6L6GC STR-448, 445, 443, and 441...

[DECEMBER]

6L6GC STR-448, 445, 443, and 441... what's good for what in a Mark V? I do bright, clean clean tones and tight, sharp chugs with thick low-mids. But the low-mids can get boxy and the high end can get harsh by trying to get enough clarity in the mids with the presence knob.
I'm gonna need new tubes soon and can't afford to try them all. Recording thru reactive load boxes, it gets a bit too bass-heavy and mid-scooped. These STR-440's are 12 years old. They're smoother and more focused than the JJ 6L6GC, while the JJ gets harsher, with a little more, but less refined, mids.

 

[bandit2013]

The STR440 tubes have their own characteristics. Sometimes I feel they are the best option for a few amps. Mostly the Dual Rectifier (Roadster or the MWDR).

I have tried just about every power tube on Mesa's list of STRs. The exception were the STR450 EL34. With some of the current production tubes, the one's I felt were lame in every other amp I have tried actually sounded the best in the Mark V90 (perhaps the character flaw my particular amp has may have skewed my opinion). I was very impressed with the STR441 tubes. I had them when they first came out but never tried them in the Mark V90, but I did with the JP2C as the STR440 tubes were long overdue for retirement. STR443 was just ok, STR448 was much better, and the STR445 got very close to the hard to get STR415 power tubes. So what worked well for the JP2C, did not cut it with the Mark V90 with the exception of the STR441. Also tried them in the Mark VII and thought, I can deal with that. I can see why Mesa is using the STR441 as the stock tube for the Mark V. They sound really good. I believe the ones I have are green coded tubes.

They were close but could not deliver the sound of what I favored the most in the Mark V90, the SED =C= 6L6GC (Mesa STR454). The =C= tubes I ran were not branded by Mesa but from another resource. Too bad they are out of production and have been for a while now. To date, I have not found a power tube that surpassed the =C= 6L6 in the Mark V90.

Your best bet would be the STR441. You do not need to take my recommendation and wait for others to respond to your request.

 

[GJgo]

IMO best all around is the 448, and best for metal is the 445. Keep in mind this is "in the room feels" though, on a close mic recording it makes no difference.

Also for your MkV you're going to want RED or YEL for the inner Class A pair, and YEL or GRN for the outer Class A/B pair.

 

[rarebitusa]

Just a data point. My V:90 also had a set of old STR-440 YELs and probably a safe bet they were the originals, at least 8 years old. There were no issues with them but on a tube rabbit hole dive fueled by some folks here replaced them with new STR-441s GRYs in the outer sockets, STR-440 GRNs in the inner sockets. I was pleasantly surprised ... the amp was noticeably more alive. Especially 90W SimulClass could honestly say I heard that 3D sound. Edge voicing was now really good with 90W Simul and that's a mode that I've struggled to like in the past. YMMV

 

[DECEMBER]

Just a data point. My V:90 also had a set of old STR-440 YELs and probably a safe bet they were the originals, at least 8 years old. There were no issues with them but on a tube rabbit hole dive fueled by some folks here replaced them with new STR-441s GRYs in the outer sockets, STR-440 GRNs in the inner sockets. I was pleasantly surprised ... the amp was noticeably more alive. Especially 90W SimulClass could honestly say I heard that 3D sound. Edge voicing was now really good with 90W Simul and that's a mode that I've struggled to like in the past. YMMV

I've been emailing with MB support and they said the 441 is probably not a good idea if I'm having trouble with boxy low-mids.
I want more clarity without necessarily being brighter. I can turn up the presence and treble, but it gets harsh, yet it's still lacking definition in the mids.
I don't know if it's better to get a darker tube and turn the presence up more, or get the brightest tube and use less presence...
I don't need scooped... it gets too scooped and boomy thru some of my reactive loads.
I need tight bass and clarity and presence in the mids, and treble without harshness.
I hate the way they write the descriptions, because it makes all 4 of them sound like "oh yeah, that's exactly what I need!"... **** marketing...

