Using Ext Amp connection for Marshall

[PeHaLine6]

I'm thinking to buy Marshall dsl20 cr amp. Let's imagine I have a preset which has 8 snapshots. At top there are dirty sounds (FS2->) and at bottom there are clean snapshots (FS8->). Is it possible to do so that if I use any of dirty snapshots, Helix Floor gives always a "command" to Marshall to use the dirty channel? And, if I use any of clean snapshots, Helix gives a "command" to Marshall to use the clean channel?

 

Just thinking that if this function always switches the amp channel to something else than current, then it is not perhaps what I want (say a case when I have FS2 snapshot on, and I then select FS3 -> would it now switch the Marshall channel to clean channel or not? FS2 and FS3 should both be dirty in my scenario.

 

Should I use TS or TRS cable between Helix and the amp? I don't need FX loop of the amp.

[Schmalle]

When you plug a TS jack (cable) in the Marshall's F/S socket: does this engage the Marshall's FX loop? If that is the case you need a TRS cable to connect Helix Ext Amp and Marshall F/S sockets.

Use Command Center's Ext. Amp Command to do the channel switching. Program a footswitch if you want to be able to change channels while staying on a snapshot. Otherwise program an Instant Command per snapshot.

[rd2rk]

Each Snapshot has 8 "Instant Commands" (IC) which are sent on Preset load and Snapshot (SS) load.

Assuming that your DEFAULT Snapshot (the one active when the Preset is SAVED) is SS1, when the Preset loads all configured Instant Commands in SS1 will be sent when the Preset loads.

 

NOTE - All 8 Instant Commands BEING USED need to be configured in all Snapshots, else they will send the default value for that command type.

IOW - If you are using IC1 to send command type EXT AMP, IC1 must be configured to send the desired EXT AMP command is each Snapshot.

 

When you load a different Snapshot, any Instant Commands (IC) whose values have changed will be sent.

If the values have NOT changed they won't be re-sent.

 

You only need one IC for your EXT AMP command, so say you use IC1 for that in all Snapshots.

 

If IC1 in SS1-SS4 is set to switch to the dirt channel and you are only switching between the dirty sounds, the EXT AMP command will only be sent once.

If IC1 in SS5-SS8 is set to select the clean channel, that command will only be sent when you select one of those Snapshots and IC1 will not be sent again until you again select SS1-SS4.

 

In this way you can toggle your amp's channels on a per Snapshot basis.

 

[PeHaLine6]

Okay thank you rd2rk :) I appreciate your help! You wrote "If IC1 in SS1-SS4 is set to switch to the dirt channel"; how can I set it like that?

Say concerning a dirty snapshot, I set command type EXT AMP using Instant1 and select "Tip", how does Marshall know in this case that the channel must be changed to dirty (or remain it as dirty if it already is like that)?

 

Till now I have thought that "tip" is always related to channel switch (changes to other channel) and "ring" is related to reverb (that is just a guess).

 

Did you mean I should set IC1  (tip) to all 8 snapshots, no matter are they supposed to be dirty or clean?

[rd2rk]

On 9/22/2025 at 10:37 AM, PeHaLine6 said:

Okay thank you rd2rk :) I appreciate your help! You wrote "If IC1 in SS1-SS4 is set to switch to the dirt channel"; how can I set it like that?

Say concerning a dirty snapshot, I set command type EXT AMP using Instant1 and select "Tip", how does Marshall know in this case that the channel must be changed to dirty (or remain it as dirty if it already is like that)?

 

Till now I have thought that "tip" is always related to channel switch (changes to other channel) and "ring" is related to reverb (that is just a guess).

 

Did you mean I should set IC1  (tip) to all 8 snapshots, no matter are they supposed to be dirty or clean?

 

It's analog. All that's happening is that a circuit is either open or closed.

IDK which is which on that amp, you'll need to experiment a bit, but let's say that TIP is CHANNEL, OPEN is CLEAN and CLOSED is DIRT.

Set the IC on the CLEAN Snapshots to EXT AMP>NONE and the DIRT Snapshots to EXT AMP>TIP.

