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Loadbox + Ir Response ideas
Old 14th October 2013
  #1
Gear Nut
 

Loadbox + Ir Response ideas

Okay

Ive been through quite an adventure finding a way to Mike amps in a satisfying fashion. Unfortunatly....I dont have the resources to do in my current situation (Room is too small, etc). Im a very "feel" based player. WIth a good Pre/DI, Im okay with simulations, but I still like real amps alot more.

So far, what Im thinking of doing is being a loadbox, running a lineout through a nice DI and using IR responses in the computer. Thoughts? What am I missing? Any potential issues? Im planning on building the loadbox... :-)
Old 14th October 2013
  #2
Gear Nut
 

Oh, and I am aware of the Torpedo loadbox.....but I dont like being tied down to a piece of digital gear that will go obsolete....would rather keep up with software!
Old 14th October 2013
  #3
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mcgruff's Avatar
 

Being = buying or being = building?

If you're going to build one, the Aiken reactive load design is perfect. It doesn't have all the features of a Palmer (volume, line out, that's it) but it's a good quality circuit. Very easy to build - basically the kind of thing electronics magazines would recommend as a beginner's project before going on to tackle harder projects like amp-building.

It doesn't have a speaker sim built-in so you'd need to use software like LeCab (free) to process the raw amp signal. There are a ton of free impulse responses available on the net and you can even edit them to taste quite easily with any audio editor program.

Although I really don't like amp sims, cab sims aren't too bad IMO. You do lose out on some real-world effects like speaker distortion at high volumes but, apart from that, they sound pretty good.
Old 14th October 2013
  #4
Gear Nut
 

Being was supposed to be "building", thanks for the catch.

Yes, I was planning on doing the Aiken design. I have quite abit of experience building things, should be very easy.

Right, thats exactly what Im planning on doing. Given the acoustics of the room Im working in, cab simulations are a step up (not to meantion Im not good at micing cabs right now!)

My only question is can I run Aikens design straight into an interface, or would I have to fandangle a line-out? Im assuming the latter...


Quote:
Originally Posted by mcgruff View Post
Being = buying or being = building?

If you're going to build one, the Aiken reactive load design is perfect. It doesn't have all the features of a Palmer (volume, line out, that's it) but it's a good quality circuit. Very easy to build - basically the kind of thing electronics magazines would recommend as a beginner's project before going on to tackle harder projects like amp-building.

It doesn't have a speaker sim built-in so you'd need to use software like LeCab (free) to process the raw amp signal. There are a ton of free impulse responses available on the net and you can even edit them to taste quite easily with any audio editor program.

Although I really don't like amp sims, cab sims aren't too bad IMO. You do lose out on some real-world effects like speaker distortion at high volumes but, apart from that, they sound pretty good.
Old 14th October 2013
  #5
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mcgruff's Avatar
 

The Aiken input takes the speaker out from the amp.

The output is line level (controlled by the 1k pot) so you can plug in to anything with a line in.

You could consider adding a ground loop switch and a reactive/resistive switch. I didn't include them in my own build. The resistive/reactive switch may not be much use except to remind you how much better a reactive load is but the ground loop switch could be useful.

Let us know how you get on.
Old 15th October 2013
  #6
Here for the gear
 

As a manufacture of Professional Loadboxes I can say that it can be difficult to find the parts for a reactive load, the value and current ratings for the given instructors on the Aiken design are hard to find, and building your own (inductors) would be even more risky to a beginner. Regardless even with a restive load there is still way more feel that with amp sims. I did a shoot out with Reactive vs Restive Loads and like I had expected it was mostly a linear eq difference than a non-linear distortion difference. It is something that can easily be done by adding an eq and putting in the reactive load curve. If you want to try to hunt down the parts that is cool too, a reactive load would make things a little easier ITB.

Keep in mind though the Aiken design does not have a true line out and would at minimum need an unbalanced to balanced converter. That way you would not need a DI in the signal path.

