FX Loop install question Orange Rocker 30

[frankencat]

Just purchased the Zero Loss FX Loop kit and am getting ready to install it. It seems pretty straight forward and I am just going to open the connection (somehow?) right before the signal comes into the Master Volume pot and insert the loop there. I don't have a schematic for the amp and I was wondering if anybody that has access to one can answer a question or two for me?

The first one is - is there a convenient place on the PCB to insert the loop? If not I am thinking of disconnecting the PCB mounted Master Vol pot and turning it sideways and "flying" the other leg and ground to the PCB. Obviously this would require total dis-assembly and removal of the PCB from the chassis to do correctly - which I want to do. But if there is a more convenient way to do it that is still serviceable and reliable and doesn't destroy things in general I would love to hear it.

The second is, where is the best place to tap power for the FX Loop from? Again I don't have the schem...I can probably figure it out but it would be easier if someone could take a peek for me and save me some time. Also should I use PI or Screen supply (and again, where to tap on the PCB)?

Third, If I tap the PI supply do I need to adjust the voltage as per Step 15 of the instructions and if so, what resistors and values do I need to replace?

Thank you all in advance for your help. Looking forward to getting this rocking in the Rocker!

Regards,
Frank
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[frankencat]

Anybody?

[frankencat]

Link to install instructions: http://home.comcast.net/~jbjdav26/Loop% ... %201B4.pdf" onclick="window.open(this.href);return false;

Also some pics of the PCB I found online: http://www.ajaudio.co.uk/ORANGE%20ROCKE ... REPAIR.htm" onclick="window.open(this.href);return false;

Thanks

[frankencat]

Ok got it in. Sounds great. BTW, the Metro Loop sounds great. Really transparent so far and very little if any change to the character of the amp. Worth the $$ IMHO.

-Frank

[frankencat]

Here's an update: Initially I had installed the loop before the master volume and it worked fine but this amp has a separate clean channel that doesn't go through the tone stack and master volume so it didn't work for that. So I moved the insert point to the phase inverter cap and it now works on both channels but it is super noisy/hissy. Anybody else run into this. Is there something I need to tweak to get it to quiet down? Thanks.

[neikeel]

Please keep going!

We are interested and observing, but I, for one, have not peered inside a Rocker 30 although I did have a look at the schematics a couple of years ago.

[frankencat]

Thanks for the reply. I ended up moving it back to the MV on the dirt channel and it sounds really good there with no noise issues. It's not that big of a deal for me because in practice I tend to stay on the one channel when I am playing out with a band etc. It is a pretty standard setup, very similar to a classic Marshall MV setup. Everything is running within spec and I am burning it in for a little while right now but I suspect it will be happy.

So to summarize, the best sounding way that I found is to insert it before the MV. That is to say between the treble and master volume pots in standard fashion. The PI cap is C25 for those who want to experiment. I tapped power from the screen supply and I see right around 302vDC at the FX board B+ @ 120vAC from the wall. I did have to mod a little, by laying down the big cap on the FX board and laying it down. I ran some hard leads to it from the soldering pads and hot-glued it in place on the board where it should be secure. I used a 22k resistor from the screen supply B+ which was right around 336vDC. Hope this helps others out there as I found almost no information on a mod that I am sure many folks are interested in.

Pics here:

http://img.photobucket.com/albums/v293/ ... 111906.jpg" onclick="window.open(this.href);return false;

http://img.photobucket.com/albums/v293/ ... 111856.jpg" onclick="window.open(this.href);return false;

http://img.photobucket.com/albums/v293/ ... 111846.jpg" onclick="window.open(this.href);return false;

Peace.

[SDM]

Started writing this to reply to your noise thread, but will add it here:

All comes down to optimizing signal to noise ratios. With the loop installed pre-master, it saw the full bore preamp signal, and thus signal to noise ratios were optimal (or more than close enough to it at least, don't have the schem of this amp) through the loop.

