[BUILD] 1176LN Rev D DIY

[canidoit]

I think you have the new board.  No jumpers needed. 

I have the matched 2N5457's on my store.  I haven't started stocking the 3708 and 5088's yet.  I've been super busy with some new stuff, I will look into this again this week.

Mike

This is how my Mnats Xformer board look like. Do they look like the new Mnats one that does not require jumpers or leads for th altran Xformer? I haven't found any instructions on these except what's written on the board.

 

[luis]

Can the output transformer be damaged if wired wrong? I wired mine wrong and burned the r32 resistor and now i´m afraid that my output tranformer might be damaged.

Also, is it possbile to check if the transformers (input and output) are working with a DMM?


Thanks

 

[Echo North]

canidoit:
If that is your board then you need to add 2 sets of jumpers.  Luckily the instructions are right on the board.

Luis:
I doubt it's damaged. Lots of people have accidentally wired the OT wrong and had R32 flame up (including me!). 

Mike

 

[Dean Roddey]

So here are some more dumb questions...

What are the gray dotted lines in Skylar's wiring diagram for? Does that indicate shielded cable I guess?

Also, it's not obvious to a software guy like me just looking at it, but I assume that one of the positions on the meter selection knob in the rotary version is the power off switch for the unit?

And what does NC mean in the diagrams? Obviously they are grounds, but not sure what initials are for. And if it's a ground, why, for instance, does it run over to the meter or ratio board, but show no connection to the meter or ratio board? I'm sure I'd see the answer to this when I go back to the wiring guide, but I'm just pointing out what doesn't make sense as a non-electronics guy, so that maybe it can be clarified in the diagram.

 

[Echo North]

So here are some more dumb questions...

What are the gray dotted lines in Skylar's wiring diagram for? Does that indicate shielded cable I guess?

Yes.

And what does NC mean in the diagrams? Obviously they are grounds, but not sure what initials are for. And if it's a ground, why, for instance, does it run over to the meter or ratio board, but show no connection to the meter or ratio board? I'm sure I'd see the answer to this when I go back to the wiring guide, but I'm just pointing out what doesn't make sense as a non-electronics guy, so that maybe it can be clarified in the diagram.

You connect one end of the shield to ground because if you connected both you would have a ground loop (or be susceptible to one).

Mike

 

[canidoit]

And what does NC mean in the diagrams?

I thought it meant "not connected".

 

[Echo North]

And what does NC mean in the diagrams?

I thought it meant "not connected".

Yes, that end is "not connected" to avoid a loop.

 

[canidoit]

canidoit:
If that is your board then you need to add 2 sets of jumpers.  Luckily the instructions are right on the board.

OIC, you have to read up to the third line and the ABCDEF is underneath my Altran.

So B to C and E to F

 

[Echo North]

And also the the two links for no H-Pad up by the input.

 

[luis]

I think you have the new board.  No jumpers needed. 

I have the matched 2N5457's on my store.  I haven't started stocking the 3708 and 5088's yet.  I've been super busy with some new stuff, I will look into this again this week.

Mike

Hey Mike match them all, and I think it would be great if you could sell all the pots and specially the SPDT switch because in Europe is very dificult to find!

Thanks

 

[Echo North]

Hi,

I'm working on all of these things right now.

I'm reviewing pot samples as we speak.  Stocking the right pots will take a huge investment.  It is on my list once I get through the next large project.

Transistors with high HFE will come sooner.

Mike

 

[Dean Roddey]

Why do I see in some folk's pictures a 2 watt resistor on one of the wires coming from the power transformer? I ordered it because it's in the BOM, but I don't see everyone using one in the various pics I've looked at, as best I can tell.

 

[Dean Roddey]

My other dumb ordering snafu was that somehow I ordered a freaking 19" deep enclosure. So it gigantically larger than required. I could move into it basically. Oh well, at least I shouldn't have any hum issues. I can keep the power transformer about a quarter mile from the other components.

 

[luis]

Why do I see in some folk's pictures a 2 watt resistor on one of the wires coming from the power transformer? I ordered it because it's in the BOM, but I don't see everyone using one in the various pics I've looked at, as best I can tell.

I think you are refering to the meter lamp, wich need 2 watt resistors.

 

[Dean Roddey]

And more dumb questions... Whose POV are the Input/Output designations on the Hairball input xformer board? So the XLR/T-Pad go to the Input terminals and the Output terminals go to the input on the main board?

 

[luis]

My other dumb ordering snafu was that somehow I ordered a freaking 19" deep enclosure. So it gigantically larger than required. I could move into it basically. Oh well, at least I shouldn't have any hum issues. I can keep the power transformer about a quarter mile from the other components.

;D Yeah, but the giant case will not come pre-grounded!

 

[Dean Roddey]

Why do I see in some folk's pictures a 2 watt resistor on one of the wires coming from the power transformer? I ordered it because it's in the BOM, but I don't see everyone using one in the various pics I've looked at, as best I can tell.

I think you are refering to the meter lamp, wich need 2 watt resistors.

So they are piggybacking that onto two of the power transformer inputs into the board?

 

[canidoit]

Why do I see in some folk's pictures a 2 watt resistor on one of the wires coming from the power transformer? I ordered it because it's in the BOM, but I don't see everyone using one in the various pics I've looked at, as best I can tell.

I think you are refering to the meter lamp, wich need 2 watt resistors.

So they are piggybacking that onto two of the power transformer inputs into the board?

This is a better view. I have seen that big chunky resistor on the left side as well. I think it's both AC on both 1st and 3rd of the Molex. From the pics I have gathered, it goes to the VU lamp. Measure the power coming from the wire going to the 1st and 2nd molex and see if it comes out with 35 volts. The 220 ohm 5 watt resistor is to downgrade the 35 volts to 11.78 volts for the lamp. I haven't gone that far with my build but if those wires to the molex pulls out 35 volts, then I guess thats where the 35 volts are being sourced for the VU lamp for the 220R resistor. Wait till someone can confirm this before trying it incase I am wrong???

 

[Echo North]

That is the voltage dropping resistor for the VU lamp.

The secondary is wired with a center tap (0V).  The voltage between either side of the secondary and the center tap is 25V.  So set your DMM to AC and put your + on either the right or left terminal, then your - on the center terminal and you should get roughly 25V.

Your lamp likes 11V and it doesn't care if it's AC or DC.  Here's where Ohm's Law (V = IR) drops by to help us.

We need to drop the voltage by 14V.  I know my VU is drawing about 0.063A.

R=14/0.063A
R= 222R

There is really no need to guess.

Edit:

Also, if P=V*A, then in this case we've got about 1W of power.  A 2W resistor should do.

Mike

 

[luis]

....

Luis:
I doubt it's damaged. Lots of people have accidentally wired the OT wrong and had R32 flame up (including me!).  

Mike

Well, my compressor passed sound before, the meter moved (when I had the OT correctly wired) and now after burning the  R32 due to ot wired wrong , the sound does not pass neither the meter moves.
I already unsolder all transistors, and will try again with new transistors. My doubts:

- even with the transistores damaged should the sound pass?
Can the wrong OT wiring damage other components beside R32?

Thanks