X250.5 question

aljordan · 19th May 2008, 03:05 AM

Hi,

I am running a Lynx Two B Sound Card directly into a Pass Labs X250.5. The Lynx is switchable between -10dBV and +4dBu outputs. Will running the +4 setting in any way overload the inputs on the Pass X250.5?

Thank you,
Alan

Nelson Pass · 19th May 2008, 04:42 AM

If you mean +4 dBv, this is shy of the power of the amplifier if you
run it at 26 dB. Later versions of the 250.5 are shipped with a 26 dB
default, jumperable to 30 dB. If you have an earlier one, the easiest
solution is to add some resistance in series with the input, say 5.6K
ohm on both + and - inputs, but I wouldn't do this unless you actually
experienced a problem, since the spec is the max, and likely you will
not see the figure.

-10 on the other hand, is probably not enough.

aljordan · 29th May 2008, 07:33 AM

Hello,

Thank you for answering my query. I read in the X250.5 user manual about the improved harmonic and RF filtering of the .5 amplifiers. Given this, is there any reason to run power condition or regeneration in front of the amplifier?

Thanks,
Alan

Nelson Pass · 29th May 2008, 08:25 PM

Line filtering which doesn't limit the input draw is my preference,
which largely corresponds to the Richard Grey type filters,
parallel LC across the line, resonant at the line frequency.

Having said that, Wayne was running a PS Audio Power Plant
Premier with three amplifiers and liked the results. It did
ultimately break, although we don't know why.

I consider three of our amplifiers a bit excessive, though.

19th May 2008, 03:05 AM	#1
aljordan diyAudio Member Join Date: May 2006	X250.5 question Hi, I am running a Lynx Two B Sound Card directly into a Pass Labs X250.5. The Lynx is switchable between -10dBV and +4dBu outputs. Will running the +4 setting in any way overload the inputs on the Pass X250.5? Thank you, Alan

29th May 2008, 07:33 AM	#3
aljordan diyAudio Member Join Date: May 2006	Thank you and one further question Hello, Thank you for answering my query. I read in the X250.5 user manual about the improved harmonic and RF filtering of the .5 amplifiers. Given this, is there any reason to run power condition or regeneration in front of the amplifier? Thanks, Alan

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19th May 2008, 04:42 AM	#2
Nelson Pass The one and only Join Date: Mar 2001	If you mean +4 dBv, this is shy of the power of the amplifier if you run it at 26 dB. Later versions of the 250.5 are shipped with a 26 dB default, jumperable to 30 dB. If you have an earlier one, the easiest solution is to add some resistance in series with the input, say 5.6K ohm on both + and - inputs, but I wouldn't do this unless you actually experienced a problem, since the spec is the max, and likely you will not see the figure. -10 on the other hand, is probably not enough.

29th May 2008, 08:25 PM	#4
Nelson Pass The one and only Join Date: Mar 2001	Line filtering which doesn't limit the input draw is my preference, which largely corresponds to the Richard Grey type filters, parallel LC across the line, resonant at the line frequency. Having said that, Wayne was running a PS Audio Power Plant Premier with three amplifiers and liked the results. It did ultimately break, although we don't know why. I consider three of our amplifiers a bit excessive, though.