johnwmclean
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Posts posted by johnwmclean
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Its probably a spilt board.
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shit awful disease, sorry for your loss Chris.
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Happy Birthday Birgir!
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Happy Birthday!!
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You could put rocks in it.
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There is no generic or universal enclosure as such.
I recommend having a look at modushop, the pesante dissipante range could be the ticket. But you’ll need to tap heatsinks and drill holes for the panels. Modushop customise as well, so you could have everything done there from your drawings. eBay is another good source for enclosures.
Front Panel Express is a great company for getting drilling of your panels done, you need to work with their proprietary software which is downloadable and fairly easy to use.
Unfortunately none of this is cheap...
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Happy Birthday Kerry!
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Kimber Kable won me over
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hApPy BiRtHdAy!
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DCA Aeon 2 Noire
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Happy Birthday Chris! Hope you have a good one!
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Voja,
your opening post says you’ve been reading hc threads for 2 years, then how the fuck did you miss spritzers general disposition, man up and grow some, your sensitivity is making me puke,
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I dialled back the bias from 20mA to 17.2mA, installed a 562k resistor in parallel over one of the 175k resistors and achieved 24.8V bias voltage across the 20k resistor and Vce of the PZTA42 is 13.25V. Thanks to simmocon on this for the ground work for the 400V Carbon! The offsets on troubled board (after dialling down the bias) drift slowly down from around 5V. Still not sure why at 20mA bias I was getting no drift, I’ll leave that a mystery.
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Yes Identical bias for all 4 phases, I have it all out on the bench now and will test and probe to see what I can find. As well as implementing simmocon’s mod for 400V.
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19 hours ago, mwl168 said:
I am theorizing that if the amp has oversized heatsink that barely gets warm the offset may drift much less. But this is just a guess.
And that makes sense. But doesn't explain in my instance why 2 identical channels on the same sized sink have very different thermal drift outcomes. (1 channel has an offset of under 1 volt and stays there and the other channel is around 13V and slowly drifts down to under a 1V in around 40min.
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“Normal” behaviour from my experience at a cold start offset is around 10 - 20 VDC and drifts down to under a 1VDC after 20 - 40 minutes.
So yeah I thought it’s abnormal.
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Great reporting Simmconn, I’ll be very interested in a follow up of where you end up after dialing back.
One channel of my latest build has little to no drift at all (no servos installed), which is odd behaviour from my experience.
After 45 minutes warmup offset and balance can be trimmed to under 1VDC.
From a cold start everything is now under 1 volt and stays that way. I’m curious as to the reason, do I need fix or leave as is? -
As long as voltage is good you probably don’t need a load.
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Very sad news so sorry for your loss Steve.
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Anyone up for a group buy of IXCP10M90S ?
in Do It Yourself
Posted
When I get home after this weekend, I’ll check my stock, see if I need a top up.