4CM FOR THE HD500

Introduction

This document describes how to integrate the HD500 into a Four Cable Method (4CM) setup.  The configuration described works for me and may (or may not) need tweaking to get working for other people's setups.  I have tried to make it as generic as possible so as to work for everyone.  The setup should work for an HD Pro also but is untested.

The cabling for 4CM is strange and wonderful and takes a bit of thinking to get your head around it.  Following this guide:  you can get by without working out how it works but it will be helpful to you if you do. There is a primer on 4CM here --> http://line6.com/support/docs/DOC-2523 and you may want to read through this to get your head straight on how 4CM works.

Aside from the cabling:  finding the correct levels is the other big of headache with 4CM.  I have included two possible basic configuration methods for the HD500. 

• The first method uses  'Instrument Level' (-10dBV) throughout and is probably best if you want to use the HD500 for effects only. 
  
  
• The second method is an alternative setup for if you want to use the HD500 for both modeling and effects, in situations where your 'real' amplifier pre-amp is much louder than the modelled ones'.  It uses 'Line Level' (+4dBU) on the HD output but turns down the real pre-amps. This effectively gives you more headroom the modelled pre-amps. 

Either may work for you - trial and error is the key.  Start with the first method and then only move to the second method if you need to.

Cabling

This is the standard 4CM cabling:

All cables can be  standard guitar-type cables.  The HD500 FX Send jack is actually stereo (TRS) but a standard guitar cable can be used here: from firmware 1.40 onward, the FX Send will be automatically mixed to mono when a standard mono guitar cable is used.

If you have MIDI channel switching on your amp then I strongly recommend that you try a MIDI cable also. This allows you to change your HD patch and amp channel with a single button press - very cool!  Check your amp manual and/or the Pod HD Forum for more details.

Amp Settings

*  These controls may or may not exist depending on your amp. Set them as suggested if they do.  Don't worry if they don't.

**  Note: on many amps the Master control is implemented after the effects loop.  On some other amplifiers the master control is implemented before the effects loop.  In this case the output volume on your effects unit becomes the master control for the amp and you may need to turn the master control on your amp way high to provide a signal into the effects loop.  Equally, you would need to turn the HD500 Master level down !   

HD500 Settings

The settings below are the same for both methods except those in red which are for the first method and blue which are for the second method:

*  Note:  on many amps the Master control is implemented after the effects loop.  On some other amplifiers the master control is implemented before the effects loop.  In this case the output volume on your effects unit becomes the master control for the amp and you may need to turn the master control on your amp up way high to provide a signal into the effects loop.  Equally, you would need to turn the HD500 Master level down !

Patch Setup - Effects Only

This is a setup for a patch using Effects only.  The settings below are the same for both methods except those in red which are for the first method and blue which are for the second method:

Control

1. Start off by creating a completely ‘Blank’ patch with no effects set and no amp model selected.
2. Move the mixer device to the very end of the effects chain by moving all of the effects blocks in front of the amp model.
3. Add an ‘FX Loop’ effect to the effects chain somewhere near the middle.
4. Add a studio EQ just before the FX Block. No EQ changes should be set but the gain should be raised by +12dB *.  This compensates for a level drop between the HD Input and the HD FX Loop.
5. The mixer channel A level should be set to around -1.5 dB for method 1 or around -14 dB -12dB for method 2 and Panned to Centre. Mixer channel B level should be set to 'Mute'.  Note that this level may vary quite a bit between amps.  The best advice is to flip the Amp Loop on and off and adjust the Mixer output level until the level is the same with the loop on or off.
6. Any effects that you want ‘in front’ of the Amp can now be inserted into a free block to the left of the ‘FX Loop’ block in the effects chain. Typically these might include Compressor/Overdrive/Distortion and Wah.
7. Any effects that you want in the ‘Loop’ of the Amp can now be inserted into a free block to the right of the ‘FX Loop’ block in the effects chain. Typically these might include Delay/Modulation and Reverb.
8. Try and ensure that the ‘Output’ or ‘Level’ for each individual effect does not make the overall volume level louder or quieter.  This will avoid level problems with the patch overall.
9. Set ‘Input 2 Source’ to ‘Variax’ even if you do not have one.  This will reduce background noise on higher gain patches and will help keep the input gain at the right levels.   This setting is found within 'System Settings' but is set for each patch individually.

