Help with a quick question re: Speakers?

[MarkDonMel]

Hi all, glad the board seems to be back up and running. 

A quick question, asking for help with my situation.  I don't have either of my multi-meters, they are buried in storage and unattainable.  The two speakers in the picture are in my combo amp cab (legend).  The aren't soldered or "hardwired" to the amp, they just plug and unplug into the back.  When I was shopping for the valve jr. I thought I would just unplug them from the back of my combo and plug them into the back of the vj, but I read warnings re: ohm values.  So, my question is, with my speakers wired like this, they are in series, correct?  If they are 15 ohm each, that equals 30 ohms?  Seems like a lot, but I don't know jack.  Which one of the jacks on the back of the vj should I use?

Also, I eventually plan on building a small cab for this amp with one or two 10 or 12 inch speakers.  Is there anything I should consider before choosing, arbitrarily, a certain ohm value speaker?  I was thinking of making a cab with like 2 10" 8 ohm speakers.  Is there any difference in sound or responsiveness with the different ohm values?  Thanks.

I'd really like to play this amp this evening, so if anyone can help I'd be most appreciative.

Thank you,  Matt.

[Ge_Whiz]

No, they are in parallel as shown. Impedance about 8 ohms.

[rockgardenlove]

Yep, use the 8 ohm tap.

[MarkDonMel]

Cool.

Even thought it equals 7.5 ohms?  I really am new to this... The instructions the came with the v jr. clearly say not to hook the amp up to speakers with a lower ohm than what the jack is rated for. 

Thanks. Matt.

[rockgardenlove]

Yep, that's right.  A small mismatch won't be an issue, it's fine.  I believe that the impedance of the transformer is a little high on the primary side anyways, so going a bit lower might actually be beneficial. 

[MarkDonMel]

Right on.  Thanks much, I really appreciate it!