 

[DECEMBER]

IMO best all around is the 448, and best for metal is the 445. Keep in mind this is "in the room feels" though, on a close mic recording it makes no difference.

Also for your MkV you're going to want RED or YEL for the inner Class A pair, and YEL or GRN for the outer Class A/B pair.

I captured my IRs close-mic'd and thru reactive load boxes -> IRs, there's quite a noticeable difference between the STR-440 and JJ's, and only half the tracks are coming off the Mark V power amp, the other half are off a solid-state stereo power amp (wet/dry/wet, Mk V is the dry center channel).

 

[bandit2013]

Boxy low mids, felt the Mark V90 just had characteristic honky mids you cannot get away from. Not sure if it is inherent in the preamp or is it part of the tuning area of the phase inverter and negative feed back. This character flaw is also apparent with the Mark IVB which is reason I sold it.
I am surprised that MB said the tube they ship the Mark V90 with as stock to be a bad choice.

Based on the tube descriptions on Mesa's Web site: Copied from Mesa (current description)

The MESA® 6L6 STR 441 is an exceptional vintage-voiced 6L6 with superb low end, neatly tucked mids and an exceptionally smooth, tapered top-end for a warmer, richer and sweeter tone. They help provide the Treble and Presence Controls with an extended usable range without adding unwanted, detached “buzz”, “sizzle” or harshness.

The MESA® 6L6 STR-443 is a premium grade, vintage-voiced 6L6. They are beautifully balanced, offering a deep low end, controlled, tailored low-mids with a pleasing sparkle and chime on the top-end that provides a pleasing clarity. High quality structural integrity provides consistent, reliable performance, making this tube a great choice in any 6L6 based amp, and for any style of music.

The MESA® 6L6 STR-448 is a premium grade 6L6 with a balanced voice and plenty of punch and headroom. They produce rich low end, tight, full midrange and pleasing top end that is present where it counts, yet also warm and cohesive. Structurally sound and high quality, these tubes are consistent and reliable, making them a great choice for any 6L6-based amp and applicable to most any style of music.

The MESA® STR-445 is a 6L6 that shares some qualities of a 6CA7 in that it has tight, articulate low-end for excellent bass definition along with beautifully balanced mids and a chiming top-end that cuts without harshness. It’s a great choice for our Rectifier Series to tighten low-end, add top-end cut in a perfect “Rock/Claw” frequency, while avoiding “buzz” or “sizzle” in the upper octave.

I will have to say this, when the STR440 tubes became out of production back in 2019, The STR441 and STR443 and STR445 got released. The description of the STR441 was much different that it is now. The STR443 was said to have tucked mids and detached buzz and harshness. That was a hint on the STR440 as those tubes had that buzz and harshness character but that is what made the Dual Rectifier sound good. The STR440 and STR443 (un related tubes) do have one characteristic than the others, more low end bloom at reduced volume. that made the Shred feature on the JP2C a useful tool when trying to run at bedroom level, it cut the bass down a bit, so it was not too boomy. Not needed at gig level though. The STR445, STR448 and STR415 seems to share a similar low end characteristic, they maintain good balance from low to high at reduced volume levels. No need to run the shred mode on the JP2C.

Since you say you ran the JJ tubes, those would be the same as the STR445. I did not favor those in the Mark V90, the same would go for the STR448 and the STR415 (Mesa's benchmark tube, they have some but very hard to get as they are not a catalog item). I found the STR448 to be very similar in character but not as much midrange as the STR445. Both were on par with the Sylvania STR415 when used in the JP2C. I did try these same tubes in the Mark V90 and felt I did not care much for the mud. The tubes in question were green coded tubes except for the STR448 which were grey. Sure, they work really good in a Class AB amp like the JP2C but that amp does not have the honky midrange poison the Mark IVB and Mark V90 seem to deliver. The Mark VII on the other hand is much closer to the JP2C, no honky boxy tones when using the STR445, it got boxy with the STR415 and STR448, ok with the STR440, boring with the STR443 and decent with the STR441 tubes. My taste for sound may be different than yours. I personally despise ice pick and boxy tones. Reason why I gave up on the Mark V90.

