Parallel effects loop for Marshall style amps

jerrydyer · Post by **jerrydyer** » Tue May 08, 2007 1:11 pm

did you alreacdy count mine? works killer its in this one see siggy

Stonersteve · Post by **Stonersteve** » Thu May 10, 2007 4:48 pm

I spend the afternoon putting Larry's loop together and ran out of parts .... here is a pic, hope this will work without hum or strange noises .

Is it a problem to put this close to the output tubesockets ???

Stefan

Stonersteve · Post by **Stonersteve** » Thu May 10, 2007 6:30 pm

Don't worry Larry. The circuit is not visible

5150loveeddie · Post by **5150loveeddie** » Fri May 11, 2007 3:05 pm

Larry if I send you a drawing of the loop in a visual PTP can you tell me if its ok, I'm such a monkey for reading shematics........duh

jngreene79 · Post by **jngreene79** » Fri May 11, 2007 5:09 pm

Larry sent it to me a couple of days ago (thanks Larry!) and I've staked an entirely new high gain preamp board. I hope George's parts come Sat. I've incorporated it into my preamp layout. I'll zap it to you as soon as I make sure all is well with it

-James

OUTLAW1969 · Post by **OUTLAW1969** » Sat May 12, 2007 12:47 am

Hey, I just found this post. What a goldmine of info!!!!

I am gonna have to try this, if Larry will send it to me.

I would like to do something along the lines of ThinLizzy's version that I can mount separately inside my headshell. That way I can avoid cutting a few holes in my JMP.

I have to admit that I am very excited at the possibility of finally having a loop on the JMP, but do not want to get too excited in case the kid from last month screwed things up for the rest of us.

Sending a PM to Larry now.

5150loveeddie · Post by **5150loveeddie** » Sat May 12, 2007 2:27 am

jngreene79 wrote:Larry sent it to me a couple of days ago (thanks Larry!) and I've staked an entirely new high gain preamp board. I hope George's parts come Sat. I've incorporated it into my preamp layout. I'll zap it to you as soon as I make sure all is well with it -James

Thanks man! Larry did send me a nice version, easy to understand one!!

Larry you rock, like always, Danke

!!

OUTLAW1969 · Post by **OUTLAW1969** » Tue May 15, 2007 8:01 am

Larry, thanks for the help.

I may have a few other questions after building the "external loop", and placing it inside the headshell like ThinLizzy did. I am still not sure where to run the wires to, on a MV amp.

franc · Post by **franc** » Sun May 20, 2007 3:05 am

I still haven't figured out where to put the extra tube and the circuit around it.

For a 100W chassis I can see an extra tube added to the left, an extra small board added to the left for the circuitry.
But for a 50W chassis, where to put it?
Is the short end of the chassis the only place to horizontally place the tube?
Can't see that happening, really...

Would und the board be an option?

thinlizzy · Post by **thinlizzy** » Sun May 20, 2007 4:40 am

Did you see my solution, to put it in the headcase?

Marcel

joshwilson3 · Post by **joshwilson3** » Tue May 22, 2007 2:16 am

You guys that have Larry's loop in. If you have an external preamp. Can you guys plug the external preamp in the back of the amp to use the power amp? I'm wondering how well that works using Larry's loop as a slave.

Thanks

jngreene79 · Post by **jngreene79** » Tue May 22, 2007 6:38 am

Yep, you can run an external preamp into the effects loop return. You can A/B them with a switcher. When using the return, the volume is a lower and (on a master vol) the Master has no effect on the return volume. I think Larry has addressed this and ways to remedy it. I'm trying to build a Dumble style clean channel into a small box and us that for cleans. Very cool loop, Larry

franc · Post by **franc** » Tue May 22, 2007 1:41 pm

thinlizzy wrote:Did you see my solution, to put it in the headcase?

Marcel

Yeah, I did. Not bad, but not something I could sell with my amps...

I'm thinking about a separate, steel/alu box, holding tube and extra components, that I mount on top of the chassis. Piggy-back style. Will the box provide enough shielding?

novosibir · Post by **novosibir** » Tue May 22, 2007 4:26 pm

franc wrote:I'm thinking about a separate, steel/alu box, holding tube and extra components, that I mount on top of the chassis. Piggy-back style. Will the box provide enough shielding?

On the input side of the chassis an aluminum box is doing well!

On the PT side you'd need a steel box, because aluminum doesn't shield against the PT's magnetic field.

Larry

franc · Post by **franc** » Tue May 22, 2007 5:13 pm

I was thinking right beside the choke, on top of the inputs

on the empty spot.

Just a shallow box that holds the board and components, one hole in the chassis to feed the wires through.
The fx in and out + pots will be on the back of chassis, besides the outputs (shielded wires?).

This way you could even add the fx loop to existing amps without having to modify too much.

Metropoulos Forum

Parallel effects loop for Marshall style amps

half finished ...