Dayton APA 150 mods?

I've been looking at this amp for possible mods
but I am stumped at the bridged configuration.

First there is a switch; but then you are to connect
the (+) left output to the (+) speaker and then the
(-) right output to the (-) speaker.

That just seems a little odd. . . .The right channel
must always be driven out of phase and the switch
just puts an input into both channels. Therefore the
(-) left output and the (+) right output are really the
ground reference.

I've never seen an amplifier labeled in this manner
but it would simplify some parts of the circuit design.

Anybody have further insight?
 
Carver made several amps with one channel inverting and the speaker posts as you described. It's OK for bridging, but not the best from a stereo standpoint. Carver later discontinued this practice.

Rockford Fosgate also did this on most of their amplifiers too.
 
Anyone experiment with these little guys?

Parts-Express.com: Dayton APA150 150W Power Amplifier | Power amp subwoofer amp class AB amp stereo amp APA150 mono amp home theater amp sub amp low pass home theater audiophile 150 watt 150W gifts1117

Can be had for almost nothing, just wondering if anyone has tried one out and has impressions of the sound and build quality...

If there is any half-decent parts in it is seems like a great modding candidate, and with the level control you could use it as a nice iPod system.

Any thoughts?

I have one, but I am out-of-town, so no pictures for a while.

It does have a toroidal transformer, but only a square tube for a heat sink. Both the sound quality and part quality is okay but not real inspiring. I am thinking of one day upgrading the input amp to see if that helps. Many people have had problems with the volume pot, so that should be upgraded, or replaced by a stepped attenuator.
 
I am stumped at the bridged configuration.

First there is a switch; but then you are to connect
the (+) left output to the (+) speaker and then the
(-) right output to the (-) speaker.

That just seems a little odd. . . .The right channel
must always be driven out of phase and the switch
just puts an input into both channels. Therefore the
(-) left output and the (+) right output are really the
ground reference.

Anybody have further insight?

This is the way virtually all bridgeable car amplifiers are set up. Having the speaker outputs arranged like this makes the phase correct when in stereo operation if the right channel is inverting all the time. Perhaps the switch lets it require only one input so that two amps can be used for left and right.
 
Founder of XSA-Labs
Joined 2012
Paid Member
I have this amp and it a nice amp for the price. I use it to drive a subwoofer so the built in low pass crossover (with adjustable frequency) is handy. I have tried it with my regular stereo speakers and it works quite well for most uses. If you look at the output on an FFT it’s not going to be as nice as one of my DIYA Class AB Amps that’s for sure. But for the price, it’s well built and feature packed. Very compact due to the on-demand air cooling. I am not going to mess with it - use it for what it is. Want a better amp? Make anyone of the myriad of offerings available. It’s tough to make a stereo 75w discrete output Class AB with toroidal trafo, heatsink, metal case, buttons, knobs, volume pot, RCA connectors, banana output connectors, IEC jack, fuse, power cord, indicator light, line-pass through, wake-from-sleep upon demand, and adjustable low pass XO - all for $130 with a 1 yr guarantee. :)
 
Last edited: