Power amps into surge protector/Conditioner or DIRECT to wall? Final verdict?

A whole house surge protector is nothing but a bunch of large MOVs put across the AC lines (and to ground which is also important). This is not a bad thing, this is a good thing. It will have no impact on the sound at all.  Schneider/Square-D, Eaton and any number of well known and reputable companies make these. They are relatively inexpensive, but there are larger and smaller ones. If you are in a lightning prone area, go for the big one. It is not going to survive a lightning strike right next to your house, but can survive one in the neighbourhood.

The good thing about putting one at the panel, is then you have the inductance of the AC wires from your panel to your equipment to soften the spike. I would like to think that any competent piece of audio equipment, especially really expensive equipment has some level of built in surge protection as well. The combination of the whole house and the in-equipment is likely to get you through most anything.

Simple power bars with simple surge protection will put more MOVs across the line. Being at your equipment, that is going to help even more. Some basic power bars add some inductance, which will help more, but that will add impedance to high current draw.  Some devices will go even further with larger inductance and circuits after the inductor and provide (in combination with your whole-house protector), protection for just about anything, but it does increase impedance between the AC line and your equipment. You can decide if there is any sonic impact of that or not.

First point, DO NOT CLICK erik_squires affiliate links, after he has fed you untrue information!

If you are interested in the Furman PST-8 that he promotes, this is the only link to use AFTER clearing your internet browser of cookies:

https://www.amazon.com/Furman-Aluminum-8-Outlet-Protection-Conditioning/dp/B000YYVLAK

If you don't know what an affiliate link is, or how it profits erik_squires to feed you lies, read the following post:

https://forum.audiogon.com/posts/1820850

Secondly, Furman SMP is NOT real series mode surge technology!

https://forum.audiogon.com/discussions/furman-smp-is-not-real-series-mode-surge-technology

Furman does not license series mode surge technology. They were sued by Zero Surge - the originators and license owner of the series mode technology patent - and lost. Furman was forced to call their technology SMP (Series Multi-Stage Protection), which still uses MOVs.

Real series mode surge protection does not use MOVs, because MOVs degrade with surges. This is the whole reason series mode surge technology was invented, to avoid the use of MOVs.

erik_squires:

Right. So the SMP is always on, there’s no activation lag. It also provides relatively low over-voltage protection. These may not be surges, but long lasting events. This can happen if your electric provider doesn’t balance the loads right.

This is not true! The part of SMP that is series mode surge technology is always on. However, this section is more limited in its capabilities with let-through voltages, compared to real series mode surge technology. The MOVs and EVS (Extreme Voltage Shutdown), other parts that makeup SMP (Series MULTI-STAGE Protection), have a delay before kicking in.

I just did a little bit of research sadono and I believe you have you facts wrong.

• SurgeX sued Furman for trade-mark infringement and false advertising. They did not sue them for patent infringement. They cannot legally use a term/logo like SMP (Series Mode Protection) which appears to be a trademarked term and false advertising likely because it implies a relationship to SurgeX, but I am guessing on that last part.
  

• The SurgeX site has a reference to their two original patents. They are from the 80's. 
  
• https://patentimages.storage.googleapis.com/12/92/3b/86aee532396c8d/US4870534.pdf   
  
• https://patentimages.storage.googleapis.com/d5/03/32/db000be262ff24/US4870528.pdf
  

Any protection from those would be long over. I looked on USPTO (patent database) and there are new ones, but they seem to add features or include a transformer in the circuit.

sadono,  Can you please describe what "real" series mode surge protection is?

The picture of the Furman unit here: https://www.furmanpower.com/series-multi-stage-protection-smp on the left (from the large inductor and over) seems to match what is described/drawn in the SurgeX patents I linked to from the 80’s. On the right appears to be some traditional MOVs, and probably some voltage detection to turn on/off the relay on the right side. The additional use of the MOVs is a good thing and probably makes the circuit on the left perform better.

sadono91 posts11-05-2019 11:18pm
This is not true! The part of SMP that is series mode surge technology is always on. However, this section is more limited in its capabilities with let-through voltages, compared to real series mode surge technology. The MOVs and EVS (Extreme Voltage Shutdown), other parts that makeup SMP (Series MULTI-STAGE Protection), have a delay before kicking in.