Do not select an amp model for an 'effects only' patch as this will then be in competition with your real pre-amp in and will probably sound poor..

*  Note (Oct 2012):  The FX Send level is set by the gain level Studio EQ in step 5 above and is dependent on your choice of Input sources. 

• If you set your POD Input Sources to Input 1 = Guitar/Input 2 = Variax (as suggested in step 9) then you should set the level to +12dB as suggested. 
• However, if you prefer to use set your POD Input Sources to Input 1 = Guitar/Input 2 = Same then you should set the level to just +6dB to avoid over-boosting your amp input and causing unwanted clipping.

Patch Setup - Amp Model

If you want to use a modelled patch while in 4CM instead of your amp's pre-amp this is simple. 

Start with a patch as created under 'Patch Setup - Effects Only' above but with the following changes.

• Remove the Studio EQ Block
• Remove the FX Loop Block
• Select an Amp Model
• Set the amp gain and volume level so that the Amp volume roughly matches the real pre-amp volume.

A Note on Levels

When doing the basic 4CM setup, before overlaying your choice of effects, you should be looking to make sure that volume levels are kept close to the right level.

• The input into the amplifier should be the same as when you plug your guitar in directly.
• The send from the amp back to the HD should be at instrument level and no louder than when it was sent.
• The output from the Pod HD should be the same volume level as when the amp loop is turned off

All in all, the ideal setup is when your volume levels in 4CM are identical to if you were just plugging the guitar into the amp directly with the amp loop turned off.  The setups above aim for this but it is possible that you may need to adjust levels at some point.  Some hints then.

• The HD's FX Loop Send level is effectively the level sent out to the amplifiers' pre-amp and allows you to cut the level - not boost.  This is unfortunate because the HD seems to drop a few dB between it's input and Loop send. 
  
  That is the reason for the studio EQ at step 4: to boost the FX Send Level a little - i.e. the level going into the amp input.  If you need to adjust the level up or down, it is probably best to adjust the gain level on that EQ.  On my HD, using the Studio EQ as I describe gives you 'unity' gain - no boost or cut - between the input of the HD and the loop.  I would expect this to be the case with other HDs also.

• The HD's FX Loop Return Level controls the level coming back from your amp's pre-amp into the HD Loop return and allows you to boost the gain level - not cut.  It should not need to be adjusted unless you find that the FX loop Send on your amp cuts your gain level.  Then you can raise it by a few DB to compensate.   Try flipping the Amplifier effects loop on and off.  If things get quieter then try boosting the loop return.

• You should do all level checks like this using a patch without additional effects (apart from the FX and Studio EQ blocks).  This is cause the overall levels can be pushed up and down by individual effects. When you do add the additional effects, pay attention to output level settings in the individual effects and try and keep things at the same level as when the effect was turned off.

If you have a Line-level FX Loop on your amp then you can use a device such as the Ebtech Line Level Shifter or GLab SA-1 to do the conversion between +4dBu and -10dBv.  The GLab in particular is highly adjjustable to match exact levels where an amp loop is a bit weird. Other, similar devices exist - Google is your friend .

Summary

That is it.   I wrote a more comprehensive guide specifically for the Marshall JVM that has more info and tips that may be relevant.  This is posted here --> http://jvmforum.com/phpBB3/viewtopic.php?f=9&t=5333 and may be worth reading also.  Other guides are posted on the Line 6 Forum too.

If you find any errors with the text above or want to contribute to this document:  please send me a message.

Cheers.

JIM, November 2011