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Crate Powerblock Mod

Discussion in 'Amps and Cabs [BG]' started by SheaNC, Jul 14, 2014.


  1. SheaNC

    SheaNC

    Jun 15, 2006
    Marysville CA
    I have a Crate Powerblock which works great; it's an old friend. But, I want to modify the tone stack so it's better suited for bass. Right now the 3-band eq is: 110Hz/1kHz/10kHz. I want to change it to something like, 40Hz/600Hz/5kHz, which my ear is more accustomed to as a bass amp.

    Now, some people are thinking, "Dude, just stick this-or-that box or eq in front of it and use that." But I have a method to my madness. Specifically, I want to keep the unit completely self-contained, and I really love the overdrive it creates with the onboard preamp. All it needs is more useable tone controls.

    Besides... It's paid for.

    Additionally, if the speaker sim could be permanently bypassed, that would be great.

    So my question is, can this be done? How hard is it? (I'm not an amp tech but I have tinkered). Is there someone who could do it for me?

    If this mod is impossible, I will sell this little guy because I just don't use it anymore. But, I am hoping there is a genius in the TB community who can help :)
     
    Last edited: Jul 14, 2014
  2. basscooker

    basscooker Commercial User

    Apr 11, 2010
    cincy ky
    Owner, ChopShopAmps
    Oh, I'm watching. I have one that sits on top of one of my columns in my avatar. I put a GEB-7 in front of it, dial in a bit of grit on the amp, and it rawks. (well as much as a 150 watter can) I'd love to scoot the amp's eq down the spectrum a bit and loose the pedal.
     
    SheaNC likes this.
  3. Passinwind

    Passinwind I know nothing. Commercial User

    Dec 3, 2003
    Columbia River Gorge, WA.
    Owner/Designer &Toaster Tech Passinwind Electronics
    I found a schematic via Google -- looks like a Fender tone stack variant for bass and mids, and a pretty straightforward separate treble control circuit. A tech who's up to speed on surface mount work may just be able to make it happen, assuming caps of the same physical size are available in the needed values.

    Not positive at first glance which part is the speaker sim, but any decent tech who's willing to take this on can probably figure that out on their own anyway. Whether any of this will actually sound good and/or be reliable is way beyond my crystal ball gazing powers though...[​IMG]
     
  4. fdeck

    fdeck Supporting Member Commercial User

    Mar 20, 2004
    Madison WI
    HPF Technology LLC
    I agree with Charlie. If the schematic is available, it won't be a difficult mod for a tech to change the capacitors in proportion to the frequency changes desired. As for disabling the speaker sim, it's probably some kind of Sallen-Key low pass filter (hint hint) and can be disabled just by removing the caps.
     
  5. seamonkey

    seamonkey

    Aug 6, 2004
  6. spankdaplank

    spankdaplank

    Jan 19, 2003
    Philippines
    Calling Doctor Frankenstein, you are wanted in surgery... Dang, I don't have my Powerblock anymore. This sounds like it could be fun.
     
  7. coughiefiend

    coughiefiend

    Nov 12, 2013
    Virginia
    Definitely watching this one. I sold my PB a while back, but keep thinking about picking up another.
     
  8. basscooker

    basscooker Commercial User

    Apr 11, 2010
    cincy ky
    Owner, ChopShopAmps
    I have wondered why they stopped making them. Mine has been flawless. Not one hiccup, sounds alright with bass, and better than expected for guitar. I can't remember if it takes a boost pedal or if there's a way to go from clean to crunch, but my guitar has a volume knob that I know how to use, so...
    Maybe I'll look into this mod myself. My friend got one he never uses anymore, maybe he'll let me have it cheap. GC blew them out at $99 and when they turn up used, they usually stay above $1oo, sometimes even $150.
     
  9. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    I really dig my Power Block...for guitar.
     
