The Hughes & Kettner User Forum

Would you like to react to this message? Create an account in a few clicks or log in to continue.
The Hughes & Kettner User Forum

The Unofficial guitar amp and cabinets forum for users of Hughes and Kettner products. We are not affiliated with Hughes and Kettner!!


5 posters

    Helix as the FX for a GM40- 4 Cable method

    spikey
    spikey


    Posts : 63
    Join date : 2016-10-14

    Helix as the FX for a GM40- 4 Cable method Empty Helix as the FX for a GM40- 4 Cable method

    Post by spikey Fri Jan 20, 2017 11:35 pm

    Helix as the FX for a GM40- 4 Cable method OxCN9Gj

    Drawing out loud here-

    Using Helix as the FX rack for the H&K GM40. Not sure if the GM40 FX loop is Line or Inst level, so adjust accordingly.
    In this diagram the front end of the GM40 gets the Helix wah, a dirt pedal. After the GM40's preamp it gets a Helix volume pedal, delay and verb.
    All switchable on or off by the Helix controller.

    Use the Cabs in Helix or use the Redbox in the GM40, or both (or none and use the cab).


    You can also set up Helix (in the control area) to send midi CC messages to the GM40, to switch the GM40's midi changeable functions cheers
    guitarsoul
    guitarsoul


    Posts : 6
    Join date : 2017-04-24

    Helix as the FX for a GM40- 4 Cable method Empty Re: Helix as the FX for a GM40- 4 Cable method

    Post by guitarsoul Wed Apr 26, 2017 7:29 am

    Hi!!!
    This is very interesting ...
    I'm going to buy both now in June and I want to use it that way ..
    I just do not know how to configure Helix to control the amp presets through Midi.
    Can you help with that part?
    hug
    bordonbert
    bordonbert


    Posts : 1772
    Join date : 2015-01-28
    Age : 72
    Location : Southern England

    Helix as the FX for a GM40- 4 Cable method Empty Re: Helix as the FX for a GM40- 4 Cable method

    Post by bordonbert Thu Apr 27, 2017 6:18 am

    Purely as a reference, from the owner manual Tech Specs:

    Fx Send Nominal Level, (Clean without Boost all pots centred) = -10dbV (316mV RMS)

    Fx Return Nominal Level, (Clean without Boost all pots centred) = 0dbV (1V RMS)
    Fx Return Nominal Level, (Clean without Boost all pots centred except Master set max) = -10dbV (316mV RMS)
    Fx Return Max Input = +14dbV (5.02V RMS)

    dBs confuse a lot of people and it isn't surprising! For those who don't work with them every day, they are NOT a measure of anything in themselves, they are a comparison of two quantities. i.e. they are telling you how many times bigger one thing is than another. e.g. A gallon of milk is 8 pints, so a gallon is +9dB (8x) above a pint. Or a more relevant example, an amplifier's frequency bandwidth -3dB points are the points where the power has dropped -3dB (1/2) in comparison to its mid range level for equal inputs.

    The H&K levels are specified as "dBV". The "V" is the standard suffix to tell us the voltages we are considering are compared to 1V as a reference. So they are "[so many times] as big or small as 1V".

    The outputs mentioned will of course be affected by the input level. The specified input sensitivity of the amp is -23dBV (71mV). This would be the input level which gives those specified Fx Loop levels. The max input signal without boost is specified as 0dBV (1V). In my experience most guitars are capable of putting out signals a fair bit above that 71mV level.


    _________________
    Newcastle Brown, can sure smack you down
    You take a greasy wh*re, and a rollin' dance floor
    You know you're jailhouse bound!

    Rock On Humble Pie
    Syn666
    Syn666


    Posts : 64
    Join date : 2015-11-04

    Helix as the FX for a GM40- 4 Cable method Empty Re: Helix as the FX for a GM40- 4 Cable method

    Post by Syn666 Mon May 29, 2017 9:20 am

    Sorry to barge in, but the flexibility and effects quality of the newer Helix LT have been under my radar, since the price is around € 500 cheaper then the full Helix here in Europe.

