I made a dozen amps in 2019 using the IcePower IecEdge 1200AS1 mono amp modules.  I spend months tweaking the module to make is sound way, way better than stock.  I can do these same mods to the PS Audio amps or any other amps that use these IceEdge modules.  It is easier to do the mods on mono amps but it can be done on the stereo module as well.

The PS Audio 1200 mono blocks are very good amps.  They take the IceEdge modules and remove the coupling caps and  47K resistors that are no longer needed (because of the added tube input stage)....and then add a tube buffer and there you go.  A good amp.  However, they don't do any serious mods to the IceEdge modules, the AC power supply inlet, etc. and the binding post system are not good.  The IceEdge module already has 27db of gain.  It does not need an input stage.  If you add an input stage, you are just adding that sound.  However, since PS Audio does not  tweak the IceEdge module then some distortions need to be masked via using a good tube buffer....this makes sense.  However, even better is to remove the distortions from the module and then you don't need a tube buffer and you get better sound for way less (modded Rouge or Apollon amp).  If you want a little tube sound then adding a tube line stage or DAC makes more sense.  I do not remove the tube input stage on my mods to the PS Audio 1200 amps. 

But if you really like your PS Audio amp then your are going to LOVE it modified.  Everything will be better.  However, if you want this level of sound and don't want to spend $6600 then modding a Rouge dual mono stereo amp will blow you mind for way less.

You can buy a dual mono stereo IceEdge amp from Rouge Audio Design for about $1550 delivered to the US.  These are the exact same modules that PS Audo uses.  The input impedance of the modded amp would be 150K per phase.....real easy to drive.....higher input impedance gives better sound.

Legacy Audio is also selling a dual mono stock IceEdge amp for $4785.......if you own one of these I can mod that too.  However, the Rouge Audio Design is exactly the same thing for $3200 less.

You can also buy a stereo IceEdge 1200AS amp from Nord, Apollon or Rouge for around $1200.  There are used stereo IceEdge amps on the market from time to time (Mivera brand and others) that can be purchased for $800 or less.  Lots of options.

A modified IceEdge module gets you 600 watts a channel into 8 ohms and 1200 watts a channel into 4 ....this is a ton of power.
Some speakers crave this kind of power.

 

Pricing:  
Mods to a stereo amp using one AS1200 module would be $500.  This would include WBT output connectors.  If you already have WBT connectors then the price would be $350.  A four channel amp (like the Apollon 2400 that has two AS1200 modules and four outputs) would be $950.....or $650 if you already have WBT connectors.  Mono blocks add $100.

All prices plus return shipping