Valve amp head to cab question

Discussion in 'Ampage Area' started by Jockabilly, Apr 4, 2019.

  1. somebodyelseuk

    somebodyelseuk Country Gent

    Jan 22, 2013
    Birmingham, UK
    I expect your cab is wired thus -

    [​IMG]

    With the addition of a second jack and a switch, this would do the job, and youe 5 watt amp would only be having to drive one speaker.

    [​IMG]

    I'm hoping @markeebee will take a squint and confirm it'd be suitable.
    All you'd need to buy is a non-grounded jack socket, a DPDT switch and a bit of wire, with a rating high enough to handle the current. Total cost, not more than a tenner, I estimate.
     
    Jockabilly likes this.
  2. hcsterg

    hcsterg Country Gent

    Feb 13, 2012
    France
    Thanks Jockabilly ;) ! I even don't know because I do not count. It's certainly too high... My amps are only one-of-a-kind handmade with passion and I have no production at all for that reason. :oops:

    [​IMG]

    A+!
     
    new6659 likes this.
  3. Jockabilly

    Jockabilly Synchromatic

    Age:
    47
    593
    Sep 15, 2018
    Argyll
    It certainly looks like no expense has been spared in it's creation and you have a work of art there!
     
    hcsterg likes this.
  4. markeebee

    markeebee Country Gent

    Blimey, you're in trouble if you're relying on me :confused:

    Yeah, that'd work nicely. Or you could omit the switch and use the contacts of a standard 'Cliff' type jack socket......

    [​IMG]

    Positive of speaker C to terminal 1, positive of speaker A to terminal 2. Negative of speaker C to terminal 4, positive of speaker D to terminal 3.

    No plug inserted, 1&2 are connected together, as are 3&4, and effectively its the same as switch in 4x10 position.

    Plug inserted, the terminals disconnect and it's the same as switch in 1x10 position.

    Having said all that, I'm pretty sure it'll sound fine just running it as a 4x10.
     
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  5. somebodyelseuk

    somebodyelseuk Country Gent

    Jan 22, 2013
    Birmingham, UK
    Well, I remember you posting about some amps you'd built, so I figured you know what you're doing.
    That jack socket did occur to me, but wasn't sure what they're called or how to wire one. You've actually helped me solve a quandry of how to wire an extenion speaker for my Dad's amp.
    Cheers
     
  6. Jockabilly

    Jockabilly Synchromatic

    Age:
    47
    593
    Sep 15, 2018
    Argyll
    Afraid I haven't kept up with the thread but I have put my money down on this little 5W head and it should be here on Wednesday so I will know soon whether it will work. I am hoping it will be just fine but if it's not I may look at doing a little tinkering with my cab as advised above although I think I would be looking at only cutting two of the speakers out of the loop as the 5w head is actually sold as a package with two 10" cabs so I guess it must be able to drive that many speakers at least.
     
  7. somebodyelseuk

    somebodyelseuk Country Gent

    Jan 22, 2013
    Birmingham, UK
    Also doable, but you need to break in to different wires on the cab... essentially, you'd have to use two speakers in parallel plugged to the 4 ohm socket... from memory, you said it could run 4 or 8 ohms.

    [​IMG]
     
    Last edited: Apr 9, 2019
    Jockabilly likes this.
  8. Jockabilly

    Jockabilly Synchromatic

    Age:
    47
    593
    Sep 15, 2018
    Argyll
    Yes the amp has three outputs. One is marked as eight ohm and the other two are marked together as one x four ohms or two x eight ohms.
     
  9. Jockabilly

    Jockabilly Synchromatic

    Age:
    47
    593
    Sep 15, 2018
    Argyll
    Well I have to report that the 5W Subzero head arrived about 30 minutes ago and I am pleased to say that it drives my 4x10 cabinet without any problem at all. It is actually plenty loud for household use. Does have a little bit of hum but I have had Marshall's and Peavey's in the past that had louder hum. Not so many features as my 50Watt head with nothing but volume on the clean channel and gain, volume, treble and bass on the dirty channel but I can do everything else from my effects units so, overall I am relieved and happy with my £100 purchase :D
     
  10. somebodyelseuk

    somebodyelseuk Country Gent

    Jan 22, 2013
    Birmingham, UK
    That's groovy.
    No wiring or additional money spending required then? ;)
     
    Jockabilly likes this.
  11. Jockabilly

    Jockabilly Synchromatic

    Age:
    47
    593
    Sep 15, 2018
    Argyll
    Indeed not. The whole impedance matching and ability to drive speakers on the output of Valve amps is a bit of a mystery to me. I really need to find some literature and bone up on it. Strange that even the retailers whose brand it is couldn't tell me whether the head would drive my cab. You would think that they would know what their products are capable of in order to promote them and maximise sales.
     
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