PM-1000 racking - cutting down to size

[idylldon]

[quote author="Echo North"]Another question:

For the phase the three wires coming from the xlr input go to one side of the DPDT switch and then I connect the three coming from the gain knob to the other side?

I do that but have no signal...how should I be hooking it up to the DPDT switch?[/quote]

Those diagonal lines are jumper wires. The ground wire from the XLR is not needed on the switch, but you should use shielded cable for the run between the XLR connector and the switch. Ground the shield only at the XLR end. If you use Neutrik connectors that have a ground tab on them, you can use the shield wire as a jumper between that ground tab and pin 1 on the XLR, killing the proverbial two birds with one stone.

If you mount the switch with the XLR wires pointing up to the top of the chassis, then the phase will be:

Switch down: normal phase
Switch up: reversed phase

Cheers,
--
Don

 

[Echo North]

Awesome!

Thanks again guys. I'll get back on this tonight with a lot more knowledge in hand. Once I get the Phantom and phase installed, I'll be ready to rack!

Mike

 

[JdJ]

Hey everybody-

Thanks for all the info posted this far. I have a few questions that I'm sure most can answer.


Sco- First regarding the DI- it appears that you have a switching 1/4" jack correct? I assume if this is the case that the switch de-activates the mic input/transformer.

I can't quite tell where it goes in between the transformer/board terminal- which terminal and which lead?

Here's an other one- did you all just tie the mic input ground to the chassis directly? I can't really tell in Sco's original pic, but I don't see a ground coming from the input XLR, and the original ground on the red cable (leading to the gain pot) was trimmed from the factory.

One last thing- How the he** do you get the nuts loose on these pots? The threaded sleeve just seems to be turning with the nut as I try to loosen it- I'm afraid I'm going to have to destroy the pots just to get the ones I don't need out!

Thanks!!

--Josh

 

[Scodiddly]

[quote author="JdJ"]
Sco- First regarding the DI- it appears that you have a switching 1/4" jack correct? I assume if this is the case that the switch de-activates the mic input/transformer.

I can't quite tell where it goes in between the transformer/board terminal- which terminal and which lead?
[/quote]
Yup, it's a switching jack. I think it's the yellow wire from the transformer that I'm interrupting. It's whatever wire is the "output" from the input transformer, so I go between that and where it connects to the circuit board. corrected 1/24/2006

Here's an other one- did you all just tie the mic input ground to the chassis directly? I can't really tell in Sco's original pic, but I don't see a ground coming from the input XLR, and the original ground on the red cable (leading to the gain pot) was trimmed from the factory.

Grounding is interesting - the chassis is not connected directly to the circuit board. I think that I ended up doing star grounding, by only having one chassis connector that actually grounded to the chassis (a 1/4" jack for unbalanced output). Everything else floated, including using a nylon Re'an jack for the DI so that it wouldn't ground to the chassis.

One last thing- How the he** do you get the nuts loose on these pots? The threaded sleeve just seems to be turning with the nut as I try to loosen it- I'm afraid I'm going to have to destroy the pots just to get the ones I don't need out!

Yup, you'll find some tight ones. Use a socket and ratchet, and just keep at it. I've had ones that spun a bit like you describe, and they still worked fine after I finally got the nut loose.

 

[JdJ]

Grounding is interesting - the chassis is not connected directly to the circuit board. I think that I ended up doing star grounding, by only having one chassis connector that actually grounded to the chassis (a 1/4" jack for unbalanced output). Everything else floated, including using a nylon Re'an jack for the DI so that it wouldn't ground to the chassis.

Cool- this seems pretty straight forward. Did you end up attatching a ground lead to the red input line where I see the heat shrink in the original pic (where the casing is stripped before the wire meets the gain pot)? I would assume that you'd want to use the ground in the 3-conductor line for its shielding properties instead of running a separate ground wire to pin 1 on the input, right?

Can you phase reverse the grounded 1/4" unbalanced output? I was thinking these would have to float too if I wanted the phase switch to work on them as well.

Cheers-

--J

 

[Echo North]

Phantom Power Problems

Ok, So I fed the orange wire 48v from the power supply. No Phantom power. I tested with a multimeter and there are 48 volts being fed into pin 2 and 3 at the xlr input. This is correct right?

What could my problem be? I have old xlr connectors that indicate at

3
1 2

pin configuration. Is that the problem?

isn't usually:

1
3 2

Any idea's?

Mike

 

[Scodiddly]

Yup, should be 2 & 3. Make sure pin 1 is grounded, otherwise you don't have a circuit.

 

[Echo North]

Opps...I wasn't grounding it. I probably shouldn't be allowed near electrcity knowing as little as I do :?

Scoddidly did you cut down the little side lips on the face place of the PM1000 so if fit flush against the rack face plate? If so, how did you do it?

