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10" Champ 600 extension cab - how small can the cab be?

Discussion in 'Amp Central Station' started by NoTeleBob, Feb 28, 2021.

  1. NoTeleBob

    NoTeleBob Tele-Holic

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    Per the subject, looking to build a little extension cab for my Champion 600 RI. This is mostly just as a "bedroom" amp, but I could see me using it to play out.

    I'd like to make it look like a miniature mini-stack. That would mean a cab for the 10" that would be about 12" square, 10" deep. Would that be utterly ridiculous with a 10"? Perhaps just too pressure baffled and unable to move the coil? Maybe OK if the cab is fully or partial open back?

    As an alternative, I could go with an 8" in the cab... the current combo 600 is sporting a Jensen Mod 8".

    Thoughts, comments, etc?
     
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  2. etype

    etype Tele-Afflicted

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    But you are using the original combo as the "head"? Or is there really an extension speaker jack? Gotta be careful with that output transformer.

    It's just me, but I'd go 2x12" or maybe 4x8", oh yeah!
     
    Last edited: Feb 28, 2021
  3. Dacious

    Dacious Poster Extraordinaire

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    If the cabinet is open back it just needs to be big enough to mount whichever speaker you install. If sealed, a little bigger.
     
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  4. Boreas

    Boreas Friend of Leo's Silver Supporter

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    I don't know why it wouldn't work as long as you use a 4 ohm speaker. I would leave the back 1/2 open or use a port. But get a speaker designed for an open back.

    I think I would just buy a bigger combo amp for gigging rather than carrying two small cabs.
     
    Last edited: Mar 1, 2021
  5. printer2

    printer2 Poster Extraordinaire

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    How about 14" x 12" x 8" ? That would be about the least I would go with a 10". It would be better if most of your dimensions are not too similar. 12 x 12 x 10, you get all the lengths roughly the same, might sound boxy. Also I would go with a thin sheet baffle across the top and bottom back making it a part open back. Or go with the 8" with 13" x 12" x 7 1/2". Same as the original Champ, although square rather than slanted. I'll be making a pair to sit the long direction up, on my desk. Not quite stereo, well not yet. I use 1"x 8" pine boards for the 8".
     
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  6. archetype

    archetype Fiend of Leo's

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    ^This. Size it for making it work and sound right. Not by how it looks with the 600. You want it to sound like a guitar amp and not a guitar amp in a box.
     
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  7. Jbnaxx

    Jbnaxx Tele-Meister

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    I would look at the dimensions of some good sounding 1x10 combos and work from there. A cab can be too small even if it’s open back. I have had some good results with 8” in a small closed back cab......but limited success with 10” and 12”. The bigger speakers will sound boxy if the cab is not correct.
     
  8. printer2

    printer2 Poster Extraordinaire

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    It all depends on the speaker. There is the 'Q' of the speaker. It is how high the response is at resonance. Open back speakers have larger Q's than closed back speakers so they can make the bass. Other speakers like a closed back cabinet and this raises the resonant frequency as well as the Q of the system (speaker plus cabinet plus amp). A solid state amp or tube amp with a lot of negative feedback has greater dampening and they dampen the Q of the speaker. You can split the difference and go between an open back cabinet and a closed back with some speakers. Looking at the speaker and how it has been used before is a reasonable guide. But if you repurpose speakers as I do from 40-70's hifi consoles you give your best guess. I built a box around a speaker in a tabletop radio as I thought the box too small and the bass would cancel out. After it was all made it was fine either way. It all depends.
     
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  9. Jbnaxx

    Jbnaxx Tele-Meister

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    I wish I had a better understanding of all of the speaker parameters. Every time I tried on of the T&S calculators, I get a huge box size.

    If there is a good reference, I would be interested in learning more.
     
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  10. Jbnaxx

    Jbnaxx Tele-Meister

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    I had a Champ 600 that I put in a combo cab sized the same as a SuperChamp XD with a 10” speaker. It didn’t really sound all that special.

    I think about the best bang for the Champ 600 was to put a more transparent grill cloth on it and a Weber replacement speaker and use it for what it is...... a neat little amp.
     
  11. teleman1

    teleman1 Friend of Leo's

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    I'd do two things. #1 get a Weber 6 ich to replace the stock speaker; ENTIRELY WORTH IT! Then go into manhood as I have. An 8" speaker cabinet, dovetailed. Great speakers around to choose. 17.5X 16 X11. OP, if you PM you cell, I will send a pic of it. Just a perfect size for an 8 ". I have 4- 1x8's, 1-1x10, & 1x12. THe bass is deeper than any other 1x8, especially being in a tight combo cabinet. Now you have the facts where real men go, and they go 8!
     