The Simul-class power vs the Class AB power will have a major difference in overall tone. Simul-class will have more power tube distortion than the Class AB and will also have more brightness (not referencing ice pick either). Consider color codes red, yellow for Simul-class or it may have the tendency to get on the muddy side (depends on the tube in question). I had to change from the greens to yellows in the STR445 tubes for the Mark VII as it did not do well at gig level with the greens.

So what tube did Mesa suggest you use? or did they leave you in the dark without a recommendation? Just to point out, different amps will have a different response with the power tubes. It will either sound really good or like crap. Adding in reactive loads will also affect the sound, If it has no filtering capabilities, perhaps you need to add something to its output like a line level filter or 31 band GEQ to get the honky box out. Doubt that will make a difference though. If the reactive load box has a balanced XLR jack, it may be possible. If it uses an unbalanced TRS, you may need to add in a pad filter or converter before you ram it into a PA system. Sometimes a dynamic compressor may help with eliminating unwanted frequencies that may be more dominant in the mix.

I would not say the Mark V90 is all that bad, reactive loads can make any amp sound terrible if they lack any filtering capabilities. That is why I generally do not use them.

 

[bandit2013]

@DECEMBER

I get your point. I did find a link where you shared some music. Cool stuff BTW.
https://boogieforum.com/threads/do-you-feel-it’s-a-waste….88054/#post-541508

Not sure what would work to improve the overall tone of the Mark V90 to get away from the boxy midrange. The last thing you want is a thin sound. Not quite sure how the STR443 will behave in the Mark V90. My Mark V90 is on the fritz so I cannot just pop them in and see how it changes things.

 

[DECEMBER]

So what tube did Mesa suggest you use? or did they leave you in the dark without a recommendation? Just to point out, different amps will have a different response with the power tubes. It will either sound really good or like crap. Adding in reactive loads will also affect the sound, If it has no filtering capabilities, perhaps you need to add something to its output like a line level filter or 31 band GEQ to get the honky box out. Doubt that will make a difference though. If the reactive load box has a balanced XLR jack, it may be possible. If it uses an unbalanced TRS, you may need to add in a pad filter or converter before you ram it into a PA system. Sometimes a dynamic compressor may help with eliminating unwanted frequencies that may be more dominant in the mix.

They said "Rather than recommending a specific tube, I'll go through the four Mesa branded 6L6s and you can make your own educated decision." Which was kinda underwhelming, because I can already see the descriptions on the website, and like I said, they're written in a way that makes all of them sound like it's exactly what I need.
They said 443 is brightest, but more scooped, and the reactive loads already make it a bit too scooped. Said 441 is probably not what I'm looking for if I'm having trouble with boxy mids. Said 448 has a very full midrange that's good for everything.
The website description says 441 gives more usable range on the treble and presence knobs, but they said it would be less...
I feel like where I have the presence and treble, it's bordering on too harsh but lacking clarity in the mids. So I don't wanna up the presence, don't need more of that high treble. So I'm thinking, would 441 allow me to turn up presence more, or will it be more constrained?
I guess 445 sounds most like what I need, high end that cuts without buzz or sizzle, and tight articulate low end.
I guess the main goal is more clarity in the mids and bass, and minimal harshness with high gain. And no scooped mids, because my EQ and load boxes are doing enough scooping.
I have one guitar in drop-C that has the nice thick low-midrange that you get from a baritone, but my other guitar in drop-D gets more boxiness in the low-mids. They both have the same EMG bridge pickup and the same active EQ pots (VMC, EXG, active tone).
I have a 10 band parametric EQ first in the loop, then split to a stereo FX chain to a solid-state stereo power amp, and the dry returns to the Mark V. I use the slave out, and load boxes to silence the amp. The sound thru IRs changes a lot depending on what load or speaker is connected. And the slave out sounds the same as any output on any of the load boxes.

