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REPRO Passive reamp Box Build Thread

Posted: Sat Oct 11, 2014 4:11 pm
by Joe Malone
New Black Case Version (Build is the same as old version below)
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OLD Version Case
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First unpack kit and check you have all the parts below. Plus box back panel not shown in photo.
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Start assembly by fitting the Female XLR inside the case.
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Use the 2 black self tapping screws to hold it into position.
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Fit JLM14 transformer into plastic clip
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Remove protection plastic from double sided tape on clip
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And stick to box hard against the top edge and as close to the XLR as possible
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Screw ground lug to transformer with lock washer, ground lug, lock washer and 3M 6mm screw in that order.
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Fold ground tab on XLR 90 degrees and solder to transformer ground lug.
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Pre solder XLR pin 1 and strip the end of the spare green wire and solder to XLR pin 1
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Cut green wire about 10mm away from solder and slide off green plastic.
Twist wires and solder to XLR ground tab.
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Pre solder XLR pin 2 and pin 3. Twist blue and yellow wires tightly and solder Blue wire to pin 3 and Yellow wire to pin 2.
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Fold legs of TRS jack as shown below and fit the 2 fibre washers.
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Fit into hole in case.
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Use black dress ring and chrome nut to tighten to case.
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Pre solder the 3 legs sticking out of the TRS Jack.
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Cut pot locating tabs from the 1k and 100k pots.
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The 2 pots will go into the case as shown with 1k on left and 100k on right looking from on top.
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It is worth writing the pot values on there back covers as you will not be able to see these values once fitted in the box.
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Fold centre wiper lug down as shown on both pots.
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Fit both pots as below and by adding the washer and nut to each and tightening down.
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Solder pot centre wiper lugs together.
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Tightly twist transformer Red and Green together and wrap tinned wire ends to 1k pot as shown.
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Solder Red wire to volume pot lug. and add second stripped and soldered green wire supplied into volume pot lug with transformer green wire.
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Solder both green wires in the volume pot lug.
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Strip and solder end of orange wire supplied to impedance pot lug as shown.
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Twist orange and green wires together.
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Cut twisted orange and green wire down in length so they reach the jack terminals with a bit to spare. Strip and solder both wire ends.
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Solder green wire to bottom TRS jack terminal. And solder orange wire to top TRS jack terminal as shown.
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Cut black wire shorter and slide end back into the black heatshrink tube so it will not short to anything.
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Cut transformers plastic clip down so the diecast lid just presses on it when fitted.
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Double check your wiring and trim any sharp points on the end of any soldered wires.
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The reamp box can now be tested. In and out and controls are as shown below. Setting level and impedance pots to half there travel is a ideal starting point.
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If the box works and you are not going to paint it now it is time to fit the knobs, logo, labeling & back of box.
Labeling can be done with dymo/brother labeling or by hand with permanent pen.
You could use any of the terms listed LINE INPUT = INPUT = IN. AMP OUTPUT = OUTPUT = OUT. VOLUME = LEVEL. IMPEDANCE = Z. etc
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Re: REPRO Passive reamp Box Build Thread

Posted: Thu Jun 15, 2017 1:47 pm
by Lachie
Is it possible to add a second 1/4" unbalanced output to these by just piggy backing another jack onto the first?
Or perhaps more complicated?
Thanks
Lachie

Re: REPRO Passive reamp Box Build Thread

Posted: Thu Jun 15, 2017 2:43 pm
by Joe Malone
Lachie wrote:Is it possible to add a second 1/4" unbalanced output to these by just piggy backing another jack onto the first?
Or perhaps more complicated?
Thanks
Lachie
Yes you can parallel a second jack directly across the first jack.

If you get hum loop when using 2 amps only connect the tip to the second jack.

Re: REPRO Passive reamp Box Build Thread

Posted: Thu Jun 15, 2017 2:51 pm
by Lachie
Legend, thanks Joe.
Any easy way to avoid that possibility?

Re: REPRO Passive reamp Box Build Thread

Posted: Thu Jun 15, 2017 5:48 pm
by Joe Malone
Lachie wrote:Legend, thanks Joe.
Any easy way to avoid that possibility?
Yes use 2 x REPRO boxes :-)

You will find the second socket will never need the 0v ground if the amps are mains powered with earth pin plug.

But you can add a ground lift switch to switch the 0v on to the second socket or not.

Re: REPRO Passive reamp Box Build Thread

Posted: Fri Jun 16, 2017 1:32 pm
by Lachie
Ha, yep. Thought that might be it.
That's definitely the plan, though I'd like to build a few into a 1ru chassis as it's more functional than a reamp box to me.
It'd just be nice to be able to have a single reamp channel be able to feed 2 amps/pedals rather than use 2 REPRO channels on the one source.

I know this is off topic but can you point me to the best kit of yours for a simple 2:1 balanced mic mixer w/volume controls for each input?

Thanks again!

Re: REPRO Passive reamp Box Build Thread

Posted: Tue Aug 01, 2017 12:05 pm
by Joe Malone
Lachie wrote:Ha, yep. Thought that might be it.
That's definitely the plan, though I'd like to build a few into a 1ru chassis as it's more functional than a reamp box to me.
It'd just be nice to be able to have a single reamp channel be able to feed 2 amps/pedals rather than use 2 REPRO channels on the one source.
Use the second socket with only the tip wired trick it will work ok but just not as quiet as 2 transformer isolated output will.
I know this is off topic but can you point me to the best kit of yours for a simple 2:1 balanced mic mixer w/volume controls for each input?

Thanks again!
Check out our new STATTEN kit for making passive mixers with level and/or pan pots

https://www.jlmaudio.com/shop/index.php

Re: REPRO Passive reamp Box Build Thread

Posted: Sun Sep 03, 2023 12:22 pm
by TheFrozenone
Hey Joe,

So I've got one built and running but it seems as I dial up the "Impedance" control there is a hum or even a "ring" that comes on. With "Impedance" all the way down it sounds pristine.

Could this just be bad grounding from my outlet? (Old house, iffy grounding).

Re: REPRO Passive reamp Box Build Thread

Posted: Tue Sep 26, 2023 1:17 pm
by Joe Malone
TheFrozenone wrote:
Sun Sep 03, 2023 12:22 pm
Hey Joe,

So I've got one built and running but it seems as I dial up the "Impedance" control there is a hum or even a "ring" that comes on. With "Impedance" all the way down it sounds pristine.

Could this just be bad grounding from my outlet? (Old house, iffy grounding).
Sorry missed this notification for some reason.

There are lots of reasons for hums. The lower impedance setting will make a lot of amps quieter and high impedance will allow more noise pickup. If you move the REAMP Box around and the noise changes it is usually the unbalanced cables picking up direct hum from something nearby or injecting hum directly into the transformer in the reamp box. Also depends on whether both the XLR and TS devices are grounded or not as the REAMP isolates the 2 so both need to be grounded.