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Planar Speaker Asylum Welcome! Need support, you got it. Or share your ideas and experiences. |
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In Reply to: RE: Satie, thanks for the picture posted by Satie on August 14, 2010 at 13:17:11:
coupling caps. When I spoke to the maker of my preamp about using it with a Pass Labs X250, he had this to say:
"However, I see that it is a DC amplifier (can amplify signal right down to 0 Hz) and that may be an issue with any tube preamp. There are bound to be some start-up or switching transients in the tube circuitry that will pass straight through the power amp to the speakers and cause some popping and significant cone excursions. You can take precautions, such as always powering on the preamp 30 sec before the power amp and vice-versa on power down, but sooner or later you may end up damaging the power amp and/or speakers (although the power amp should have built in protection). If you do choose to go with this amp, perhaps you should consider canceling your preamp order and I will refund your deposit. I would hate to see you do damage to your power amp or speakers."
Regards,
Lloyd
Lloyd Peppard
Mapletree Audio Design
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Lloyd was definitely against using his preamp with an amp capable of DC amplification. Doesn't this mean that if the amp has frequency response of 7 hz to 100k hz, the amp would not amplify the DC signal generated by the preamp and therefore the amplified DC signal would not get to the speaker? By having a lower cutoff to frequency response, the amp is filtering out DC.
I was blowing fuses on start-up with the Threshold wired direct to the mid/tweeter panel. Isn't it possible that my preamp generated the DC, the amp amplified it because the frequency response of my amp must be 0 hz to 100k hz. There is no high pass filter on the internal crossover for the mid. The high pass mid filter is on the external crossover. The fuse responded appropriately protecting the mid from DC? An un-amplified DC signal would have been harmless.
And if that is the case, wouldn't an active crossover which sent only 350 hz and higher to the mid/tweeter panel protect the midrange from DC?
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Follow Ups
- Satie, I don't think my preamp has - rrob 15:08:32 08/14/10 (3)
- RE: Satie, I don't think my preamp has - Satie 16:02:24 08/15/10 (2)
- RE: Satie, thanks for checking - rrob 16:33:04 08/15/10 (1)
- RE: Satie, thanks for checking - Davy 17:34:21 08/15/10 (0)
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