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EMOTIVA Thread Q&A [TECHNICAL TALK ONLY] - Page 512

post #15331 of 17194
Quote:
Originally Posted by lorjam View Post

Oh man! Looks like the ET3 is just the thing I need to turn "on" my UPA-1s after the power strip powers them into standby. Glad I checked the thread.biggrin.gif

By the way, my UPA-1s are connected to a Onkyo PR-SC5507 which has not had a problem since I bought it about three years ago. It replaced a PR-SC886 which worked perfectly until it was stolen (the bastards!).
post #15332 of 17194
Quote:
Originally Posted by lorjam View Post

Oh man! Looks like the ET3 is just the thing I need to turn "on" my UPA-1s after the power strip powers them into standby. Glad I checked the thread.biggrin.gif
You could use a smart strip - plug in a small ac-to-dc adapter of 6-12vdc output and connect to one of the UPAs and daisy chain from that one to the next one. I've been using a smart strip to turn on my main 2 channel amp using a USP-1 preamp to trigger it. I also plug in my low watt usage stuff like the DVD player - tuner etc so they don't suck up juice when they should be off. I'm not sure how much juice this saves but it does make the living room dark at night. Before that it had many dim glowing LEDs that lit it up like a night-light.
post #15333 of 17194
Anyone heard the XPR-5, that is a monster and class H too!
post #15334 of 17194
I have a Adcom GFA555II 2 channel and a GFA2535 3 channel power amp from the 90s. Would a XPA-5 be much better sonicly? Thanks
post #15335 of 17194
Quote:
Originally Posted by alan_ct View Post

I have a Adcom GFA555II 2 channel and a GFA2535 3 channel power amp from the 90s. Would a XPA-5 be much better sonicly? Thanks

I doubt it!
post #15336 of 17194
Quote:
Originally Posted by gferrell View Post

Anyone heard the XPR-5, that is a monster and class H too!

Yes. I heard it with Lord of the Rings : Part 1 today and will probably settle in in a few minutes for Part 2. biggrin.gif
post #15337 of 17194
is Mark Schifter currently affiliated with Emotiva Electronics? TIA
post #15338 of 17194
Quote:
Originally Posted by kps88user View Post

is Mark Schifter currently affiliated with Emotiva Electronics? TIA

NO! Check out this post in another thread in response to your question.

Bill
post #15339 of 17194
Quote:
Originally Posted by alan_ct View Post

I have a Adcom GFA555II 2 channel and a GFA2535 3 channel power amp from the 90s. Would a XPA-5 be much better sonicly? Thanks

As fate would have it, I own and use all of the amps you mentioned. The Adcom 555 II is a very nice amp..I bought it in the 90's and never used it much until a few years ago. I've had it hooked to a pair of Magnepan 1.7's and it sounded wonderful. It's currently being used in bridged mode to drive a Magnepan CC3 center channel speaker in the same system as the Magnepan 1.7's. I use a vintage Threshold S500e to drive the 1.7's now. The Adcom GFA2535, which is a 4 channel or three channel configurable amp , sounds very nice as well, but doesn't have anywhere near the power of the XPA-5. It's rated at 4 x's 60 watts per channel in 4 channel mode OR 2 x's 60watts per channel and 1 x's 200watts per channel in three channel mode. (all at 8 ohm load). In non bridged mode, it is rated at 90 watts per channel times 4 at 4 ohms.

That 200 watt bridged channel has limitations. For example, I tried using it to drive that Magnepan CC3 center channel speaker and it didn't like that load one bit. It would overheat and sound strained. The bridged Adcom 555II sounds far better and runs cool. I am using that 2535 now, at least two channels of it, to drive my rear speakers in that system..a pair of Magnepam MMG's. It works just fine in that application. In non bridged mode, the 2535 has no problem handling 4 ohm loads.

I use my XPA-5 in my main system built around Thiel 3.6's, to drive the surround channels in a 7.2 configuration. It's a very powerful amp and sounds great. I don't think it sounds any better than the Adcom 555II though, they are both fine quality pieces of gear. Within it's power limitations, the Adcom 2535 is a fine sounding amplifier..HOWEVER...it is a 60 watt per channel amp at it's core. Bridging one of the sides to gain a 200 watt rating into a single channel works as long as the speaker you are driving is 8 ohms. If it's less than that, that bridged channel will have issues. Even within that limitation, I don't think that bridged 2535 channel could be considered the equal of a channel of the XPA-5.
post #15340 of 17194
Quote:
Originally Posted by gferrell View Post

Anyone heard the XPR-5, that is a monster and class H too!
Yes, I got one in anticipation of our HT build. Tried it for a week with my Jamo R909 speakers. Works just as great as my two XPA-1.

