Replaced Adcom GFA555Mk2 with XPA-1's

[bryanzim]

I've had a pair of Adcom GFA-555Mk2's in bridged mode driving a pair of Infinity Kappa-9's for quite some time(about 20 years). When my Sony ES-9000 preamp finally gave out in November, I upgraded to the Onkyo PR-SC5508 since I wanted HDMI switching and XLR outputs.

The Kappa-9 woofer's also decided to suffer from foam rot this year. So I replaced them with Eton 12-680/62 woofers. The difference being that the Eton's are wired in parallel and the Kappa Woofers used to be in series. I measured the produced spectrum and it was flat from about 35Hz-20KHz. So what was once about a 4 ohm speaker now is somewhere around 2-3 ohm.

But I digress. So I decided to take a plunge an upgrade the unbalanced Amps to balanced. After searching the web for quite a while I stumbled across Emotiva XPA-1's. I read the forums, reviews, and user manuals and only found nothing but positive things to say. So I ordered a pair.

Well, they arrived last Thursday evening. I brought them in(they weigh like a real amp) and let them sit till the next day. The upgrade went fairly smoothly except for having to make a new speaker cable for the wide posts.

And then I turned them on....

Now I've been quite pleased with the Adcom setup that I've had, but the XPA-1's just produce a more complete sound stage. The bass is fuller and tight and they don't sound colored at all just natural. The extra capacitance storage keeps the surges located at the unit and not through the wall socket(less lights dimming).

The other noticable item was the dead silence. The Adcom's always had a low hiss that you could hear when you got close to the speaker, but the XPA-1's were just quiet.

Even with the power hungry Kappa-9's I don't think I exceeded 5-6 lights on the meter when turning it up. In fact I'd say it was deceptively loud since the music was still crystal clear.

So far I'm quite pleased and well see how things progress over the 30 day trial period, but I highly doubt that I will be returning them.

Bryan Z.

[browe1967]

Cool. It's always good whne the new toys make you happy.

Welcome

[Deleted]

Feb 28, 2011 18:03:19 GMT -5 bryanzim said:

I've had a pair of Adcom GFA-555Mk2's in bridged mode driving a pair of Infinity Kappa-9's for quite some time(about 20 years). When my Sony ES-9000 preamp finally gave out in November, I upgraded to the Onkyo PR-SC5508 since I wanted HDMI switching and XLR outputs.

The Kappa-9 woofer's also decided to suffer from foam rot this year. So I replaced them with Eton 12-680/62 woofers. The difference being that the Eton's are wired in parallel and the Kappa Woofers used to be in series. I measured the produced spectrum and it was flat from about 35Hz-20KHz. So what was once about a 4 ohm speaker now is somewhere around 2-3 ohm.

But I digress. So I decided to take a plunge an upgrade the unbalanced Amps to balanced. After searching the web for quite a while I stumbled across Emotiva XPA-1's. I read the forums, reviews, and user manuals and only found nothing but positive things to say. So I ordered a pair.

Well, they arrived last Thursday evening. I brought them in(they weigh like a real amp) and let them sit till the next day. The upgrade went fairly smoothly except for having to make a new speaker cable for the wide posts.

And then I turned them on....

Now I've been quite pleased with the Adcom setup that I've had, but the XPA-1's just produce a more complete sound stage. The bass is fuller and tight and they don't sound colored at all just natural. The extra capacitance storage keeps the surges located at the unit and not through the wall socket(less lights dimming).

The other noticable item was the dead silence. The Adcom's always had a low hiss that you could hear when you got close to the speaker, but the XPA-1's were just quiet.

Even with the power hungry Kappa-9's I don't think I exceeded 5-6 lights on the meter when turning it up. In fact I'd say it was deceptively loud since the music was still crystal clear.

So far I'm quite pleased and well see how things progress over the 30 day trial period, but I highly doubt that I will be returning them.

Bryan Z.

;D

[mickeyharlow]

I doubt it too.

[denpuresound]

Feb 28, 2011 18:03:19 GMT -5 bryanzim said:

I've had a pair of Adcom GFA-555Mk2's in bridged mode driving a pair of Infinity Kappa-9's for quite some time(about 20 years). When my Sony ES-9000 preamp finally gave out in November, I upgraded to the Onkyo PR-SC5508 since I wanted HDMI switching and XLR outputs.

The Kappa-9 woofer's also decided to suffer from foam rot this year. So I replaced them with Eton 12-680/62 woofers. The difference being that the Eton's are wired in parallel and the Kappa Woofers used to be in series. I measured the produced spectrum and it was flat from about 35Hz-20KHz. So what was once about a 4 ohm speaker now is somewhere around 2-3 ohm.

But I digress. So I decided to take a plunge an upgrade the unbalanced Amps to balanced. After searching the web for quite a while I stumbled across Emotiva XPA-1's. I read the forums, reviews, and user manuals and only found nothing but positive things to say. So I ordered a pair.

Well, they arrived last Thursday evening. I brought them in(they weigh like a real amp) and let them sit till the next day. The upgrade went fairly smoothly except for having to make a new speaker cable for the wide posts.

And then I turned them on....

