Class D size vs standardization

Discussion in 'Amps and Cabs [BG]' started by cheechi, Apr 27, 2019.

  1. This may just turn into a rant.

    The standard 19" rack unit is still a perfectly good way to manufacture bass amps. Except for some reason most Class D amps. Many class D amps are about the same size and shape. Roughly 2U tall by 'half U' (though many are too wide to sit 2 wide in a 2U case) wide. Did or does something inside determine this is the proper size? They don't all have a fan, so it's not that they have to be tall enough for a square fan port at the rear. Yes, rack ears are available for some class D that I have looked at, which acknowledges that the standard rack size is still important for a modern product to be used but doesn't really explain why not just make the amp fit in 1U to begin with.

    My expectation is most of these amps could have been built into a vented top 1U chassis, give more room to spread out multiple smaller heatsinks or more surface area for a larger one to be passively cooled. Other than being able to sit atop a 210 cab stood vertically is there really much benefit to the typical class D form factor? They do look silly on top of something as wide as a 115 or 410 let alone an 810, while a rack case, regardless how tall looks a lot less silly.

    So here is my thought process. Many of the early Class D amps are offered in 250-350W and 450-550W the higher choice. Now many of the 450-550W are being replaced by 700-800W versions. If each of these were 1U instead of their taller designs, I could buy a new 1U with a beefier power section and have 2 different sounding preamps and 2 different power rated power amps in a 2U case. Now you don't need to sell your MB500 if you need more power, you can get a Darkglass 900 to go with it. (also, why do none of the Tonehammer amps have an effects loop?) Not often do I get to crank an 800W amp, but some of them do have an interesting, not unpleasant type of power distortion. If I want that sound but it's too much power, I can use the lesser of the power amps available in its sweet spot instead. These do sit in (sometimes very narrow) sweet spots though, hence having 2 at different power ratings gives more of a versatility that's still both light and relatively small.

    It also means you could use existing, already industry standard 1U preamps with your new class D amp's power section without it looking ridiculous or having to buy a dedicated power amp. Let's say a 4U shallow case with 4 total preamps and 2 total power amps, mixing and matching old and new, tube pres and full ss amps, etc. or subtract a pre and add a wireless, or whatever. And probably amps + case still be under 30lb.

    Further, if manufacturers standardized a rear vent location, an external fan could be mounted cooling through both vents because they are stacked making a square out of two rectangular vents. For how many years have bass amp heads been manufactured within 1-2 inches of the same width? Why go away from all that now?

    All of this means nothing without a time machine. But it would be nice going forward if they would standardize on a 1U tall size, that a standard set of rack ears could be made for any future heads to use in common.

    And yes apparently it has become a rant. I apologize to you all.
    FunkyD, zon6c-f and mikewalker like this.
  2. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
    Players wanted smaller, the form factor is based on accessibility to the features (controls, switches & jacks) as well as what players perceived as the most convenient range of sizes. 1U equipment is not all that popular, you put it in a rack and the rack depth needed to match up with the amp depth otherwise you couldn't get your had in there to connect and disconnect cables. That's why the smallest standard rack is 2U, which defeats the very feature of size (and weight) than many players request.

    If you need a different format, there are some amps/preamps that meet your requirements.
  3. Nobody much wants the horse for your course.
  4. Jeff Scott

    Jeff Scott Rickenbacker guru..........

    Apr 11, 2006
    Uh, really?

    Given just this bit of insight, none of the rest of your "rant" holds up, IMO.
    JMarkD and Aqualung60 like this.
  5. Fun Size Nick

    Fun Size Nick

    Feb 21, 2006
    London, UK
    It only matters if you want to use other rack gear along with the amp. If you don't (and it seems that a large proportion don't), then a flat amp with a big footprint is a less portable shape than a a slightly taller amp with a much smaller footprint. I have an Aguilar TH350 that fits in a gig bag pocket - that's a huge benefit for big city travel by rail & bus.

    Also, the Tone Hammer 500 & 700 amps do have an effects loop - it's only the TH350 that doesn't.
  6. In an age when many musicians are going ampless and use DI boxes, how an amp looks is even less important than it used to be. I never remember plugging into a backline and thinking "Wow, that rig looks great.", but I'd be impressed if it sounded good. For decades now we've had to deal with bulky black cabs, rat fur, confusing racks and sore backs. The idea of carrying a rig around the size of a toaster and a suitcase that has twice the power of an SVT is appealing to many, regardless of looks.
    leftyjohn, /\/\3phist0, CJL and 2 others like this.
  7. Wisebass


    Jan 12, 2017
    Lost in Space
    Hi cheechi :)

    Size matters! :D

    may the bass be with you

    Gaolee, birminghambass and JRA like this.
  8. I've got nothing for you other than the fact that I don't own a rack and don't really even know anybody that does. When I replaced my first head with my current one, my thinking wasn't about getting ears to fit a rack, it was the fact that I got literally twice the non-peak power at approximately half the weight. Cutting a few cubic inches in bulk was also a plus.

