Drive pedals in low impedance modeller loops

[MBT74]

I’m using the GT-1000 Core at the moment, but I’ve had similar issues with the Helix / HX Stomp in the past.

When I run certain drive pedals in the loops of the modeller, the pedal loses much of the great response, breaks up faster and is much brighter than when run out of the loop. This isn’t surprising since the Core has a 1k output impedance on the send so it’s like running a buffer pedal before these drives.

Is there an effective way to have these types of drives in the loops but still respond more like they were first in the chain?

Would running something like the Shnobel Tone buffer as the first pedal in the loop help? It has a 50k output impedance so, in theory, everything downstream in the loop should be more protected from the low impedance send from the modeller.

 

[jay mitchell]

Is there an effective way to have these types of drives in the loops but still respond more like they were first in the chain?

If you're a DIY type, yes: place a series resistance in the signal lead, either in a custom cable or inside the dirt box. The value should approximate the average AC source impedance of your guitar. If you place the resistor inside the box, you could make it variable (with a pot), which would allow you to use the box either way: in the loop or in front of your rig (IOW, with the resistance dialed down to zero).

 

[EOengineer]

A couple years ago I was using the HXFX with my favorite analog drive pedals in the loop. I experienced a similar problem as you’re describing. It’s an unaddressed problem in the modeling HW space.

We tend to think of buffered loops as being a good thing, especially in tube amplifiers where you’re primarily running to delays and verbs. The buffers wreck those of us who just want to patch in our favorite fuzz face or whatever.

Modifying the impedance may help out. I really hope we see hardware in the future that allows setting the impedance on the loops. It’s kind of important to be able to do that.

 

[EOengineer]

If you're a DIY type, yes: place a series resistance in the signal lead, either in a custom cable or inside the dirt box. The value should approximate the average AC source impedance of your guitar. If you place the resistor inside the box, you could make it variable (with a pot), which would allow you to use the box either way: in front of your rig, or in the loop (IOW, with the resistance dialed down to zero).

Is this conceptually similar to what Fulltone does with the Fulltone 69 where there’s a 250k input pot that can be rolled back to clean up the circuit? Basically just applying some resistance?

 

[jay mitchell]

Is this conceptually similar to what Fulltone does with the Fulltone 69 where there’s a 250k input pot that can be rolled back to clean up the circuit? Basically just applying some resistance?

I have no idea. I'm not aware of any device that includes a variable series resistance. To provide that would imply that you expect the device to be used in an effects loop.

 

[Tito83]

Is this conceptually similar to what Fulltone does with the Fulltone 69 where there’s a 250k input pot that can be rolled back to clean up the circuit? Basically just applying some resistance?

Sunface is the same. It's like a volume pot of your guitar or any typical high impedance passive volume pedal. Dont know about the pedals exactly, but on a guitar it's a variable resistance connecting to ground. It's like you're throwing your sound to ground as you lower the resistance. What's been suggested it's adding a variable resistance in line with the signal.

The HXFX doesn't have the same variable input impedance which is a major mistake IMO.

You can on other L6 devices that have it set the input impedance change on the footswitch that turns the loop on. I've suggested adding the input impedance parameter in the fx block itself to solve this, but hasn't happened yet.

I’m using the GT-1000 Core at the moment, but I’ve had similar issues with the Helix / HX Stomp in the past.

When I run certain drive pedals in the loops of the modeller, the pedal loses much of the great response, breaks up faster and is much brighter than when run out of the loop. This isn’t surprising since the Core has a 1k output impedance on the send so it’s like running a buffer pedal before these drives.

Is there an effective way to have these types of drives in the loops but still respond more like they were first in the chain?

Would running something like the Shnobel Tone buffer as the first pedal in the loop help? It has a 50k output impedance so, in theory, everything downstream in the loop should be more protected from the low impedance send from the modeller.

The Boss stuff you'll need something else if that's your goal, but it would be a pain to make it all work together. The buffer won't really work because you'd need something that matched the input buffer of the pedal you're trying to make work properly.

 

[Sascha Franck]

I asked something similar to this when looking for a buffer compatible fuzz.
Apparently things can at least partially be solved by a little DIY thing. I got that as an answer in that thread:

Guitar Pickups Simulation

Schematics & circuits for guitar effects with vacuum tubes and solid state electronics. FREE downloads of schematics such as TS-9, Fuzz Face and other classic rock devices.

www.muzique.com

Haven't tried myself yet.

 

[Chocol8]

The transformer based pickup simulator would definitely be my choice over a resistor, but I do have to ask, why put dirt pedals in the loop?

 

[EOengineer]

The transformer based pickup simulator would definitely be my choice over a resistor, but I do have to ask, why put dirt pedals in the loop?

Programmability. In my case I was using snapshots and wanted to selectively incorporate those drives with all the other effects changes happening.

 

[Tito83]

Programmability. In my case I was using snapshots and wanted to selectively incorporate those drives with all the other effects changes happening.

If you really want to you can buy a programmable looper. Split the signal before and after the FX loop on the effects unit you have on two different loops on something like the Boss ES5, GigRig whatever. That way you can have your guitar going straight to the dirt pedals and into the fx return of the HX with whatever you want and, when needed, you turn on the other half for the effects that need to go before dirt.

