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#286272 - 01/10/10 02:47 PM EP350 problem and Axiom's solution
Ken.C Offline
shareholder in the making

Registered: 05/03/03
Posts: 18044
Loc: NoVA
I've mentioned this in passing before, but my EP350v3 has had a rather odd problem. At relatively low volumes, it didn't properly reproduce bass, until it had been triggered on by higher volume. If I stuck my ear up against it, I could hear that it was making a static-y approximation of the input signal, an octave or two above where it should be, and certainly with no bass whatsoever. I variously thought that the problem was caused by the auto-on circuit, my receiver, the cable, etc., but narrowed it down to happening only when the sub had first been powered on and then fed a low volume signal. If I pumped up the volume to the point that the sub really came on, then turned it back down again, it worked for the rest of the listening session.

I originally described it to Axiom as a squeak, so they shipped me a box and had me send it in. They tightened seals, etc, and sent it back to me. Unfortunately, when they sent it back, the problem was still there. They were fairly convinced it was a mechanical issue--I assume because they hadn't been able to reproduce the problem. I'm guessing Axiom tests stuff at a higher volume than I often use. ;\)

In any case, I exchanged a few more emails with JC, and finally realized I could record the sound with my iPhone (of all things). I sent along a couple of clips (which you can hear here and here). The first clip was just the static-y sound. In the second (ignoring hte bits where I touched the grill cloth accidentally), I'm turning up the volume and the sub transitioned into producing real bass about halfway through. Listen to these clips on headphones or on decent speakers--laptop speakers don't tell you anything.

The next email I got back said that they were going to ship me a new amp design to try out. Cool! A couple of weeks later, I received a very, very large package. It was... a whole new EP350. I had kind of wondered why JC asked what finish my sub was in...

Unfortunately, while the new sub solved the first problem, it had a pretty bad hum. I told JC (starting to feel pretty rotten about bugging them about this in the first place...), and he said that they would send me a new replacement amp, which they did. I switched out the amps and found out why they sent me a whole new sub--the new amps aren't the same physical shape as the old ones, at all. Here's a few shots of the new amp, inside and out.




Outside




Inside




The case, sans the amp--notice how the amp compartment is sealed now?




The new amp and the newer amp, side by side


As you can see, Ian and crew have made the same change as far as input connectors on this amp as on the new EP800 amp. I had to do a little 1/4" jack swapping before the newest one started working, but it's been solid since then. No hum, no static, just niiice bass. I'm guessing they've gone to a class D design as well.

Thanks to JC, Ian, and Peter for all the work they did on this and for their patience.
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#286274 - 01/10/10 02:53 PM Re: EP350 problem and Axiom's solution [Re: Ken.C]
CV Offline
Founder, Axiom Upgrade Club
shareholder in the making

Registered: 07/20/06
Posts: 11709
Loc: Richland, WA, USA
Pretty pictures. I'm glad your issue was resolved. Another win for Axiom.

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#286275 - 01/10/10 02:53 PM Re: EP350 problem and Axiom's solution [Re: Ken.C]
onn Offline
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Registered: 02/28/08
Posts: 999
Loc: Edmonton Alberta
That's great news Ken
Nothing beats Axiom customer service.
Mel
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#286276 - 01/10/10 03:02 PM Re: EP350 problem and Axiom's solution [Re: Ken.C]
EFalardeau Offline
connoisseur

Registered: 08/27/07
Posts: 3400
Loc: Laval, Quebec, Canada
Cool!
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#286279 - 01/10/10 04:00 PM Re: EP350 problem and Axiom's solution [Re: Ken.C]
ClubNeon Offline
connoisseur

Registered: 02/06/09
Posts: 3466
Loc: Western Maryland, USA
 Originally Posted By: kcarlile
I'm guessing they've gone to a class D design as well.

I thought with the way you were going that this was going to be a complaint. Glad everything worked out, without too many back-and-forths.

Regarding the Class D, I think that the previous amp was class D already. It would seem that there'd be much more difference between a Class A/B to D change (heat sinks for one). While "audiophile" quality, full-range Class D amps are relatively new, they've long been used for subwoofers. It's much easier to create frequencies below 200 Hz with PWM (Pulse Width Modulation) than 20,000 Hz.
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Pioneer PDP-5020FD, Marantz SR6011
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#286283 - 01/10/10 04:15 PM Re: EP350 problem and Axiom's solution [Re: ClubNeon]
Ken.C Offline
shareholder in the making

Registered: 05/03/03
Posts: 18044
Loc: NoVA
AFAIK, the last EP350v3 amp did have heatsinks. I honestly don't remember at this point--the thing's been sitting in a box in my office for a few weeks. Finally left Friday, with the UPS guy bitching about it all the way...
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I am the Doctor, and THIS... is my SPOON!

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#286284 - 01/10/10 04:26 PM Re: EP350 problem and Axiom's solution [Re: Ken.C]
ClubNeon Offline
connoisseur

Registered: 02/06/09
Posts: 3466
Loc: Western Maryland, USA
Oh, I thought you were comparing those two in the picture above saying the newer one was now Class D. Both of those seem too similar to be drastic redesigns.

But yeah, if there were large heat sinks on the other one you had, it would more than likely have been AB.
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Pioneer PDP-5020FD, Marantz SR6011
Axiom M5HP, VP160HP, QS8
Sony PS4, surround backs
-Chris

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#286286 - 01/10/10 04:32 PM Re: EP350 problem and Axiom's solution [Re: ClubNeon]
Ken.C Offline
shareholder in the making

Registered: 05/03/03
Posts: 18044
Loc: NoVA
No, those are the two new ones--the humming one and the good one. I never took the old amp out of the case, but it had a black finish, and was much smaller in height. Axiom still has the pic on the EP350 page:


Incidentally, I see in the photo gallery for the EP350, they have a bunch of pictures in different custom finishes.
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I am the Doctor, and THIS... is my SPOON!

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#286289 - 01/10/10 05:11 PM Re: EP350 problem and Axiom's solution [Re: Ken.C]
SirQuack Offline
shareholder in the making

Registered: 01/29/04
Posts: 13579
Loc: Iowa
Dang, they have a new amp for the 350v3's already, man they just came out with these not that long ago with rave reviews....which is why I have two...
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#286295 - 01/10/10 05:56 PM Re: EP350 problem and Axiom's solution [Re: SirQuack]
Ken.C Offline
shareholder in the making

Registered: 05/03/03
Posts: 18044
Loc: NoVA
Randy, it doesn't actually sound different, at least as far as I can tell. I'm sure it's more efficient, though--less energy lost as heat, that means more energy goes to the sound.
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