    So my question is as follows: I have already quite a few sounds (with and without FX) progreamme don the GM40; if I use the Helix to swiitch channels, does it use the programmed sounds on the GM40 just by using PC messages via MIDI, or would I have to program each and every MIDI setting in the GM40 on the Helix LT itself?

    Of course I'd switch off effects on the GM40, since I'm interested in using the Helix as a pedalboard substitute.
    Syn666
    Syn666


    Posts : 64
    Join date : 2015-11-04

    Helix as the FX for a GM40- 4 Cable method Empty Re: Helix as the FX for a GM40- 4 Cable method

    Post by Syn666 Mon May 29, 2017 9:49 am

    Also, is the GM40's loop line or instrument level. Not to ignore Bordonbert's input, but for the technically ignorant, an easier answer would come handy...
    bordonbert
    bordonbert


    Posts : 1772
    Join date : 2015-01-28
    Age : 72
    Location : Southern England

    Helix as the FX for a GM40- 4 Cable method Empty Re: Helix as the FX for a GM40- 4 Cable method

    Post by bordonbert Mon May 29, 2017 12:51 pm

    It's line level Syn666, but only in the sense that it is "a line" coming out and returning, but that doesn't really tell you anything.  I could just say "Line level" and leave it at that but it would give you absolutely nothing real to work with in a practical sense.

    What is their definition of line level?  It isn't necessarily the same as everyone else's definition.  There is no standard definition other than to say we use 1V as a reference and quote our own choice for line level with respect to that.  That's what decibels are there for but that is too deep for most non-tech people to want to grasp naturally.  The idea is simply that an instrument level signal is taken in at the front end where it goes through a few amplifying and processing stages.  It then goes through the Fx Loop section at a higher level than at the input so it is less sensitive to noise which will get added.  We would always want to get signal levels up higher where we can for that reason.  My guess would be that the power amp wants to see about the level I quoted from the manual for full output so it is set to that to match.  And as you can now guess, there is also no standard as to the input level for a power amp.

    Likewise, instrument level is not defined anywhere, it just means the signal of that particular instrument.  As a guide, guitar output can be anything from a few 10s of millivolts to about 1V.

    And we haven't even considered the impedances the signal comes from and goes into which will change all levels drastically.  Now that IS getting more technical than most people understand.




    The best we can say is that if you put in 71mV from your guitar, (H&K's specified nominal input sensitivity), you would get 316mV out if you select the Clean channel with Boost off and keep everything else centred, and the amp would expect to see the same 316mV back at the return.  Call those line level if you wish, they are within the ballpark to be considered standard as levels at preamp outputs and loops.  These levels are all very rough as you have oodles more gain on tap and controls to take levels down where necessary.  For example the Return would accept signals up to just over 5V before anything inside overloaded and you couldn't turn it down internally to prevent it.


    _________________
    Newcastle Brown, can sure smack you down
    You take a greasy wh*re, and a rollin' dance floor
    You know you're jailhouse bound!

    Rock On Humble Pie
    Syn666
    Syn666


    Posts : 64
    Join date : 2015-11-04

    Helix as the FX for a GM40- 4 Cable method Empty Re: Helix as the FX for a GM40- 4 Cable method

    Post by Syn666 Mon May 29, 2017 1:22 pm

    Thanks, Bordonbert!
    Benny
    Benny


    Posts : 17
    Join date : 2020-12-03
    Age : 51
    Location : Ireland (Kilkenny)

    Helix as the FX for a GM40- 4 Cable method Empty Re: Helix as the FX for a GM40- 4 Cable method

    Post by Benny Thu May 19, 2022 10:18 am

    I recently purchased a Helix Floor.

    I have the GM40 setup on 4CM with Send 1 and Return 2 on the Helix.

    The GM40 Manual states the following...

    Heads Up: You can bypass GrandMeister Deluxe 40’s preamp by routing amp models into the FX Return. However, when you switch channels its power amp is re-voiced to deliver the best tone for that channel. This means every channel sounds different, even if you decide to use only the power amp! You probably want the amp model’s sound and volume to remain consistent with your original programming. If so, you’ll have to remember which channel you used for programming and select it when you activate the amp model. However, the better option is to program a preset to do this for you.