  12. mistermullens

    mistermullens Poster Extraordinaire

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    I have a C600 and I'd love a matching cab to do exactly what you had in mind. I'd love to see pics when you're finished with it.

    When these first came out, I had one, and found the stock speaker to be mediocre at best. I used to run it through a 1x10 Lopoline cab, I miss those guys, and it sounded great! I sold it years ago, but recently came across a good deal on one, and pulled the trigger. My feelings on the stock speaker remained, and I discovered that Eminence makes a hemp replacement speaker (620H). I like the Cannabis Rex, so I pulled the trigger. That, along with some new JJ Tubes, did wonders for the amp.

    I know, I'm rambling, but to your point, I run mine through a Blues Junior cab (no amp) with a C-Rex, and use it at practice. My rhythm section loves the tone with my Les Paul Jr and Casino. Yes, there is a speaker mismatch, but I haven't had any issues. A 1x10 is nice, and I"m even thinking of going 2x10.

    Something like this.
     
  13. NoTeleBob

    NoTeleBob Tele-Holic

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    Yea, that's what I'm afraid of. I guess I'll just experiment a bit.

    I've done that. The factory "cloth" is like a blanket over the speaker. I have a 8" Jensen Mod in there, JJ tubes... along with a real grill cloth. I bought it with the first two mods... but the third was huge.

    How about a tall/vertical 2x10 cab? (Just thinking that would look kuel... no idea how it would sound. That might be important).

    I may go the relatively matching route and see what it sounds like. I no longer have a shop, but I could punch out a test cabinet to see what it sounds like and make a better looking one if I like it.
     
  14. VintageSG

    VintageSG Friend of Leo's Ad Free Member

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  15. PhredE

    PhredE Tele-Afflicted

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    To OP: If you could identify which particular speaker is involved, we could help by pointing to online speaker calculators and similar resources, and, even lookup parameters and what might be suitable (or not).

    printer2's suggestions are good. If I go off target below, I hope someone can provide a reality-check, but here goes..

    In general, 'guitar' speakers typically don't have a strong 'preference' for being open or sealed box. Personal preferences drive that decision primarily, most individual drivers perform about as well one way or the other.

    Like printer2 said, first look at the Q -- especially the parameter listed normally as Qes. That is usually the best single parameter to judge whether a particular speaker will function best in a sealed or open box. Then, looking at the rest of the Theile-Small parameters can also be helpful in designing a good or even optimal box.

    Also, printer2 suggested to avoid making a box symmetric in any two dimensions: aka 12x12x10, or 11x9x9, etc. Don't do that (use 2 equal sides)! Use a geometry that every side is not the equal of any other: 13x11x9, 12x11x10, etc. Symmetric sides lend the interior to generating 'standing waves'. An open box can circumvent a certain proportion of the problem, but it's best just to design around it.

    For example, if you look at just about any speaker listed (especially non-guitar speakers) on Parts Express, they provide 2/3 sections about the speaker characteristics. Those *can* tell a lot about a speaker (in the absence of being able to hear it firsthand).

    PA Description for C-Rex (12", 8ohm):
    https://www.parts-express.com/Eminence-Patriot-Cannabis-Rex-12-Guitar-Speaker-8-Ohm-290-824

    PA Description for their PA-310 (8ohm) Pro Woofer:
    https://www.parts-express.com/Dayton-Audio-PA310-8-12-Pro-Woofer-295-032

    Notice that there is a LOT more info for the woofer (non-guitar) speaker.
    It can be tricky, but trying to dig up as much info as possible about a guitar speaker in question can be really helpful (but not always easy).

    Then, to kind of go full circle, the official online description of the C-Rex at Eminence (8ohm):
    https://www.eminence.com/pdf/Cannabis_Rex.pdf
    You'll notice more info, but still no Q parameter nor full set of Thiele-Small params.


    *some* online speaker calculators (no affiliation, just results from a quick Googling -- some I have used, others not so much):

    https://www.diyaudioandvideo.com/Calculator/SpeakerBoxEnclosure/

    http://www.mh-audio.nl/Calculators/ReflexBoxCalculator.html

    http://www.bcae1.com/

    (and others..)

    Edit: Forgot to say, that many smaller practice type amps can sound really good when paired up with a bigger/better speaker. The speaker in most practice type amps leaves a lot to be desired.
     
    Last edited: Mar 3, 2021
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