FX Loop question

[Chalky]

Hi

another one for you; I inserted a Line 6 Echo Park into the FX loop, which when switched on via the front panel altered the voicing significantly , and unpleasantly, why is this ....anyone?

cheers

 

[steelhorse]

What amp are you using this with because different amps have different types of effects loops....

 

[Chalky]

Hi

I am using a JVM 205C

 

[steelhorse]

SERIAL / PARALLEL FX LOOP

The JVM is equipped with a series / parallel FX
loop. Connect your external FX equipment input
to the JVM SEND jack, and the FX output to the
JVM RETURN jack. As described previously,
this effects loop can be bypassed from the front
panel and the amount of effect can be dialed in
with the MIX control.

The +4dBu/-10dBV switch allows you to
configure the loop for its use with either
professional equipment (+4dBu setting) or with
guitar level effects like effects pedals (-10dBV
setting).

When MIX is set to WET all the signal goes
through the external loop, adding more direct
(unprocessed) signal as you turn it towards
DRY. This allows you to mix any amount of the
external effect without loosing or degrading the
direct signal quality.

When mixing the WET and DRY signals the
external effects processor’s output should be
configured to remove the direct (unprocessed)
signal or unpleasant phasing effects may occur
when mixing it again in the amplifier.

If the amplifier sounds thin after connecting an
external effect check that no direct signal is
being returned from the processor’s output.
Note that if the FX loop is ON and the MIX
control is set to WET without an external
processor connected, the amplifier will be
muted.

POWER AMP INSERT / SERIAL LOOP

This is a passive loop connected right before the
master controls. It is a line level loop so it is
recommended to only use high headroom
devices to avoid signal degradation. Plugging
only into the return jack allows the use of the
JVM’s power section overriding the preamp.
Master controls and the emulated line out are
located after the serial loop so it is still possible
to take advantage of those features when using
an external preamplifier.

The loop can be taken off the circuit by pressing
the BYPASS switch, but as opposed to the Series / Parallel

 

[steelhorse]

If it sounds better to you through the fx loop that's where it should remain.

I have a graphic eq through one of my amp loops and it sounds nasty in front, but great in the loop. Just the nature of the beast. Just be sure it's in the correct loop and setting as referenced above.

 

[RussT]

Hi all.

Signed up specifically for this cuz i saw this thread online because i am thinking of buying a JVM205c.

So i'd be so greatful for a reply.

firstly - i've read that this amp has both series and parallel fx loops...how is this possible?? from my experience, parallel loops are ones that have the wet/dry mixer like this does, so it indicates to me it is more on the parallel side..

which is kinda a problem

i use a boss gt-10 in the effects loop of my current amp (marshall jcm2000 stack). i only use the GT for effects only - mainly phasers, flangers, uni v, rotary and delays and reverb, hence why it sounds pretty good in the loop.

however i currently use a serial loop with that setup and it sounds fine. i've had problem with the gt in parallel loops, losing sound etc and just don't like them i guess haha.

the gt is an important part of my live sound and the JCM205c i hope to purchase will be my amp to play smaller venues.

Can anyone talk to me more about the dual series and parallel effects loop going on with this and how you swap between the two? Steelhorse your reply was pretty good but i don't get the 'power amp insert' section??

cheers guys

ps i use a POG 2, red witch fuzz, boss eq and roland space echo front of the amp and then gt10 in fx loop.

 

[RussT]

how do you switch between series and parallel effects loop?? i don't get it?? i am keen on buying this amp but have bad experiences with parallel loops and these descriptions sound like it is more of a parallel loop hence the wet/dry signal mixer?

 

[Wycked Lester]

check it out yo,....

a parallel loop will only send PART of your signal to the loop, thru the efx, and back into the amp to then be mixed with the 'dry' part of the signal that stayed in the amp.

A series loop sends ALL you signal out the send, into your efx, and back into the return of your amp. This is the 'normal' or 'standard' type loop, and is how you want to do it most of the time.

If your using a parallel loop, you have to set your efx processor so that it ONLY OUTPUTS THE EFX WITH NO DRY SIGNAL...., or 100% wet. like you would a verb unit that is patched into an aux on a mixing console. In other words, if you just listened to what came out of the efx unit, it would ONLY be the effect, NOT the actual sound of the guitar mixed with it.... in the case of a parallel loop you mix it the dry guitar signal with the EFX signal to get your sound,.....


...on a series loop you set your wet/dry ratio ON THE PROCESSOR.


another thing,... your getting confused on terminology....

efx send = preamp out
efx return = power amp it

same things, just different words

....another way to look at it is this....
A series loop is the exact same thing as a paralell loop if the parallel loop mix knob is turned all the way up.

 

[dhaywood17]

The JVMs have a 'mix' control knob next to the effects unit on the back and this controls the amount of dry and wet signal being mixed.

