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Gear Discussion Forums => Bass Amps & Effects => Topic started by: drbassman on March 03, 2014, 07:07:06 PM

Title: Just wait till you see what I did...... Mesa surprise
Post by: drbassman on March 03, 2014, 07:07:06 PM
Stay tuned.  More to come soon.
Title: Re: Just wait till you see what I did...... Mesa surprise
Post by: drbassman on March 04, 2014, 06:41:17 PM
Got this today.......

(http://i2.photobucket.com/albums/y16/drbassman/AMPS/DSCN0093_zps188fadc0.jpg) (http://s2.photobucket.com/user/drbassman/media/AMPS/DSCN0093_zps188fadc0.jpg.html)
Title: Re: Just wait till you see what I did...... Mesa surprise
Post by: saltymonkey on March 04, 2014, 06:56:15 PM
Nice!!!! Love the color! Classy. Are those 15s? I have the same head. I bet that sounds fantastic. Still working my way through all the voice positions. How do you set it Doc?
Title: Re: Just wait till you see what I did...... Mesa surprise
Post by: Pilgrim on March 04, 2014, 07:14:33 PM
DANG!!!  That's a lot of cool lookin' "stuff"!
Title: Re: Just wait till you see what I did...... Mesa surprise
Post by: Dave W on March 04, 2014, 08:58:50 PM
two 4x10s? Tell us more!
Title: Re: Just wait till you see what I did...... Mesa surprise
Post by: Psycho Bass Guy on March 04, 2014, 09:09:08 PM
Aww you got my hopes up. I was hoping you had upped the horsepower and would be sporting the new Strategy. Oddly enough, I just finished jamming on my old 400+ right before I sat down to check things out here. If there would be one improvement I could make to it, it would be to give it a 6550A/KT88 output section which would beef up low end punch considerably. A pair of 6L6GC's can put out the same amount of power as a single 6550A/KT88, but only half the peak plate current, and current is where low end comes from.
Title: Re: Just wait till you see what I did...... Mesa surprise
Post by: the mojo hobo on March 05, 2014, 05:22:29 AM
two 4x10s? Tell us more!

Looks like 15s to me.
Title: Re: Just wait till you see what I did...... Mesa surprise
Post by: drbassman on March 05, 2014, 05:50:17 AM
Nice!!!! Love the color! Classy. Are those 15s? I have the same head. I bet that sounds fantastic. Still working my way through all the voice positions. How do you set it Doc?

Thanks!  Both are Scout 15s with the 12" radiator in the bottom.  I love the sound of these cabs.  Much richer/deeper than the Powerhouse models.  They are larger and with the extra 12" speaker just plain sound better to me.

I set the selector switch to 5, maximum bass!  All of the other dials are pretty much at 11 or 12 o'clock.  The tone is deep and full and the gain gives it a bit of old school sound.  I love the amp.
Title: Re: Just wait till you see what I did...... Mesa surprise
Post by: drbassman on March 05, 2014, 05:57:09 AM
Aww you got my hopes up. I was hoping you had upped the horsepower and would be sporting the new Strategy. Oddly enough, I just finished jamming on my old 400+ right before I sat down to check things out here. If there would be one improvement I could make to it, it would be to give it a 6550A/KT88 output section which would beef up low end punch considerably. A pair of 6L6GC's can put out the same amount of power as a single 6550A/KT88, but only half the peak plate current, and current is where low end comes from.

Well, thus far, I'm happy with the low end from this rig.  Part of the issue I was having before is the Powerhouse models are known for rip roaring mids and upper ends.  Part of that comes from the fact that the cabs are totally different from the Scouts.  I know the design dictates the freq response significantly and I always liked the sound of my old Scout cab.   

I set the controls on the speakers to Normal across the board and that seems to be working.

As for low end, the guitar player at practice last night was complaining about the low end bugging his ears.  I think I have enough now!

As for master volume, this amp has plenty.  With the Gain at 12 o'clock, I have the master set at 8 to 9 o'clock, barely on IMHO.  It's really doing fine thus far.
Title: Re: Just wait till you see what I did...... Mesa surprise
Post by: drbassman on March 05, 2014, 06:00:43 AM
DANG!!!  That's a lot of cool lookin' "stuff"!

