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Adding delay to a '74 Marshall JMP via jumped cables or line out?

Steve73

Member
Messages
5,203
Hi guys,

I am just trying to figure out the best way to add some delay to a '74 Marshall JMP. So far, I've tried the analog delay straight in to the amp (which is almost cranked) and it wasn't too successful. Pretty messy. I've also tried the delay in between channels via jumper cable. Again, too messy. Next, I tried sending a cable from the unused bottom Marshall input (using top input of the Normal Channel for the guitar's input) to a delay and then into the normal channel of an AC30 as a wet rig. This really sounds great and is what I was looking for. The grit and presence of the Marshall but with a bit of depth. I plan to use the other Top Boost Channel as a clean channel with an AB box. So it will be a 'Wet Dry A/B Clean Dirty' type of rig.

With that in mind, I do use a Ho attenuator with the Marshall so I could possibly also add a variable line out to it. For you guys that have tried the line out method to add some delay to amps post power section, is there any advantage with using a line out versus using the jumped cable out methoed that I described above? Thanks for any help!
 

JJman

Member
Messages
994
The method you are using will not provide a properly distorted signal to the wet amp while the Marshall is cranked for distortion. So your echoes will always be "clean" even when the Marshall is cranked. This assumes your echoes will be quieter than the dry signal, as most are.

I'm picking up one of these to do some experimenting since it has a "speaker" mode. It's certainly cheap enough and I needed to use that gift card.





Based on the schematic the "speaker mode" provides a "line out" using a simple voltage divider tap on the speaker signal which is sent thru an impedance changing tranny. Using this approach, all the properly distorting signal from the output of the Marshall will be the source for the signal you send to the wet amp. Just use a transformer/adapter to bring the impedance back to guitar-type on the output of the DI unit. Also cheap.

 

Flameout12

Member
Messages
1,177
Somehow you gotta tap the line out...the DI will work fine. This way you are re-amping the Marshall output and you have all kinds of options, including just using your AC30. :dude
 

JJman

Member
Messages
994
The one I ordered is the Hosa DIB-443. It looks like the Palmer's 3 "attenuator" modes are similar to the 2 mode switch on the Hosa. Palmer looks more geared toward a guitarist. I suspect the Palmer may not have an impedance matching tranny inside since the word "impedance" does not appear on it and the instruction do not show the option of plugging a guitar straight into it.

I understand there are tonal considerations with all this but I think everyone should carry a DI "just in case" like if your amp dies and you need to go into a board. It happened to me one time and a DI would have helped.
 

dunara

Member
Messages
1,900
A lot of attenuators have a 1V line out which can be used as a feed to your echo. That way, you are using your prime overdriven amp sound as your echo send.
I use my Weber Mass to attenuate, and to feed the signal from the dimed JTM45 to my echo, which returns through an HH solid state amp. The two heads feed the two sides of a 4X12" which I've wired up as two 2X12" half-cabs. Elegant, and great-sounding.
 




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