Only thing is the speakers I want to build are 95 dB efficient. This means 125 Watt would be enough for peak reference (105 dB) at listening position (12 feet) and 400 Watt is more that these speakers can handle.

BTW, Class H means it doesn't soak up to much energy. It's a Class AB evolution.
post #15341 of 17194
Quote:
Originally Posted by erwinfrombelgium View Post

Yes, I got one in anticipation of our HT build. Tried it for a week with my Jamo R909 speakers. Works just as great as my two XPA-1.
Only thing is the speakers I want to build are 95 dB efficient. This means 125 Watt would be enough for peak reference (105 dB) at listening position (12 feet) and 400 Watt is more that these speakers can handle.
BTW, Class H means it doesn't soak up to much energy. It's a Class AB evolution.

These numbers are at the rated 1kHz freq correct?
No speaker has equal efficiency across the entire audio band so more power is usually welcome vs less.smile.gif
post #15342 of 17194
My only complaint with class H (and I currently run 4 class H amps) is at low volumes they don't sound as good as my class A/B amps running in class A. However I rarely listen at low volumes.
post #15343 of 17194
Quote:
Originally Posted by gferrell View Post

My only complaint with class H (and I currently run 4 class H amps) is at low volumes they don't sound as good as my class A/B amps running in class A. However I rarely listen at low volumes.

I thought they are not fully class H but a hybrid? (two power rails)

http://emotivalounge.proboards.com/index.cgi?action=display&board=amps&thread=24997&page=2#417104
post #15344 of 17194
Quote:
Originally Posted by bootman_head_fi View Post

I thought they are not fully class H but a hybrid? (two power rails)
http://emotivalounge.proboards.com/index.cgi?action=display&board=amps&thread=24997&page=2#417104
Dan's description: >>We have a two rail design in the XPR-5.<< So technically, that's Class G.
Quote:
The general consensus is that Class-G runs from a low voltage rail until the signal goes beyond a certain voltage, and a higher rail (or rails) is switched in. Class-H refines this to use a variable higher voltage rail (or rails), also known as a modulated rail. Article.

This wiki article states the same.
post #15345 of 17194
Quote:
Originally Posted by alan_ct View Post

I have a Adcom GFA555II 2 channel and a GFA2535 3 channel power amp from the 90s. Would a XPA-5 be much better sonicly? Thanks

 

It is likely that there will be very little difference between them if they are both working within their design parameters and not clipping. But the Adcom has a fairly low power output by today's standards so it is possible that you would be driving it into, or approaching, clipping during the loud peaks of movie material. If you are approaching clipping this could cause the Adcom to sound 'strained' or 'harsh', especially on loud passages. If you are actually driving it into clipping, you will know - it will sound awful (and can endanger your speakers too). For movie applications, I would say that the 200 watts (8 ohms) of the Emo amp would be a better option for you.

post #15346 of 17194
I have to agree about the low wattage. I'm getting lazy in my old age and didn't look up the specs on the 2535 amplifier. The XPA-5 is an excellent amp with plenty of power which is needed by many speakers in home theater. I have an XPA-3 and it never sounds strained, unlike a lower powered receiver I used to use.
post #15347 of 17194
Quote:
Originally Posted by gferrell View Post

My only complaint with class H (and I currently run 4 class H amps) is at low volumes they don't sound as good as my class A/B amps running in class A. However I rarely listen at low volumes.
Are you ACTUALLY running an XPR (or some other class H)? Because I actually have three of them & find the XPRs to be the EXACT opposite of what you state. Just sayin...
post #15348 of 17194
Quote:
Originally Posted by Theresa View Post

I have to agree about the low wattage. I'm getting lazy in my old age and didn't look up the specs on the 2535 amplifier. The XPA-5 is an excellent amp with plenty of power which is needed by many speakers in home theater. I have an XPA-3 and it never sounds strained, unlike a lower powered receiver I used to use.

 

The Adcoms the OP mentions seem like pretty good amps - he can possibly press them into service in another capacity. Ditto your remarks wrt to the XPA-3. 

