, I guess John Larkin would know a place or two.


I went to the Kiefer Blvd place, and they didn't have large center-
tapped 48V transformers, but I called again today and they have a box
full of 24V stuff... time to pay them another visit...

Thanks, good to know they do such sales.

[...]

--
Regards, Joerg

http://www.analogconsultants.com/

 

[Joerg]

mrdarrett@gmail.com wrote:

On Mar 24, 2:14 pm, Joerg <notthisjoerg...@removethispacbell.net
wrote:
mrdarr...@gmail.com wrote:
On Mar 24, 1:29 pm, Joerg <notthisjoerg...@removethispacbell.net
wrote:
[...]

I just don't know where such a place would be near Sacramento, I don't
think the guys at Kiefer Blvd run such sales. The Bay Area should be
better, I guess John Larkin would know a place or two.
I went to the Kiefer Blvd place, and they didn't have large center-
tapped 48V transformers, but I called again today and they have a box
full of 24V stuff... time to pay them another visit...
Thanks, good to know they do such sales.

[...]

--
Regards, Joerg

http://www.analogconsultants.com/


Actually we went to the Surplus Stuff place on Folsom Blvd (it's not
Kiefer after all - or is there another one on Kiefer Blvd itself?)
because my wife and I wanted to take a look at the flea market going
on next door. They had a lot of old low-power stuff (reel-to-reel
tape players, VCRs) at the flea market but nothing that looked like it
could handle several hundred watts.

Lots of car audio amplifiers for sale, too. But that's no fun...
already built...

Kiefer is the waste and recycling collection site for Sacramento.

Where is that surplus place on Folsom Blvd?

--
Regards, Joerg

http://www.analogconsultants.com/

 

On Mar 24, 1:29 pm, Joerg <notthisjoerg...@removethispacbell.net>
wrote:

mrdarr...@gmail.com wrote:
On Mar 22, 3:34 pm, "Paul E. Schoen" <pst...@smart.net> wrote:
mrdarr...@gmail.com> wrote in message

news:37c1b825-37ff-4042-8c36-e5a294c4b4bb@s12g2000prg.googlegroups.com...

So let's say I want to build an LM3886 amplifier.
http://www.national.com/mpf/LM/LM3886.html
At 68W RMS, assuming 50% efficiency, I'd need at least, what, a 150W
transformer, right?
And if I build two for stereo, that would be 300W required. 70V
secondary, center-tapped, to get +/- 35V.
Those things are expensive on Mouser ($60+). Especially considering
the LM3886 only costs $7 or so.
Any suggestions where I can get such a large transformer for cheap?
Thanks,
Michael
Why do you need a transformer? The amplifier has direct output drive with
+/- 28 VDC supplies. You can use two inexpensive 100 watt switchers, and
add a little series inductor and a really big capacitor on each, to take
care of HF switching noise and short burst peak power requirements. You
could even use 24 VDC supplies, which might be more common, and available
very cheap surplus or used.

Paul

24VDC supplies are commonly used for...?

Mostly for industrial gear. Meaning that 12V supplies at a scrap yard
that sells to hobbyists cost a whole lot more than 24V supplies of which
they often have a lot. 48V is also popular, can be found in scrapped
telco gear.

Ok, thanks.

I just don't know where such a place would be near Sacramento, I don't
think the guys at Kiefer Blvd run such sales. The Bay Area should be
better, I guess John Larkin would know a place or two.

I went to the Kiefer Blvd place, and they didn't have large center-
tapped 48V transformers, but I called again today and they have a box
full of 24V stuff... time to pay them another visit...

Or do you mean regular computer ATX supplies, -12-0-12?

Could I take two ATX supplies, and tie them like this to get -24-0-24?

---------- ----------
| ATX | | ATX |
| Supply 1 | | Supply 2 |
| | | |
---------- ----------
| | | |
-12V +12V -12V +12V
| |___________| |
| | |
| | |
-24V 0 +24V

That can get noisy, their -12V is too weak and often they misbehave when
going underneath their minimum load. You'd have to keep listening to
AC-DC or Meat Loaf where the audio will be at max all the time ;-)

Or just put a few 10W automotive lights in there...?
http://web2.murraystate.edu/andy.batts/ps/POWERSUPPLY.HTM

Another source would be, you guessed it, a big old stereo amp.

Yep, there's always Goodwill...

--
Regards, Joerg

http://www.analogconsultants.com/

Thanks,

Michael

 

On Mar 24, 2:14 pm, Joerg <notthisjoerg...@removethispacbell.net>
wrote:

mrdarr...@gmail.com wrote:
On Mar 24, 1:29 pm, Joerg <notthisjoerg...@removethispacbell.net
wrote:

[...]

I just don't know where such a place would be near Sacramento, I don't
think the guys at Kiefer Blvd run such sales. The Bay Area should be
better, I guess John Larkin would know a place or two.

