Metropoulos Forum

I have a JTM45 with the LEFX loop, with Eventide Time and Mod factor pedals I get very loud pops and all kinds of loud digital hash noise when the effect is engaged. True Bypass and DSP modes both exhibit major noise/pop issues. These are powered with the Eventide/CIOKS Powerfactor supply. Same problem with my new X2 Ditto Looper from TC. Any ideas? It almost seams like there is a ground loop or DC leakage on the send/rx lines. Thanks! Peter

OK, this is fixed. Couple of points, maybe already known. The LEFX circuit has a small DC offset ~800mV when you come out of standby, the offset slowly drops to zero volts. This offset causes loud pops with tru-bypass FX, if you wait 20 or 30 seconds the offset goes to zero and the pops disappear when you switch the effect in and out. When the time/mod factors have the tru-bypass disabled there is no problem. The Ditto as far as I know (I'll read the manual now...) can not disable the true baypass, so you get the pops when you come out of standby for 20 or 30 seconds, (Only when switching the looper on and off). Again, if you wait long enough the pops go away.

Problem two was I had to power the Ditto from another one of the Powerfactor DC sources, it seams I had co-mingled non-isolated DC power outputs between the effects going from the guitar to the Metro JTM45 and the EFX loop devices. These must need to have isolated DC supplies or you get a very bad ground loop. Cheers!

Hi,

I have installed about one year ago a Zero Loss Loop kit in my Marshall JMP 2203 original of 1976. All this time everything was OK with the loop but yesterday I change one of the pedals that I had in the loop chain. It was a Delay pedal. When I conected the pedal, the loop sound desappeared. Now I test the loop with only a little wire (bypassing it) but the sound sounds very very low. It´s the same with any configurations and pedals on it. It´s like the loop sound was there but with very low volume. Whe I swich off the loop with the includded switcher everything is OK and the amp sounds as it has to be. I have revised the solding points and everything is ok. Could you tell me what thing can be wrong, please? I hope you can help me. I was very happy with loop sound and his features.

With Kind regards

Thank You

Johnny

Any help, please??

I am looking to install a loop that will allow me to run a noise gate so I can quiet a noisy preamp...will this one work?

Johnny Bloody wrote:Hi,

I have installed about one year ago a Zero Loss Loop kit in my Marshall JMP 2203 original of 1976. All this time everything was OK with the loop but yesterday I change one of the pedals that I had in the loop chain. It was a Delay pedal. When I conected the pedal, the loop sound desappeared. Now I test the loop with only a little wire (bypassing it) but the sound sounds very very low. It´s the same with any configurations and pedals on it. It´s like the loop sound was there but with very low volume. Whe I swich off the loop with the includded switcher everything is OK and the amp sounds as it has to be. I have revised the solding points and everything is ok. Could you tell me what thing can be wrong, please? I hope you can help me. I was very happy with loop sound and his features.

With Kind regards

Thank You

Johnny

I installed a zero loss loop in my 2204 ckt tonight and I can't get it to work . Its doing basically what you described except in never worked . Volume is good when loop is bypassed .I've connected it every way I know including as per the instructions and it just won't work . Ground is good , Voltage at the test point is 314vdc . I'm thinking either a def transistor or diode . Calling George tomorrow

Problem solved. I contacted George who very kindly solved my problem (failed one of the transistors). Now everything works as before.

Thanks to George and Metroamp for your kind attention and effectiveness!

Cheers;)

A friend recently acquired a Weber 6s100 and wants to add in an effect loop to it. I have installed this kit before on a JCM800, but am unsure how the install for this would work in the Weber amp. Any suggestions on the best way to add in this effects loop?

Hoping someone may be able to help. I have a metro 2203 that is modified with an added gain stage (sir style mod) and a zero loss loop and ppimv..
I am modding it to be channel switching via foostwitch. I am using a skipzcircuit channel switch board and the added daughter board for extra relays. Basically a 3 channel amp( 1959,2203,sir). I began installing the channel switching mod last night but ran into an issue. In 1959 mode I am switching the master volume out of the circuit. It has its own gain pot to control the volume. I only have 1959 mode connected at this time and it works correctly with the fx loop bypassed.. However, when I turn my fx loop on, it introduces a lot of noise and hiss. I cant figure out why this is happening. It was getting late so I didnt have a whole lot of time to troubleshoot. I have used this same amp for years with the fx loop and it has worked great. Not sure what is happening. Any ideas?

Update..

May have found the answer. If this is the case, I may add an additional MV in the path... Ill experiment and report back

"So, main issue is that (at lower master settings at least), your master volume pot is attenuating the preamp signal down so you can play at quieter volumes of course. The master is now also acting as a send control for the loop too though, and the signal the loop is fed (and puts out) is much much lower now than the loop (or effects in it) is "expecting"/is designed for. The return side of the loop is still "expecting" a much higher signal and is set to boost that signal back full bore to the poweramp/PI. Noise floors do not change and are now relatively much much higher compared to the low signal level, hence noise floors are much more apparent due to the return boosting them out of proper proportion to the preamp signal. Signal to noise ratios are just way off."

I added the mv back in the circuit and the issue has disappeared. I am going to have a separate MV for each channel to avoid issues. All is good now

Hi.

I have a 2006 1987X with the stock loop and I'm thinking it's causing problems that i described in here:

http://forum.metroamp.com/viewtopic.php?f=12&t=44105

I'm thinking it's clipping and therefore the looper doesn't sound too great. Would upgrading to the zero-loss loop help in this situation?

Thanks.

cebix wrote:Hi.

I have a 2006 1987X with the stock loop and I'm thinking it's causing problems that i described in here:

http://forum.metroamp.com/viewtopic.php?f=12&t=44105

I'm thinking it's clipping and therefore the looper doesn't sound too great. Would upgrading to the zero-loss loop help in this situation?

Thanks.

^this was going to be my next suggestion lol. But, for some reason, I'm stuck on the looper not liking being fed into an overdriven amp attenuated with a master vol.

Hi guys, i want to install metroamp fx loop in my Marshall SL5. Is it possible or not?
This is the schematic:
https://www.flickr.com/photos/76376621@N04/14735985331/

Sorry, but I have been searching for quite awhile.

I am looking for help on knowing where to measure the B+ supply voltage for the Phase Inverter supply so I get the correct value for the decoupling resistor.

I have a JCM800 2204 with PCB and two vertical input. Thank you for any help.

Dear all ..

two questions

1. is it possible to fit ZL loop to a JMP2204 ( 1978 model ) - without drilling extra holes - was thinking use one of speaker socket holes - 6.25mm TRRS ?

2. Optimal position for ZL in Marshall 2210 head 1986 ... ?

cheers in advance