 

[rarebitusa]

Just a data point. My V:90 also had a set of old STR-440 YELs and probably a safe bet they were the originals, at least 8 years old. There were no issues with them but on a tube rabbit hole dive fueled by some folks here replaced them with new STR-441s GRYs in the outer sockets, STR-440 GRNs in the inner sockets. I was pleasantly surprised ... the amp was noticeably more alive. Especially 90W SimulClass could honestly say I heard that 3D sound. Edge voicing was now really good with 90W Simul and that's a mode that I've struggled to like in the past. YMMV

Oooppps I need to correct a misprint in my previous post. It was 448s, not 440s in the inners sigh. So it should have read

STR-441s GRYs in the outer sockets, STR-448 GRNs in the inner sockets.

that aside... what I probably heard more was the difference between a new set of tubes and ones that had significant mileage on them. What I didn't do was throw the old 440s back in and check the difference.

 

[bandit2013]

@rarebitusa brings up a good point about the Mark V90. No reason you cannot run two different pairs of tubes in the amp. The center pair will define the overall tone, the outer pair will just enhance the sound. What to use though, that is a tough call. Sounds more like an experiment due to the nature of the load boxes and how it will affect the tone of the amp. I tried the JP2C with the RockCrusher and noted it made a change to the overall sound. It does have some filtering that helped. Running the Mark V90 through the same load box actually made it sound better, same for the Roadster. I gave up on using load box and found a better way to capture sound from the speakers. A dynamic compressor preamp before the mixer did a huge difference overall. Sure, I have compressors and limiters on the mic inputs of my mixer, however, I could not capture the actual room sound which is what I wanted to get. The Focusrite Scarlett Dynamic Octopre did the job quite well. Actually made the SM57 sound good and not filtered and boxy. I did not buy it for recording guitar, it was more or less to mic the drum set with dynamic mics that got noisy when I had the phantom power turned on for the condenser mics. Phantom power on my board covers all channels when it is turned on. Same with the digital recorder. At least with the Scarlett I can select in banks of 4 which have phantom power. The Recording rabbit hole is deeper than the tube or speaker hole. It can easily cost more than you want to spend.

I have a feeling you may have to experiment to find out what works for you. When it comes to tone chasing the power section, hard to say what the end result will be with any load box in the mix. That adds a level of complexity to the sound. Sorry I cannot be of any help on that.

 

[DECEMBER]

@rarebitusa brings up a good point about the Mark V90. No reason you cannot run two different pairs of tubes in the amp. The center pair will define the overall tone, the outer pair will just enhance the sound. What to use though, that is a tough call. Sounds more like an experiment due to the nature of the load boxes and how it will affect the tone of the amp. I tried the JP2C with the RockCrusher and noted it made a change to the overall sound. It does have some filtering that helped. Running the Mark V90 through the same load box actually made it sound better, same for the Roadster. I gave up on using load box and found a better way to capture sound from the speakers. A dynamic compressor preamp before the mixer did a huge difference overall. Sure, I have compressors and limiters on the mic inputs of my mixer, however, I could not capture the actual room sound which is what I wanted to get. The Focusrite Scarlett Dynamic Octopre did the job quite well. Actually made the SM57 sound good and not filtered and boxy. I did not buy it for recording guitar, it was more or less to mic the drum set with dynamic mics that got noisy when I had the phantom power turned on for the condenser mics. Phantom power on my board covers all channels when it is turned on. Same with the digital recorder. At least with the Scarlett I can select in banks of 4 which have phantom power. The Recording rabbit hole is deeper than the tube or speaker hole. It can easily cost more than you want to spend.

I have a feeling you may have to experiment to find out what works for you. When it comes to tone chasing the power section, hard to say what the end result will be with any load box in the mix. That adds a level of complexity to the sound. Sorry I cannot be of any help on that.

