Grounded Bridge amp, Eagle 7

hi everyone, im fascinated with this amp design posted by sumaudioguy, this is the electron kinetics eagle 7 power amplifier, just a quick questions to the experts here, is it possible to diy this thing? how difficult to balance the high and low sides of the bridge?, this is similar to crown/amcron macrotech and microtech series, i like the benefits of these designs like single filter cap, single winding on transformer, full utilization of the power supply, and low stress output stage, most of all is awesome bass response. thanks in advance
 

Attachments

  • E-7-2-schem.jpg
    E-7-2-schem.jpg
    386 KB · Views: 1,431
  • e7a_lg.jpg
    e7a_lg.jpg
    333.8 KB · Views: 1,200

wg_ski

Member
2007-10-10 5:21 pm
In principle, it's similar to the macrotechs, but this uses all-discrete error amps. The Crowns use op amps for high and low side error amps, and for the common mode amp. It's not difficult to "balance", feedback forces balance between the high and low sides.

Duplicating the "awesome bass" may not be as straightforward. The power supply looks like a phase-controlled regulated one (using Q40). It's similar to what they used to use in the old HP lab supplies for the pre-regulators before they went switchmode. It's really old school, and not something you see often in audio amps. You may or may not be able to use just any old transformer with those. Of course, you could just use an oversized toroid with good regulation. You would get a good, but not necessarily the same, result.
 
In principle, it's similar to the macrotechs, but this uses all-discrete error amps. The Crowns use op amps for high and low side error amps, and for the common mode amp. It's not difficult to "balance", feedback forces balance between the high and low sides.

Duplicating the "awesome bass" may not be as straightforward. The power supply looks like a phase-controlled regulated one (using Q40). It's similar to what they used to use in the old HP lab supplies for the pre-regulators before they went switchmode. It's really old school, and not something you see often in audio amps. You may or may not be able to use just any old transformer with those. Of course, you could just use an oversized toroid with good regulation. You would get a good, but not necessarily the same, result.

Ive read somewhere that theres a factory modification to upgrade this amp, they remove those regulator circuits (Q40), it may be possible that the grounded bridge designs have greater control on woofers due to push pull action on both sides of bridge?, Electrovoice P3000 is also ground bridge design and great for subs... Thanks
 

wg_ski

Member
2007-10-10 5:21 pm
A bridged (grounded or otherwise) amplifier has no better "control" than an equivalent conventional one. It's all on the power supply. The stouter the better for subwoofer apps especially. The subjective bass quality in my experience has to do with how much (or little) it clips in operation at the desired output levels, and more importantly, how bad (or good) its behavior is when it does clip. The better the supply regulation, the better it does at both. Remember, that sub amps *will* be driven to at least occasional clipping, and when you do clip it runs *open loop* with Zout set by the power supply. The amplifier circuit topology is seldom the limiting factor.