Question on BI amping?

[vintage 5.0]

I was wondering if you had two Dynaco ST 70 tube amps and you wanted to hook them both up to one set of speakers and run them in dual mono how would you do it?

 

[jaymanaa]

I'd probably experiment with using one in stereo mode for the woofers, and the other for the high drivers, 70s, lose a lot when you bridge them.:thumbsdn:

 

[Blitzen]

I think better to use one amp per speaker, with one channel on the highs and one on the lows. You'll be less likely to run into problems running out of steam from the higher power necessary for bass. Of course, a lot depends on your speaker efficiency...and listening volume.
I'm considering doing this as I have another ST70 waiting in the wings for refurbishing. Eventually I'll have to make up my mind if I really want to refurbish it exactly like the one being used, however.

 

[vintage 5.0]

I am using 4 ohm MB quart tower 3 way speaker. They seem fairly efficient to me. Thanks for any info that is why I love this site so many in the know.

 

[mashaffer]

To do it right IMO you will need to modify your crossovers so that you can drive the woofers straight (no crossover components at all in the woofer circuit and no connection to the other drivers) and the crossover to the mid and tweeter intact but separated from the woofer so the other amp channel can drive those correctly.

Then you need a line level crossover (either active or passive) after your preamp to split up the signal at the normal woofer crossover point. If you have enough gain the passive line level crossover is super cheap and the mods to your speaker are all subtractive (no new components except connectors) so is also cheap.

Just my two pence.

mike

 

[PakProtector]

I'd probably experiment with using one in stereo mode for the woofers, and the other for the high drivers, 70s, lose a lot when you bridge them.:thumbsdn:

Their 'bridge' switch actually puts them in parallel. Now if you feed the two channels a balanced signal; one plus the other minus, and hook a load up to both output transformers it works well. Try phase splitting with a UTC A-18.
cheers,
Douglas