Champ output transformer output

[Oddvar]

I am building a champ amp, and I have an OT that has 4/8/16 ohms outputs, but I only need the 8 ohm. Is it ok to connect only one lead and leave the others not connected?

[terminalgs]

Is it ok to connect only one lead and leave the others not connected?

Yes


Tape them up/insulate them

[kagliostro]

Yes ..... but may be no

it depends on the OT you have

Franco

[drgonzonm]

Yes ..... but may be no

it depends on the OT you have

Franco

could you please give an example. 

[HotBluePlates]

could you please give an example.

Some Hammond OT's have multiple secondary windings, and proper interconnection of all windings provided gives the best performance from these transformers, even when only part of a single winding could match the load.

Granted, the OP almost certainly doesn't have one of these.

[HotBluePlates]

I am building a champ amp, and I have an OT that has 4/8/16 ohms outputs, but I only need the 8 ohm. Is it ok to connect only one lead and leave the others not connected?

Yes, but No (for different reasons than Kagliostro probably meant):

Whether you're building a 5F1 tweed Champ or an AA764 blackface Champ, there exists a feedback loop with parts values suited for the original secondary impedance.

Since you'll be using an 8Ω speaker and not 4Ω, connect that 8Ω tap to the speaker jack.  But modify the connection of that series feedback resistor to connect to your 4Ω tap (in whatever manner is most convenient in your build).  Then insulate the end of the 16Ω tap and tuck it away.

Even though you're only drawing power from the 8Ω secondary tap, the 4Ω tap will have the same voltage present as though it were the only tap on the OT and your speaker was connected there.  It will then also deliver the designed-amount of feedback voltage into your feedback loop.

If you were to otherwise wire up the amp per the layout, but using only your 8Ω tap, you'd have √2-times the designed-amount of feedback voltage going into your loop.

[2deaf]

I am building a champ amp, and I have an OT that has 4/8/16 ohms outputs, but I only need the 8 ohm. Is it ok to connect only one lead and leave the others not connected?

What exactly is this transformer?  Is it for single-ended use?  What is the nominal primary impedance?

[kagliostro]

could you please give an example.

Replay #4 confirmed

Franco

[Oddvar]

Hi and thanks.  I am using the Hammond 1760c.  The reason is that I only have 8 ohm 10 inch speakers to use,  and a small old Pro junior cabinet.  The chassis, 5f1, is very small and doesn't allow for more jackoutputs, I could maybe get on extra inn, but cramped.

[kagliostro]

OK, I understand

follow HBP replay #5 and you are fine

Franco