Yeah, I'll probably get a pair of 445 and 441. Since I use it mostly on 45W, I can do comparison recordings of each pair in the inner sockets, and see what mixing them all in 90W does.
The 441: "provide the Treble and Presence Controls with an extended usable range without adding unwanted, detached “buzz”, “sizzle” or harshness..."
and the 445: "tighten low-end, add top-end cut in a perfect “Rock/Claw” frequency, while avoiding “buzz” or “sizzle” in the upper octave..."
... both sound like what I need, though these seem to be the most opposite two of the four.
(And I have no idea what "Rock/Claw" means...)
And they make my magic numbers: 441 =9, 445 =13.

Mesa told me I should be using a 'better' load like the CabClone, and that the Powerhouse has the same load...
Has anyone compared either of these with the Suhr RL, Fractal X-Load, TwoNotes Captor, or Rivera Mini Rock Rec? I have these 4 already, and have no need for an attenuator or IR loader (or even a line out, because the amp has the slave out. I wish they would make a cheaper version that is just a load)... is the Powerhouse/CabClone load significantly better than these others to warrant double the cost?

 

[bandit2013]

All good questions. I have the Rivera Rock Crusher Recording model, the full size version. It works well and did not seem to swamp the transformer all that much. It also has two voicing switches, edge and warm that can be used with things change when you add in more load and less speaker. I have run it with the Mark V90 and the Roadster. When I used with the V90, I had a Celestion Creme 90W Alnico loaded in the combo. That in itself cut more top end and harsh frequencies (it literally removed the ice pick). I would not call the Rock Crusher recording all that spectacular, but it did not make for a boxy sound since it had an EQ to tailor the output to the mixer.

As for the Mesa descriptions of their tubes, take it with a grain of salt. Before Gibson took over, they had different descriptions as well as what amp they were used with.

• STR443 was stock for the JP2C
• STR441 was stock for the Mark V90
• STR445 was stock MWDR and MWTR.
• The left-over supply of STR440 tubes were mostly used with the LoneStar while they had them as well as the Filmore.

I would have to look up some old posts when I swapped the tubes in the JP2C. I may have copied the original descriptions. Curious how different they were if I did.

As for load boxes and such, hard to say. Thought the Two Notes Torpedo Studio or Live rack unit was the best thing, before they dropped then from production. Not cheap products either. I heard good things about Fryette stuff. Never tried them. There are just load units out there, Fryette also has those as well as Rivera in the larger models.

I will remain silent on the load box stuff as I cannot contribute to that topic as I no longer make use of attenuators for recording purposes.

 

[GJgo]

They said "Rather than recommending a specific tube, I'll go through the four Mesa branded 6L6s and you can make your own educated decision." Which was kinda underwhelming, because I can already see the descriptions on the website, and like I said, they're written in a way that makes all of them sound like it's exactly what I need.

FWIW, as long as you have healthy power tubes that aren't TOO cold or TOO hot, I'd recommend focusing on your speaker choice instead. The speaker & the microphone choice are the top 2 determinants of tone.

 

[rarebitusa]

microphone choice

What are you using these days?

 

[DECEMBER]

I will remain silent on the load box stuff as I cannot contribute to that topic as I no longer make use of attenuators for recording purposes.

FWIW, as long as you have healthy power tubes that aren't TOO cold or TOO hot, I'd recommend focusing on your speaker choice instead. The speaker & the microphone choice are the top 2 determinants of tone.

