[TrungT]

^^^^^
To me, the easy way to control the power of your amp is use power console, like Belkin PureAV or Monster console, they can remote turn on your amp by your receiver.

[topp]

I was hoping to make it more like a commercial amp and have the remote trigger on the amp.

Thanks,
Topp

[srb]

Back in February I asked Tom at Class D Audio if he might consider offering a 12V trigger module.  His reply was
 
"We are working on a sound activated power on, and a 12V trigger is a good idea so I will get one ready in the near future. We do have a 12V in +/- 50V out SMPS power supply with trigger, but that is mostly for auto and marine use."
 
I stated then that maybe half of his kit buyers might purchase it.  Maybe that was a bit optimistic, but 1 out of 3 probably isn't too far off the mark.  I guess the near future isn't quite here yet, but I still think it would be a popular and appreciated accessory offering.
 
Steve

[wgscott]

I still don't know what to do with the purple grid wire.

Tom verified it should be grounded (suggested to the chassis, which implicitly gets the ground from the mains).

[wgscott]

Has anyone installed an IR-activated remote-control relay for a power switch?  I'd really like to do this but haven't a clue how to go about it.

I recently found this thing on the interweb:
http://www.tauntek.com/tinyir2-learning-ir-remote-control-receiver.htm

It seems like the right thing, but maybe a bit advanced for me.  Also, I have no idea how to find a suitable relay and to hook the two up.

This question was along similar lines to the 12 volt trigger (which I would prefer, if I had something to supply the trigger).  Tom suggested this would work with the amp on/off switch, but not for the mains. 

I've also found for $50 an external trainable IR-activated 120V 15 amp on/off.  My power conditioner also has one, but I can't get it to work (but it might be replaced under warranty).

I guarantee there is a market for remote on/off.

[topp]

I did send an email to Tom asking his input.  He said the trigger should turn off the power to the transformer and not the switch on the board.  But I am not sure why, I was assuming so it completely cuts power and there is no power draw.  I originally thought just to have a 12 volt relay that closed the switch on the board.  However, I am not sure if the receiver's trigger output has enough current to keep the relay closed.  I thought I remember seeing someones amp that they made something to turn on and off the amp, but I can't seem to find it anymore.

Thanks,
Topp

[wgscott]

The face plates I ordered from Front Panel Express arrived today, so I put the panel on my Nova case to get an idea for how it will look when properly assembled (please ignore all the wires, etc).

[corndog71]

Ok, that is pretty damn cool!

[wgscott]

Thanks again for your advice and encouragement.  (I'll probably need more soon.)  Especially ditching the gain controls on the front.  I might put them on the bottom, or just replace them with resistors. 

[wgscott]

The ability to run two amp boards from the power supply, along with the extra space in the cabinet, compelled me to order a second amp board.

I figure I will start out passively bi-amping ("fool's bi-amping") until I figure out how to add an active crossover. 

Are there any good DIY active crossover kits?  I had a brief google search that came up with this:  http://www.audio-kits.com/page/page/4071180.htm

If I do this, I want to make sure what I get is good enough not to degrade the quality, and if I can cram it into the same cabinet, my wife might not even notice....

Then I guess I need to do a bit of speaker surgery to remove the passive crossovers.

[avionic]

http://www.minidsp.com/

[jtwrace]

avionic has posted probably the best idea for active.

I would recommend you read JohnR's very thorough review.

http://www.hifizine.com/2011/03/refining-a-4-way-open-baffle-speaker-minidsp-2x4/

[wgscott]

Thanks, both of you.  Those look incredibly helpful.  I'll read soon...

So, to make sure I am clear on the concept, I am taking my signal from my DAC via my pre-amp, then put it through the miniDSP, and then into the amps?  So it gets converted from digital to analogue, then back to digital, where it is processed, and then back to analogue a second time?  Wouldn't it be better to process the signal first, before sending it to a single DAC?

[jtwrace]

Thanks, both of you.  Those look incredibly helpful.  I'll read soon...

So, to make sure I am clear on the concept, I am taking my signal from my DAC via my pre-amp, then put it through the miniDSP, and then into the amps?  So it gets converted from digital to analogue, then back to digital, where it is processed, and then back to analogue a second time?  Wouldn't it be better to process the signal first, before sending it to a single DAC?

Source > DAC > PreAmp > DSP > amp(s) > speakers = 

[corndog71]

For the record there is nothing wrong with passive crossovers.  The best speakers I've heard had passive crossovers.  Going active can actually be more complicated. 

I'm not saying you shouldn't do it.  Just know it may not be as simple as it seems.

[jtwrace]

For the record there is nothing wrong with passive crossovers.  The best speakers I've heard had passive crossovers.  Going active can actually be more complicated. 

I'm not saying you shouldn't do it.  Just know it may not be as simple as it seems.

I don't think anyone said that there was something wrong with them...Yes, it is complicated and will take time and lots of effort. 

Back to Class D Audio...

[wgscott]

Source > DAC > PreAmp > DSP > amp(s) > speakers = 

Right, but isn't that glossing over what DSP stands for?  i.e.,

Source > DAC #1 > PreAmp > ADC #2 > DSP software > DAC #3 > amp(s) > speakers = 

[wgscott]

I don't think anyone said that there was something wrong with them...Yes, it is complicated and will take time and lots of effort. 

Back to Class D Audio...

I never left it.  I just got a second amp board in the mail today, and, in fact, I am re-soldering the old potentiometers and soldering the two new ones as I type, clearing my nose of carcinogenic fumes.

I suck at soldering.  I think the last time I did this I used Pb.

[JohnR]

Right, but isn't that glossing over what DSP stands for?  i.e.,

Source > DAC #1 > PreAmp > ADC #2 > DSP software > DAC #3 > amp(s) > speakers = 

Not necessarily a The ADC and DAC are tightly coupled so you don't get jitter errors between them.

Or, get a digital I/O card for the miniDSP (or whichever crossover you use)

[wgscott]

Well, it will be awhile before my wallet recovers anyway, so I can spend some time reading up on the options.

Meanwhile, I need to tidy up what I have so far, which is now a SDS-254 vertical bi-amp.

The wiring is a bit of a mess, so I think I might need to re-do it from scratch.  The case is fairly crammed now.

[revised]I had a bit of a low-volume buzz sound from one amp board, but it turned out the ground wire between it and the power supply came loose.

Would housing the toroid and power supply in a separate (metal) box improve signal/noise at all?  I assume tidying the wiring and double-checking all the connections could only help.   

Also, I get an audible pop in the speakers when each of the two amps powers up.  Is this normal?