Hammond 125D Hookup for ECL84 Tubes

[TIMBO]

Hi Guy's. Not sure what tabs to hookup the ECL84s to for a 8 and 4 ohm speaker, the only info i got is 15k:8ohm


http://www.hammondmfg.com/125.htm

I usually have 8 and 4ohm speaker connections in my builds, Also is the size of the speakers a problem to the small tubes as my speaker box has two 12" Mod 50's wired to 4 ohms. Thanks

[DummyLoad]

15000 : 4ohm use 1 & 3
12800 : 8ohm is close enough to 15000 so use 4 & 6

--DL

[TIMBO]

Thanks DL 

[TIMBO]

Thanks guys,got that part sorted but if i was to have only one 4ohm speaker jack that would be easy but if i have 1x 4ohm and 1x 8ohm jack do i need to ground tag 4 as i have grounded tag 1 as you would.  Any problems on the size of the speakers for these little TUBES ??? Thanks

[tubenit]

Any problems on the size of the speakers for these little TUBES ???

Not sure that I understand the question, but I run my SoLow Watt into one 8 ohm  Cannibis Rex  (Emminence speaker).

With respect, Tubenit

[DummyLoad]

if i have 1x 4ohm and 1x 8ohm jack do i need to ground tag 4 as i have grounded tag 1 as you would.

no, you use one pair or the other pair exclusively - not both, unless you use a switch - simplest method would use DPDT sw - a 2A toggle or rotary will work fine. you need only one jack. still two holes in chassis though. use a 4TDP rotary and wire up 2, 4, 8, & 15ohm.
 
           4ohm
         1 x   x 3
           |    |
 spk (-) x    x spk (+)
   
         4 x    x 6
            8ohm

--DL

[TIMBO]

Thanks DL, Tubenit, what i mean is does the actual size (8",10",12",15")speaker make the tubes work any harder to push the cone. Thanks

[birt]

Thanks DL, Tubenit, what i mean is does the actual size (8",10",12",15")speaker make the tubes work any harder to push the cone. Thanks

don't worry about that.

[PRR]

> make the tubes work any harder

Cathode-bias amps, the tubes "work harder" when _silent_. They take-in all the power they will ever put out, waste most of it, but divert some power to the load and run cooler.

> does the actual size

For a given acoustic level in the room, more/bigger speakers need _less_ power from the amp. Take a flea-watt amp. Connect it to a Full Stack (eight 10"s) and to a car door speaker. You can annoy the whole neighborhood with the Stack. Doing the same with the car speaker needs 10+ times the power.

[TIMBO]

Thanks guys