My_Ref Fremen Edition - Beta build/Fine tuning

[ClaveFremen]

I can show you how I branched mine (see attachment and pay attention on traasnformer's label and colors order).

Colors are written in French:
Violet/Gris -> Purple / Grey
Bleu/Rouge -> Blue / Red

Your transformer do have a label with secondaries indication?

The build seems fine but I can't see the input cap... are you DC-coupling?

And smoothing caps?

 

[bcmbob]

Big Caps in, Sonicaps mounted at C13 and heat sinks on R3 / LM3886.

 

[ClaveFremen]

And transformer label?

 

[bcmbob]

Unfortunately this toroid doesn't have that detail on the label. What's in the picture is what I've been using on the V1.2 and V1.3 amps as well as the BrianGTs. Red/Hot (outside on terminal) wires to AC1 & AC2 - Black wires (Neut on above photo - two inside wires) to grounds. On Siva's V1.3 I used two ground wires direct from the Euro style terminal to include the extra ground terminal he put on that board.

 

[bcmbob]

Here is the V1.3 connections. Green wires in this pic are the same as the black inside wires of the Euro terminal on the test rig for the FE.

 

[bcmbob]

Sorry, I missed posting these two pictures. Now it might make sense.

 

[ClaveFremen]

mmh... without secondaries indications I can't figure out how to tell if wiring is correct...

 

[bcmbob]

In the picture on post #126 the black and blue wires from the transformer form a continuity loop. The yellow and red wires form the other. Does that help? I have an extra Antek unit with info on label but it is 34V

 

[ClaveFremen]

In the picture on post #126 the black and blue wires from the transformer form a continuity loop. The yellow and red wires form the other. Does that help? I have an extra Antek unit with info on label but it is 34V

Do you remember transformer data (VA, code, etc.)

On Antek website there are datasheets with secondaries indications

 

[ClaveFremen]

What's in the picture is what I've been using on the V1.2 and V1.3 amps as well as the BrianGTs. Red/Hot (outside on terminal) wires to AC1 & AC2 - Black wires (Neut on above photo - two inside wires) to grounds.

When you make a center tapped connection from a double secondaries transformer on centre tap goes neutral from one secondary and hot from the other.

So that connection is not right for the FE, you should discover which of the wires tied on center tap on RevC is hot.

 

[bcmbob]

These are the pieces I got from ApexJr.

Wattage: 160
120 VAC @ 60HERTZ
White/White.

If your NAC1/NAC2 correspond to ground on the other MyRefs - and your AC1/AC2 is the same as those on the older MyRefs, then we should be O.K.

I've used these on every MyRef I have built.

 

[ClaveFremen]

If your NAC1/NAC2 correspond to ground on the other MyRefs - and your AC1/AC2 is the same as those on the older MyRefs, then we should be O.K.

No, it's not so... see my previous post.

One of the wires you connected to PGND on Rev C is hot, that wire on the FE must go to AC1 or AC2

 

[bcmbob]

O.K. I'll try to trace it down. Can you explain what is different between this and the MyRefs. I'm not understanding. Why is it more critical in this case?

 

[ClaveFremen]

In the picture on post #126 the black and blue wires from the transformer form a continuity loop. The yellow and red wires form the other. Does that help?

this say that black/blue are one scondary and yellow/red the other.

 

[bcmbob]

On a spare (twin) If I connect one probe to either white AC supply wire on the toroid, there is NO continuity to any of the secondary out leads. Don't know where to go from here.

In the U.S. black is hot and white is common. I can assure which is which from the house service box all the way to the toroid, but with no indication of continuity on the toroid itself, It's only a guess.

I can hold off till I get a proper unit from Antek if that's your recommendation. It would be here by the end of the week

 

[ClaveFremen]

O.K. I'll try to trace it down. Can you explain what is different between this and the MyRefs. I'm not understanding. Why is it more critical in this case?

See this picture from Decibel Dungeon (double secondaries to center tap, like in RevC):

The dot indicates hot (phase). (read this)

In Rev C a center tapped transformer is needed since it uses a single bridge, the FE uses a double bridge, each of these bridges needs a secondary.

In center tapped connection virtual ground comes from secodaries wiring, in double bridge (and thus double secondaries) virtual ground come from the bridges.

On the transformer you should have a label like this:

(picture from Decibel Dungeon)

Or at least a model number so that you canfind a datasheet on manifacturer website.

The FE is wired like double bridge Gainclones:

 

[bcmbob]

Understood. This has been my guide and I now see the differences. These ApexJr toroids are of the blue highlighted type..

I'll contact Antek in the morning. I have two of the correct toroids in the Integrated build but I'm not going there

Thanks for your time and support.

P.S. I looked last year and only number on the label is a customer number. That's what one gets when buying "surplus" goodies

 

[ClaveFremen]

For transformers in picture;

AC1 Red
NAC1 Yellow

AC2 Blue
NAC2 Grey

 

[bcmbob]

Sounds great, but how did you determine that?

 

[ClaveFremen]

Sounds great, but how did you determine that?

As you can see on decibel doungeon picture the dot (phase) on each secondary in on the upper lead, as it is on the primary.

So upper wire is AC (phase/hot) and lower one NAC (neutral).

But I see now that phase in your picture is inverted (lower lead), so it is the contrary:

AC1 Yellow
NAC1 Red

AC2 Grey
NAC2 Blue

But probably it works also like in the previous post but it would be out of phase.

Any transformer guru can confirm it?