Mike

 

[JdJ]

Can you phase reverse the grounded 1/4" unbalanced output? I was thinking these would have to float too if I wanted the phase switch to work on them as well.

Sorry- I answered my own question on this one. I just realized that your phase switch is on the input like the original. I was planning on putting it on the output to avoid the "pop." Since the switch will be on the output, I guess I'll have to float the 1/4" and XLR outs.

 

[Scodiddly]

[quote author="Echo North"]
Scoddidly did you cut down the little side lips on the face place of the PM1000 so if fit flush against the rack face plate? If so, how did you do it?[/quote]

With a metal-cutting abrasive circular saw blade. But I only did that all the way around on the first one - it was a lot of work and made it harder to remount the face plate. Now I just do the ends, and use some brass trim on the sides of the cutout (actually top & bottom of the rack face cutout) to hide the rough edges.

 

[Echo North]

A huge thanks to Scodiddly and idylldon!

Got everything working last night and it sounds great!

Mike

 

[hrasco]

I have been able to find a diagram of the colored leads on the output transformers. I have not been able to find one for the input transformers. Could anyone direct me to one or, failing that, provide one?

Thanks so much

Hank

 

[Scodiddly]

[quote author="hrasco"]I have been able to find a diagram of the colored leads on the output transformers. I have not been able to find one for the input transformers. Could anyone direct me to one or, failing that, provide one?[/quote]

I hadn't thought of making one, but since I've got a couple modules handy it's a good thing to do:

Yellow + out (this is where you'd put a DI jack)
White - out (grounded)
Brown input center tap (for phantom power)
Blue input I1
Green input I2

I1 and I2 are the balanced inputs - not sure about polarity, those are just the labels on the circuit board.

 

[JdJ]

Just wanted to echo the thanks-

I think it is really cool that people who have already completed their projects continue to come back and contribute to these threads- thanks for helping the rest of us!

Just have to get a chassis, but everything is wired up functioning and sounding good. I did end up replacing C37 with a Nich PW 220uF- definitely a noticeable improvement in clarity.

Looks like I'll be cappin' the rest.

Have a bunch of people done the Wima .01uF bypass caps?
Other impressions on cap choices/value changes? It seems like there was a bunch of info on the old forum which is now inaccessible...


Cheers

--J

 

[hrasco]

Thanks, Scodiddly. Those of you building from input modules are already "hooked up" at the input end. I'm building a "basket case" I bought that is being built from main/monitor modules. Thanks again for your help.

Hank

 

[digitaldrummer]

Hi guys. as far as the DI jack goes, I've pulled the yellow wire (input transformer out) where it was on the board and routed it to the switching jack (which is stereo, but ignore this as I'm only using tip/ring), then back to the board. I used some scraps of the 2-cond shielded wire and tied the shields together on the "ring" of the 1/4 jack. then I tied one of the shields to the empty solder cup (which appears to be the board ground). Am I doing this right?
http://www.digitaldrummer.net/pm1000/dicloseup.jpg

I really appreciate all of the great info from everyone. As soon as I get this figured out, then I just have to mount everything in my chassis and recap. Had a successful power-up earlier this week.

thanks, Mike

tracking my progress here:
http://www.digitaldrummer.net/pm1000.htm

 

[digitaldrummer]

[quote author="idylldon"]

Those diagonal lines are jumper wires. The ground wire from the XLR is not needed on the switch, but you should use shielded cable for the run between the XLR connector and the switch. Ground the shield only at the XLR end. [/quote]

idylldon, are the DPDT switches you used on-on type (i.e., 2 positions)? I have some on-off-on... not sure they would work here.

thanks, Mike

 

[idylldon]

[quote author="digitaldrummer"][quote author="idylldon"]

Those diagonal lines are jumper wires. The ground wire from the XLR is not needed on the switch, but you should use shielded cable for the run between the XLR connector and the switch. Ground the shield only at the XLR end. [/quote]

idylldon, are the DPDT switches you used on-on type (i.e., 2 positions)? I have some on-off-on... not sure they would work here.

thanks, Mike[/quote]

Yeah, they are "on-on" switches. You should be able to find some pretty easily close to home. I usually order a bunch at a time when I do an order from Mouser, and I get the Mountain brand. They seem to hold up very well.

Cheers,
--
Don

 

[Echo North]

Scodiddly,

I got my 1/4 switching jacks from mouser today. What terminals did you use?

It seems stright forward...I ran the signal through the two end terminals and you can see it break when the 1/4 cable is inserted by I'm getting no sound on the inserted instrument. The signal is sent through the tip correct?

How did you set yours up?

Thanks again,

Mike

 

[Scodiddly]

I connected both sleeve terminals together - those are the ones at the end where the plug goes in - and to ground on the circuit board. Then the wire from the transformer to the tip contact which gets disconnected, and the return wire to the tip contact which connects to the inserted plug.

Those jacks are a little confusing to work with - I tend to screw it up completely now and then.