Thanks Al.  I ordered the speakers in black originally, but my sales guy called to tell me Mesa had a promotion on for free upgrades to the dealers, then they could charge whatever they wanted for them in order to boost sales.  Normally $189 per cab for the upgraded cosmetics.  My guy gave it to me at a cost I can't really mention.  However, I love those guys!
Title: Re: Just wait till you see what I did...... Mesa surprise
Post by: Dave W on March 05, 2014, 12:09:13 PM
Ah, I knew they had to be too big for just 1x15s. I've never had a problem with low end from my 2 1x15 EV Mesas, but that's just me.
Title: Re: Just wait till you see what I did...... Mesa surprise
Post by: drbassman on March 05, 2014, 12:15:22 PM
Ah, I knew they had to be too big for just 1x15s. I've never had a problem with low end from my 2 1x15 EV Mesas, but that's just me.

Yeah, there's something about the radiating cabs that really appeal to my ear and brain.  I'm a fan!
Title: Re: Just wait till you see what I did...... Mesa surprise
Post by: Highlander on March 05, 2014, 03:09:16 PM
Nice looking rig...

Could someone explain the "radiating" component or is their a drawing that shows the arrangement around...?
Title: Re: Just wait till you see what I did...... Mesa surprise
Post by: Granny Gremlin on March 05, 2014, 03:56:55 PM
It's a "passive radiator."  Basically replace the port (a given volume of air) with a speaker cone (with no motor/magnet, or just not connected to anything).  The mass of the cone, and it's resonance point, is akin to the the mass of air in a port. Tuning the system is done by adding weight to the cone (there is often a bolt you can add washers to, often on the back, but I put mine on the front for easier tweakage) vs changing the volume of the port (length and/or width).  Theoretically very similar designs but they end up not sounding exactly the same (I tend to prefer passive radiators) and end up being (usually, but not always) more easily user-tunable than ported boxes.

So.... if you ever have a drive unit with a cracked magnet (e.g. shitty stamped frame late 70s PA stuff or white van speakers) whack off the motor with a hammer and you have a PR to play with (you will likely need to add weight and stiffen the cone which can be done by painting it with puzzcoat/hodge podge or just plain old watered down white/wood glue). 

Back when I ran a venue, I wanted the PA to look vintage (mostly indie rock shows), so I scored a pair of those old Traynor 4x12 vertical line arrays (I already had a pair of Sun horns to go on top) for almost nothing because half the drivers were blown.  I converted the broken drivers into PRs.  Later I replaced the remaining drivers with modern (heavier duty) bass drivers (an EV and a Black Widow each IIRC) which worked great because those cabs are a little on the small side for 4 modern 12s, but just 2 was about right.  Those things kicked and I only ever ran them at half the power they could take.





Title: Re: Just wait till you see what I did...... Mesa surprise
Post by: Highlander on March 05, 2014, 04:15:15 PM
That makes sense... cheers...

I've been running my old Marshall 4x12 with just the 2 replacement 75w speakers running, leaving the old remaining Celestion pair in place but not powered... put out a lovely sound until the head died...
Title: Re: Just wait till you see what I did...... Mesa surprise
Post by: drbassman on March 05, 2014, 05:09:49 PM
The passive 12" radiating speaker faces down in the bottom of the cab.   The cab is also ported in the back.
Title: Re: Just wait till you see what I did...... Mesa surprise
Post by: Dave W on March 05, 2014, 10:10:17 PM
I'm familiar with the concept from seeing and hearing some stereo speakers with  passive radiators in the 1970s. Never tried a bass cab with one. No one design is perfect, I'm sure they have their pluses and minuses like every other design. It's all about whether the sound works for you.
Title: Re: Just wait till you see what I did...... Mesa surprise
Post by: Psycho Bass Guy on March 05, 2014, 10:59:46 PM
Well, thus far, I'm happy with the low end from this rig.

Your amp is made the way I wish mine was. I forget that not all the folks here automatically know what type of output tubes are in their amps.

 As nice and as versatile as my Bass 400+ is tonally, it's not real big on punch, and that's even after I've tweaked the preamp and power section a bit. It's a great amp, but big iron and big output tubes= big sound and my Mesa is just kinda "medium" in both departments; yours is a whole 'nother ballgame. The Prodigy is basically the 400+ redesigned exactly the way I was suggesting the 400+ be improved, and most likely for the same reason. They're both 225-250 watt tube amps, but the 400+ uses twelve 6L6GC's to your Prodigy's four KT88's. Even with that ghastly amount of power tubes in the 400+, the supply and drive section never really push them to their full potential. (I'm just like an old gearhead boring out engine blocks.)

