FX loops coming to Metro.

[budubum]

To Budubum,
Since you've got a PCB replacement board in a RI, take a look at the pic below, let me know the space you have there from board to chassis, and resonance pot to chassis. Some ideas on how it'd could hook up, it'll be tight, but has worked out fine in similar RoccO'cconor modded amps. You may want/need to also rotate the resonance control so the pot's lugs/cap are pointing away from the loop board, but that may not be needed.

thanks SDM.

ok i measured the amp soon as i saw your post.

heres it:

from far left of V1 to the round curve of the resonance pot`s cap lead is ca. 12cm

from heater wall to teh board is ca. 5 cm.

the deepness of the chassis from TOP to bottom of chassis where the sockets are mounted to the chasiss is ca. 6½ cm

i know eaxactly where/how to put the b+ wire now. want it under the board then throught that little hole and up to the alternate B+ point on the preamp like youve circled.

sorry for using CM rather than inches as we dont measure inches in Sweden therefore we do metric.

thanks in advance.

[SDM]

Sounds like you've got the B+ hookup worked out well. Board is around 8.7cm long, about 4.5cm wide (max with extra washers on jacks that you may need). So it should fit in there. Installs over V1 and V2 have so far not been an issue, even in high gain modded amps, but hard to predict that for sure in every case.

Do try rerouting and insulating that cap lead first to be sure that in itself doesn't cause any problems. If all is good I think the loop should be okay there.

[jasonp]

pic

http://i69.photobucket.com/albums/i59/p ... oop002.jpg" onclick="window.open(this.href);return false;

Looks great dave .
sozo's?

[psychodave]

[quote="jasonp"][quote="psychodave"]pic

http://i69.photobucket.com/albums/i59/p ... oop002.jpg" onclick="window.open(this.href);return false;[/quote]

Looks great dave .
sozo's?[/quote]

Yes. I put them in a few years ago. Sounded much better afterwards IT is basically stock except for the 10k piggyback on V1 and the .68uF bypass cap on V2. EL34s and now the loop.

[Krinkle]

pic

http://i69.photobucket.com/albums/i59/p ... oop002.jpg" onclick="window.open(this.href);return false;

Looks great dave .
sozo's?

It does look great. I would prefer to install my loop on the end too, I'd rather not install it over the preamp sockets in case I need to mod or touch up solder joints. So, no issues so far?

[psychodave]

[quote="Krinkle"][quote="jasonp"][quote="psychodave"]pic

http://i69.photobucket.com/albums/i59/p ... oop002.jpg" onclick="window.open(this.href);return false;[/quote]

Looks great dave .
sozo's?[/quote]
It does look great. I would prefer to install my loop on the end too, I'd rather not install it over the preamp sockets in case I need to mod or touch up solder joints. So, no issues so far?[/quote]

No issues at all. Works perfectly and is quiet!!

[SDM]

Very minor update on instructions. Only change is an added note about using a scrap piece of wood or such in the chassis when drilling the holes. This to help avoid the possibility of having a drill bit grab and "take off" on you, possibly hitting/damaging the board or nearby wires.

I typically use a stepper bit, so very hard for that to happen, but with a regular bit could be an easy mishap.

Latest instructions Rev 1B.4

Template for drilling

[skidbrake]

Hi Steve,

Thanks for your many contributions to this forum. I just received my Metro FX Loop and am about to install it in my Metro JTM45.

Instead of using a panel-mounted switch, could I use a foot switch? It would be nice to be able to switch the FX loop on/off from my pedal board.

If possible, how would you go about wiring this?

Thanks for your time and thoughts.

[SDM]

The bypass switch has the raw amp's full strength untouched signal on it, so wouldn't be ideal to move the switch outboard to a footswitch. Could lose highs could or add noise if long cable run is needed.

So, the easiest thing to do would be to put a bypass switch inside the loop chain where impedances are low and long cables not a problem. The loop you should find to be quite transparent on it's own, so just bypassing all effects in the loop, with a switch inside the loop, should really work/sound pretty much just the same as bypassing the loop entirely.

If you absolutely need the loop bypassed entirely, then a relay could be used in place of the panel switch, but you'd need a power supply for it and of course a footswitch jack. So things get more complicated. I did make prototypes with such a setup but in the interest of simplicity, minimizing the board size, and since the loop was so transparent, felt the above option for bypassing was easy enough/best for those that needed to do so.

[skidbrake]

Thanks. After giving those options some thought I've decided to use a true bypass box to control the FX coming into the loop.

Space is tight in my JTM 45 and it's a very quiet amp that I want to keep that way, so I decided to not use a panel-mounted switch.

Below are a few progress shots of the switch-less FX Loop install that may be of interest to forum members.

I haven't forgotten to connect the decoupling resistor ... just hadn't connected it when I took this picture.



The twisted pair of shielded wires wouldn't fit the mini-turret holes on the PCB, so I soldered & shrink-wrapped an inch of smaller gauge wire to the ends. I kept them as short as possible and they fit the turret holes perfectly.



On the Metro JTM 45, the PI connection is on the board. I grounded both of the shielded cables to the pot bus.



Metro's drilling template was exact. As a precaution, I checked the scaling on the printed version of the template and discovered that Adobe Reader sends docs to my printer at 93%. Yikes. After fixing the print preferences it printed to scale. I hand-measured the back plate anyway, but having an accurate template made it much easier.



I'll test it tomorrow and adjust the signal pot, if necessary.

[skidbrake]

UPDATE:

I finished the install and the FX Loop sounds fantastic. My JTM 45 is even quieter now than it was before this mod (and it was very quiet before).

Using shielded cable makes a difference. Also, while I had the amp out of the box I shielded the bottom of the enclosure with a $2.48 piece of thin sheet metal from Home Depot.

To test the loop I plugged in a Boss DD-3 and switched it on and off, at different volumes, to see if it altered the tone in any way. No detectable change in tone or white noise, for that matter. It's transparent.

I tested a Boss chorus pedal and had the same results. The only noise I experienced was from a Boss RV-5 reverb, but that is the pedal's fault. I may need to shop around for a better reverb effect, or find a mod kit to cut the hiss this thing generates.

So now my signal chain is:

In front: Strat --> Tuner w/bypass --> Blues Driver --> EQ --> Amp
FX Loop: Send --> Delay --> Reverb --> Return

To those reading this who are considering this mod but are concerned about tone degradation or noise, don't be. Grading this mod on a 10-point scale, I give it a solid 10 on every level ... material quality, ease of installation and performance.

Nice product, Steve and George! Thanks for making it available to us.

-Mike

[SDM]

Glad you like it Mike, I'm sure the pics will be useful for others too.

[jerrydyer]

these are very clean. Why dont you do a channel switch board to end the problems of all problems. Get them as small as possible make with about 3 DPDT switches on board. No pops , no gliches and Ill stock up. Im sick of that problem. I have one more experiment to try and then if it doesnt work Im giving up on multiple changes at once. Its a peice of cake to do one or two but try doing routin, gain stages and MV or no MV all at once? no good.

[Riscchip]

I received my loop kit today. I look forward to installing it in a new building I'm doing.

What kind of shielded wire should I be using with it? Is it the Belden stuff from the store?

Thanks!

[SDM]

Riscchip, it should have come with the shielded wire needed. Maybe it's hidden in packing layers somewhere? If not, let the Metro guys know, I'm sure they'll get it right out to you.