Parallel effects loop for Marshall style amps

johniss0001 · Post by **johniss0001** » Mon Apr 07, 2008 8:24 pm

i am sold on this it sounds good it sounds like it suits what i need cause i am playing status quo stuff and i want to be able to switch reverb/delay/chorus in and out and have my amps own natural characteristics

franc · Post by **franc** » Wed Apr 09, 2008 9:40 am

novosibir wrote:Just switch the send signal after the .47 to ground. This doesn't pop and the effects device already won't be fed anymore - and the decay of the effects amount before switching won't be cut awful.

Larry

Do you reckon it would matter if I'd use a footswitch with a long chord to send it to ground? There would be no actual signal going through it anyway, but any side-effects?

Why would an extra hole to switch it on or off be a waste anyway? I't not about disabling the loop, it's about disabling the effects that are in the loop all at once!

novosibir · Post by **novosibir** » Wed Apr 09, 2008 11:15 am

If you're using a shielded cable, like on BF & SF Fenders the Reverb mute is done, shouldn't be a problem. Although, haven't tried it yet.

Larry

franc · Post by **franc** » Wed Apr 09, 2008 11:16 am

Thanks, it's basically guitar cable with plug and a switch.

franc · Post by **franc** » Sun Apr 13, 2008 12:43 pm

Would it be a good idea to replace the standard loop of a Silver Jubilee 2558 combo with the Larry-Loop ?

Would it make sense?

http://www.drtube.com/schematics/marshall/2550amp.gif

ibmrjustin · Post by **ibmrjustin** » Tue Apr 15, 2008 11:40 am

Could someone email me the loop. I PMed the OP my email but havent received it. Maybe he's busy and thats cool. Anybody else? justin@jdavistreecare.com

Thanks

Justin

franc · Post by **franc** » Fri Apr 18, 2008 2:16 am

franc wrote:Would it be a good idea to replace the standard loop of a Silver Jubilee 2558 combo with the Larry-Loop ?

Would it make sense?

http://www.drtube.com/schematics/marshall/2550amp.gif

Larry?

novosibir · Post by **novosibir** » Fri Apr 18, 2008 8:30 am

franc wrote:Would it be a good idea to replace the standard loop of a Silver Jubilee 2558 combo with...

... with anything else might be better that it's now.

That's not a loop in the 2550/2555/2558 - it's a sickness.

Larry

wdelaney72 · Post by **wdelaney72** » Fri Apr 18, 2008 10:29 am

ibmrjustin wrote:Could someone email me the loop. I PMed the OP my email but havent received it. Maybe he's busy and thats cool. Anybody else? justin@jdavistreecare.com

Thanks

Justin

Go back to the beginning of the thread and you'll find the instructions of how to get the loop.

That's not a loop in the 2550/2555/2558 - it's a sickness.

Good stuff, Larry.

franc · Post by **franc** » Fri Apr 18, 2008 11:06 am

Thanks Larry.

Any suggestions on how to implement? I'm not sure what to do with that R12.
What does it do?

novosibir · Post by **novosibir** » Fri Apr 18, 2008 12:34 pm

franc wrote:Any suggestions on how to implement? I'm not sure what to do with that R12.
What does it do?

It's a local feedback, to limit the amplification of this stage and to reduce the stage's input sensitivity.

Anyway the loop should be placed between the Output Master and the PI, so jumper the orig. FX jacks internal and put an ADDITIONAL loop section in.

Larry

franc · Post by **franc** » Sun Apr 20, 2008 2:31 am

Thanks Larry! Will do

psychodave · Post by **psychodave** » Tue Apr 22, 2008 10:58 am

PM sent for PDF of loop. Thanks. 8)

johniss0001 · Post by **johniss0001** » Wed Apr 30, 2008 2:48 am

i am attempting to build the loop but i want to clear afew things up for starters this loop isn't going in a marshall so that is the confusing part.

ok sound citys have a weird way of doing things and looking at a 50 watt schematic there is a weird divider before the PI B+ so this is a tad confusing

scematic below of sound city
http://www.soundcitysite.com/sc_webpages/sc_50_plus.jpg

and is it safe to issume that pins 4,5 and 9 are grounded?

Capi · Post by **Capi** » Fri May 02, 2008 3:33 am

Hi Larry, thanks for the schem

I am working on a class A amplifier and I would like to install this loop. The amplifier has three gain stages, equalizer and master. Run at 310-320V in the preamp section. EL34, 6L6, KT66 at the power amp ...

I want to install the loop after the master. Do I have to modify some value of resistance to drive correctly the power amp?