Another thing to keep in mind for best results you are going to need to get a hold of impulses that were made for setups with a power amp in them. Guitar power amps color the sound. Most guitar impulse creators go through the FX loop of their amp to make the impulse, meaning if you use the line out on your loadbox and use a tube power amp IR then the sound will be much darker and muddier in the mids than it should be. Recabinet is the only product currently that provides solid state powered IRs.

Also don't push away the Torpedo so much because it is digital. The FIR architecture has been around since the 80's and has been left untouched. The only big differences today are oversampling and faster processing (lag) times. Right now both DSP's and CPUs are equally capable of processing FIRs as the bandwidth that all modern DSPs and CPUs operate at have virtually no additional overhead in the execute stage of FIR's meaning 99.9% of the latency is coming from the slow loading speed of the audio clock. Due to this latency I can't see anyone making FIRs with a Kernel size over 1024 sample and as such if you never intend on using the Torpedo's build your own cabinet simulator then it will be outdated the day all DSP and CPU based FIR convolution becomes outdated, and I don't see a platform like Nebula really kicking in for a replacement for impulses anytime soon, if ever.
Old 15th October 2013
  #7
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mcgruff's Avatar
 

The Aiken output will plug straight into an audio interface. It's not essential to convert it to balanced (although I guess that would be a nice improvement on the basic design), and you don't actually need a DI. This clip was recorded with the Aiken output plugged straight into an RME Multiface line in and I think it does a great job of capturing the sound of my 5F1 champ.

I agree that building your own inductors may not be a good idea. In theory, it seems simple but the OP in that gear page thread had problems with home-made inductors saturating. The ERSE inductors I linked to here have been used successfully by several people, including myself.

The capacitor should usually be a high-quality item as well, although I managed to cheat a bit with some cheaper electrolytics (22uF, 100V, 1.5A ripple) back to back in a series/parallel array. Mine only has to handle a mighty 4W.

I'd recommend people consider some of the commercial options too. You will probably get more features and I guess DIY isn't for everyone
Old 15th October 2013
  #8
Gear Nut
 

Quote:
Originally Posted by mcgruff View Post
The Aiken input takes the speaker out from the amp.

The output is line level (controlled by the 1k pot) so you can plug in to anything with a line in.

You could consider adding a ground loop switch and a reactive/resistive switch. I didn't include them in my own build. The resistive/reactive switch may not be much use except to remind you how much better a reactive load is but the ground loop switch could be useful.

Let us know how you get on.
Ah! Thats what I get for being lazy not looking up the schematics! For some reason I didnt think the output was line level (Darn brain )

Definitly going to add a ground lift, current revision has the resisive/reactive switch already. :-)

Quote:
Originally Posted by TheWinterSnow View Post
As a manufacture of Professional Loadboxes I can say that it can be difficult to find the parts for a reactive load, the value and current ratings for the given instructors on the Aiken design are hard to find, and building your own (inductors) would be even more risky to a beginner. Regardless even with a restive load there is still way more feel that with amp sims. I did a shoot out with Reactive vs Restive Loads and like I had expected it was mostly a linear eq difference than a non-linear distortion difference. It is something that can easily be done by adding an eq and putting in the reactive load curve. If you want to try to hunt down the parts that is cool too, a reactive load would make things a little easier ITB.

Keep in mind though the Aiken design does not have a true line out and would at minimum need an unbalanced to balanced converter. That way you would not need a DI in the signal path.

Another thing to keep in mind for best results you are going to need to get a hold of impulses that were made for setups with a power amp in them. Guitar power amps color the sound. Most guitar impulse creators go through the FX loop of their amp to make the impulse, meaning if you use the line out on your loadbox and use a tube power amp IR then the sound will be much darker and muddier in the mids than it should be. Recabinet is the only product currently that provides solid state powered IRs.