    Depending on the head, I also imagine that it's not all that hard to make some ears to fit a rack with a couple of hours and maybe a square foot of sheet metal.
    tradernick, Fun Size Nick and cheechi like this.
  9. JRA

    JRA my words = opinion Gold Supporting Member



    hey, i'd love it if i could just run out and get all the things i can imagine...

    that would be so cool.

    for me.

    Wisebass and JMacBass65 like this.
  10. I've only played the 350. I looked at photos of the back of the other two and totally missed that it's on the front. doh.

    Thank you all for correcting my error. Although it is clear nobody wants the standard to be 1U or 2U, It would still be nice if all of the small amps were the same physical size, and I do think the industry should have worked that out before the first wave were released.
    Fun Size Nick likes this.
  11. bucephylus

    bucephylus Supporting Member

    Aug 18, 2002
    Central Ohio
    FWIW, the Demeter amps are built in both configurations.

    Also, better designers, like @agedhorse / Mesa, do offer rackmount kits; even if they aren’t the physical configuration you want.

    You mentioned history, which has a lot to do with where we are now. The early micros were specifically designed for easy schlep; for example, in gig bags, as @Fun Size Nick mentioned.

    Now, the amps are getting more powerful, and capable of being used on larger backlines. I agree they look, ummm, unexpected on larger cabs. I gigged the Shuttle 9.0 on a Berg NV610 for a couple of years. Devastating rig. The Shuttle actually displaced a TE Hexavalve. The NV610, perhaps my fav all time cab, is reputed to be best matched with tubes. But, what I found is that cab LOVES power, plain and simple. The Hex sounded great on it. The tiny Shuttle 9.0 just took it up a notch. Yes, Class D Watts really are the same watts.

    My $0.019 derail on the Class D watts thing is that people are getting confused between watts and transient, perhaps burst, capability. In that latter case, the newer Class D modules are showing much better performance, to the extent that newer Class D amps can do the big backline. To your original point, there are ways to put the Class D amps in racks. You just need to look at the product field more broadly.
    cheechi likes this.
  12. fdeck

    fdeck Supporting Member Commercial User

    Mar 20, 2004
    Madison WI
    HPF Technology LLC
    The telephone relay rack has been replaced by the backpack as the standard for amp size. ;)
  13. Most ppl want the smallest lightest gear atm. The nice thing is if you want rack gear, you can probably find a quality rig for cheap. But it won’t be small and light.
    jamro217 and pie_man_25 like this.
  14. Stranger Danger

    Stranger Danger Feel Like A Stranger Supporting Member

    Jan 3, 2010
    Denver, CO
    Because it doesn't make sense trying to sell something very few people want. There are still options for people who want what you want but the great majority of bass players as evidenced by sales want small and lightweight Class D heads and thats what dominates the market. Sorry buddy.
    mcnach likes this.
  15. fdeck

    fdeck Supporting Member Commercial User

    Mar 20, 2004
    Madison WI
    HPF Technology LLC
    By the way, I certainly appreciate the problem.

    One thing about relay racks is that they were ubiquitous long before anybody made a bass amp. That means there would have been a ready supply of racks, mounting accessories, and pre-made chassis parts when demand emerged for installed sound systems and touring companies. Bass amps were all manner of sizes until bassists started using pro-sound power amps.

    So it's just a historical accident that the new micro heads didn't have a pre-existing format to grow into.
  16. mrjim123

    mrjim123 Supporting Member

    May 17, 2008
    Semi-retired picky player
    I worked in electronics manufacturing for decades and I know that development engineers already have to juggle a LOT of considerations (considerations you've probably never even though of) w/r to a product's package and the selection and placement of components within the package - EMI, radiated emissions, cooling, manufacturability, safety, I could go on (and note that these requirements are IN ADDITION to the base requirements). I've sat in countless meetings where even the most minute design detail is discussed week after week after week. Of course, all of this engineering labor really drives up development costs. The industry as a whole is not about to saddle itself with an additional requirement that would benefit so few but add to the product cost for everybody.

    In other words, it's far more complex than you would think to simply require that a product be a specific size and shape.
  17. nilorius

    nilorius Inactive

    Oct 27, 2016
    Riga - Latvia
    Today there the big size amp is the wourth thing, people need power, small size, light weight and good size and more possibilities.
  18. 19" wide is way too big to carry on my back with my bass.
    I would not buy one.

    I can not think of one that does not have a fan.
    Also the Aguilar and Darkglass you mention in your OP currently have a rear fan as does the all the Mesa Subway series amps.
    /\/\3phist0 likes this.
  19. Turbo Sparky

    Turbo Sparky Supporting Member

    May 14, 2018
    South Eastern U.S.
    M900: Non-rackable.
    19" will not fit into a typical bass gig bag pocket.
    GK makes several micro-bass amps that are 1U tall, with available rack ears, with full FX loops...and fans.
    2U shallow cases are cool, and there are these things called rack shelves and hook-n-pile (Velcro) fasteners.
    Should all SUVs be standardized also? Just one brand of cola?
    Freedom of choice.
  20. avvie


    Oct 12, 2010
    Maui, HI
    The entire point is to be lightweight, easy to carry and fit in a gig bag. You are NOT the target demographic.
    pie_man_25 likes this.