Need help to understand the HT power supply in this schematic

[shooter]

Hi,


Anyone understand the HT part of this power supply? D12,13,14,15 and the two zener diodes ??





Thanks,


Billy

[shooter]

WOW


How the hell did that happen? That posted as if it was from Shooter??????????????????


I will log out and back on to see if I am planobilly or shooter...lol


Billy

[Planobilly]

Test

OK, looks like I am planobilly again.....have no idea how that happened

Billy

[PRR]

I hope you two figure out your identity crisis. It is very worrisome when computer log-ins appear to be switched.

> D12,13,14,15 and the two zener diodes ??

Give us an image we can read. I even got a wide-screen, but this is wider and MUCH too tall. When manipulated it loses quality.

Nevertheless, I have extracted the small area you mean.

This is apparently an >450V design. That means stacked-caps. That means trouble with un-equal voltage-split across the stack caps.

The first-caps are solidly equalized by the PT CT.

The 2nd-caps are loosely equalized by two 220K resistors.

They apparently felt that was not enough. And ran a 95V Zener between the two stacks' center points. If they get more than 95V apart the Zener pulls them together.

95V Zeners are rare. 47V Zeners are common. Use two.

We want bi-directional so 95V *either* way is clamped. There's a way to do this with two Zeners (four here). However you can use plain (cheap) diodes to steer the voltage onto one (two) Zeners.

It does seem like belt and braces and screw and duct-tape design. But the whole amp seems an exercise in excess parts.

[Planobilly]

Thanks PRR,

I assumed the zeners clamped the voltage. I had not encountered this sort of power supply before. The whole EVH 5150 is a bit of a strange beast to begin with.

I am trying to build something similar to the second channel and combine a typical Bassman circuit as the first channel. We have it up and running or at least the second channel but I have many issues to solve. Actually I am not sure me and my buddy Dave can make the new amp work at all . I have more hum and hiss than I can live with so I am taking another look at the power supply design we used which was not built like the schematic.

Sorry about the crappy schematic post....I should have provided a link.

Thanks,

Billy

[shooter]

It's the real shooter, sorry Bill, used your 'puter to hunt down info.

there's the schematic Bill's asking about

EDIT:  the later version did away, wisely?, of that section.

[Willabe]

It's the real shooter, sorry Bill, used your 'puter to hunt down info.

So you 2 know each other?

And Shooter you logged onto the forum on Billy's computer, didn't log out and then Billy posted thinking he was logged on under his/Billy's name?   

[sluckey]

That would explain it. But one is in Michigan and the other is in Homestead Florida.

[Planobilly]

Shooter and I live a long way  apart but this is the Bermuda Triangle down here where I live so anything is possible.....lol

Actually he came down to visit me.

Cheers,

Billy

[shooter]

It does seem like belt and braces and screw and duct-tape design. But the whole amp seems an exercise in excess parts.

PRR you have captured the design perfectly!

But one is in Michigan and the other is in Homestead Florida.

just 24hrs away, divide that by the number of hours in 59yrs and it's like a drive to the beer store

[EL34]

Ok, I am curious how this happened?

Looks like shooter used Billy's computer at one point and logged in here as Shooter?

Then Billy got logged in automatically because shooter had used that computer last and it remembered his log in

Is that correct?

[shooter]

That was it, I was assisting bill on a project, he was busy and I needed an answer to a bias question, logged in, got my answer here but forgot to log out, long day, tired, walla

[pompeiisneaks]

Lol you guys scared Doug :)

[PRR]

> you guys scared Doug

We had another member making trouble and trying to break into other members' accounts.

This did not look like that, but still extremely strange.

There is always the risk that my dogs will sneak onto the computer when I am away and start posting dog-topics, or growling at other members under my name. I figure that is unlikely. (The little dog can't reach, and the big dog is too dumb.) Since the next nearest folks who know this forum are 30+ miles away, and don't know quite where I live, I don't usually log-out.

However when a fellow member is in your house (or you both at the same library computer), it would be nice to agree who is who and log-out when done. Also LOOK at the top of the page and see if it says "Hello YOU" and your avatar, angry-sheep or dog-man or whatever.

Glad you guys got together. Glad you straightened out who is who.

[shooter]

I don't usually log-out.

my down-fall, I only have cats to worry about, and they CAN type!

[sluckey]

I had that problem too! Installed a nice aquarium screen saver and cat has not used the keyboard since. 

[shooter]

Nice!  In the cornfields I only have WiFi, so I just disable the connection, the cats can type away without eating my bandwidth!  They still like digging  old tubes outta the bins, batting them down the stairs and watching them shatter!

[Planobilly]

It actually took me a bit to even remember who "Shooter" even was. I forgot "Shooter" was at my house. Some guy named Dave was here...lol If I had put two and two together I would have realized how that could have possibly happened.

There are so many behind the scenes uncommanded actions that occur with computers anything is possible now days.

Anyway no harm done.

Cheers,

Billy