Now I've been quite pleased with the Adcom setup that I've had, but the XPA-1's just produce a more complete sound stage. The bass is fuller and tight and they don't sound colored at all just natural. The extra capacitance storage keeps the surges located at the unit and not through the wall socket(less lights dimming).

The other noticable item was the dead silence. The Adcom's always had a low hiss that you could hear when you got close to the speaker, but the XPA-1's were just quiet.

Even with the power hungry Kappa-9's I don't think I exceeded 5-6 lights on the meter when turning it up. In fact I'd say it was deceptively loud since the music was still crystal clear.

So far I'm quite pleased and well see how things progress over the 30 day trial period, but I highly doubt that I will be returning them.

Bryan Z.

Bryan,

Very nice indeed having two XPA-1's at 500W into 8 vs. my XPA-5 pushing 200W into 8.

I wonder what the sonic presence difference is with that extra headroom running MonoBlock's vs. the five channel amp in Stereo Mode?

Since I listen to mostly STEREO Mode here, would love to try two MonoBlocks vs. the -5, and see if I can hear and/or feel that extra power sonically speaking.

What is your feelings and/or experience on this matter?

DPS

[aboroth00]

I'm surprised those Adcoms held up so well in bridged mode. The K9's dip into 1-2ohms at two difference places and the bridged adcom must've seen a nasty 1ohm dip.

It's a good thing you got the XPA-1, those things put massive current into 2 ohms. No other Emotiva amp can. Glad you're happy with the upgrade. The only question is: are you running the K9's in extended mode? It'll drop the impedance to 1ohm.

Otherwise how are the polydomes and the polygraphs holding up? Shame the foam went, but you usually could it get refoamed for not too much.

[bryanzim]

aboroth00
I do run the Kappa-9's in extended mode. I just find it hard to give up all that extra bass. Although I did go through some fuses on those Adcom's from time to time. First time I blew them was on "Dark Side of the Moon"

The polydomes and the polygraphs are still in good shape. I did get a refoam kit but decided to update to the Eton since they had better power handling capability and are built like a tank. Very happy with the change.

I will probably keep the Kappa-9's for quite a while yet. Just a good sounding speaker.

DPS:

The bridged Adcom's produced 900W RMS into 4 Ohms supposedly while the Emotiva's are rated at 1000W RMS into 4 Ohms. So power wise they were about equal.

However, the Emotiva's just produce way more dynamic range than the Adcom's ever did. I think it is the large capacitance storage which allows them to respond to dyanmic transiets quickly and effortlessly.

So raw power is not the only factor in how good the system is going to sound. But IMO you can't have too much and I feel that to get the ultimate out of a system the monoblock is the way to go. I would have got 4 of them if I had the space to put them.

All:

After a couple more days the XPA-1's just seem to be breaking in some more and sounding better all the time. I'll have to report back after another week of listening.

Bryan Z

[aboroth00]

Very good to hear Bryan.

Without the power that you have, Im going to cross the K9's with a sub otherwise my amp would whimper and fry on the low end. I plan on horizontally biamping with some ATI amps.

Have you heard about the replacement drop in for the polydome? It's supposedly a marked improvement on the Infinity.

[bryanzim]

I've heard about the polydome replacement but never did find an exact model number. Do you know what it is?

[aboroth00]

It's right here: www.madisound.com/store/product_info.php?products_id=1088

The only problem I've heard of is a mismatch of impedances. I haven't verified this but you'll have to look this up. There are differing posts on this.

I'm trying to pick up a Kappa 7 with the replaced domes to see how they are.

[bryanzim]

A mismatch in impedance will cause a slight shift in the crossover point of the filter. Depending on how much, it may not even be noticeable.

The more important issue is whether the sensitivity is close enough to the original such that the adjustable rheostat in the back can be used to match it to the rest of the drivers.

If you do get a sample then post how they sound.

I did another speaker measurement today and found that they are reasonably flat from 40-20Khz. But there is some dipping in the 80-800 range. So I guess the Polygraph has developed some stiffness or maybe the dips have always been there. I'll wait until one of them goes before I do anything.

[bryanzim]

After a couple more weeks listening, I won't be returning the XPA-1's. I have heard sounds that I've never heard before in both movies and cd's because of the clarity. Just amazing.

However, I have had issues where the front panel lights turn all red during a really high impact scene with a lot of bass and then nothing comes out of the speaker. I have to power off and on the XPA-1 to get the sound to return. Anyone else seen this? What do the all red lights mean?

[Deleted]

Mar 19, 2011 15:42:29 GMT -5 bryanzim said:

However, I have had issues where the front panel lights turn all red during a really high impact scene with a lot of bass and then nothing comes out of the speaker. I have to power off and on the XPA-1 to get the sound to return. Anyone else seen this? What do the all red lights mean?

I have not yet experienced this phenomenon with my mono blocks. Red lights, I believe, means the amp went into protection mode.

[RightinLA]

Mar 19, 2011 15:42:29 GMT -5 bryanzim said:

After a couple more weeks listening, I won't be returning the XPA-1's. I have heard sounds that I've never heard before in both movies and cd's because of the clarity. Just amazing.

