Gk MB-500 or Aguilar TH-500?

[svlilioukalani]

The Tone hammer lacks high end. I almost sold mine after my first gig with it. Then I listened to a recording of that gig. It was by far the best bass tone I have put out in a loud band setting. It is not a clean amp like the GK. And I normally like a good clean sound. But what matters is how it sounds at the gig. And this is where the amp rules. If you want clean and bright go GK. If your after a big sound with teeth, get the TH500.

 

[12bass]

As I recall, the engineers at Genz Benz claimed to have made some tweaks to thermal management which allowed them to produce more power than Bang & Olufsen's nominal ratings. Perhaps other manufacturers have made similar modifications? I seem to recall Dave from Aguilar saying something about being very conservative with the power amp section in the Tone Hammer. Frankly, I hoped that Bass Gear Magazine would have tested the various amps using the ICEpower modules to give us some better real world measurements. However, for some reason BGM seems to have avoided doing such tests (e.g. the Genz Benz ICEpower amps).

 

[The Regulator]

GK MB-500 with a SansAmp VT Bass for the best of both worlds.

 

[jthisdell]

I demoed the TH and the GK and bought the TH. Have gigged with it a dozen or so times and it has been easy to get good tone. Very solid low end. very good quality DI. Not a lot of superfilous features. One mystery about the TH is the Drive control. At low settings it adds some harmonics (tubey) but as you dial it up it acts as both a HPF and increasingly as a LPF. See the TH500 Megathread page 92 for a detailed explanation and some cool graphs that tell the story. This explains the comment above about the high end of the TH. Unfortunately the TH manual does not explain this at all. A lot of good discussion and testimonials in that thread, very, very little negative comments. Both are quality USA made products.

 

[FirewalZ]

I have the GK MB212-ii combo, very portable, very loud and has a solid tone. However, like what others have said, it is more of a clean and modern sort of sound. I play mostly classic rock and Blues using a P with flats and sometimes wish for a woolier and vintage tone. I've thought about getting the TH AGS pre-amp pedal..

 

[Kukulkan61]

From what Ive researched and read I think the GK MB FUSION 500 would give you the best of both worlds of the Agy and MB 500...

 

[bassMG]

I knew this would raise a few eyebrows! But it's absolutely true. The power of these three amps is determined by which model module they use. In all three of these amps the ICEpower class D modules are being used in bridge-mono mode, which of course allows for maximum power from them at a given load impedance. The "independent" tests to verify the output power claims are done by the manufacturer of the ICEpower class D modules themselves, Bang & Olufsen. The results are published on their detailed data sheets, available here: Link Removed
But if you wish to see a truly independent test of the 125ASX2 module by a third party, here are BHK Labs measurements of the Calyx Femti amplifier and the Bel Canto Design e.One REF500M that uses it. You'll see that their test results on both amps are very close to those actually published on B & O's datasheet.

Some bass amp manufactures who claim 500W @ 4ohms are not mentioning that 500W is not actually achievable from the 125ASX2 - unless the distortion is well over 1% AND the mains line voltage is 230V AC. IMHO, Aguilar is one of the most honest in their TH350 and TH500 power ratings. The 350W and 500W figures really are achievable at 1% THD @ 120V AC.

Here is a list of some bass amps which use the ICEpower ASX2 series class D modules (all in bridge-mono mode). Keep in mind that these are the power ratings at 1% THD and with a 230V AC mains voltage. Power ratings at 120V AC mains voltage will be only about 83% of these figures (again, refer to the B & O datasheets):

50ASX2 - 180w at 4ohms:

GK MB200 and any 200 watt GK combo
Fender Rumble 200 and any of the 100w/200w combos
Traynor SB200 and 200 watt combos

125ASX2 - 450w at 4ohms:

Aguilar Tonehammer 350
Eden WTX500
Fender Rumble 500, any Fender 350 w combo
Genz Benz Shuttle 6 and Streamliner 600
GK MB500, MB500 Fusion and any GK 500 watt combo
Kustom KXB500
Tecamp Puma 500 (1 rack unit)
Traynor SB500H

250ASX2 - 850w at 4ohms:

Aguilar Tonehammer 500
Genz Benz Shuttle 9 and Streamliner 900
GK MB800 and MB800 Fusion
Tecamp Puma 900
Demeter 800w class D amps

Dose Markbass use the 50, 150, and 250 ASX2?

 

[engedi1]

I used the TH500 for a number of years and eventually realized that I wanted a slightly more modern tone. Now I am using a GK 1001 RB (kinda wish I had bought the 700 RB as this thing is so loud it is almost scary.) When I want to warm it up, I engage my TC Spark boost which can add really warm lows and mids and a few overtones. These two together are getting me the most rock n roll tone I have ever acheived, but I am into a slightly aggressive tone and the GK stuff is always somewhat aggressive due to the grindy upper mids IMHO. I too am leaning towards a an MB 500 as I miss the small form factor of the TH500.