Loop moved to post master position, you should find that the noise disappears (or gets buried/inaudible beneath the amps own natural noise floor) if you optimize signal to noise ratio again. Only way to do that with loop post master is to crank the master/s well up, why post-master is not an optimal place for the loop. With the loop post-master, you also get the noise floor of your pedals/outboard gear running full bore to the power amp at all times, no attenuation, which can make things worse depending on your pedals/effects noise floors and overall volume you want to run the amp at.

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.

Some options:
-Just run the loop on the lead channel only, put it back before the master where it was operating with the proper signal levels. Have to forgo clean effects (though could add another loop specifically for that channel), but this is the ideal way to go.

-Do not know the schem of this amp, but could try to see if the clean channel could be tweaked a bit to use the master. This may get rather complex and require added switching and such, not be practical.

-Add a "global master" pot following the loop to feed the PI. Run the stock master and clean volume high as needed for good levels through the loop, global master now sets overall/final volume of the amp. This is an easy route, but requires another control/pot added in somewhere.

-Adjust the loop send and return strength to optimize signal to noise ratios for the volumes you typically play the amp at. This would be dependent or your particular amp/settings/outboard gear as to how to tweak the loop properly for your set up. Since it involves modifying the loop a bit, is a "do at your own risk" kind of thing. Is not a recommended or an officially supported thing.

Future ZL loops may get some sort of send/return control soon to suit more amps/setups, but as my description from the store reads: (these current loops are) "designed specially for Metro kits and specifically with these classic Marshall circuits in mind" -meaning 2203/4 type amps, those that preceded it, are the ideal amps to use them in, what the loops were/are intended for. Many are used successfully in other amps too, but not all are a perfect fit of course (and that, as well as much of the above, often goes for any loop, not just the ZL loop).

Any way, glad you are happy with moving the loop back to the lead channel only, pre-master again. That is indeed the ideal place for the loop. If you do want to try a different approach though, send me a PM, will follow up via email from there if/as needed.

[frankencat]

Thanks Steve, much appreciated. I think I will leave it for now.
Frank

[Stratophil]

Hi there!

I have a Rocker 30 and want to install an fx loop. If possible, on both clean and dirty channels.
I play master volume all cranked on dirty, with a huge pedalboard in front (and in the futur : reverb and delay in paralel in the loop).

First question : Does the kit fit my amp? (European 230V DC)

Second : I think I have to install the loop after the master volume... Will there be noise? Hiss?

I'm french and don't understand english so good... so... excuse me if I ask sonmething that has been answered. I just want to be sure.

Here you'll find the schematics :
http://i23.photobucket.com/albums/b374/ ... 3c6fc2.png" onclick="window.open(this.href);return false;
http://i23.photobucket.com/albums/b374/ ... 06a447.png" onclick="window.open(this.href);return false;

Thank you very much!

Philippe

[frankencat]

I ended up with the loop on the OD channel only. It sounded great there and I just did not use the clean channel enough to spend any more time with it. The kit fits the amp fine and is well thought out. I did have to reposition the large cap on the fx loop board but it was simple to do. I think with enough patience and skill it could be made to work equally well on both channels.

[Stratophil]

Ok, thanks!
I will try...

[Stratophil]

I just install the loop before C25 cap. It works, but with a lot of "hiss".
So, I have to try between treble and master volume pot (I use the Rocker 30 as a single channel amp, so... not a problem for me).
The problem is, the C25 just broke when I tried to replace it... I have to wait for a new-one...

[Stratophil]

Well...
C25 is fixed now
I have moved the loop between trebble and master volume pots.
It works much much better!

BUT :
- When the loop is "on" and when there's something plugged in (even just a small jack), there's a significant hum
- No problem with the loop "off" or with the loop "on" and nothing plugged
Maybe a ground loop somewhere... I will search this afternoon...
If someone has an idea...

frankencat, where have you plugged your grounds (pcb and each signal wire)?

Thanks!
Phil'