However, I have had issues where the front panel lights turn all red during a really high impact scene with a lot of bass and then nothing comes out of the speaker. I have to power off and on the XPA-1 to get the sound to return. Anyone else seen this? What do the all red lights mean?

What volume level are you using to drive the XPA-1's into overload? I can't imagine having my system that loud.

[bryanzim]

What volume level are you using to drive the XPA-1's into overload? I can't imagine having my system that loud.

Not really loud. It happens on scenes with a lot of LFE effects. The last time it happened was when I was watching "The Day After Tomorrow" when the tsunami washes up to the library. It's happened 4 times since I've installed the XPA-1's.

I guess it's the Kappa'9 impedance at the really low frequencies.

I have listened to really loud music without a problem.

[BillBauman]

Mar 19, 2011 21:34:06 GMT -5 bryanzim said:

What volume level are you using to drive the XPA-1's into overload? I can't imagine having my system that loud.

Not really loud. It happens on scenes with a lot of LFE effects. The last time it happened was when I was watching "The Day After Tomorrow" when the tsunami washes up to the library. It's happened 4 times since I've installed the XPA-1's.

I guess it's the Kappa'9 impedance at the really low frequencies.

I have listened to really loud music without a problem.

It sounds like something's not quite right here. What gauge is the new speaker cable you built for the XPA-1's? Also, since you have the equipment, and I'd be really curious to find out what happens, would you be willing to swap the XPA-2 and XPA-1's such that the XPA-2 is driving the front speakers, and if possible, then, use the old speaker cable that you were suing with the Adcom? This would help determine if this is really a pure amp power issue, or if there's something else going on. If it's just amp power, then the XPA-2 will go into protect mode, as well. If it's something else, then I would expect the issue to go away, and it's time to start looking for the cause of why the XPA-1's are going into protect mode.

[roadrunner]

Bryanzim

That is one of those Qs that I would want to run by Lonnie. About the only thing that occurs to me is something is appearing to present a dead short to the protection circuits... near zero impedance. The only condition that I have ever heard Lonnie mention driving the XPA-1 into protect mode is when the wall outlet reaches a point where it is not capable of providing the needed power which causes the rail voltage to sag and the protection circuits kick in to prevent damaging your speakers.

Basically, Lonnie has said that the XPA-1 is so robust you could drive a railroad spike with it. ;D ;D Seriously, do you have a dedicated circuit of at least 20 amps for powering the XPA-1s? What gauge wire was used to provide the dedicated circuit? Are you powering other equipment with the same circuit? And, as Bill B referred to, what gauge wire was used to connect the Kappas to the XPA-1?

I would call Lonnie and see what "Mr. Wizzard" thinks is happening.

[bryanzim]

What gauge is the new speaker cable you built for the XPA-1's?

I'm using 8 gauge welding wire speaker cable with soldered banana plugs on each end. So I don't think that there is a problem with the cable.

The only condition that I have ever heard Lonnie mention driving the XPA-1 into protect mode is when the wall outlet reaches a point where it is not capable of providing the needed power which causes the rail voltage to sag and the protection circuits kick in to prevent damaging your speakers.

Everything is run through my APC S-20 power conditioner because of the bad power where I live, i.e. brownout's and some surges. So I can believe that there may be a condition where the S-20 cannot supply all the needed current thereby resulting in a sag. When the protection occurs it happens with both XPA-1's and has included the XPA-2 also.

I guess I should look at multiple power conditioners run off different circuits as a future upgrade.

[aboroth00]

Hey Brian, if you haven't seen the K9's impedance curve here it is.



It dips to about .75ohms at about 35-40hz. It's a killer dip which is probably killing the XPA-1 into protect mode. Lonnie has stated that the amp will do 2ohms with no problems. Check out this thread: emotivalounge.proboards.com/index.cgi?board=ampfaqs&action=display&thread=15571.

So it seems like you may be possibly exceeding the capabilities of the outlet and not the amps. Maybe it's time to knock those things into "normal" rather than "extended." I would hate for you to damage those Emit K's on the K9's. I've heard the Emit K's on the K9's are more powerful than Emits on other speakers and it'd be hard to find a matched pair.


I'm not sure how the impedance curve looks after you changed out the woofers. By wiring the woofers in parallel I believe you're decreasing the resistance on the woofers making the require more current. How come you didn't just get them refoamed? The 12" Kappa woofers sound great and I wouldn't imagine replacing them with anything other than Kappa woofers.

My K9's are stock, but I don't push them as hard you are so *fingers crossed* no amp turns off in the near future. I would never really recommend a power conditioner, or anything to improve performance such as power cables, but RGPC makes some fine equipment that most people rave about.

How about some pics when you get a chance? How are those Polydome K's holding up? I would try visiting audiokarma.org on the Infinity forum. There a lot more Infinity Kappa owners over there who could help you. I believe there is a member there with the same setup.

[aboroth00]

Pic isn't really working, but here's the link: www.audiokarma.org/forums/attachment.php?attachmentid=57056&d=1186696256.

As for how you've changed the impedance, maybe you can produce an impedance curve and determine for yourself.