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Old 10th October 2010, 08:13 PM   #921
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Default DH-200 versus XL280 PS caps.

Help?!!

I've heard from another hafler fan the "280" caps are superior to any other DH series PS caps

DH-200 model# & other info: 3186EE103U075BMA2; 362 8902 56699; 7800 micro F
XL-280 model# & other info: 3186DE782U075BJA2; 362 8710 56699; 10K micro F
both have the same voltage & temp specs.

also how do I measure '280 channel bias? I see the adjustment pot and I'm acutely aware of the importance of same, about 330ma I think.

thnx in advance, tony
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Old 10th October 2010, 11:59 PM   #922
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Pull one fuse on one channel circuit card, clip on ammeter, adjust, replace fuse. Repeat for other channel.
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Old 13th October 2010, 11:43 PM   #923
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At the risk of igniting a heated debate, except for output, is Cat 5e a good replacement for any wire in an amp that carries signal?

If not, what would you hafler gurus recommend?
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Old 14th October 2010, 12:23 AM   #924
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I use CAT6 in all my amp signal level and have good results with 5E also.
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Old 15th October 2010, 02:37 AM   #925
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Quote:
Originally Posted by gp4Jesus View Post
...except for output...
Here I meant "connecting the finals to the output jacks" Here I would use OFC 12ga

As for the Cat 5e, I have miles of it.

thanks tony
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Old 30th October 2010, 04:33 AM   #926
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Default PS caps for a hafler XL-280

I have an extra set from an XL-280. Are these a good choice to improve PS capacitance & ESR?

I'd like to squeeze these into one of my '280s. is the effort worth it? The $ was right @ under $15 for 4 from ebay.

also how to check DC offset?

thanks tony
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Old 4th November 2010, 10:20 PM   #927
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Default XL-280 stuff

Two items:

1. Looking for power supply improvements or upgrade ideas other than those on TnT-audio.com

2. On the XL-280 schematic I noticed 2 types of grounds.
(Pg 17 of the .pdf)

One looks like a bent pitch fork (chassis ground?) The other, an inverted pyramid.

What concerns me is the 100nF caps that appear to rely on a chassis ground* connected to the final's PS rails near the MOSFETs.
* grounded through the heat sinks attached to case w/sheet metal screws.

Is it worth it to improve it? Can I run a connection to where C20 & C21 are grounded? Or where the RCAs have a way-better chassis ground?

Thanks tony
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Old 5th November 2010, 09:02 PM   #928
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Default DH 500 PS cap upgrade question

Nippon Chemi-Con or Mallory of about the same uF value?
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Old 7th November 2010, 02:07 PM   #929
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Quote:
Originally Posted by scott wurcer View Post
... I run mine (bias) at 450mA (~50W)...
What do you mean "~50W"? Lower power by way of lower rail voltage?

You're welcome to PM your reply

Thnx tony
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Old 7th November 2010, 11:36 PM   #930
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450mA bias times 60V rail voltage is 54W bias (per channel).

This gives about 400mA bias in the outputs, so a peak bias of 800mA before going into class B, or 560mA RMS, which would be 2.5W/8R in class A.
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