Adcom GFA 555 II With Niles HPS-4 Speaker Selector for Protection

pongshi

I have an Adcom 555 II amp on the way as a replacment/backup for my current Hafler DH-500 which is being used to drive my Polk SDA SRS speakers. I currently have my Hafler routed through my Niles HPS-4 speaker selector. The Niles HPS-4 has built in speaker protection and can handle up to 250 watts per channel. I basically just use the switch to switch between my Polks and the other set of speakers, and I never run them both at the same time.

I have heard a few of the horror stories of the Adcom GFA 555 and 555 II frying speakers due to the lack of speaker protection, but it seems like a great amp for its price. Would the HPS-4 serve as a viable speaker protector from this issue? I sincerely hope I didn't make a mistake since I have already ordered the amp.
Thanks

boston1450

I had the GFA555 hooked to my SDA2b's & it was a perfect match. Never used other speakers while hooked to it-or used a Niles. Although ive read others have used them. Maybe they will chime in. Enjoy your new amp

pongshi

Glad you like your GFA 555. I almost bought one instead of the 555 II. It seems there are a lot of folks who have run GFA 555 and 555 II that have had zero issues and like this amp (like yourself). I hope for the same. Though I realize it is a rare occurrence, I am just wondering if my speaker selector provides any protection against the DC surge that I have heard sometimes kills speakers with this unit. It is not real clear to me if the niles would protect my speakers against this type of failure with the GFA 555 or 555 II. Thanks

MrBuhl

I do not have the Adcom, but I do run the Niles in my garage setup with a H/K receiver so I can switch between deck and garage speaks. I believe the Niles is a complete pass-through unit, and would provide little to no protection.

MrBuhl

Hmm... a quick look at the Googles, and it appears there is a protection circuit designed to keep your amp from overloading, I can't say if it also protects your speakers in some way. See attached snip from the owners manual:

tonyb

The best protection in my book is control of that pesky volume knob.

xjghost

tonyb wrote: »

The best protection in my book is control of that pesky volume knob.

Yea tell me about it.......

pongshi

I am listening to my new arrival... The Adcom GFA 555 II simply walks all over my Hafler DH-500. Though my Hafler is a good amp, it just does not have the clarity of the Adcom. The Adcom is in the livingroom. The Hafler is now in the bedroom. Yes, I am running it hooked up to Niles HPS-4 speaker selector switch.

gudnoyez

Glad your liking it, got a 555 II myself pushing a pair of 2B's, I have 3 Adcoms, happy with all of them.

xjghost

pongshi wrote: »

I am listening to my new arrival... The Adcom GFA 555 II simply walks all over my Hafler DH-500. Though my Hafler is a good amp, it just does not have the clarity of the Adcom. The Adcom is in the livingroom. The Hafler is now in the bedroom. Yes, I am running it hooked up to Niles HPS-4 speaker selector switch.

I got one from a pawn shop for $100 but it sounded distorted. I have it in the shop now having them check it out. I am running my 3.1's with a hafler 500 right now and I really like it. Cannot wait to get it back.

pongshi

If your Adcom sounds distorted and your Hafler doesn't, there must be an issue with the Adcom. I find my Adcom has much more clarity in the mid and high ranges than my hafler. I can't really tell which amp has the advantage in the low frequencies yet. They seem to be pretty close there. Both my Hafler and the Adcom are stock. I am sure either one could be exceptional with modifications.

leftwinger57

I also run a series 1 GFA 555 and it is also hooked up w/ a Niles SP-6 speaker selector that also has protection switch. I only once ran all my sets at the same time and nothing happened not a thermal L.E.D light came on or any distortion w/ any of my speakers. Of course I do not do that as a practice and as some here have said adding a selector only introduces noise downstream. Well nuts to that, there is not one bit of difference when I ran my sets seprately or through the selector. Clear out those golden ears of yours.... ( not to anyone specific)

pongshi

Leftwinger57,
I don't run both sets of speakers at the same time though I have tried it for a couple of minutes and everything seemed to be okay. The image gets a bit lost running all 4 speakers at the same time and 2 channel turns into surround sound. I do not notice the sound degraded at all with just one set of speakers running. I am not sure about the sound being degraded with multiple sets because it is hard to listen critcally with all 4 going and I don't want to tax my equipment.

leftwinger57

Ponghi, getting back better later than not at all. I have to agree w/ the term clarity when talking about Adcom series 1 555. Some say it's bright I haven't heard that many other ss amps to say it's bright or neutral but what I can say that it comes no where near it's 200 wpc potential which is what I always wanted, An amp that has enough power to push any speaker set I could afford and not clip or over heat or go into some protection mode if it has one. Since no gain controls all work is done through the NAD 1020a pre which is uber sensitive, opens up the SDAs sound stage and if it's bright that can be adjusted through the pre. I do not have to do much except be very careful w/ the volume control, a tad to much over 9:00 pos the walls or what's on them do start to shake a bit. Again I never run multiple sets at the same time but do change off for variety depending on the mood, source or just haven't heard that set in a while. Doing all 4/5 sets in one 18'x 15' living room is nutty.

heiney9

Nothing in the Niles switcher will protect your speakers when DC is present. When people talk about the rare instance and amp "takes out a speaker" there is DC present. Unless of course you are worried about overdriving the amp, causing it to distort and then clip the signal frying the voice coil................still the Niles won't help with that either.

Get rid of it if you can, it's just something else adding noise in the signal chain.

H9