Also don't push away the Torpedo so much because it is digital. The FIR architecture has been around since the 80's and has been left untouched. The only big differences today are oversampling and faster processing (lag) times. Right now both DSP's and CPUs are equally capable of processing FIRs as the bandwidth that all modern DSPs and CPUs operate at have virtually no additional overhead in the execute stage of FIR's meaning 99.9% of the latency is coming from the slow loading speed of the audio clock. Due to this latency I can't see anyone making FIRs with a Kernel size over 1024 sample and as such if you never intend on using the Torpedo's build your own cabinet simulator then it will be outdated the day all DSP and CPU based FIR convolution becomes outdated, and I don't see a platform like Nebula really kicking in for a replacement for impulses anytime soon, if ever.
Hey man, Ive been following your site for awhile, nice to hear from you. Im about an hour and a half south of you, so we ware local.

Ive been looking at parts express, and seem to have found suitable inductor....Im going to digg deeper because I might be missing something! Interesting, Ill have to look up that eq curve too, depending on how the inductor search pans out.

Well, Im only running a 3ft cable from the load box to my interface, Going to a balanced line seems excessive? Maybe Ill experiment with one of Rod Elliot's circuits in front.

Thanks for that, thats the type of info Im looking for!

Good info too.....I just dont know if I can swing 1000$ + for one. They are amazing! But definitely out of my budget at the moment....

@Mcgruff: DIY is my lifeblood!!!
Old 15th October 2013
  #9
Here for the gear
 

Noise on a loadbox isn't much of an issue, the biggest reason to balance the signal is because you get circuit protection. In the schematics posted here with the resistive divider if a joint to ground goes bad like the ground pin to the volume knob, close to the full signal of the amp will be sent to your A/D converter which can cause permanent damage. Simply adding a transformer or even opamp based balance circuit will keep the full signal away from your converters.

Not really necessary but I tend to make things safe just in case Murphy's Law decides to kick in, but that is just me.
Old 15th October 2013
  #10
I do exactly what the OP described, quite often, using a THD Hot Plate or a custom reactive load that Steve Fryette built me. The problem I've been having is that it just isn't that practical or portable most of the time - what I've found is that while there are tons of decent cab IR's out there from guys like Kazog (ReCabinet) and Redwirez, and the Torpedo boxes do work well, they are all a bit of a compromise since the amps weren't really designed to work under those circumstances. Basically, it can get pretty tweaky!

So I went to Steve and we came up with a product to address the actual issue, rather than simply try to shove existing amps through a hole they really weren't designed to fit in. It is a one-watt amp with a built-in load and line out, designed from the ground up to sound good direct. I also had him build in a tube DI, to make re-amping easy, to be able to capture the performance without the amp sound, and to make the device more generally usable (mostly, so that you can easily record bass through the same unit).

It is on Kickstarter right now - $500 to contribute and get a unit, check it out.

We designed the GP/DI as a tool for audio engineers, not just for guitar players. Most of the features are aimed to make using it in a [home] studio environment as friendly as possible - multiple balanced outs, both line and instrument level in, and so on. It actually acts as a reamp tool, as well, both for itself and any other amp - you just feed your line signal to the GP/DI, and take the direct out to the amp, then mic it or however else you want to capture it.

I'm not saying that this is the only solution, just that I wasn't happy with doing what the OP asked. I spent THOUSANDS of dollars on equipment and software to do what he's asking, and I ended up resorting to designing my own version.

To the OP: If you're dead-set on making the amp-into-load-into-computer setup work, ask anything you'd like, I've tried it all at this point. Just be warned that it likely won't be cheap! I'm not trying to hijack your thread by pushing my project - it is just that I designed the thing to address this very problem.

Below is a little direct-vs-mic-at-speaking-level demo I put together of the GP/DI:

Old 16th October 2013
  #11
Gear Nut
 

Hi Paul, thanks for the post!