 

[NKBassman]

The GK will stay pretty clean at high volumes, whether you like it or not.

The Aguilar has a much more vintage "old school tube amp" tone, whether you like it or not.

Both are capable of "meeting in the middle", so to speak, but they each excel at tones at opposite ends of the spectrum. In other words, they're both great!

FWIW, I like a more old-school tone, and hated the sound of the Boost channel on my GK MB-800, so I traded it for the Aggie.

 

[mjmeche]

I would think the MB Fusion 500 would be a great amp too to look at!

 

[FirewalZ]

The GK will stay pretty clean at high volumes, whether you like it or not.

The Aguilar has a much more vintage "old school tube amp" tone, whether you like it or not.

Both are capable of "meeting in the middle", so to speak, but they each excel at tones at opposite ends of the spectrum. In other words, they're both great!

FWIW, I like a more old-school tone, and hated the sound of the Boost channel on my GK MB-800, so I traded it for the Aggie.

So what about a GK with the TH pre-amp pedal? I already have a GK and this is the direction I'm thinking when I need a more old school tone, anyone use that combination?

 

[NKBassman]

So what about a GK with the TH pre-amp pedal? I already have a GK and this is the direction I'm thinking when I need a more old school tone, anyone use that combination?

I've never tried the Tonehammer pedal, but I imagine this would be a great combo! Best of both worlds!

 

[Treb]

As I recall, the engineers at Genz Benz claimed to have made some tweaks to thermal management which allowed them to produce more power than Bang & Olufsen's nominal ratings. Perhaps other manufacturers have made similar modifications? I seem to recall Dave from Aguilar saying something about being very conservative with the power amp section in the Tone Hammer. Frankly, I hoped that Bass Gear Magazine would have tested the various amps using the ICEpower modules to give us some better real world measurements. However, for some reason BGM seems to have avoided doing such tests (e.g. the Genz Benz ICEpower amps).

Are those tweaks encasing the module and placing a fan at one end, in essence creating windtunnel?

The icepower modules are very well protected (thermal, overcurrent, short circuit on output), and can be used without the use of a fan. Just leave it some breathing room around the module. If you want to prevent thermal shutdown the use of one or more fans is pretty much a requirement. That is likely the reason icepower doesn't recommend to use the 250asx2 module to run a 4 ohm load in BTL mode. The datasheet doesn't mention it...

 

[mam1862]

Another vote for the GK MB Fusion. I like the Aguilar but the Fusion is a real good amp that could give you the best of both worlds.

 

[agedhorse]

I knew this would raise a few eyebrows! But it's absolutely true. The power of these three amps is determined by which model module they use. In all three of these amps the ICEpower class D modules are being used in bridge-mono mode, which of course allows for maximum power from them at a given load impedance. The "independent" tests to verify the output power claims are done by the manufacturer of the ICEpower class D modules themselves, Bang & Olufsen. The results are published on their detailed data sheets, available here: Link Removed
But if you wish to see a truly independent test of the 125ASX2 module by a third party, here are BHK Labs measurements of the Calyx Femti amplifier and the Bel Canto Design e.One REF500M that uses it. You'll see that their test results on both amps are very close to those actually published on B & O's datasheet.

It raises the eyebrows of those who understand the details contained within the spec sheets (which you have missed) as well as the different applications that these products have been designed for.

Quick background so that you don't make more assumptions that are not correct... I have been working with class D and PWM for many years, both in the audio field as well as in the industrial control field as an EE. I have worked with IcePower products for about 15 years, first in the touring pro audio powered speaker market and later adding the musical instrument amp market. I have a much deeper understanding of their technology than most engineers do, and also was awarded a patent for technology that is related to operating these parts approaching the boundary limits.

1. Data sheets are GENERAL guidelines that are provided to allow inexperienced developers of their product to design a part into a system. Like everything general, there is an awful lot of additional information contained between the lines IF you have an advanced understanding of how the particular technology works. If you don't have an advanced understanding, then you should not be messing with what is called "off sheet" data.

2. If you were to follow and understand the data sheets, you would realize that the 250ASX2 module is not specified for, nor is there any data provided for 4 ohms BTL operation. However, I was the first to recognize that there was favorable off-sheet data supporting 4 ohm BTL operation and my former employer was the first to release commercially an amp with this module (with other manufacturers following, some figuring out how to get 900 watts, others less) with no reduction in reliability. We worked hand in hand with IcePower to develop this application, and there was plenty of extreme testing done to insure robust reliability margins. This relationship continues with new products.