With most of my big amps in storage for the divorce, I only have my Mesa 400+ on a Trace 1153 1x15 for practice at home and my Trace Elliot VR350/Acme Low B Series I 4x10 which stays at church. The Trace on its Acme cabinet will rearrange your insides if I ask it to, but mostly I play pedal tones on my 95 Fender AmStd Jazz V and have it dialed to bring the mids more up front the more I dig in. If I get really into it, it gets into downright Geddy territory- while rearranging your insides. My Mesa is sweet, but it just ain't got that grunt. Yours, OTOH, should, though the crazed idiot in me wants the bigger model for myself, because, well, because I do. Maybe after me and the missus finish parting company...
Title: Re: Just wait till you see what I did...... Mesa surprise
Post by: drbassman on March 06, 2014, 06:26:18 AM
Your amp is made the way I wish mine was. I forget that not all the folks here automatically know what type of output tubes are in their amps.

 As nice and as versatile as my Bass 400+ is tonally, it's not real big on punch, and that's even after I've tweaked the preamp and power section a bit. It's a great amp, but big iron and big output tubes= big sound and my Mesa is just kinda "medium" in both departments; yours is a whole 'nother ballgame. The Prodigy is basically the 400+ redesigned exactly the way I was suggesting the 400+ be improved, and most likely for the same reason. They're both 225-250 watt tube amps, but the 400+ uses twelve 6L6GC's to your Prodigy's four KT88's. Even with that ghastly amount of power tubes in the 400+, the supply and drive section never really push them to their full potential. (I'm just like an old gearhead boring out engine blocks.)

With most of my big amps in storage for the divorce, I only have my Mesa 400+ on a Trace 1153 1x15 for practice at home and my Trace Elliot VR350/Acme Low B Series I 4x10 which stays at church. The Trace on its Acme cabinet will rearrange your insides if I ask it to, but mostly I play pedal tones on my 95 Fender AmStd Jazz V and have it dialed to bring the mids more up front the more I dig in. If I get really into it, it's get into downright Geddy territory- while rearranging your insides. My Mesa is sweet, but it just ain't got that grunt. Yours, OTOH, should, though the crazed idiot in me wants the bigger model for myself, because, well, because I do. Maybe after me and the missus finish parting company...

Yeah, I think the 88's are really doing the job for me.  Our little club seats about 175-200 people and the Prodigy has tons of power left over for the venue.  There's something really deep and smooth about the Scout cabs with the 15 and 12" speakers.  I sold the one I had to get the Powerhouses and wished I didn't.  So, now I'm back to where I wanted to be with two of the nicest cabs I've ever used.  I'm happy!   :mrgreen:
Title: Re: Just wait till you see what I did...... Mesa surprise
Post by: Granny Gremlin on March 06, 2014, 08:36:16 AM
The passive 12" radiating speaker faces down in the bottom of the cab.   The cab is also ported in the back.

That's weird and interesting to me.  It's just like some cabs have 2 ports (or 2 PRs for that matter - there's a bunch of home theatre subwoofers like that) instead of one.  As long as they adjusted the port size and PR cone weight accordingly, there's no reason for that not to be a valid approach.

I do wonder why they did that, like what would be the advantage.

I've been running my old Marshall 4x12 with just the 2 replacement 75w speakers running, leaving the old remaining Celestion pair in place but not powered... put out a lovely sound until the head died...

Yeah that's the idea.  It likely could have been optimized by adding some weight to the Celestions (and box size, or internal volume, was likely not ideal, but could be tweaked somewhat, dfepending), but I find them slightly more forgiving than ports (especially if the PRs have frames and spiders vs the cheap ones that are just a disc of weighted foamcore attached to a surround - they distort more, especially if not tuned properly, because there's no mechanism to ensure linear in-out travel).  .... I am kinda surprised that nobody's actually made a production cab like this yet actually.  I think it would be huge with punk and _core players.
Title: Re: Just wait till you see what I did...... Mesa surprise
Post by: drbassman on March 06, 2014, 10:07:20 AM
That's weird and interesting to me.  It's just like some cabs have 2 ports (or 2 PRs for that matter - there's a bunch of home theatre subwoofers like that) instead of one.  As long as they adjusted the port size and PR cone weight accordingly, there's no reason for that not to be a valid approach.

