Assembly Instructions

[kid]

What is the likelyhood that the assembly instructions will be updated very soon? I have many questions regarding this and would like to avoid asking them all here if the assembly page is going to be updated soon.

[tpryan]

I'll be out of town until 11/12. Instructions will be updated by 11/19. The posted instructions are for the previous board revision, but are still useful for the general order of assembly. You can refer to the A12 instructions regarding voltage regulator adjustment.

[kid]

Any chance you might be able to give some insight into what to do for the jumpers? I've got everything assembled and would like to start testing. I just don't know what to do with the jumpers.

[tpryan]

J3 and J4 should be jumpered like the A12 and N72, with the "outside" pair connected unless you have ground loop problems.

J5 connects the 604R load resistor. Keep this jumpered unless you're driving a 600 ohm load, like an old tape machine or mixer. The great majority of modern gear will has input impedances of 10K or higher.

J1 and J2 select input impedance. For most mics, jumper the pair of headers closest to the input transformer and leave the other pair open. For 50 ohm ribbon mics, use two jumpers perpendicular to the input transformer.

[tpryan]

Updated J99 assembly instructions are up. Please let me know if you discover any problems.

[auralman]

For purposes of the jumpers? It would really help. For the N72, also.

Thanks

[tpryan]

J99 - Step 8
N72 - Step 6

[auralman]

apologies, but I don't understand - the jumpers aren't connected in those photos? They're on the PCB, but nothing's strapped?

[tpryan]

No, the jumpers are not installed in the photos. But what is unclear about the instructions?

[Category 5]

The only thing not clear in the instructions is when jumpering the input transformer for a 1000ohm load (standard mics) J1 and J2 should be jumpered together using the TOP 2 pins. The assembly only specifies that J1 and J2 should be jumpered using a single jumper, but do not specify whether it is the top or bottom pins.

As stated a couple of messages back in this thread, it should be the top 2 pins (closest to input tranny).

Shane

[auralman]

I keep not having time to finish these things...but here I am


Okay - my confusion is this - There is no J4 on my board. Just a J3 with 4 pins. This is why I have no idea what to do with it. Doesn't match instructions, pictures, ???

Otherwise happy and digging it. the N72s kill.

[tpryan]

You must have a rev 2.x board. For 1000 ohm input impedance, jumper the right hand pair of J3 and leave the left hand pair open. For 250 ohm input impedance, jumper the top and bottom pairs of J3. This is with the board oriented with the contols on the left and XLRs on the right. You can always figure this out from the schematic and transformer data sheet if you forget.

[auralman]

rawk. much thanks tim. that totally answers the question

[auralman]

HELP!

It seems like everything is hooked up right, voltages are kosher...but no sound. I hear the amp working - i.e. when I turn it up I hear the noise floor come up, but no input signal is getting there. Same thing happened to me with the N72, just had to apply the jumper at CONN3...but there doesn't seem to be instructions for me to follow for the rev2.0 board up on the site anymore. Suggestions?

[tpryan]

Do you have jumpers or "load isolators" installed at Z1 and Z2? Do you have the coax jumper installed between J4, J6 and J5, J7?