Very cool product, excited to see hwo it turns out. Wish it was released already, Im coming own to LA next week and would love to hear one in person. Mind elaborating on exactly what it does? Is it a speaker emulated line out, or were you running it through an impulse of the sab you used in the demo? WHile Im defintiyl interested in it, I honestly doubt it is what I need....I do alot of metal/death metal...but Im still curious to try one out for maybe cleans, or heck, just because it looks like an affordable multifunction box :p

What did you find the best setup was? WIth all the guitar tones I do in the first place....tweaking them is super essential one way or the other....not too worried about that. What issues did you run into initially? What were the best impulses you could find?

Quote:
Originally Posted by dented42ford View Post
I do exactly what the OP described, quite often, using a THD Hot Plate or a custom reactive load that Steve Fryette built me. The problem I've been having is that it just isn't that practical or portable most of the time - what I've found is that while there are tons of decent cab IR's out there from guys like Kazog (ReCabinet) and Redwirez, and the Torpedo boxes do work well, they are all a bit of a compromise since the amps weren't really designed to work under those circumstances. Basically, it can get pretty tweaky!

So I went to Steve and we came up with a product to address the actual issue, rather than simply try to shove existing amps through a hole they really weren't designed to fit in. It is a one-watt amp with a built-in load and line out, designed from the ground up to sound good direct. I also had him build in a tube DI, to make re-amping easy, to be able to capture the performance without the amp sound, and to make the device more generally usable (mostly, so that you can easily record bass through the same unit).

It is on Kickstarter right now - $500 to contribute and get a unit, check it out.

We designed the GP/DI as a tool for audio engineers, not just for guitar players. Most of the features are aimed to make using it in a [home] studio environment as friendly as possible - multiple balanced outs, both line and instrument level in, and so on. It actually acts as a reamp tool, as well, both for itself and any other amp - you just feed your line signal to the GP/DI, and take the direct out to the amp, then mic it or however else you want to capture it.

I'm not saying that this is the only solution, just that I wasn't happy with doing what the OP asked. I spent THOUSANDS of dollars on equipment and software to do what he's asking, and I ended up resorting to designing my own version.

To the OP: If you're dead-set on making the amp-into-load-into-computer setup work, ask anything you'd like, I've tried it all at this point. Just be warned that it likely won't be cheap! I'm not trying to hijack your thread by pushing my project - it is just that I designed the thing to address this very problem.

Below is a little direct-vs-mic-at-speaking-level demo I put together of the GP/DI:

Old 17th October 2013
  #12
Quote:
Originally Posted by iampoor View Post
Hi Paul, thanks for the post!

Very cool product, excited to see hwo it turns out. Wish it was released already, Im coming own to LA next week and would love to hear one in person. Mind elaborating on exactly what it does? Is it a speaker emulated line out, or were you running it through an impulse of the sab you used in the demo? WHile Im defintiyl interested in it, I honestly doubt it is what I need....I do alot of metal/death metal...but Im still curious to try one out for maybe cleans, or heck, just because it looks like an affordable multifunction box :p

What did you find the best setup was? WIth all the guitar tones I do in the first place....tweaking them is super essential one way or the other....not too worried about that. What issues did you run into initially? What were the best impulses you could find?
Thanks!

If you're coming to LA, PM me and I should be able arrange a demo with [one of] the prototype(s).

As to what it is, that is all on the Kickstarter page (yay, over 50%!), but a simple explanation is "one-stop-shop-for-direct-guitar-and-other-things". It has an amp (with a ~1w tube power amp), a load, and a "recording-voiced" line out in it. It also has a built-in Tube DI (how A Designs gets away with the price on the RedDI, I have no idea - Steve's is very, very similar in design) and can accept line level signals, so you can easily use it as a re-amping device or as an effect. In fact, you don't need anything like the X-Amp with it - it will just work as a reamping-facilitator on its own!

As to your needs...
You do metal, and you've never heard of Fryette?



Seriously, it can do metal with the best of them - it is essentially a Deliverance shrunk down to size. The only reason most of the demos have been cleaner/rockier/more mid-gain/clean oriented is because neither I nor Steve can competently play metal of any sort that was produced after the 80's.

