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Helix with mesa recording preamp in loop


Kaintuck
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So I'm just learning about my setup and thought some of you folks may be able to help.  I have the Helix rack, hooked up using 4 cable to a Mesa Rectifier recording preamp, and this outputs to a mesa stereo 2:100 power amp.  

 

Basically I'm trying to use the recto preamp as my amp, I have it hooked up per 4 cable method,  the effects loop in place of the amp, and everything works, with the exception of I get a fair amount of hum to the speakers.  I have the input gate on, but this doesn't really do anything for the hum.  I've tried running my rocktron hush in between the send on the mesa and the return to the helix, and this just kills my volume even if the rocktrons gate isn't on.

 

I took a mesa preset I had and just substituted the fx loop for the amp so I could compare the Helix rectifier model with the real thing, but the extra noise on the "real" preset is aggravating.  What should I be doing different??

 

Thanks a lot for any advice!

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5 hours ago, Kaintuck said:

What should I be doing different??

 

Hard to know, since we don't really know what you're doing now.

 

For starters, are all of your devices connected to the same EMI/RFI filtered surge suppressor, connected to a wall socket with a reliable (tested) ground, that isn't on the same circuit as any major appliances, fluorescents or rheostats?

 

Are all of your devices interconnected with high quality shielded cables that you know for sure are good, that is, they haven't been laying around improperly coiled and stored in the same box you threw them in the last time you played a gig (I remember those!)? Have they been stepped on, kicked around and run over by dollies and amp casters a hundred times in the 20 years since they were new?

 

Are you running other devices with possibly questionable and/or non-isolated power supplies?

 

Are there power cables in parallel and in close proximity to audio cables? 

 

Do you live near high power electrical towers or cell towers? Are nearby neighbors Ham Radio geeks? I MAY be stretching here, BUT........

 

When you're talking about "hum", those are all major things and minor details that need to be considered before anybody can start to guess at other possible causes, so start there.

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And then there's the tubes in the Mesa, the tube sockets, and the other assorted bits and bobs that constitute a real live tube amp. Nothing you do to anything in the circuit before the amp matters if the problem is in the amp itself. How old is it? Had it checked out by a pro lately?

 

Hang out a while, I may think of something else that can cause "hum".

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Thanks for the reply...everything is connected to a Furman power filter, the electric should be good in the house (house only 5 years old) and there was nothing else on the circuit.

 

As luck would have it, all the cables are new as of last Friday when I purchased them, and I don't get the noise just using the helix.

 

The 2:100 power tubes I don't think could be the issue, as I'm using them for my power amp for the helix as well.  The rectifier preamp, though, that's a thought.  I bought it used a few months ago, and have not had it checked out.  It's from 2012.  I have done nothing to it, so that may be an area for me to look.

 

The thing is, it's exactly the same hum I get from any other high gain amp.  (I have a road king that does it too).  I should have been more clear on that.  However, I can gate the effects loop on the road king and get rid of it....I can't in this case.

 

What I will try tomorrow is running the rectifier preamp as a standalone, gating the effects loop and see if that works.  I suspect it will but i will report back.  But I think my real issue is how do I go about using either a helix gate or my hush in series with the mesa to block the standard high gain hum?  If I can use a helix gate adding a block somewhere in the chain, where might that work?

 

Thanks a lot for the help

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So I have the same pre amp and power amp and I have to say that combo sounds amazing! I used to have an ISP Decimator 2 in a loop and placed it after the loop that I'm using for 4CM. In the latest firmware update I've found that the Horizon Gate works just as well as the Decimator.  If you have another loop available, I'd suggest using 2 loops for 4CM so that in the global settings you can change them to different level settings. For example Send 1 to Return 2 and in global settings set Send/Return 1 to instrument and Send/Return 2 to Line. If you don't have and extra loop just set your 4CM loop to Line. Hopefully that helps, let me know.

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2 hours ago, Kaintuck said:

But I think my real issue is how do I go about using either a helix gate or my hush in series with the mesa to block the standard high gain hum?  If I can use a helix gate adding a block somewhere in the chain, where might that work?

 

Try it and see. If you're replacing the Mesa Preamp with a Helix amp in 4cm, there's a parameter called "HUM" that's there specifically to model or eliminate that well known characteristic of Tube Amps.

 

10 minutes ago, HillsideDeafener said:

If you have another loop available, I'd suggest using 2 loops for 4CM so that in the global settings you can change them to different level settings. For example Send 1 to Return 2 and in global settings set Send/Return 1 to instrument and Send/Return 2 to Line.

 

This is totally unnecessary. The FX Loop Block has SEND and RETURN levels you can use for the same affect.

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Well rd2rk no it’s not necessary but it’s optional. Not for solving his problem but using 4CM in general. The Send being instrument level and the Return being line level seems logical to me and I found that the pre amp feel improved, like I say try it. But if you’re using one loop for 4CM then you’ll want to check what the level setting is in the global setting. For me I have to set the level to Line when using one loop, if it’s set to instrument the signal is way too hot and with that comes the noise. It’s the same for all 3 of the Mesa Boogie amps I own. 

