Help with some wiring

**Only Alive** · 04-07-2006, 02:53 PM

Ok, so I'm trying to make an attenuator, ala Major Tom. It's for a HRDlx. I've got a 8 OHM 100 watt L-pad, speaker wire, and speaker connector thingies. And that's about all I know. I've got a diagram, but I'm unsure on how to connect it in the spot cirlced below:

As a matter of fact, I'm not even sure how to connect the wires to the L-pad; this is a new experience for me. If someone (I'm looking at you Tom

) could help walk me through the process, that would be great.

-Nick

Major Tom · 04-07-2006, 04:41 PM

I would solder the wires at the LPad, but you could buy some crimp on connectors - the slide on spade lug type used for speakers, 3/16"wide, and put those on the ends of the wires. You would first have to flatten the lugs on the LPad, they are curved. They are also pretty flimsy, so be careful sliding them on. You can buy those I think at radio Shack or auto parts stores.

Here's how to connect, the 3 lugs are marked (embossed into the ceramic casing) 1, 2, and 3:

Lug 1) gets two wires, one to the ground side of the amp's speaker out, and one to the speaker. Put it on the terminal of the speaker that does not have the dot (usually a red dot)

Lug 2) connect to the terminal of the speaker that has the dot

Lug 3) connect to the amp's speaker out, the non-grounded side. If it has a 1/4"

It doesn't matter if you reverse the wires on the speaker, it only matters if you hook up an external speaker - you want them on correctly so both speakers will be in phase.

Connectivity - I attached a pic below of one mounted on a bracket with a 1/4" phone jack, and a 2 foot cable with 1/4" phone plug. The plug of the cable goes into the amp's speaker out jack, the plug of the amp's existing speaker cable plugs into the attenuator's jack.

Same as above;

Lug 1) 2 wires, 1 to the ground of the cable/plug. 1 to the ground terminal of the jack

Lug 2) the tip connection of the cable/plug

Lug 3) the tip connection of the jack

Plug the new attenuator's cable/jack into the internal speaker out of the amp (on my HR, they ain't marked, if you plug it into the wrong one = no sound)

Plug the existing speaker cable/plug into the jack of your new attenuator.

Test it

If you don't get any sound, turn it off.

You may get some smell like burning fish oil from a coating on the resistance element, that should quit after a while. If it smokes, turn the master volume down.

**Only Alive** · 04-07-2006, 04:48 PM

Major Tom saves the day again!

Quick question: I've got some of these fellows, as they were reccomended to me for the project. What are they for? Are they the crimp connectors you mentioned?

EDIT: Also, how long should this project take? I'm worried about not having my amp back together by Sunday morning.

-Nick

Major Tom · 04-07-2006, 05:31 PM

Quote:

Originally Posted by Only Alive

Major Tom saves the day again!

Quick question: I've got some of these fellows, as they were reccomended to me for the project. What are they for? Are they the crimp connectors you mentioned?

EDIT: Also, how long should this project take? I'm worried about not having my amp back together by Sunday morning.

-Nick

Those are male connectors, you would have needed the female. They are also a bit wide at 1/4", although the female ones may have worked ok.

How long....? if you put it on a bracket (you need to for the heat produced), getting that together is the hardest part. Drilling the holes, etc. I don't know, it shouldn't take that long...

**Only Alive** · 04-07-2006, 05:39 PM

Quote:

Originally Posted by Major Tom

Those are male connectors, you would have needed the female. They are also a bit wide at 1/4", although the female ones may have worked ok.

How long....? if you put it on a bracket (you need to for the heat produced), getting that together is the hardest part. Drilling the holes, etc. I don't know, it shouldn't take that long...

Yeah, I've got some female connectors too. I'll probably end up soldering it though, it seems like that would be more solid. I *think* I've got it from here, but I may have more questions later on

-Nick

**Only Alive** · 04-07-2006, 06:38 PM

Hmm, I'm looking at the attenuator pic you posted... I wasn't actually planning on doing it with a 1/4 inch plug like that, I was just going to wire the attenuator (somewhat) permanently into the chain. Can i do that?

-Nick

Major Tom · 04-07-2006, 06:55 PM

Quote:

Originally Posted by Only Alive

Hmm, I'm looking at the attenuator pic you posted... I wasn't actually planning on doing it with a 1/4 inch plug like that, I was just going to wire the attenuator (somewhat) permanently into the chain. Can i do that?

-Nick

Yes. The advantage to the plug n' play version is that it is instantly reversible in case there is an issue, plus you can transfer it to another amp later if desired. Other than that, no problem.

**Only Alive** · 04-07-2006, 09:45 PM

Quote:

Originally Posted by Major Tom

Yes. The advantage to the plug n' play version is that it is instantly reversible in case there is an issue, plus you can transfer it to another amp later if desired. Other than that, no problem.

I can't quite figure out the directions now that I'm leaving out the plug.

I think I get what is attached to lug 1: one from the amp's speaker out (I'm not sure what "grounding side" is, there's only one wire coming out of the speaker out, then it splits to 2), and one going to the speaker (no dot)
Lug 2: Connect to speak (with dot)
Lug 3: Amp's speaker out, non-grounded side. Once again, it's one cable that splits into 2, and I'm not sure how to tell which is which.

-Nick

**Only Alive** · 04-07-2006, 11:53 PM

Hmm, scratch that, I think I've got it. It's put together, and it's tested. It works. Now I just gotta buy a bracket tomorrow and mount it. Thanks Tom, you've been a great help, as always.

-Nick