If you want to hear heavy, here's a demo of Page Hamilton from Helmet playing the thing (mic'd at speaking volume, because we were still working on the direct out at the time):



As far as the other demo goes, yes it is an analog "speaker emulated" line out. It is actually quite different from the usual "speaker emulated line out" that is included on many amps - for one, it is actually well-thought-out, and for another it is functionally different.

As far as the IR's/LoadBox/LineOut thing went, honestly I tried just about everything, but it was so tweaky that I usually just 'settled' for something that kinda worked. I like the Redwirez IR's, and I like the Guitar Rig 'Control Room Pro', and I like ReCabinet - I also hate all three, depending on what I'm doing. I also don't usually have the 45 minutes or so it takes to dig through all the options - I usually am doing film/TV composition when I'm direct in, and time is a real commodity in that game. I honestly never do metal, so I have no idea what might work best for that - though RedWirez is a good place to start.
Old 19th October 2013
  #13
Lives for gear
 

Quote:
Recabinet is the only product currently that provides solid state powered IRs.
This statement is not accurate as Redwirez, OwnHammer and Two Notes (with whom I am affiliated and have created over a dozen cab profiles) use a clean high wattage solid state power amp for IR sampling.

Building your own loadbox shouldn't be too hard as long as your construction is clean and to spec. These projects become much simpler if the adjustment for attenuation is removed (ie set to 100%). By choosing an appropriate iso transformer for the line output, you may also eliminate the need for your DI to interface.

The Two Notes WOSIII can be downloaded and cabs bought a la carte so you can get started without cash outlay. It will also load and play third party IR's such as the Redwirez or OwnHammers mentioned above. You may also have a suitable IR loader within your Daw or as an add-on (Nebula). Should you choose to use the effects send or line out from your amp, the WOSIII has power amp emulation modeling and other products may do the same thing as well.

We're also looking forward to hear what Paul and Steve at Fryette come up with, This is an excellent concept and if it sounds like their amps as promised, will surely be a big hit.

Andy Home Page (E)
Old 19th October 2013
  #14
Here for the gear
 

Dear all,

if you don't mind another manufacturer coming in ^^, I'll add a little something.

Quote:
As a manufacture of Professional Loadboxes I can say that it can be difficult to find the parts for a reactive load, the value and current ratings for the given instructors on the Aiken design are hard to find, and building your own (inductors) would be even more risky to a beginner.
I agree: the parts are hard to find, it is most of the time easier to build them custom, but not for only one loadbox unless you want to pay a lot for those.

Talking about risks, thermal control of the loadbox is important. Those little boxes can run hot, so you have to keep in mind the power/current rating of all the parts of your DIY loadbox.

Quote:
Recabinet is the only product currently that provides solid state powered IRs.
Two Notes uses linear SS power amps, and we also recommend our customers to use a linear SS power amp if they want to achieve their own IR captures. We provide a dedicated free software called BlendIR and a tutorial, that works for any IR capture process actually:

Torpedo BlendIR: Capture Tutorial

Torpedo BlendIR | Two Notes Audio Engineering

This said, using a guitar amp can be very interesting in a creative process, if you do not plan to be really close to your real system.

Quote:
Right now both DSP's and CPUs are equally capable of processing FIRs as the bandwidth that all modern DSPs and CPUs operate at have virtually no additional overhead in the execute stage of FIR's meaning 99.9% of the latency is coming from the slow loading speed of the audio clock. Due to this latency I can't see anyone making FIRs with a Kernel size over 1024 sample and as such if you never intend on using the Torpedo's build your own cabinet simulator then it will be outdated the day all DSP and CPU based FIR convolution becomes outdated, and I don't see a platform like Nebula really kicking in for a replacement for impulses anytime soon, if ever.
I am not sure I understand what you call the "audio clock". You're talking about the audio buffer size and sample rate ?