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15 minutes ago, HillsideDeafener said:

Well rd2rk no it’s not necessary but it’s optional. Not for solving his problem but using 4CM in general. The Send being instrument level and the Return being line level seems logical to me and I found that the pre amp feel improved, like I say try it. But if you’re using one loop for 4CM then you’ll want to check what the level setting is in the global setting. For me I have to set the level to Line when using one loop, if it’s set to instrument the signal is way too hot and with that comes the noise. It’s the same for all 3 of the Mesa Boogie amps I own. 

 

If it works for you, great. It's certainly simple to do IF you have a spare loop, and it's Global, as opposed to per preset. But if you DON'T have a spare loop, it's good to know that there's an alternative.

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Awesome info guys thanks a lot.  Mr Hillside, if you have exactly the same setup as me, maybe you can help with my confusion as to how to hook this up.  I do have a decimator I can use, just dont know where to put it.  The gate in the fx loop calms my road king down very well, but this here setup is a different animal. The tone is killer, btw, you're correct.  That's why I want to get this working so much.

 

Rd2, this hum parameter...I think I tried it to no avail, but would it really work anyway if I'm not using the Helix amp, instead goin with the rectifier?

 

Currently, I go into the Helix with the guitar, Helix send 1 to mesa Preamp input, fx send on mesa preamp to Helix return 1, and since the mesa preamp has 2 returns, I have them both hooked up to the 2 1/4 outs at the Helix.  Finally, both mesa preamp live outs go to the 2:100 power amp.  The mesa preamp gain is bout 9, and I'm boosting the front end with a Helix boost preset, so I know there's a lot to tame here, but does my hookup sound right?  So far I've tried my Rocktron Hush twixt the fx send on the amp and the Helix return1.  Also tried it between the Helix send1 to the rectifier preamp input, and both clip the sound way down. 

 

I havent dl'ed the new firmware yet, but I will since it has that new gate, but I'm still lost as to how to get this hooked up.  Thanks again guys

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1 hour ago, Kaintuck said:

Rd2, this hum parameter...I think I tried it to no avail, but would it really work anyway if I'm not using the Helix amp, instead goin with the rectifier?

 

 

My point was that tube amps hum, it's the nature of the beast and, for accuracy's sake, L6 modeled it.

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I ran something very similar with my Mesa Boogie Mark I reissue:

 

Helix Send 3 @ instrument level -> Mark I Guitar Input

Mark I FX Loop Send (level knob maxed) -> Helix Return 4 @ line level

Helix Main Output @ line level -> Mark 1 FX Loop Return

 

I always get some hum from a tube preamp, I put a Noise Gate Block directly after the preamp return or send/return block.  If the hum is too loud that it is noticeable against the guitar volume, I would look at the preamp, possibly it needs to have a gnd switch flipped or just better conditioned power or a tube replaced...etc.

 

Sorry if any of this is repeated from above.  Anyways, you will always get a little hum from the tube power amp as well.  I recently switched to a Line6 Powercab, I use a Triaxis preamp always followed by a Noise Gate block, and I get complete silence when I am not playing, even at extremely loud levels, it's a bit spooky!

 

Edit: Not sure why you are running back through the Rectifier preamp to get to your power amp.  Have you tried running directly from the Helix to your power amp?

 

Edit: You are using a LOT of gain - rectifier gain on 9 and sending it a boosted signal, that is going to create a lot of hum.

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If I'm reading your setup correctly, it seems like I'm doing the same thing as you were....are you suggesting I go from the helix outs directly to the power amp inputs?  And wouldn't that be a problem since nothing would be hooked to the preamp return?

 

The hum isn't oppressive, I would just like to cut it back a bit.  I know the gain is a lot lol....it just sounds crushing tho

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You can tap the send from your Rectifier preamp without sending it a return back, it's not a problem.

 

Or you might try this:

 

Guitar -> Helix Input

Helix Send 1 @ instrument level -> Rectifier Preamp Input

Rectifier Preamp Main (Live) Output (just use one of them...) -> Helix Return 2 @ Line Level

Helix Outputs @ line level -> Power Amp Inputs

 

In this setup you don't even use the FX Loop of the Rectifier Preamp.

On my Triaxis, using the Output instead of the Send includes the volume knob on the front panel, so I can turn it down and use the same Send set @ instrument level.

- or -

You can set the send/return block to Line Level and turn down the send level of the block, as rd2rk suggested. 

(The issue is that a your rectifier preamp definitely takes and instrument level input, and probably sends line level out of the output for a power amp.)

 

Another little trick is to use the circular output block at the end of the first line/DSPchip as your Send, and then use the circular input block the beginning of your bottom line/DSPchip for your Return.  The Return input block will have a Noise Gate built in.  This can save you two or three blocks, but has the side effect of putting all the pre-Rectifier blocks on one DSP chip and the post-Rectifier chips on the other.  However, since you are not using any Amp/Cab models in the Helix, processing power limitations probably won't be an issue for you.

 

Yet another option would be to run Helix -> Rectifier -> Power Amp.  This means all of your effects, including delays and reverbs, run before the Rectifier, but a lot of folks put  delays and reverbs on their pedalboards and run them into their amps and are just fine with it.  It all comes down to what you prefer.  It also turns your rig effectively mono, so that might be a dealbreaker for you.

 

EDIT: I just looked at the Rectifier Preamp manual, and it doesn't look like you can completely turn off the dry signal back to the FX Loop return, you can only turn it down to 10%)  Also, on page 12 there are a couple of paragraphs that basically say people prefer the sound by NOT using the FX Loop.

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