RE: +2

RE: +2

Posted by Triode_Kingdom (A) on May 28, 2015 at 08:17:13

In Reply to: RE: +2 posted by 91derlust on May 28, 2015 at 00:35:00:

"Glad you had a chuckle. I'm not an EE - am I expected to know this, or is asking questions okay?"

I wasn't laughing at you, it just reminded me that we have a few members here who invented hi-fi. They're constantly "discovering" micro-minutiae that the rest of us should care about, often just by listening. :)

"So, the fluctuations do occur in SET amps playing music, but should average over time. Are the fluctuations relevant then, or should a supply provide enough energy to handle these over the time taken for the averaging to occur? Or both?"

The fluctuations must be averaged over time for the purpose of determining whether average current is really changing. However, they represent *instantaneous* changes, because they mirror what the source material is doing. In that respect, the power supply must be designed so that those instantaneous current changes don't create instantaneous voltage changes on the B+ rail. IOW, the PS must be able to hold it's voltage constant despite changes in average current, as well as the instantaneous current changes that result from amplifying music. The former is where regulation comes in. However, in a SET, average current changes are really miniscule, so I don't worry much about power supply regulation. The instantaneous current changes are a big deal though. Luckily, the supply only needs to exhibit a low Z output over frequency to deal with that. This is a reasonably simple goal to accomplish, and we have tools now that weren't readily available 20 years ago. The supply can be modeled in SPICE, and the simulation will let the designer "look" back into the supply to see how it will react to the amplifier's instantaneous current demands. LTspice (also known as Switcher CAD) is free to download online.

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Follow Ups Full Thread

Topic - PSUD Playtime - 91derlust 02:40:51 05/27/15 (36)

RE: PSUD Playtime - Mike C 15:28:40 06/07/15 (1)

RE: PSUD Playtime - drlowmu 15:21:07 06/11/15 (0)

Limitations of PSUD - Triode_Kingdom 15:48:07 05/27/15 (1)

RE: Limitations of PSUD - 91derlust 17:33:08 05/27/15 (0)

RE: PSUD Playtime - drlowmu 09:03:41 05/27/15 (21)

850mV - Caucasian Blackplate 11:21:42 05/27/15 (20)

RE: 850mV - 91derlust 17:39:06 05/27/15 (19)

The Serious Stereo amp has 850mV PS ripple? - 91derlust 20:59:27 05/29/15 (16)

Don't Know That !! - drlowmu 13:42:09 05/31/15 (15)

RE: Don't Know That !! - 91derlust 13:17:10 06/01/15 (4)

RE: Don't Know That !! - Tre' 13:55:27 06/01/15 (3)

RE: Don't Know That !! - dave slagle 17:52:23 06/01/15 (2)

RE: Don't Know That !! - rage 11:45:02 06/04/15 (0)

Yes. Thank you. (nt) - Tre' 22:18:35 06/01/15 (0)

RE: Don't Know That !! - cpotl 00:53:55 06/01/15 (9)

RE: Don't Know That !! - Al Noakes 08:32:50 06/01/15 (4)

Apples and Oranges and Peaches - drlowmu 08:49:12 06/01/15 (3)

RE: Apples and Oranges and Peaches - Al Noakes 10:18:23 06/01/15 (2)

RE: Apples and Oranges and Peaches - drlowmu 16:56:16 06/03/15 (1)

RE: Apples and Oranges and Peaches - Al Noakes 06:37:53 06/04/15 (0)

RE: Don't Know That !! - drlowmu 07:13:17 06/01/15 (3)

RE: Don't Know That !! - cpotl 07:33:08 06/01/15 (2)

RE: Don't Know That !! - drlowmu 08:52:33 06/01/15 (1)

RE: Don't Know That !! - cpotl 09:01:54 06/01/15 (0)

RE: 850mV - drlowmu 16:00:33 05/28/15 (1)

RE: 850mV - Caucasian Blackplate 19:09:46 05/28/15 (0)

RE: PSUD Playtime - Tom Bavis 07:36:36 05/27/15 (9)

+2 - Caucasian Blackplate 11:24:41 05/27/15 (7)

RE: +2 - 91derlust 19:46:27 05/27/15 (6)

RE: +2 - Triode_Kingdom 22:06:50 05/27/15 (3)

RE: +2 - 91derlust 00:35:00 05/28/15 (2)

RE: +2 - Triode_Kingdom 08:17:13 05/28/15 (1)

RE: +2 - 91derlust 13:06:41 05/28/15 (0)

RE: +2 - Paul Joppa 20:17:39 05/27/15 (1)

Informative, as usual. - 91derlust 21:54:33 05/27/15 (0)

+1 What Tom said (nt) - Triode_Kingdom 10:40:35 05/27/15 (0)

Follow Ups

RE: +2 - Triode_Kingdom 08:17:13 05/28/15 (1)

RE: +2 - 91derlust 13:06:41 05/28/15 (0)

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