    I only use Pre Amps on the Helix and use my own Cabinet. Should I place the Pre Amp block on the Helix before the send and return, in the Middle or after Send/Return. Sorry, I think the explanation from the manual is a little ambiguous. Thanks, Christian
    bordonbert
    bordonbert


    Posts : 1772
    Join date : 2015-01-28
    Age : 72
    Location : Southern England

    Helix as the FX for a GM40- 4 Cable method Empty Re: Helix as the FX for a GM40- 4 Cable method

    Post by bordonbert Thu May 26, 2022 4:20 pm

    If you mean the H&K's Fx setup then there is no question of In front/Middle/After really. What they are saying is that you should ignore both the amp input and the Fx Send and just plug your Helix output directly into the H&K Fx Return. The Fx Return is effectively the input to the Power Amp section with a few wrinkles. You are then not using the main H&K Preamp section in any way. Your Helix has become the sole preamp and whatever you set up in there is what the power amp will use as its signal - mostly!

    I think the confusing bit may be that when you select different channels the H&K preamp is revoiced with different circuit options in a fairly unusual and complicated way. These circuit changes are put in place to alter stage gains and background channel tonal characters. The Return from the External Fx is still taken through the amp's Resonance, Presence, and internal Fx units before being sent on to the Power Amp so these would be in place even for your Helix preamp signal. Some of these settings may be different for the different channel selections, remember that each channel remembers its settings when just switching between them and not using whole amp voices, so you must make sure each channel you select has similar settings for these otherwise the power amp tone will change as you swap between them.

    I'm sure once you get the Helix up and running it will sort itself out. It isn't hard to get your head around once someone has pointed you to it. Just make sure that each Channel you use or each voice you select has the same settings for its external effects, my guess is you would just want them to be turned off completely as you are relying on the Helix for all that. Without looking carefully, I'm not even sure that it will be necessary to select different channels in order to get different sounds. When used in this way the GM36 is the same for all channel selections as there is nothing that I can see which is altered after the Fx Return socket.

    And that is the only complication in this. I do know first hand the internal circuitry of the GM36. The GM40 is not in the public domain and probably is unlikely to ever escape captivity nowadays. However it can't be much more terribly complicated than its older brother. These "families" of units are always built one on the other's shoulders. I feel fairly certain that there won't be too many radical changes made in the power amp voicings, though for H&K to mention it like that there must be some.

    As a starting point just plug the Helix directly into the Fx Return and ignore all of the rest. Does that help?


    _________________
    Newcastle Brown, can sure smack you down
    You take a greasy wh*re, and a rollin' dance floor
    You know you're jailhouse bound!

    Rock On Humble Pie
    Benny
    Benny


    Posts : 17
    Join date : 2020-12-03
    Age : 51
    Location : Ireland (Kilkenny)

    Helix as the FX for a GM40- 4 Cable method Empty Re: Helix as the FX for a GM40- 4 Cable method

    Post by Benny Fri May 27, 2022 1:06 pm

    Bodenbart,

    You are a fountain of knowledge and the goto for definitive answers on technical questions regarding H&K. Yes your answer did answer my question. Thank you for taking the time to answer and explain in layman’s terms. I really appreciate it.

    bordonbert likes this post

    Benny
    Benny


    Posts : 17
    Join date : 2020-12-03
    Age : 51
    Location : Ireland (Kilkenny)

    Helix as the FX for a GM40- 4 Cable method Empty Re: Helix as the FX for a GM40- 4 Cable method

    Post by Benny Fri May 27, 2022 1:07 pm

    Bodenbart,

    You are a fountain of knowledge and the goto for definitive answers on technical questions regarding H&K. Yes your answer did answer my question. Thank you for taking the time to answer and explain in layman’s terms. I really appreciate it.

    Sponsored content


    Helix as the FX for a GM40- 4 Cable method Empty Re: Helix as the FX for a GM40- 4 Cable method

    Post by Sponsored content


      Current date/time is Thu Mar 28, 2024 6:39 pm