I like my mic'd speaker sound, but I'm in an apartment and do my best work after midnight. So I captured IRs of my speakers with the mics I record them with. 4 speakers in a stereo wet/dry/wet config, a 2x12 on the Mk V for dry (after FX loop EQ) and a stereo solid-state 2x12 for stereo wet FX. 2 mics/speaker (8 total).
I recreated the rig with IRs (8 IRs in place of the 8 mics). The dry 2x12 gets the Mk V slave out, the wet 2x12 gets the outputs of two load boxes on the stereo amp.
When speakers are connected to the Thru of the load boxes, the slave/line outs -> IRs sounds very close to the real mic'd speakers, but when I go silent and switch to using the internal dummy loads, the mids go flat and the Suhr and X-Load UK voicing get REALLY boomy and mid-scooped. Tbe X-Load US voicing and TN Captor aren't so bad, but they still go flat in the mids (lose that 3D depth to the mids that's still there thru IRs when speakers are the connected load). Then the Rivera Mini Rock Rec sounds really flat and boxy, almost all mids, not too different from the flat sound you get from plugging the FX send -> IRs.
The Suhr is the worst: way too bass-heavy and scooped, but only on the Mark V, not the solid-state power amp, so I'm thinking it has a lot to do with how it's reacting with the tubes. The Suhr RL seems to be favored by the majority
I know tubes won't change that much, but I need a new set soon anyway, so I'm trying to put a lot of thought and research into which ones I get. Mesa website says power tubes are at their best 1.5 years at 10-15 hours/week... I use mine 30+ hours/week. I have the 12 year old 440's that I've had for 4 months, and a quad of JJ's that have been used full-time for 6 months. They were newer, and the Mk V had all kinds of noise and signal-loss issues when I got it, so I put the JJ 6L6GC's and all new preamp tubes in it. And I need to put one of these sets back in my other amp, I just took the 440's out of it to compare to JJ, and the JJ's have a more pronounced harshness with less focused mids.
I haven't been able to find any videos or feedback about the Powerhouse vs any of the 4 loads I have, so I'm reluctant to spend $470 on an open-box to find out if it might actually be significantly better than what I have. Because I don't need an attenuator, or IR loader or anything, so I've been avoiding the $6-700+ boxes. I need at least 3 for the w/d/w setup, and sometimes put two 8 ohm loads on the Mk V to see what mixing them does.
The weakest link in my chain is the loads, because I like the mic'd speaker sound and the line out -> IRs sound when speakers are still connected. But I need silent recording for the apartment.

 

[rarebitusa]

When speakers are connected to the Thru of the load boxes, the slave/line outs -> IRs sounds very close to the real mic'd speakers, but when I go silent and switch to using the internal dummy loads, the mids go flat and the Suhr and X-Load UK voicing get REALLY boomy and mid-scooped. Tbe X-Load US voicing and TN Captor aren't so bad, but they still go flat in the mids (lose that 3D depth to the mids that's still there thru IRs when speakers are the connected load). Then the Rivera Mini Rock Rec sounds really flat and boxy, almost all mids, not too different from the flat sound you get from plugging the FX send -> IRs.

FWIW I kinda constructed my own reactive load, actually a modification to a TN Captor, adding a 2nd order stage to essentially what is a single order RL. Thru the rabbit hole dive I learned a bit about RLs and how they react to a tube power output. What you describe is in part what I ran into with many attempts at complete silent recording setup with an RL. In the TN case the WOS cab simulator essentially filters the raw signal and makes it usable post tracking. But for a realtime recording the realtime delays in monitoring were too long. This is just my current take, doesn't mean it is right.

The fixed RL is attempting to recreate a speaker load, which is inherently dynamic. Oh I did all the LTSpice modeling and circuit characterization, but once I realized this I focused on finding the right "amp match" for the fixed components. It took alot tweaking of the amp setup and dialing in what sounded best thru a mix of EQ and gain. But it just didn't work for every amp setup. Every voicing took on a new set of amp tweaks to find the sweet spot. That got a bit tiring.

Eventually I turned to "reamping", with the RL, with the amp cranked took the slave out to another amp's effects in and ran a low vol setup from there. That started to sound much better. Finally I build an analog cab sim pedal, just a bunch of filters with pot tweaking capability. Takes the slave out signal and produces a line out level that was acceptable for silent recording. I've left it there for now as playing live is sucking up most of my time these days.

I do think that a reamping solution like a Freyette or a Boss Waza is more the way to go these days. Straight attenuators IMHO will always color the amp tone. An RL needs that post cab sim SW. Again just one players two cents.

