Hooking up sub with 4 ohm speakers and tube integrated

[EmperorNorton]

Hey folks
just a question.  I had a subwoofer taking the 8 ohm signal from both channels of the Primaluna and from the sub output terminals to the two Heresies.  Now I have the 4 OHM rated Cantons connected straight from the Primaluna.  To put the sub in the mix, can I just do the same as above, except running the positive wires from the left and right 4 Ohm terminal on the amp?

thx
Mike

[MacGeek]

Nice rig.

That should work assuming one speaker pair at a time from the amp to sub to speakers.

Let us know how it sounds and which combo you like better.

 

[EmperorNorton]

Thanks

Yes, will be going from L/R speaker outs on amp to L/R hi level ins on sub then from L/R hi level outs on sub to each speaker

[geoffr]

That

[scorpio333]

I do mine weird, but it works for me. Run cheap, thin, old wires from L/R speaker outputs to corresponding inputs on sub. Connect speakers as normal. I don't have 4 ohm speakers, but not sure that would make a difference.

[Sir Thrift-a-Lot]

Actually, if I am understanding you correctly, that hook up is using a passive xover in the sub.   If that is the case going with 4 ohm speakers will either give you one octave of overlap where the sub and sats both play or it will create a one octave hole where neither plays (an over simplification, but essentially correct).   I would suggest putting a 4 ohm resistor across the terminals of the satellites so that the xover in the sub "sees" 8 ohms.   Then they will play nicely together.   Use one of those heavy 20 watt ceramic jobs.   

Strike that.   That would be parallel and will take it further in the wrong direction.   You actually want to put the resistor in line with the positive speaker cable.   That would be series and will raise the resistance.   The problem there is that it will also decrease your output at the subs, so it may not be a good solution of your levels are fixed.

[MacGeek]

So that runs the speakers full range?

[Sir Thrift-a-Lot]

So that runs the speakers full range?

No, the speakers still run at whatever the sub's passive x-over is crossing them at.   However, if the resistance is different that what it is "looking for" that affects the frequency at which they cross.   Doubling or halfing resistance equals a one octave difference in a first order network.

[Sir Thrift-a-Lot]

I just reread the OP.   It looks like you are wanting to run the sub and the sats from the OPTs of the amp.   Is that correct?   If so, that sounds like a great way to melt some iron to me.   Tube amps are even much more finicky about proper loads than SS ones are.

If you hook an 8 ohm sub and 4 ohm sats to the amps output, it's going to "see" 2.66 ohms.   Check the specs on your Primaluna, but I strongly suspect they won't allow for that small of a load.

[EmperorNorton]

time to call primaluna

[Sir Thrift-a-Lot]

Does the Primaluna have an output for another amp (something after the volume pot)?   The easiest solution would be to run the speakers full range and run a powered sub.   Even then, you'll want to ask them about the 4 ohm load.

[Sir Thrift-a-Lot]

Which one do you have?   The 300 and 400 list a sub out on their spec sheets.

[EmperorNorton]

I have a Primaluna Dialogue Two.  It has no sub output   The sub I have is a powered sub but it was purchased used and not sure what brand it is as there are no brand markings.  Its a fairly hefty, small downward firing sub with a front port and the 8 inch woofer is covered by a metal grill, Also  It does have "power consumption 300W" underneath the power cord

[EmperorNorton]

Just a quick follow up from my email to Primaluna.    They advise connecting the  loudspeakers and the sub each directly to the amp, connecting the sub to the 8 ohm tap and the Cantons to the 4ohm tap. 

They cite REL article here. 
https://rel.net/how-to-connect-your-rel-to-a-tube-amplifier/