The Channel on the Marshall will remain in the selected status (OPEN/CLEAN or CLOSED/DIRT) until you select a Snapshot that changes the OPEN/CLOSED status -NONE=OPEN/CLEAN or TIP=CLOSED/DIRT.

Again, you'll need to experiment to figure it out.

If you have the actual Marshall Pedal you can use a multimeter/continuity tester to see if the circuit is open or closed when the button is activated.

[Schmalle]

On 9/22/2025 at 6:37 PM, PeHaLine6 said:

Till now I have thought that "tip" is always related to channel switch (changes to other channel) and "ring" is related to reverb (that is just a guess).

The ring contact is for switching the FX loop in your Marshall.

[PeHaLine6]

Okay thanx for all replys. Atm I have Peavey Delta Blues 115 Tweed combo but I could not get channel switch to work via Helix with this amp. Hence I'm considering to get Marshall dsl20 cr. So, I assume this item from Helix manual concerns Peavey, at least my Peavey:

"The Helix device's ability to control external amp channel and/or reverb switching has been tested with many popular amps and heads. Unfortunately this does not guarantee compatibility with all products. Note that, depending on the circuitry of the channel switching jack in the guitar amp used, the EXT Amp function may not operate as expected."

[rd2rk]

On 9/23/2025 at 2:40 AM, PeHaLine6 said:

Okay thanx for all replys. Atm I have Peavey Delta Blues 115 Tweed combo but I could not get channel switch to work via Helix with this amp. Hence I'm considering to get Marshall dsl20 cr. So, I assume this item from Helix manual concerns Peavey, at least my Peavey:

"The Helix device's ability to control external amp channel and/or reverb switching has been tested with many popular amps and heads. Unfortunately this does not guarantee compatibility with all products. Note that, depending on the circuitry of the channel switching jack in the guitar amp used, the EXT Amp function may not operate as expected."

 

If you have the PV FS you can test what's happening with a multimeter or continuity tester.

If you don't have that, I had a quick look at the manual and it appears to me that there's separate switch jacks for the Channel/Boost functions and the Reverb/Tremolo functions. Since the required PV FS has only ONE TRS jack, that would seem to indicate that you'd need TWO footswitches to control all functions, but that would be weird.

 

If I were you, I would contact PV Support and see what they say about it. If you like the PV, the Marshall will be a very different sounding amp.

 

 

 

 

[Schmalle]

On 9/23/2025 at 7:10 PM, rd2rk said:

 

If you have the PV FS you can test what's happening with a multimeter or continuity tester.

If you don't have that, I had a quick look at the manual and it appears to me that there's separate switch jacks for the Channel/Boost functions and the Reverb/Tremolo functions. Since the required PV FS has only ONE TRS jack, that would seem to indicate that you'd need TWO footswitches to control all functions, but that would be weird.

 

If I were you, I would contact PV Support and see what they say about it. If you like the PV, the Marshall will be a very different sounding amp.

Helix's Ext Amp switching isn't compatible with the Peavey Delta Blues.

[rd2rk]

On 9/23/2025 at 1:52 PM, Schmalle said:

Helix's Ext Amp switching isn't compatible with the Peavey Delta Blues.

 

Just for my personal info, what method is the PV using that makes it incompatible? It appears to be simple TRS switching, as I don't see any voltage supply to the FS which uses a single TRS cable...

[Schmalle]

On 9/23/2025 at 11:54 PM, rd2rk said:

 

Just for my personal info, what method is the PV using that makes it incompatible? It appears to be simple TRS switching, as I don't see any voltage supply to the FS which uses a single TRS cable...

The Peavey switches channels using a relay. The relay is engaged when connected to a voltage. Peavey uses a negative supply voltage to do that.

 

I don't own a Helix and haven't seen the circuit board but AFAIK Helix uses a transistor based open collector circuit to switch. I would be very surprised if this isn't done with an NPN transistor. Unfortunately to switch negative voltages you'd need a PNP transistor.