I went to the Kiefer Blvd place, and they didn't have large center-
tapped 48V transformers, but I called again today and they have a box
full of 24V stuff... time to pay them another visit...

Thanks, good to know they do such sales.

[...]

--
Regards, Joerg

http://www.analogconsultants.com/

Actually we went to the Surplus Stuff place on Folsom Blvd (it's not
Kiefer after all - or is there another one on Kiefer Blvd itself?)
because my wife and I wanted to take a look at the flea market going
on next door. They had a lot of old low-power stuff (reel-to-reel
tape players, VCRs) at the flea market but nothing that looked like it
could handle several hundred watts.

Lots of car audio amplifiers for sale, too. But that's no fun...
already built...

Michael

 

On Mar 24, 2:26 pm, Joerg <notthisjoerg...@removethispacbell.net>
wrote:

mrdarr...@gmail.com wrote:
On Mar 24, 2:14 pm, Joerg <notthisjoerg...@removethispacbell.net
wrote:
mrdarr...@gmail.com wrote:
On Mar 24, 1:29 pm, Joerg <notthisjoerg...@removethispacbell.net
wrote:
[...]

I just don't know where such a place would be near Sacramento, I don't
think the guys at Kiefer Blvd run such sales. The Bay Area should be
better, I guess John Larkin would know a place or two.
I went to the Kiefer Blvd place, and they didn't have large center-
tapped 48V transformers, but I called again today and they have a box
full of 24V stuff... time to pay them another visit...
Thanks, good to know they do such sales.

[...]

--
Regards, Joerg

http://www.analogconsultants.com/

Actually we went to the Surplus Stuff place on Folsom Blvd (it's not
Kiefer after all - or is there another one on Kiefer Blvd itself?)
because my wife and I wanted to take a look at the flea market going
on next door. They had a lot of old low-power stuff (reel-to-reel
tape players, VCRs) at the flea market but nothing that looked like it
could handle several hundred watts.

Lots of car audio amplifiers for sale, too. But that's no fun...
already built...

Kiefer is the waste and recycling collection site for Sacramento.

Where is that surplus place on Folsom Blvd?

--
Regards, Joerg

http://www.analogconsultants.com/

!!! Oh I hadn't realized the Kiefer Landfill had stuff for people to
grab. I thought you pay a fee to get in and dump your stuff, only.

Surplus Stuff...
http://maps.google.com/maps?f=q&hl=en&geocode=&q=surplus+stuff,+95826&ie=UTF8&ll=38.547326,-121.383305&spn=0.022354,0.040169&z=15&iwloc=A

Well thanks for the tip re: the landfill...

Michael

 

[Joerg]

mrdarrett@gmail.com wrote:

On Mar 24, 2:26 pm, Joerg <notthisjoerg...@removethispacbell.net
wrote:
mrdarr...@gmail.com wrote:
On Mar 24, 2:14 pm, Joerg <notthisjoerg...@removethispacbell.net
wrote:
mrdarr...@gmail.com wrote:
On Mar 24, 1:29 pm, Joerg <notthisjoerg...@removethispacbell.net
wrote:
[...]
I just don't know where such a place would be near Sacramento, I don't
think the guys at Kiefer Blvd run such sales. The Bay Area should be
better, I guess John Larkin would know a place or two.
I went to the Kiefer Blvd place, and they didn't have large center-
tapped 48V transformers, but I called again today and they have a box
full of 24V stuff... time to pay them another visit...
Thanks, good to know they do such sales.
[...]
--
Regards, Joerg
http://www.analogconsultants.com/
Actually we went to the Surplus Stuff place on Folsom Blvd (it's not
Kiefer after all - or is there another one on Kiefer Blvd itself?)
because my wife and I wanted to take a look at the flea market going
on next door. They had a lot of old low-power stuff (reel-to-reel
tape players, VCRs) at the flea market but nothing that looked like it
could handle several hundred watts.
Lots of car audio amplifiers for sale, too. But that's no fun...
already built...
Kiefer is the waste and recycling collection site for Sacramento.

Where is that surplus place on Folsom Blvd?

--
Regards, Joerg

http://www.analogconsultants.com/


!!! Oh I hadn't realized the Kiefer Landfill had stuff for people to
grab. I thought you pay a fee to get in and dump your stuff, only.

Well, I don't know, it was just a thought. All I know is that the guys
up here don't let people cart things away but some places do.

Surplus Stuff...
http://maps.google.com/maps?f=q&hl=en&geocode=&q=surplus+stuff,+95826&ie=UTF8&ll=38.547326,-121.383305&spn=0.022354,0.040169&z=15&iwloc=A

Here are pictures from inside the store:
http://daviswiki.org/Surplus_Stuff

Wish those places had their stuff listed somewhere.

--
Regards, Joerg

http://www.analogconsultants.com/