And yeah, I see what you're saying about the Palmer providing the hardware IR, that makes total sense.  So you're getting all three elements on both sides of your recording chain there, that's really cool.  
 
Your setup really has me encouraged.  I'm wondering about attenuators now, instead of full blown load boxing.  
 
And that's a pretty cool attenuator.  I thought most attenuators were resistive, by nature.  Being a more reactive component for less than 200 bucks sounds like a great piece of gear.  The sound is great.  
 
Do you still manage to capture that "voice" you get from tube amps on your DI side?  There were times it seemed like my Mesa was talking to me, like a subtle wah effect, for lack of a better description.  
 

tlw
The particular impedance loading a loadbox, which completely replaces a speaker, unlike an attenuator which lowers the volume that reaches the speaker, should make no more difference to the amp's sound or volume than using an 8 Ohm speaker rather than a 16 Ohm. Assuming the speaker or loadbox is connected to the correct output on the amp, of course.

But it does, because of the impedance curve related to the type of load, itself.  A reactive load effects the impedance felt by various frequencies in the audio range, thereby changing the tone.  Here's a graph showing the difference between a reactive (speaker, or reactive load box) and non-reactive (resistive load box, hot plate) load.  This is the same curve Pete demonstrates in the above video - and he even includes sound samples so you can hear the difference as well.  
 

Voda La Void
 
Do you still manage to capture that "voice" you get from tube amps on your DI side?  There were times it seemed like my Mesa was talking to me, like a subtle wah effect, for lack of a better description.  

for PURISTS, myself included,
the miced sound always trumps any other version of this....
whether it be modelers with IR's, or direct boxes like the Radial JDX or the palmer series.
 
but, it's a good enough sound for me.
i've experimented with a few modelers, used to own a pod XT, and the palmer signal, especially with clean tones, is so close, it's really not an issue.
 
and i don't always use the weber attenuator,
the master volume control on the boogie is quite good,
and the design of the boogie is to have lots of headroom anyway, 
but, sometimes there are tones that i need the power section to bumping it on,
and then i use the attenuator.
 
the reactive quality of the weber mass lite, overcomes some of the 'load curve' issue that pete talks about.
but i never A/B tones, i simply take what i have going on, and tweak it til i like it.
 
for me, it's never been about taking my stage volume tone, and trying to duplicate it at studio and bedroom volumes....
it was always about finding a great tone, using whatever pieces i have.
 
 
 
for the purists,
putting ANYTHING in line between the guitar and amp head, and between the amp head and speakers,
is pure sacrilege.
 
LOL
 
and on certain tracks, 
that's exactly what i do,
and it's always better than anything else.
 
YMMV

My experience is mostly limited to resistive loads, which I used for troubleshooting amplifiers - if nobody wants to listen to high-volume guitars, you can be sure they really, really don't want to hear high-volume test tones!
 
However, when I built my second-generation load box, I made a point of adding some inductance. My motivation wasn't an attempt to emulate the tone of a speaker, but rather to protect amplifiers from being damaged due to initial surges (not an issue with tube amps, but can be with solid-state amps).
 
The easiest way to add some inductance to the load was to insert an iron-core inductor, the type used in power conditioners. That brought the inductance up to around 100 mH, a little high for all but the most high-powered 8-ohm speakers but fine for my purposes. You could probably use half that value.
 
Then I figured I'd go the extra mile and take into account capacitive reactance as well. I don't remember what I ended up putting in, but it was a small value, perhaps 1000 pF or so. It's not nearly as relevant as inductance. I should point out that I never recorded this setup, so I can't say if it altered the tone significantly.
 
[EDIT]
I poked around with Google and found this excellent explanation of speaker impedance. It may be more than you really wanted to know, but includes a detailed schematic diagram of the electrical equivalent for a speaker load. 

FROM WEBER:
 
"All MASS products use an actual moving speaker motor for the load and are more interactive with the output circuit of the amp"
 
I have found this claim to be true, as i've used many resisitive attenuators,
including the first one i ever heard of, the tom scholz design, the 'power soak'.
 
 
FAQ:
http://www.tedweber.com/attenuator-faq/
 
MASS LITE LINK:
http://www.tedweber.com/mass-lite
 
 

Adding the speaker motor creates frequency dependent impedance to the load box. Different frequencies generate varying degrees of counter EMF via the voice coil, just like a speaker. I never put line outs into my amps because I find that you have to spend some time and money to get a system that sounds good. People don't want to pay for the feature to be properly implemented.

Voda La VoidBut it does, because of the impedance curve related to the type of load, itself.  A reactive load effects the impedance felt by various frequencies in the audio range, thereby changing the tone.

Maybe I was ambiguous, sorry.

What I tried to say is that as far as the amp is concerned, there is no more difference in tone or volume if you switch an 8 Ohm loadbox for a 16 Ohm than if you switch from an 8 Ohm speaker to a 16 Ohm speaker.