 

[bandit2013]

I get it. That makes it more difficult. Would be nice if they made a silent speaker like they do with drum heads and cymbals. I doubt that would be a thing, having a stretched mesh instead of a paper cone to simulate the moving voice coil suspended in a magnetic field. Instead you have to spend money on an isolation cabinet. Wonder if the mesh speaker suspension that makes no noise would be something that would actually work as a reactive load. Anything has to be better than a bulk resistor with a few reactive components. Speakers themselves are a complex thing, sure, simple in design, but what that movement of the voice coil does in the presence of the magnetic field when there is changing current due to change in frequency and waveform shapes creates a unique reactance that couples back to the OT. Not saying a non-moving component like a fixed inductor and resistor cannot perform. Many of the larger load boxes make use of wire wound resistors which are basically inductors with an air core. Smaller load boxes, not really sure, never had one to open up and see what was inside. Perhaps it is the method of how the IR feature works if it simulates a speaker based on electrical impulse. Never really explored that but probably would have if my living conidtions were different.

 

[DECEMBER]

An RL needs that post cab sim SW.

I run IRs I made of my speakers in the WoS plugin. No power amp sim, EQ and Exciter off, just a flat IR loader. I recorded the IRs thru the Mk V return with presence at 0, on ch3 pentode. I actually did a bunch of IRs on different channels with pentode/triode and tube/diode. I did some with the presence up, and some thru the 10 band parametric EQ before the FX return... completely flat with 0 presence and in the IR loader flat sound the closest to the mic'd speakers. And I think they sound a whole lot better than any of the 3rd party IRs I've tried (and I went thru literally every one available in the WoS store).
The thing is, though... none of them sound good on their own. I layer 4 different IRs to get what sounds good and usable to me. A group of 4 stereo tracks: stereo wet goes to 2 tracks with a stereo pair of IRs on each - V30s w/2 mics each. Then the dry amp goes to 2 tracks with a stereo pair of IRs on each - MC-90s w/2 mics each.
I have the track group of IRs laid out exactly the same as the track group of 4 stereo pairs of 8 mics, with the same mix levels and everything.
Done a bunch of comparison recordings and with speakers still connected, the IR group sounds very close to the mic'd speaker group, maybe even better, because I can't put the speakers loud enough to get their full potential, so the amp volume is higher when going silent.
But using the dummy loads makes a big difference, and I had to start from scratch with EQ to get it to work. The Suhr RL especially gets a lot of praise, but none of them are really matching the response of a real speaker.
I haven't had any noticeable latency. I am running a Thunderbolt interface now, but I just got it. The Behringer UMC1820 had significant latency, but it had it with mics, too.

 

[DECEMBER]

Would be nice if they made a silent speaker

I had the idea to just tear the cone out of an old V30, which costs much less than a load box, but asking around, people seem to think that it won't work that way, or at least won't give the same response...
Weber has that WeberMass thing, it's a load made of a speaker motor. But it's only specced at like 60W, and they print all these warnings/disclaimers about overpowering their stuff. Actually, it's labeled "100W, for use with 60W amps or lower"...??? wtf? And the "200W" model is for "100W amps or lower". And if you "have a 50W high gain amp, you should get the 200W Mass. If you have a 100W amp, get the 200W Mass, but don't turn it up very high... "
Seems to be more focused on being an attenuator, but it says it can be a dummy load "for testing or DI use".
Someone really needs to make a silent speaker. But so many people are satisfied with the Suhr RL, and TwoNotes, and 3rd party IRs, and I just don't understand how anyone can stand it.
But I also don't understand how anyone can stand to use any amp without serious extra EQ... But I've heard plenty of recordings online of "guitar -> overdrive -> amp -> V30 -> SM57" that DO sound decent, and I just really don't get it... because when I plug into an overdrive into an amp (even the Mk V) and record it thru any speaker with any mic, it sounds like absolute trash... all mids, boxy, and a grating layer of overtones in the high end. I've never met an amp that sounded half-decent without extra EQ in the loop. The 5 band GEQ on the MkV makes it sound good out loud, but still like crap in recordings... So I don't know if it's just the electricity in my apartment is so bad that nothing sounds the way it should, or what, but even expensive amps like this sound horrid here without a lot of extra help (10 band parametric rack EQ plus more from an EQ2 pedal, and BBE Sonic Stomps).