I do wonder why they did that, like what would be the advantage.


Not sure, outside my area of expertise.  They do talk about the design a little on their web site.  Not sure it's much detail though.
Title: Re: Just wait till you see what I did...... Mesa surprise
Post by: godofthunder on March 06, 2014, 08:11:58 PM
Very cool rig ! I have been running 15s and 12s for years.
Title: Re: Just wait till you see what I did...... Mesa surprise
Post by: Psycho Bass Guy on March 06, 2014, 09:49:59 PM
Mackie brought 'back' the idea of a passive radiator coupled to a tuned cabinet to augment lows with their first series of powered studio monitors (and Mesa also used them to great effect in the old Walkabout combos). The Mackies sounded REALLY good, which is why I don't like them for studio monitors. They're almost hi-fi stereophile in their exaggeration of critical areas where in the studio, you need accuracy, not beauty. I'd track with them, but not mix or master using

A passive radiator is basically a driver with no magnet or voice coil tuned to react at port frequencies and below. If you've ever been playing and something in the room would vibrate sympathetically, it's the same principle. Since there's no coil mass (because there is no voice coil at all in purpose-built radiators), the suspension can be tuned as tight or as loose as needed to get really huge lows out of smaller diameter speakers. The downside is that unless the port is carefully physically designed, those extended lows can be out of phase to the rest of the other bass frequencies and it becomes progressively worse below the port corner frequency. Since bass wavelengths are so long (around 27 FEET for low E depending on temperature and altitude 767mph/ 41.2 Hz) it can be hard to hear, but when it's a problem, it's a MAJOR problem, which is why passive radiators are not more common. They make perfect sense for an instrument amp being powered from a single source, but when you start adding multiple cabs from multiple amps, things can get weird in a hurry.

Part of the irony of speaker science is that we are still in the second generation of driver development for most bass speakers, and the exact same principles that modern drivers use were first employed in the first permanent magnet drivers of the 1930's. There have been forays into pushing the state of the art: servo-driven subwoofers, ribbon tweeters, and a few other esoteric designs, but by and large, what little gains in speaker efficiency have been made in the past 80 years have been in the refinement of materials and cabinet reflex designs. Even the BEST subwoofers are barely 20% efficient; everything else put into them is lost as heat. If we could make drivers with an efficiency of 60% or better, high powered bass amps could literally be used as sonic weapons. That's also why it's always going to be easier to get more volume with more drivers instead of more power.
Title: Re: Just wait till you see what I did...... Mesa surprise
Post by: drummer5359 on March 07, 2014, 04:34:18 AM
That is just beautiful, congrats!  8)
Title: Re: Just wait till you see what I did...... Mesa surprise
Post by: 4stringer77 on March 07, 2014, 07:33:13 AM
If we could make drivers with an efficiency of 60% or better, high powered bass amps could literally be used as sonic weapons.
Someday bass players will rule the world like Kyle MacLachlan in Dune!
http://www.youtube.com/watch?v=TQeP6GWU0e4

Title: Re: Just wait till you see what I did...... Mesa surprise
Post by: 4stringer77 on March 07, 2014, 08:06:14 AM
Is it possible to tune the passive radiator on the Walkabout? I think it is meant to stay in the factory setting. I'd like to try the head in my combo out with a different cab sometime to see what the difference is. Sometimes it feels hard to gauge my tone from what I'm hearing immediately in front of my amp compared to what's being heard in the rest of the room. Not sure if it's room acoustics or the effect of the walkabout's cabinet design. 
Title: Re: Just wait till you see what I did...... Mesa surprise
Post by: Granny Gremlin on March 07, 2014, 08:56:18 AM
Mackie brought 'back' the idea of a passive radiator coupled to a tuned cabinet to augment lows with their first series of powered studio monitors (and Mesa also used them to great effect in the old Walkabout combos). The Mackies sounded REALLY good, which is why I don't like them for studio monitors. They're almost hi-fi stereophile in their exaggeration of critical areas where in the studio, you need accuracy, not beauty. I'd track with them, but not mix or master using

Yeah, I had use of a pair of the MKI HR824s for a while.  They were nice, but as you say too nice.  Very generous in the bass/low mid area even despite proper use of the room mode switch.  I just couldn't trust them.  Good quality drive units in that box though (Vifa), and they can be found used for very cheap.  I could have probably gotten used to them eventually, but they weren't mine and now I have something I really like.

