Mesa parallel to series effects loop mod?

[beachjammer]

Hey guys,
I know this has probably been discussed a hundred time but I'm new here

I'm wanting to hear from people that have had their effects loop modded from a parallel to a series. I've got a Rectoverb combo that I'd like to have done.

Was there a big difference?
What all did it change on your amp?
Can it be done to a Rectoverb?
How much did it cost?
Can a schematic be got for "do it your self" people?
Would having this done void the warranty and would it be worth it?

THANKS!

 

[Elpelotero]

there's a thread somewhere in here where the guy shows you pics of how to do it.

 

[Bruceta]

I posted these instructions a while ago.
http://forum.grailtone.com/viewtopic.php?p=107909&highlight=#107909

It works nice!

I hope these help.

 

[Blueser]

Excuse my ignorance, but why would you prefer a series loop over a parallel loop? I would think it would be the other way around, so that the effects unit is not in the chain when you are not using effects in a parallel setup.

The reason I ask, is that I am interested in using the effects loop on my soon to arrive Lone Star Classic, and the feedback I have received from the guy who heads the Eventide Yahoo group (Italo) recommends a +4db (balanced) parallel loop to get the best sound, without affecting your dry tone when the effects are bypassed, as the signal is not going through the effects unit's digital to analog converters, thus retaining the natural tone of the amp.

Again, this is not my area of expertise, so I am looking to learn something here. I understand that my LSC has a serial loop, but I am not sure if it is +4, or -10db, and I would like to use a rack effects unit (probably an Axe-FX from Fractal Audio, or an Eventide Eclipse).

 

[SneakyPete]

Excuse my ignorance, but why would you prefer a series loop over a parallel loop?

I use a GT-8 with my Rectoverb and using the '4CM method' (a special way of hooking up the GT-8 to the amp) allows you to move effects either before or after the preamp. With the parallel loop, I never got a 100% wet signal, so I had a noticable sound drop when using the GT-8 (I lost some of the highs and presence of the amp).

I then saw the mod posted on the forum and did it myself - it took literally 5 minutes and is easily reversable. I immediately heard a better sound with my GT-8 ad am not looking at going back any time soon.

I think, since it is reversable, that it wouldn't affect your warranty (if you change it back). One thing to keep in mind though - I disconnected the ribbon cable to the PCB when working on the amp. So, if you do this, make sure you reconnect it (I forgot and freaked out when there was no sound coming out of the amp!)

 

[Blueser]

Ahh.....Wet signal strength! :idea: I knew there had to be a reason why. I had no idea. Thanks for shedding some light on that. I appreciate it.

 

[Boge]

I posted these instructions a while ago.
http://forum.grailtone.com/viewtopic.php?p=107909&highlight=#107909

It works nice!

I hope these help.

Does this work on all rectifier series amps? I have 3ch dual recto and I'm really interested in this mod.

 

[Elpelotero]

a series loop is better for running certain types of effects through your loop. A parallel loop is better for other things, but it can be very very picky if you don't use it right. In my experience, a series loop is a little more dummy proof.

 

[Boge]

How about the gain when doing the mod to an amp? Like in parallel mode when the pot is turned up there's definitely some extra gain in the sound, but if you mod it to serial loop, there isn't change to control the gain anymore, is it going to be as if the pot was set in the middle?

 

[beachjammer]

I posted these instructions a while ago.
http://forum.grailtone.com/viewtopic.php?p=107909&highlight=#107909

It works nice!

I hope these help.

This comes up with a "Rapid Share" page. Do I have to download that software to open the file?

Thanks for sharing!

 

[Elpelotero]

How about the gain when doing the mod to an amp? Like in parallel mode when the pot is turned up there's definitely some extra gain in the sound, but if you mod it to serial loop, there isn't change to control the gain anymore, is it going to be as if the pot was set in the middle?

If I understand your question, you are referring to the mix leveling controls in the back, right?

If you mod to serial, there will still be extra gain if you crank that knob. The reason is simple: Effects loops on rectos are controlled by a preamp tube. So, in the same manner that cranking volume saturates the tubes more, cranking the levels of the effects loop knobs saturates that little preamp tube. This happens no matter if it's parallel or serial.

 

[Boge]

How about the gain when doing the mod to an amp? Like in parallel mode when the pot is turned up there's definitely some extra gain in the sound, but if you mod it to serial loop, there isn't change to control the gain anymore, is it going to be as if the pot was set in the middle?

If I understand your question, you are referring to the mix leveling controls in the back, right?

If you mod to serial, there will still be extra gain if you crank that knob. The reason is simple: Effects loops on rectos are controlled by a preamp tube. So, in the same manner that cranking volume saturates the tubes more, cranking the levels of the effects loop knobs saturates that little preamp tube. This happens no matter if it's parallel or serial.

Ok, thanks for the answer. So if I'm correct I can get totally wet signal with the serial mod with less preamp tube saturation?

 

[Elpelotero]

yes. serial sends the whole signal, unlike parallel that spilts it up into percentages.

that's why it is essential to have a very transparent/quality efx unit when using a serial loop. A bad unit will suck tone straight from the amp.

 

[Boge]

I have TC Electronic's G-Sharp multifx unit. I don't like through the parallel fx loop, and I'll think I'll do the serial loop mod some time soon, after someone confirms that the pdf made for rectoverb2 will work on my 3ch dual recto too.

 

[beachjammer]

I got the file downloaded!

Man, there's nothing to it :shock:
I was expecting the mod to be so much more than that. What a relief!

 

[Sevenstringer]

I am VERY interested in this mod on my Tremoverb
When doing so, does it defeat/disconnect the "loop active master contol"

ALSO

What is with the low volume on the clean channel??? Any way to change that??

R

 

[Bruceta]

I believe it works fol all rectos. VERY SIMPLE MOD and it's worth it.

But I don't know about the Tremoverb.
Needless to say the RK I comes with 1 series loop and 1 parallel loop. The RK II comes with 2 serial loops.

For those who have trouble with Rapidshare, here is the instruction I uploaded in Rapidshare:

 

[Klaasman]

What is the difference in doing this mod than just turning up the knob all the way? Electrically, it is almost the same thing.
I would like to say that I think the loop as it is stock sounds like crap anyway. Turning the knob up past halfway really turns the sound to poo-poo even without the effects being on.
Does this mod change that.

 

[Bruceta]

What is the difference in doing this mod than just turning up the knob all the way? Electrically, it is almost the same thing.
I would like to say that I think the loop as it is stock sounds like crap anyway. Turning the knob up past halfway really turns the sound to poo-poo even without the effects being on.
Does this mod change that.

Klaasman,
Rectos' loop is a parallel loop. A parallel loop becomes a series loop when 100% blended (turning the mix knob all the way up).

What happens is that turning the mix knob all the way up on Rectos, you blend 90% of the signal only. The loop will still sound like a parallel loop. Therefore it will still sound like crap.

Doing the parallel-serial MOD you get a pure serial loop and your 4-cm will sound great.

 

[Zoner]

Will this work on my DC and my Subway Blues? Swap a couple wires and you're in series? That would rule. I'll warm up the finger burner and give it a go. Z