Adding more speaker binding posts and wiring for more than 1 speaker ohm out?

[currly30]

Is it possible to add more binding post to the amp? Could I technically add a binding post set for each of the ohm output that the amp can be wired for and have them all connected to there respective binding post? I would only be using one set at a time. I have a few different speakers that I am currently using with the amp and they are all different ohms. Right now I have the amp set to out put at 8ohms which is pretty much the middle resistance for the different speakers but would like to be-able to output at the optimal level for each speaker.

[Paul Joppa]

It's more complicated than you think. The secondary winding is in the form of two tapped windings, which are used in various combinations of series or parallel. This is to avoid the problem of best performance on the 16 ohm tap with deteriorating highs on lower- impedance settings.

You would have to make a switch circuit, using  two DPDT switches or one 4-pole 4-throw switch per channel. At one time, we had a circuit board  that mounted on tall standoffs just below the OPT transformer, for the OPT-2. But between slow sales, rapidly rising switch prices, and the clumsy of disconnectingpower and signal lines in order to turn the heavy amp upside down  to access the switches, it was discontinued. In hindsight, an external box would probably be more practical.

[hmbscott]

I implemented a switched speaker impedance set up on my Stereomour II thats documented in the Stereomour forum see the topic “Stereomour II mods”. I used two 4PDT switches. My wiring diagram is posted in the finial post of that thread. It works great and allows me to switch the speaker outs between 2, 4, 8 and 16 ohm.  I did build a custom chassis plate to enable me to mount the switch accessible from the top side of the chassis. I’m not sure if the Sereomour and Kaiju output transformers are the same, so my Stereomour wiring diagram might not be applicable to the Kaiju.

As Paul suggests, it would be impossible to add a second pair of binding posts and have fixed wiring such that the first pair is wired for 8 ohm and the second pair is wired for 4 ohm. Because, the transformer requires a different configuration of jumpers when wired for 4 vs 8 ohm. The only way to accomplish that required change in jumpers is with switching.

[currly30]

I implemented a switched speaker impedance set up on my Stereomour II thats documented in the Stereomour forum see the topic “Stereomour II mods”. I used two 4PDT switches. My wiring diagram is posted in the finial post of that thread. It works great and allows me to switch the speaker outs between 2, 4, 8 and 16 ohm.  I did build a custom chassis plate to enable me to mount the switch accessible from the top side of the chassis. I’m not sure if the Sereomour and Kaiju output transformers are the same, so my Stereomour wiring diagram might not be applicable to the Kaiju.

As Paul suggests, it would be impossible to add a second pair of binding posts and have fixed wiring such that the first pair is wired for 8 ohm and the second pair is wired for 4 ohm. Because, the transformer requires a different configuration of jumpers when wired for 4 vs 8 ohm. The only way to accomplish that required change in jumpers is with switching.

Wow, that is a very, very, impressive and beautiful build.

[currly30]

Interesting. I would, at a minimum, have to add 4 switch mounting holes to the top plate of the amp in order to set up an ohm switching option. Do you think hmbscotts 4PDT would work on the Kaiju?

I will have to check your diagram for your 4PDT switch set up for the Stereomour II and see if its wiring is similar to the Kaiju's outputs.

[Paul Joppa]

Th Kaiju OT-5 is slightly different from the Stereomour OT-2.

[hmbscott]

Interesting. I would, at a minimum, have to add 4 switch mounting holes to the top plate of the amp in order to set up an ohm switching option. Do you think hmbscotts 4PDT would work on the Kaiju?

I will have to check your diagram for your 4PDT switch set up for the Stereomour II and see if its wiring is similar to the Kaiju's outputs.

Thanks! But, I should have properly credited Paul Joppa with the speaker switching circuit I used.

[2wo]

You might try Wiring the amp for either 4 or 16 Whichever seems more appropriate for your speaker collection And give it a try. There is a good chance that you might only need 2 settings. Depending on the speaker it might be more about more efficient power transfer than real sound quality.
And sometimes they sound better on a different tap then what the label says. You can't hurt anything by trying