RE: Ugly, it's a good thing you asked ahead of time

Posted by Ugly (A) on October 11, 2014 at 08:58:54

In Reply to: RE: Ugly, it's a good thing you asked ahead of time posted by jedrider on October 11, 2014 at 07:49:06:

"That's NOT a doubly or a doubler!"

It's something like that. I haven't bothered to reverse engineer the thing. I am not planning to reuse any of it.

"18 VAC RMS"

Reread what I wrote. Not RMS, I said zero to peak.

Here is a picture I took last night of the transformer output into the preamp when it was running. 5V/div, 2mS/div.

"You should measure and report on the scope trace at the output rails AFTER the regulators"

Did you read the post you are responding to? I described it in a way I considered to be pretty clear at the time. What exactly don't you get about my description? The picture didn't seem all that interesting to me since it looks almost identical to the one I posted last night.

Here it is. Ac coupled view of noise on +18V rail if i recall correctly. 5mV/div, 5mS/div.

"it is unclear whether the preamp runs on balanced rails OR a single rail."

Hmm. Only unclear if someone hasn't actualy been reading the thread. I mentioned before the audio sections have plus and minus 18V rails.

"I suspect balanced rails, i.e., +9-0--9 and not +18-0"

Yes it's plus and minus 18V rails.

"You should trace the diagrams out by careful examination. Here are ways voltage doublers actually work, but I don't think that is what you have"

Not doing it. The chances of me reworking the existing supply are very slim. Doesn't seem worth it at all. My preferred method is off the shelf but if I diy I'm scrapping everything and starting over.

"Yes, in general, they are NOT a good idea"

I get why they would have gone that route but there would be no reason for me to use that type of circuit if were trying to upgrade other than if I were trying to reuse some of the existing circuitry for some reason.

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Follow Ups Full Thread

Topic - Phono preamp supplies du jour. Saving money. Maximizing convenience. - Ugly 20:45:41 10/06/14 (25)

I might give this a try. - Ugly 18:55:19 10/11/14 (4)

RE: I might give this a try. - jedrider 21:56:07 10/11/14 (3)

RE: I might give this a try. - Ugly 08:31:29 10/12/14 (2)

RE: "Verry tempting." - 1973shovel 09:31:36 10/12/14 (1)

RE: "Verry tempting." - jedrider 09:51:53 10/12/14 (0)

Ugly, it's a good thing you asked ahead of time - 1973shovel 10:23:36 10/07/14 (19)

RE: Ugly, it's a good thing you asked ahead of time - Caucasian Blackplate 22:52:23 10/08/14 (13)

RE: "no harm will be done by throwing DC at it." - 1973shovel 15:59:39 10/10/14 (0)

RE: Ugly, it's a good thing you asked ahead of time - Ugly 06:34:43 10/09/14 (11)

RE: Ugly, it's a good thing you asked ahead of time - Caucasian Blackplate 16:48:26 10/10/14 (3)

RE: Ugly, it's a good thing you asked ahead of time - Ugly 21:39:23 10/10/14 (2)

RE: Ugly, it's a good thing you asked ahead of time - jedrider 07:49:06 10/11/14 (1)

RE: Ugly, it's a good thing you asked ahead of time - Ugly 08:58:54 10/11/14 (0)

RE: Ugly, it's a good thing you asked ahead of time - jedrider 07:04:17 10/09/14 (6)

RE: Ugly, it's a good thing you asked ahead of time - Ugly 21:17:04 10/09/14 (5)

RE: Ugly, it's a good thing you asked ahead of time - jedrider 07:29:50 10/10/14 (4)

RE: Ugly, it's a good thing you asked ahead of time - Ugly 08:38:19 10/10/14 (3)

RE: Ugly, it's a good thing you asked ahead of time - jedrider 09:17:10 10/10/14 (2)

Please see my new post above to CBP. It addresses some of your points. -t - Ugly 21:59:33 10/10/14 (1)

RE: Please see my new post above to CBP. It addresses some of your points. -t - jedrider 10:14:34 10/11/14 (0)

RE: Ugly, it's a good thing you asked ahead of time - Ugly 11:10:51 10/07/14 (4)

RE: Ugly, it's a good thing you asked ahead of time - jedrider 05:32:16 10/08/14 (1)

RE: Ugly, it's a good thing you asked ahead of time - Ugly 06:38:43 10/08/14 (0)

It sounds like you have it well in hand. Good luck. (nt) - 1973shovel 04:43:56 10/08/14 (1)

I hope so. Thanks! -t - Ugly 06:43:24 10/08/14 (0)

Follow Ups

RE: Ugly, it's a good thing you asked ahead of time - Ugly 08:58:54 10/11/14 (0)

RE: Ugly, it's a good thing you asked ahead of time

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