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Old 11th March 2014, 02:51 AM   #961
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Mine behaves somewhat the same. I run a bit hotter than 50 mA, and both bias and offset take a while to settle. My sinks run about 18F above ambient. Q13 is mounted directly to the sink in a store 4U case. I think it stabilizes faster than 30 minutes, but it was at least 15-20 minutes when I was measuring. Offset never got above 15 mV and settled at < 1 mV, so I didn't worry. Sound quality seems to be consistent from turn on to fully settled.
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Old 11th March 2014, 03:06 AM   #962
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Quote:
Originally Posted by BobEllis View Post
Consider a trying a DC blocker - you could be getting a bit of DC on the line.
most likely, this the reason i resist the temptation to use torroids, i am strictly an EI traffo kind of guy......
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Old 12th March 2014, 09:08 PM   #963
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Talking Finally got my badger fully up and running.

Finally got my Badger fully up and running. I am most happy with the result! I am hearing sounds in songs that I swear weren't there before!

I tested it on a dummy 4 ohm load up to approx 250W output. I bought a nice big 300w resistor so I could safely test it. I couldn't push it any further to see when clipping started because I don't have a scope here to see the waveform.

I am using +/-58 VDC dual mono 480VA traffosX2 & 24000uF/rail for each channel. I have the bias set at 50ma/device. My heatsink is from an old school 600W Kenwood car amp. It barely warms up at idle and should be more than sufficient.

Thank you OS for the design and the help!
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Old 13th March 2014, 02:50 AM   #964
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I guess I spoke a little too soon. It seems I might be having a slight thermal runaway issue. My 25mv (50ma per device) bias has reached 35mv . My heatsink was running about 30 degrees farenheit over ambient at that point. I was not using the amp loudly at all and was not averaging more than a couple watts all night

Shouldn't the thermal compensation be keeping my bias very close to my original settings?
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Old 13th March 2014, 02:59 AM   #965
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Originally Posted by Wembley View Post
I have attached my BoM for the Honey Badger, as a Mouser shared cart available at the URL below. Note that for me at least this is based on Australian pricing.

http://www.mouser.com/ProjectManager...sID=8080aaf520
Hi Wembley

I assume that this is just one channel ???

I clicked on your link and Mouser comes back with $ 69.50 USD.

The following 2 items are out of stock

KSA1381ES Transistors Bipolar - BJT PNP Epitaxial Sil

SS9014CTA Transistors Bipolar - BJT NPN/50V/100MA

KSA1381ESTU is available to replace the PNP, is it suitable ?

and for the NPN 512-SS9014CBU is available, again I ask if this is a suitable replacement.

Regards

Simon
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Old 13th March 2014, 03:09 AM   #966
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Quote:
Originally Posted by merlinx76 View Post
I guess I spoke a little too soon. It seems I might be having a slight thermal runaway issue. My 25mv (50ma per device) bias has reached 35mv . My heatsink was running about 30 degrees farenheit over ambient at that point. I was not using the amp loudly at all and was not averaging more than a couple watts all night

Shouldn't the thermal compensation be keeping my bias very close to my original settings?
Thermal compensation will stabilize bias, but not necessarily where you set it with the sinks not thermally stable. How did you set your bias? If you turned it up to 25 mV right away it will continue to increase a bit as the sinks heat up. I set mine to 16 mV and after a half hour of heating up was up close to 30. It then took a few cycles of heating and cooling to get the bias to stabilize where I wanted it. Once there it's stayed steady.
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Old 13th March 2014, 03:23 AM   #967
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Quote:
Originally Posted by BobEllis View Post
Thermal compensation will stabilize bias, but not necessarily where you set it with the sinks not thermally stable. How did you set your bias? If you turned it up to 25 mV right away it will continue to increase a bit as the sinks heat up. I set mine to 16 mV and after a half hour of heating up was up close to 30. It then took a few cycles of heating and cooling to get the bias to stabilize where I wanted it. Once there it's stayed steady.
OK that sounds reasonably close to what I am experiencing. I am now at 25mv at this (warm) temp. I am keeping an eye on my heatsink temp at its warmest spot to see if it has leveled off. It seems to be holding firm idling at ~27F over ambient.

Since I am getting this warm at idle, I am worried that the heatsink might not be quite enough. Does this sound reasonable for a heatsink temp at idle?

At 50ma per device, 150ma total X 58VDC X 2 = 17.4watts. Doesn't seem like my heatsink is going to be able to do the job if 17 watts is bringing me 27F over ambient!
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Old 13th March 2014, 03:51 AM   #968
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that's not so high i think....
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Old 13th March 2014, 04:37 AM   #969
janusz is offline janusz  Australia
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Default PS for HB

My PS for HB (attached) gave me a puzzle to solve. Yesterday I powered it up via a globe and soft start and everything worked fine. I switched it off and switched on again and suddenly my 75W globe is shining brightly. So I switched it off and it appeared that coil in soft start relay was burned.

I replaced soft start with another module, powered it up and the globe is shinning brightly again. This time coil is not burned. I disconnected capacitor banks and bridges, switched PS on, globe stayed dark and toroid gave me 2x47AC no load which is fine. I reconnected bridges, the same thing, all is fine and on each bridge I get about 44.5V DC (- to +), which seems fine.

I measure capacitor banks, each has 41.5mF which is roughly the right figure. 5W resistors are about 0.22 and fine. I haven't reconnected capacitor banks yet. Burned MURs860? But with no load they do not conduct. What could go wrong?

cheers,
Attached Files
File Type: pdf PS_HB.pdf (313.1 KB, 29 views)
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Old 13th March 2014, 04:53 AM   #970
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can you post pictures of your setup?
the glove should lit up and then extinguish after a while,
if it stays on, then something is definitely wrong,
perhaps a mistake in the wiring..
your schematic is fine but in actual wiring,
you could have made mistakes...
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