  10. Passinwind

    Passinwind I know nothing. Commercial User

    Dec 3, 2003
    Columbia River Gorge, WA.
    Owner/Designer &Toaster Tech Passinwind Electronics
    Pretty sure Jerrold Tiers either had a hand in the design or was at least working at SLM when that amp was in production, someone might want to ping him.
     
  11. SheaNC

    SheaNC

    Jun 15, 2006
    Marysville CA
    When I got mine, one of the last selling at $99, it was a cheap replacement for a Crate combo amp that sucked. The amp in the combo sucked, but the cabinet was (is) actually not bad, so I used the Powerblock with that. Not a proper bass amp, but served me well at the time, and the tubey-sounding overdrive is perfect for my Entwistle-itis. Lots of other bass players online praised their usefulness, too. I eventually got a "real" bass amp, but I still keep thinking how cool this thing would be with this modification.
     
  12. lowend1

    lowend1

    Feb 15, 2005
    I picked up mine at GC on closeout for $69. It is not a critical ingredient in my tone, but it accompanies me to every gig, and has become something of a Swiss Army Knife. It can serve as a guitar amp, bass amp (with outboard preamp or EQ), or even an emergency PA/monitor amp. I would advise against modding one in the manner described - that will limit its versatility.
     
  13. fdeck

    fdeck Supporting Member Commercial User

    Mar 20, 2004
    Madison WI
    HPF Technology LLC
    I had a Power Block that unfortunately had to go back because it developed a weird distortion even at low volume levels. I e-mailed Crate and told them that I'd love to see a bass-centric version. Internally, the design seemed well thought out from thermal and mechanical standpoint, with the finned enclosure serving as a heat sink. Now it's just my opinion that the feature and connectivity choices were too weird for widespread bass use. It seemed like one of those products that tried to be all things to all people: A guitar amp, bass amp, and stereo amp.

    There can be some things that happen behind the scenes that kill a product, such as unexpected cost-of-goods issues, or discovering that one product makes it harder to sell other products in the line.
     
  14. basscooker

    basscooker Commercial User

    Apr 11, 2010
    cincy ky
    Owner, ChopShopAmps
    I'll +1 the connections are weird. To a noob, the single output for mono use only and two outputs for stereo only can be confusing. My gui**** still to this day doesn't get it.
     
  15. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    Pretty sure it wasn't thought of as a bass amp by SLM ;) There's very little low end, not enough for bass as far as I'm concerned. I used to run a VT pedal into the fx return for a rainy day rig for a couple months, and it sounded good for bass that way, but the preamp is only suitable for guitar. I don't know...it's a weird little amp, but it's kind of cool.
     
  16. Thundar

    Thundar Living in sin at the Holiday Inn

    I actually did a few tracks in a lil podunk studio once and the bass amp there in the studio was a Powerblock with a Hartke 115XL....and I'll be damned if it didnt sound really good! I used my TBC Jazz bass with its 3 band preamp, and it held the low end nicely and plenty loud...just my two cents worth there. :bassist:
     
  17. SheaNC

    SheaNC

    Jun 15, 2006
    Marysville CA
    Along with all these other things, that blue light on the front is so bright it can light up a room if you run out of light bulbs.
     
  18. SheaNC

    SheaNC

    Jun 15, 2006
    Marysville CA
    Gosh... I need to decide what to do with this because 1) I need money and I should sell the Powerblock; 2) I would love to see the end result of this modification. I understand lowend1's point about messing with it and limiting it's versatility. But, still...
     
  19. gleneg61

    gleneg61

    Jan 10, 2008
    Osaka Japan
    I don't see the relevance of its versatility 2 u unless you're also a guitarist n run ur own PA; if ur a bassist most the time, n it's affordable n possible 2 re-rig it, do it I say. If u wanna on sell it later, there'll b plenty of bassists on TB 2 take it off ur hands. My 2c
     
  20. SheaNC

    SheaNC

    Jun 15, 2006
    Marysville CA
    Since I am no longer gigging, it would basically be a really cool little home-use amp.
     

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