On zero you will have 100% dry (unaffected) signal.
With the mix turned half way you will get 50% dry and 50% wet (effected) signals - this is parallel
Turned fully up you will get 100% wet, effected signal - this is now a serial loop and without something plugged in to the effects return on the amp you will nothing out.
The only point you get a serial loop is with the effects mix set at maximum. Anything greater than zero and less than 100% will give you some form of parallel effects mix.

The power amp insert allows you to use the amp modeling features of your effects unit to their full and doesn't route the signal through any of the JVM eq sections. Again for this you need the effects mix set to maximum other wise you will get volume reduction or if the mix is set to zero you'll get nothing.

Hope this helps a little

 

[RussT]

Thanks so much for your prompt replies guys

muchos gracias

please allow me to re-clarify and confirm what has just been said.

So the only way for this amp to have the serial fx loop 'on' is to have the mix dial on 100% wet signal right??

in regards to lester saying for parallel loops u must have the efx unit set to output all efx and no dry signal - my effect patches are already have a mix of the direct signal..so what would this sound like coming out of the parallel loop? is it just going to be harder to let the efx shine through cuz there will be extra dry signal or something?

 

[Wycked Lester]

So the only way for this amp to have the serial fx loop 'on' is to have the mix dial on 100% wet signal right??

?

yip

in regards to lester saying for parallel loops u must have the efx unit set to output all efx and no dry signal - my effect patches are already have a mix of the direct signal..so what would this sound like coming out of the parallel loop? is it just going to be harder to let the efx shine through cuz there will be extra dry signal or something?

it'll sound weird because when the DRY signal that stays in your amp combines with the portion of DRY signal that comes out of the processors....they will be just little out of phase, which will sound kinda 'nasally' ....or 'snorty' .....

i dunno, try it and you'll see what i mean......

If your wet/dry levels are being set in your processor you need to run your loop in series.

Good luck bro.

 

[RussT]

so has this amp got a "true series" effects loop if this is the case? i'm worried now about the reliability of the amps series fx loop function, most series loops i've known have nothing to do with any wet/dry mix...

and if thats the case, how come amps with only parallel FX loops don't have a 'series' function if turned all the way to 100% wet????

apologies if i sound overly cautious.. its just that these GT10's sound like utter shyte through a parallel loop...

 

[mickeydg5]

Something sounds confused.
The JVM205 has both a series/parallel loop and a series loop.
The series/parallel is between the preamp and reverb. It can adapt to semi-pro and pro equipment while using a mixer to blend. It can also be remotely switched within the amplifier.
The series loop is between the reverb and the master volumes. It can only be used with pro gear and has no remote switching within the amplifier.

 

[dhaywood17]

I can appreciate your caution on this. The simple test to see if an amp with a parallel loop will also run as a true series loop is to turn the mix up to max/100%, take any leads out of your effects return input and play. If you hear what you're playing, even if only very quietely, then it's not true series as there is still some dry signal being mixed. On the JVM with mix set to 100%, without a patch cable from effects send to effects return or something else generating a signal to the effects return (e.g. GT10), you get absolutely nothing. So quite obviously there is no dry signal being mixed with the loop.

EDIT: Mickey - my bad. Just shows how carefully I a) RTFM - read the f'ing manual and b) look at the back of my amp. But this does clear up without any question what the OP was asking. He could also just look at the user manuals on the Marshall website as I just did.

Apologies for any confusion I may have caused with my previous ramblings.

 

[mickeydg5]

its just that these GT10's sound like utter shyte through a parallel loop...

Saying you have a JCM2000 stack is a little vague. Which one?

If you are using a processor along with an amplifier that has series/parallel loops with mixing, you should take the dry signal out of the processor and output wet only. Loop levels set for -10dBm. Are you doing this?

 

[RussT]

Saying you have a JCM2000 stack is a little vague. Which one?

If you are using a processor along with an amplifier that has series/parallel loops with mixing, you should take the dry signal out of the processor and output wet only. Loop levels set for -10dBm. Are you doing this?

says DSL100 under the power switch although i thought all along it was a 50watter i bought!!! i'm pretty sure it is true series because it doesnt have any wet/dry mixer.. havent tried unplugging the return though as dhaywood suggested to see if i get any sounds..

i am using -10db setting atm sounds fine +4db is just way louder and i think drives the valves too hard so i dont use it.

cheers for the replies btw, has anyone actually got the amp that they can test this cable to send only jack method to see if the amp is true series? i haven't actually bought it yet and the only way i will buy is by ebay as it's a good $500 cheaper than music stores in my city

 

[RussT]

So just to clarify once more:

I have guitar > marshal input
marshal send > gt10
gt10 output > marshal return

unplugging gt10 output > marshal return will get two results:
True Series = no sound
or not truely series = some sound most likely fainter..?

i'll test this out tonight at rehearsals with my JCM2000 dsl100 which does not have a wet/dry mixer (so i'm already under the assumption it is true series)..?

but can't test this out at all on the JVM205c cuz i don't have one..anyone here actually use one that can confirm these tests?

just downloaded the manual and i find it a little vague compared to what i'm being told here. (like what do they mean by PRO equipment????)

but have been looking at this power amp insert/serial loop part on the back and am intrigued because it says it's the serial loop?? dhaywood said before this is for using fx processors preamps rather thanthe jvms eq. thats cool, but i don't use the GT10's preamps, when you you turn send/return mode on the gt10 you can bypass all that preamp stuff......so if i hook up to the JVM via send and return in the power amp insert wouldn't that be like it acting as the series loop?? if not then why would they label it serial loop?

 

[dhaywood17]

As far as I'm aware the loops are the same on the entire JVM range and setting the mix to 100% and having nothing in the parallel/series loop return gives no output. Direct from the JVM 2 channel manual for the parallel/series loop section "Note that if the FX loop is ON and the MIX control is set to WET without an external processor connected, the amplifier will be muted." which confirms what I posted earlier about this loop. So it is definitely capable of a true series loop. I'll admit that the second loop baffles me and I wouldn't consider using it either as it's not possible to turn it on or off with the footswitch, so I can offer no useful opinion there.

With regard to 'professional equipment' I think they're alluding towards rack effects etc. I'm not familiar with the GT10 but I'd be suprised if somewhere in the settings there aren't options for different output levels/types.

As we seem to be getting bogged down with a bit of confusion maybe we should take a step back and ask just what exactly are you wanting to acheive? I'm sure between us we can get you where you want to be. Are you looking to run all the GT10 effects in series and after the pre-amp? Or would you prefer the more generally accepted method of running drive and tone (wah) effects before the pre-amp and have the time and pitch effects after the pre-amp but before the power amp? We already know that you're not going to be usig the emulated amps from the GT10 so we can assume that you will edit those out of any pre-sets you want to use.

 

[RussT]

As far as I'm aware the loops are the same on the entire JVM range and setting the mix to 100% and having nothing in the parallel/series loop return gives no output. Direct from the JVM 2 channel manual for the parallel/series loop section "Note that if the FX loop is ON and the MIX control is set to WET without an external processor connected, the amplifier will be muted." which confirms what I posted earlier about this loop. So it is definitely capable of a true series loop. I'll admit that the second loop baffles me and I wouldn't consider using it either as it's not possible to turn it on or off with the footswitch, so I can offer no useful opinion there.

With regard to 'professional equipment' I think they're alluding towards rack effects etc. I'm not familiar with the GT10 but I'd be suprised if somewhere in the settings there aren't options for different output levels/types.

As we seem to be getting bogged down with a bit of confusion maybe we should take a step back and ask just what exactly are you wanting to acheive? I'm sure between us we can get you where you want to be. Are you looking to run all the GT10 effects in series and after the pre-amp? Or would you prefer the more generally accepted method of running drive and tone (wah) effects before the pre-amp and have the time and pitch effects after the pre-amp but before the power amp? We already know that you're not going to be usig the emulated amps from the GT10 so we can assume that you will edit those out of any pre-sets you want to use.

cheers mate. funny thing is last night at rehearsal on my JCM2000 i unplugged the return and still had a bit of sound haha looks like that isn't truely serial.

with regards to ur power amp reply about racks and output level. there is a setting for +4 db output on the GT. would it be better to use that in the power amp section for that "high headroom" it talks about?

anyhow main thing i guess i want is for my GT to be entirely in the loop with no 'tone suck' and maximum transparency, but for when i hit the effects on, for them to still sound good like they are mixed now ie no volume variances or tone sucking or basically anything that involves me hours of tweaking my effect patches. oh and i still want to be able to crank it loud like i'm in front of the amp.

 

[mickeydg5]

So just to clarify once more:

I have guitar > marshal input
marshal send > gt10
gt10 output > marshal return

You have a JCM2000 DSL100 model, 100 watts. It has what I believe to be a autoswitching series loop. The loop can be set for -10dBm (semi-pro equipment) or +4dBm (professional equipment). The level of your guitar and GT-10 input/send/return are -10dBm. So set everything to -10dBm including the DSL100 and the GT-10 programmable levels. If you use +4dBm anywhere in your combination it will produce signal overload distortion and sound like crap.

There is a better way to hook up your GT-10 and DSL100 getting way more out of the system.

Do you have any other effects connected?

Always make sure your patch and instrument cables read close to zero ohms from tip to tip and sleeve to sleeve, without any variances when twisted.