3. The THD spec. is something that must be factored into the end product's performance. For example, many folks playing bass amps (as well as guitar amps of course) are looking for an overdriven sound. The very act of overdriving a tube stage (or any form of effective tube emulation) involves the management and/or addition of musically related harmonics (depending on the particular algorithm used), which will result in a higher THD well before the power amp. The catch is that the power must be measured under such conditions AND (this is critical) the amp must be capable of supporting the additional power of these harmonics without shutdown (or failure). This is MUCH harder to execute in practice than it might seem (and is the essence of the patent), which is why some manufacturers may have had to back down on their rated power. This is very much like taking a car engine and modifying it's operation to increase the power. All of the engine's parts, as well as the entire drive train must be able to handle the additional performance, otherwise the performance will be limited by it's weakest link (or it will blow up).

4. Each manufacturer will rate their product in a way that they feel represents their performance with acceptable reliability. Unfortunately for the class D market segment as a whole, some manufacturers have had some significant stumbles with reliability because they failed to account for something critical to a successful implementation of the technology. Unfortunately, this has turned many customers off of class D as a whole, even though there are plenty of examples of high reliability products by a variety of other manufacturers. You can't judge an entire technology on any one (or a few) company's failures.

5. An important difference between musical instrument amps and "HI-FI" amps is that there is a need in the MI products for a particular tone and a feel that goes along with that tone. It's this inter-related dynamics effect that is by far the most difficult to achieve, and has been the subject of an awful lot of effort in the world of digital emulation of musical instrument amps. The basic tones are pretty easy to emulate, but the dynamic effects of how the tone changes with frequency and amplitude, and the feel that accompanies this is very, very difficult. Understanding this is crucial to understanding what is important to higher level players.

I can't get into any details of the specific mechanisms being used, but I can say that you must be very careful when comparing apples to oranges.

 

[agedhorse]

Are those tweaks encasing the module and placing a fan at one end, in essence creating windtunnel?

The icepower modules are very well protected (thermal, overcurrent, short circuit on output), and can be used without the use of a fan. Just leave it some breathing room around the module. If you want to prevent thermal shutdown the use of one or more fans is pretty much a requirement. That is likely the reason icepower doesn't recommend to use the 250asx2 module to run a 4 ohm load in BTL mode. The datasheet doesn't mention it...

In part, but there is considerably more to it. If you were to make some detailed measurements and run some engineering calculations, you would see that there are additional challenges, and they all inter-relate. The solution is multi-faceted because the problems are multi-faceted.

 

[LeftCoast]

Okay so I think I will be trying all of the above mentioned amps at my local guitar center. They usually let me play as loud as I want...within reason haha!
I like the idea of pairing the tone hammer pedal with a gk. That's interesting and May be what I'm after but I'm a hands-on guy so that will be another thing to test out.

Thanks for all the advice! I'm just getting tired of hauling my heavy SWR cabs and amp to each gig. (They sound great btw) The weight issue though...

 

[FirewalZ]

Okay so I think I will be trying all of the above mentioned amps at my local guitar center. They usually let me play as loud as I want...within reason haha!
I like the idea of pairing the tone hammer pedal with a gk. That's interesting and May be what I'm after but I'm a hands-on guy so that will be another thing to test out.

Thanks for all the advice! I'm just getting tired of hauling my heavy SWR cabs and amp to each gig. (They sound great btw) The weight issue though...

This was/is my case as well. Back in the day I was lugging around an SKB rack case and a heavy cabinet or two.....when I started to play out again a year back I got the GK MB212 combo, 35-ish pounds, loud as crap. Like you I'm looking at the TH pedal to "old school" it up a bit more, let me know how it turns out.

 

[Latitude94941]

Thanks to agedhorse for his terrific post (and for saving me a lot of typing).

To my knowledge, Aguilar has never claimed that the TH500 puts out more than 500 watts at 4 ohms. In fact they have leaned in the other direction. I saved the following text from a post from Aguilar's Dave Boonshoft, which was made in reply to a post by Tom Bowlus:

"The amp's THD varies over the frequency spectrum. The maximum (on our amp) is found at 1 kHz and is 7 percent. At 100 Hz it is 5 percent at 500 watts. Going down to about 450 watts THD is 5 percent at 1 kHz and much less at lower frequencies.

DB"

 

[bass151]

So the TH500 uses the same module as some of the 900 watt class D amps? I currently own a GB Shuttle 9.0, does that use the larger module? Is their currently a class D amp capable of more than 900 watts. I assume the so called baked in sound of some amps is generated through the preamp design.