I was under the impression that (the MkI versions at least) were just straight up PR cabs.  Don't recall seeing a port on them (the PR was under the amp on the back).  Never used the MkII versions and those might haye been different (they looked different at least).


Even the BEST subwoofers are barely 20% efficient; everything else put into them is lost as heat.

Yes, but the idea was (at least in Hifi purposed speakers) that manufacturers are sacrificing efficiency for flatter response (in the intended usable range of the driver) and extension at the extremes - though this applies more to mids and woofers than subs.  PA and instrument speakers on the other hand, tend to be significantly more efficient, at the cost of a much more volatile and shorter response curve.... but yeah, that's still not very efficient.

Is it possible to tune the passive radiator on the Walkabout? I think it is meant to stay in the factory setting. I'd like to try the head in my combo out with a different cab sometime to see what the difference is. Sometimes it feels hard to gauge my tone from what I'm hearing immediately in front of my amp compared to what's being heard in the rest of the room. Not sure if it's room acoustics or the effect of the walkabout's cabinet design. 

It's the room and also what Psycho said about the wavelengths of low frequencies being so long.  ... also if bass is going through the PA as well as live off stage you are, to a degree at least, at the mercy of the sound guy as to whether he changes your tone much or not.

You can tune any PR, but depending on the design of the PR unit, it may be easier or harder to do so.  Adding weight is generally easier then removing weight.  Like I said before, often there's a bolt on the back of the thing you can throw washers onto, otherwise you can glue them on.  Sometimes, to save costs, the PR has no frame and is just a disc (usually foam core or foam/rubber covered cardboard) glued to a surround which is in turn glued to the cabinet - stay away from those and don't try to tune them because they're finicky.

That said I would trust that Mesa has tuned these well, and not play too much with it, especially since I don't think it's got anything to do with your issue.
Title: Re: Just wait till you see what I did...... Mesa surprise
Post by: drbassman on March 07, 2014, 12:43:28 PM
Well, Psycho is correct, the tone and sound of the Scouts over the Powerhouse cabs is noticeably deeper and richer.  The incredible thing I noticed at practice the other night is the cab is as loud from behind as it is in front!  Sound just "radiates" all around it.  The cabs do sound better out in the audience, too.  As I walked out to the end of my 20 foot cord, the bass response was more perceivable, due to the wave length Psycho mentioned, and design.  I didn't perceive that much of an improved sound with the PH cabs out in front at 20 feet.

In the end, it's a better set of speakers than the PHs for my purposes and ears.
Title: Re: Just wait till you see what I did...... Mesa surprise
Post by: Highlander on March 07, 2014, 12:51:11 PM
Someday bass players will rule the world like Kyle MacLachlan in Dune!

Ari... the Bass Player, has awakened...!

www.youtube.com/watch?v=gC6WJVQvkDE

Ari-Dib... Ari-Dib... Ari-Dib... ;D
Title: Re: Just wait till you see what I did...... Mesa surprise
Post by: drbassman on March 07, 2014, 01:08:48 PM
Truth is stranger than fiction.
Title: Re: Just wait till you see what I did...... Mesa surprise
Post by: Highlander on March 07, 2014, 01:16:12 PM
Clarke's Third Law applies...
Title: Re: Just wait till you see what I did...... Mesa surprise
Post by: 4stringer77 on March 07, 2014, 02:18:54 PM
Mike Porcaro played on the Dune soundtrack with Toto. Wish the same R&D that went into sonic crowd dispersal could be applied to helping cure the ALS that Mike and others suffer from.
Title: Re: Just wait till you see what I did...... Mesa surprise
Post by: Highlander on March 07, 2014, 02:41:25 PM
Got the soundtrack (and the Eno bits), got the movies, got the SciFi Channel series', got the games, got the books (including a first ed of the first and the fourth autographed)... etc...

The "mosquito" is the most reliable youth dispersal trick...
Title: Re: Just wait till you see what I did...... Mesa surprise
Post by: Granny Gremlin on March 07, 2014, 03:34:08 PM
Some of Sting's best solo work, that movie.  :P

(I also enjoyed him in Quadrophenia)