Limitations of using parallel amp / speaker models

[dmeros]

This is an update that might be useful to people considering using the Stomp the way I am, which is to run bridge pickup of a bass through effects and into one amp / speaker, and the neck pickup going into another amp / speaker.  (think:  Chris Squire / Ric-O-Sound) 

 

Here are a couple little info tidbits that I searched for hours for and couldn't find answers to and had to learn the hard way, so I thought I'd just post this here in hopes of helping somebody else with a similar situation.  All things considered, the Stomp WILL work for me and it will allow me to take WAY less gear to gigs, so overall I'm very happy to have one! 

1)  I was concerned about having the ability to run two amp / two speaker models in parallel plus a handful of effects like compressors, EQ, tremolo, etc.  I saw that I could combine an amp and speaker into one block, called "Amp+Speaker".  I was hopeful that arranging two of those amp / speaker combinations would leave me four blocks to work with.  In a word, no.  An Amp+Speaker block is indeed one block.  BUT - it uses a LOT of DSP.  When I do that and set up the two amp + speaker models, it uses so much DSP that I can only apply very simple effects after that, and even then only one or two more, like simple EQ for example.  

So it's good to know that when they say "up to six blocks", the "up to" is a very key phrase.   If you're thinking of using two amp+speaker blocks you'll have very little to work with after that.  I have thought of a couple workarounds that will work for me, but the fairly severe DSP limitation was a little surprising to me.  

2)  Also something to note:  If running from a TRS (stereo) output on your instrument, a regular TRS cable (like a mic cable with 1/4" plugs on each end instead of XLR) will not work properly if you're thinking of using a cable of any appreciable length.  You'll get a substantial amount of bleed between the two pickups.  I spent quite a bit of time figuring out that it's not the fault of the Stomp or my bass, it's the cable from the instrument to the Stomp.  Each conductor must be independently shielded to get true separation between the two pickup sources.   I found a ProCo insert cable that is literally two mono cables "welded" together that works great, or you can use a splitter directly out of the TRS output jack on your instrument and then run two separate 1/4" cables into the Stomp.  

Anyway. .. hope that is of some help to somebody who is thinking of getting a Stomp and using it the way I am.  
 

[craiganderton]

I looked into parallel processing extensively when doing my multiband processing preset pack. So to add to your tips, here are some more.

 

• Some amps draw a lot more CPU power than others. So how many amps you can add depends on the amps+cabs you choose.
• In my 4-band presets using the Brit Trem Jump, Brit Plexi Jump, Solo Lead OD, and German Mahadeva, it wasn't possible to have four Amp+Cabs without running out of CPU. However, a workaround that works well is to use two separate Amps, and feed them into one Cab. You lose the ability to tweak each cab individually, but many times, it's the amps that benefit the most from tweaking anyway.
• Although this doesn't apply to your situation where you're feeding into the Guitar and Aux In to get stereo, for a given amount of blocks, a parallel path within a single chain will run out of CPU faster than a single path within two chains, set to the same input (e.g., Host in Helix Native).

 

One of my favorite aspects of Helix is how you can get really great stereo imaging out of it. This isn't always relevant to live use, but for the Native version, it's incredible to get stereo imaging without having to use delays or other workarounds :)