But a convolution process does not add any latency (using overlap-add method), assuming the CPU is powerful enough.

About the IR size, you should tell the frequency you're working with, 1024 alone doesn't mean anything. If you are talking about 44.1, I agree. Adding more points will increase resolution (which is not really useful in my opinion) and add reverb in the sound (the reverb of the room where the IR was captured). I prefer not to have too much reverb to keep control over it, but that is a matter of choice.

About the obsolescence of FIR technology I agree with you. It's not new, and it is still working very good.

But actually since 2009 we release products based on non-linear convolution and you can try yourself our WoS III plugin for free, play with the "overload" parameter and you'll get an idea of another approach of speaker simulation, closer to the Nebula's approach.

About the GP/DI product, good luck guys with the kickstarter! I'd love to hear the sound by myself, so far every analog speaker sim was a joke compared to digital ones, maybe that is a change. Did you guys keep one dry output (or a switchable speaker sim), just in case?

Guillaume Pille - Two Notes Audio Engineering
Old 20th October 2013
  #15
Quote:
Originally Posted by sysexguy View Post
We're also looking forward to hear what Paul and Steve at Fryette come up with, This is an excellent concept and if it sounds like their amps as promised, will surely be a big hit.
Thanks for the good wishes!

The GP/DI is basically a "shrinking" of Steve's larger amps, with a few modifications to work better with the smaller amp. Actually, that's an oversimplification - there was a lot of modification necessary to the gain staging, but the result is that it feels and sounds like the bigger amps.

Also, I don't actually work for Fryette - I'm just involved with this project, as I brought it to him and have had a lot of design input.

Quote:
Originally Posted by nonconforme View Post
But a convolution process does not add any latency (using overlap-add method), assuming the CPU is powerful enough.

About the GP/DI product, good luck guys with the kickstarter! I'd love to hear the sound by myself, so far every analog speaker sim was a joke compared to digital ones, maybe that is a change. Did you guys keep one dry output (or a switchable speaker sim), just in case?
Just a clarification: The FIR process itself doesn't add any latency, but in order to actually do the convolution, an A-to-D-to-A conversion is required, which by its very nature will add latency. Not noticeable latency, mind you - and the TwoNotes stuff is pretty awesome - but the engineer screaming in the back of my head made me want to point that out.

To answer your question, of course the internal analog sim is bypass-able - we know that people will want the option to use it with other cab sims, and who are we to deny them that possibility? There is even a "purely dry" output, so that you could send the internal "cab section" to FOH and still use the GP/DI as a preamp into a power amp with a cab.

As far as the "other analog sims" being jokes, I agree 100%. They are all basically fixed filters, some with a minimally reactive component (LCR vs RC) - which is totally NOT what a cabinet & mic sound like or do. That is why I went back to the proverbial drawing board with this design, and used my "studio-engineer-magic-knowledge" to create something that is more versatile and is actually reactive. Does it offer the kind of flexibility you can get out of IR's? Of course not - however, the amp and the "sim" are voiced to be complimentary, which is something that hasn't really been done before, mostly because most products that include a "speaker emulated out" have it as an afterthought and just use the same two circuits that have been floating around for about 40 years now.

Here's a bit of a comparison between the internal sim (still in prototype stage, mind you) and one of the Axe-FX II's built-in cabs:

Old 20th October 2013
  #16
Here for the gear
 

Quote:
Just a clarification: The FIR process itself doesn't add any latency, but in order to actually do the convolution, an A-to-D-to-A conversion is required, which by its very nature will add latency. Not noticeable latency, mind you - and the TwoNotes stuff is pretty awesome - but the engineer screaming in the back of my head made me want to point that out.
Of course there is no digital system with zero latency, I forget sometimes that it's not obvious for everybody, thank you for the clarification.

Good to know that another player is around to pair with our Torpedo C.A.B. Tech21 did not put switchable speakersim at first on their character series pedals, then changed the design to add one. That's why I asked you about that.
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