Marshall Vintage Modern loop question.

[drewl]

Hey, any you guys know if when the loop is turned on (by rear panel switch) the volume drops a bit?


Doesn't matter if a cord is jumpered between send and return, and the loop level switch is working correctly.

Just curious if it's normal for those who have one or worked on one.

Thanks.

[Enzo]

schematic?

[Chuck H]

What "vintage" Marshall has a "loop" as part of the design? I guess I don't even know what a "vintage modern" Marshall is.?.

[Jon Snell]

Try asking the Marshall Community; https://www.marshallforum.com/
They may be more familiar with your question and upload a schematic/photo including the exact model number.

[Pedro Vecino]

I have had some but have not tried the loop. This is the schematic:

[pdf64]

Unless con 2466-62-02 connects directly to the loop jacks (?), I think that’s missing the actual fx loop send and return circuits?

[vintagekiki]

Hey, any you guys know if when the loop is turned on (by rear panel switch) the volume drops a bit?

Small changes in volume drops can be noticed by changing position SW1.

Question
Whether volume drops independently from position SW2.
Whether volume drops when send and return jacks bypass with short cable.

[drewl]

Thought maybe someone knew off the top of their head.
ill look up a schematic.

Doesn't matter if a patch cord is in, when loop is turned on, the level drops.

Send level switch works.

Thanks.

[Enzo]

Pedro posted the schematic. And to pdf, the lower schematic covers the FX loop.

There are circuits on either side of the jacks, and this being a mere guitar amp, it is likely the levels are not exactly balanced.

[vintagekiki]

http://musiciansroadhouse.com/viewforum.php?f=70

http://musiciansroadhouse.com/viewtopic.php?f=70&t=11594

https://forum.metropoulos.net/viewforum.php?f=25

https://forum.metropoulos.net/viewtopic.php?f=25&t=21933

[Mick Bailey]

The send/return levels are set by fixed component values, so with no trimpot to calibrate the circuit the overall effective loop gain (or loss) comes down to component tolerances.

I've noticed with a few Marshall amps that with the loop engaged the output changes slightly, and that operating the loop level boosts/reduces the signal where you might expect the overall gain to be unity either way.

[vintagekiki]

About Fx Loop In A Vintage Modern

https://www.marshallforum.com/threads/vintage-modern-2266c-fx-loop.108782/
_{Vintage Modern (2266c) FX Loop}

https://www.marshallforum.com/threads/anybody-use-the-fx-loop-in-a-vintage-modern.107322/
_{Anybody Use The Fx Loop In A Vintage Modern?}

https://www.marshallforum.com/threads/marshall-vintage-modern.104813/page-3
https://www.marshallforum.com/threads/marshall-vintage-modern.104813/page-4
_{Marshall Vintage Modern}

https://www.marshallforum.com/search/
_{Enter Required Keywords}

https://www.thegearpage.net/board/index.php?threads/should-i-replace-the-effects-loop-on-a-marshall-vintage-modern.1988492/
_{Should I replace the effects loop on a Marshall Vintage Modern}

https://store.metropoulos.net/products/zero-loss-fx-loop-board-only ¹⁾
_{It is not an advertisement but a technical solution. see links}

[drewl]

So it is normal.

Thanks for all the links.
Been busy at work and didn't get a chance to research the issue.


Thanks again.