 

[Sascha Franck]

but I do have to ask, why put dirt pedals in the loop?

My main setup is using a GT-1000 as the "brain". In its two loops I have a bunch of dirt pedals running into some amp sim pedals (Amplifirebox and Amp Academy). The GT controls the on/off status of the loops and I can preselect which dirt boxes I want to use, in addition, the GT serves as a pre-boost for leads and also as a wah. An extremely comfortable to deal with setup.
But for the mentioned reasons, some dirt pedals sound pretty different compared to them being fed straight from the guitar. Not much of a deal with the pedals I currently use, but should I ever wanted to add a more or less traditional fuzzbox, it likely won't work too well as there's very little fuzzes doing a great job in a buffered environment.

Also, when I had my last loopswitcher based board, the sound was getting much cleaner and consistent in case I was running the guitar through a buffer of some sorts as the very first thing in the signal chain. Obviously, the same things as mentioned above apply.

Even in my small HX Stomp based setup, I used to run two drive pedals in its loop. Makes them kinda programmable and I can add pre-boosts easily.

 

[MBT74]

The transformer based pickup simulator would definitely be my choice over a resistor, but I do have to ask, why put dirt pedals in the loop?

For me, the GT-1000 is providing all modulations, reverb, amp and one delay effect. So I have two loops. One with a selection of drive pedals and another with a Mood and Thermae in it.

Some modulations I prefer before drives and some after.

 

[Chocol8]

OK, I guess you guys are way more creative with signal chains than my old fashioned ass! I would try the pickup simulator to get the impedance up before any fuzz, treble boost, or other sensitive pedals. It has been a while since I built one, but the transformers I bought last time were tiny and only a few $ each. I am a little scared to lookup what they go for now though!

 

[synthpenguin]

One thing I think is really cool about the Tone Master Pro is those two analog loops integrated in. I was kinda hoping the Stadium would have something like that.

 

[MBT74]

This might be worth a try.

https://axesselectronics.com/produc...wpKg5In7jwpWMClHA3gBPuWn3SHzRuPKFsdQLsifTUOfX

 

[hunter]

best option is run the drive before the digital multi. same problem with pedaboards/buffers and going into amps vs straight in, or the fundamental issue with reamping, profiling, etc ... those who sell buffers, reamping boxes and all claim it would be the same as the guitar plugged in, but it isn't.

 

[Sascha Franck]

One thing I think is really cool about the Tone Master Pro is those two analog loops integrated in.

To bad it's got no options to route any internal FX pre-loop. Would be tremendous if the send of the digital loop could be placed in front of the analog loops and could be taken out with the help of some relais switch, so you wouldn't run into the issues discussed here.

This might be worth a try.

https://axesselectronics.com/produc...wpKg5In7jwpWMClHA3gBPuWn3SHzRuPKFsdQLsifTUOfX

Pretty sure that's just a rendition of the circuit posted above. And for that, it's pretty expensive.

best option is run the drive before the digital multi.

Of course, but sometimes that just isn't an option (or would make things a lot more complicated).

 

[JiveTurkey]

The TBP has the two, fixed analog loops. You can't move them and the different methods of changing the rest of the signal chain flow are an abomination and basically ruin any sort of "look what I can do!" vibe you feel like a touchscreen device should be giving you.

 

[metropolis_4]

To bad it's got no options to route any internal FX pre-loop. Would be tremendous if the send of the digital loop could be placed in front of the analog loops and could be taken out with the help of some relais switch, so you wouldn't run into the issues discussed here.



Pretty sure that's just a rendition of the circuit posted above. And for that, it's pretty expensive.



Of course, but sometimes that just isn't an option (or would make things a lot more complicated).

The TBP has the two, fixed analog loops. You can't move them and the different methods of changing the rest of the signal chain flow are an abomination and basically ruin any sort of "look what I can do!" vibe you feel like a touchscreen device should be giving you.

Isn’t the whole purpose of those loops that they don’t involve any AD/DA conversions?

There’s no possible way to put them anywhere else in the signal chain without breaking that goal. If you could place them in the middle of your chain they would have to go through DA/AD conversion and it would no longer be analog.

There are other loops in the device that can be placed anywhere in the chain. I think it was a nice idea to offer both possibilities to users

 

[JiveTurkey]

Isn’t the whole purpose of those loops that they don’t involve any AD/DA conversions?

There’s no possible way to put them anywhere else in the signal chain without breaking that goal. If you could place them in the middle of your chain they would have to go through DA/AD conversion and it would no longer be analog.

There are other loops in the device that can be placed anywhere in the chain. I think it was a nice idea to offer both possibilities to users

I get the fixed positioning rationale. The signal chain methodology and management is dumb overall though. Unless they overhauled it since I had it? You awkwardly grab a signal chain type on the side and it blows up the whole thing you have built. You couldn't control the levels of external loops via expression pedal last I knew which I could do on the Kemper a decade+ ago. It's a touchscreen and I actually like the skuemorphoic thing but it still felt like using something from 2014 as far as getting around on it went.