A good loadbox isn't simply a fixed resistive load either, but is a reactive load. That's where most of the many circuits you can find online which combine high-current resistors and heatsinks fall down. For biasing an amp they might be close enough, but a reactive loadbox is more speaker-like.

"Speaker-like" because it still isn't a speaker, but used together with a DI feed from the amp's speaker outputs it can produce good enough results with the advantage of zero volume.

As for the Palmer speaker emulators, the PDI09 I use has a "normal" setting which is a high pass rolling off at around 100Hz, a gentle low pass at aroung 5K and flat through the mids with a high end peak centred at around 3KHz. It looks very much like Celestion's plots for the 12" Greenback and Alnico Blue. The "Bright" setting adds more dB to the 3KHz peak and the "Mellow" setting, which Palmer say is more "American" rolls top off quite steeply from around 3KHz. The overall response is supposed to be similar to an open-back 2x12, if you want closed back just add a bit of bass eq in the DAW.

"Normal" and "Bright" are fine for my use, being something like a Greenback/Blue and a Vintage 30. The "Mellow" setting is too dull, nothing like a Jensen kind of sound at all. It's like Palmer didn't spot that the "classic American Combo" tone isn't the result of a dull speaker but an amp that's not as bright as a Marshall or Vox and with a lot of mid on tap feeding a speaker with a deep mid-scoop, hefty lows and a bright top end. Even attached to a bright Fender-style circuit with the treble set high "Mellow" is still a bit too dull, while the other two settings are both quite usable.

The frequency figures are the result of my own testing, done by passing white noise through it and seeing what the output frequency plot looks like, I don't think Palmer themselves actually give any figures.

The Behringer speaker DI has a curve that's more like a closed 4x12 from what I've seen on-line. A bass and treble hump with a slight mid scoop between them. I've never tried one, but from reports I've seen they can apparently be quite noisy. Though some say they're fine unless you engage their on-board speaker sim or the dB pads.

In the end it's all about the many ways of getting a guitar recorded. There's no one "right way" any more than there's one "right amp" or one "right speaker."

As for attenuators, some of them seem to adversly affect the tone if the attenuation is set very high, so getting a powerful amp down to household volumes and miking that may or may not produce good results. I don't own one, but one attenuator I have heard that sounds very good to me is the one Cornell build into their amps.

tlw

Voda La VoidBut it does, because of the impedance curve related to the type of load, itself.  A reactive load effects the impedance felt by various frequencies in the audio range, thereby changing the tone.

Maybe I was ambiguous, sorry.

What I tried to say is that as far as the amp is concerned, there is no more difference in tone or volume if you switch an 8 Ohm loadbox for a 16 Ohm than if you switch from an 8 Ohm speaker to a 16 Ohm speaker.

A good loadbox isn't simply a fixed resistive load either, but is a reactive load. That's where most of the many circuits you can find online which combine high-current resistors and heatsinks fall down. For biasing an amp they might be close enough, but a reactive loadbox is more speaker-like.

 
Yeah that's what I'm looking for now, I think.  The Weber certainly sounds good, but I need complete silence, even for a 100W if I go that way, and I would like the load to be reactive so I'm focusing on more all out load box solutions.  
 

batsbrew

Voda La Void
 
Do you still manage to capture that "voice" you get from tube amps on your DI side?  There were times it seemed like my Mesa was talking to me, like a subtle wah effect, for lack of a better description.  

the reactive quality of the weber mass lite, overcomes some of the 'load curve' issue that pete talks about.
but i never A/B tones, i simply take what i have going on, and tweak it til i like it.
 
for me, it's never been about taking my stage volume tone, and trying to duplicate it at studio and bedroom volumes....
it was always about finding a great tone, using whatever pieces i have.
 
 

Same here.  I've never really had a "sound" anyway, rather I just go to record and get the best I can out of what I've got.  I'm really burnt out on the Marshall valvestate sound though, and I want to go back to tubes and give it another go.  
 
Surely a decent tube amp into a dummy load and good DI box would sound better than my valve state line out into a cheap DI...

i will say this..
no matter what attenuator you go for,
the more you attenuate,
the sh!!tier is will sound.
 
if you want to capture the sound of a Marshall, but attenuate it down to nothing, to get line level,
if it were me, 
i would build a 18 watt TMB clone,
and put a PPIMV on it, and maybe a half power switch,
and then run it wide open, and stick it in a closet or speakers in a box, and attenuate as little as possible.
 
this will sound WAY better than a 100w marshall attenuated to it's knees.
 
there are many excellent clones out there.......
 
look at something like the Suhr corso as well...
 
and the Victory BD1,
or even something like the new Line DT25, which rides the fence between tube power and modeling tech,
sounds better than most else i've heard.
 
 

the corso is awesome...
 
can be set for zero volume,
is only 5 watts to start with,
has a line level out for direct recording,
check out pete thorns demo:
 
 
 
listen in high def