post #15349 of 17194
Quote:
Originally Posted by strindl View Post

As fate would have it, I own and use all of the amps you mentioned. The Adcom 555 II is a very nice amp..I bought it in the 90's and never used it much until a few years ago. I've had it hooked to a pair of Magnepan 1.7's and it sounded wonderful. It's currently being used in bridged mode to drive a Magnepan CC3 center channel speaker in the same system as the Magnepan 1.7's. I use a vintage Threshold S500e to drive the 1.7's now. The Adcom GFA2535, which is a 4 channel or three channel configurable amp , sounds very nice as well, but doesn't have anywhere near the power of the XPA-5. It's rated at 4 x's 60 watts per channel in 4 channel mode OR 2 x's 60watts per channel and 1 x's 200watts per channel in three channel mode. (all at 8 ohm load). In non bridged mode, it is rated at 90 watts per channel times 4 at 4 ohms.
That 200 watt bridged channel has limitations. For example, I tried using it to drive that Magnepan CC3 center channel speaker and it didn't like that load one bit. It would overheat and sound strained. The bridged Adcom 555II sounds far better and runs cool. I am using that 2535 now, at least two channels of it, to drive my rear speakers in that system..a pair of Magnepam MMG's. It works just fine in that application. In non bridged mode, the 2535 has no problem handling 4 ohm loads.
I use my XPA-5 in my main system built around Thiel 3.6's, to drive the surround channels in a 7.2 configuration. It's a very powerful amp and sounds great. I don't think it sounds any better than the Adcom 555II though, they are both fine quality pieces of gear. Within it's power limitations, the Adcom 2535 is a fine sounding amplifier..HOWEVER...it is a 60 watt per channel amp at it's core. Bridging one of the sides to gain a 200 watt rating into a single channel works as long as the speaker you are driving is 8 ohms. If it's less than that, that bridged channel will have issues. Even within that limitation, I don't think that bridged 2535 channel could be considered the equal of a channel of the XPA-5.
Thanks! I will keep what I have then! They havnt failed me once yet...Im using the2535 3 channel for 200 to center and the lesser power to my surrounds!
post #15350 of 17194
Quote:
Originally Posted by bootman_head_fi View Post

These numbers are at the rated 1kHz freq correct?
No speaker has equal efficiency across the entire audio band so more power is usually welcome vs less.smile.gif
I guess you're correct. If the drivers can handle it.
post #15351 of 17194
Quote:
Originally Posted by alan_ct View Post

Thanks! I will keep what I have then! They havnt failed me once yet...Im using the2535 3 channel for 200 to center and the lesser power to my surrounds!

What speakers is the Adcom 2535 driving, especially the center channel using the bridged section of the Adcom?
post #15352 of 17194
Quote:
Originally Posted by Esox50 View Post

Are you ACTUALLY running an XPR (or some other class H)? Because I actually have three of them & find the XPRs to be the EXACT opposite of what you state. Just sayin...

I think he was talking about when the Class A/B is running in Class A, which is the first 10 to 30 watts depending on the amp. I would probably agree with that statement when talking about Class A at low volumes. Even though the gain is 29 dB on the XPR and now the XPA-100/200, I bet we would be able to pick that out at low volumes.
post #15353 of 17194
Quote:
Originally Posted by Roger Dressler View Post

Dan's description: >>We have a two rail design in the XPR-5.<< So technically, that's Class G.
This wiki article states the same.

Actually what happens with Class G is, that the supply voltage varies in discrete steps depending on the amps load and certain fallback algorithms, whilst in Class H the supply voltage is variable - not discrete - and varies depending on the amps load and certain fallback and delay algorithms. One problem to be handled by those algorithms and circuits is the handling of transients, which cross the current (lower) load window with a high slew rate.
post #15354 of 17194
Quote:
Originally Posted by jevans64 View Post

I think he was talking about when the Class A/B is running in Class A, which is the first 10 to 30 watts depending on the amp. I would probably agree with that statement when talking about Class A at low volumes. Even though the gain is 29 dB on the XPR and now the XPA-100/200, I bet we would be able to pick that out at low volumes.

For most amps it is even lower at only a few watts (<10) before going into AB.
post #15355 of 17194
Quote:
Originally Posted by bootman_head_fi View Post

For most amps it is even lower at only a few watts (<10) before going into AB.
But modern amps have only a little more distortion, inaudible levels, when in AB mode.
post #15356 of 17194
Quote:
Originally Posted by Theresa View Post

But modern amps have only a little more distortion, inaudible levels, when in AB mode.

This is correct.
I was just pointing out that most amps only have one or two watts or so in class A vs specific designs that offer more.
post #15357 of 17194
Quote:
Originally Posted by bootman_head_fi View Post

This is correct.
I was just pointing out that most amps only have one or two watts or so in class A vs specific designs that offer more.

No offense intended.
post #15358 of 17194
Quote:
Originally Posted by Theresa View Post

Quote:
Originally Posted by bootman_head_fi View Post

For most amps it is even lower at only a few watts (<10) before going into AB.
But modern amps have only a little more distortion, inaudible levels, when in AB mode.

 

I have an ageing but glorious two channel Class A amp - 50 watts of pure class A - in my music system. It serves as a room heater too! ;) But is so silky smooth.... I prefer a slightly more 'laid back' presentation for music and this amp and my old but good speakers give me exactly that. For movies I prefer a much more ruthless transparency to the source.

post #15359 of 17194
Yes, I recall that amp of yours. I would attribute its "special sound" to other factors than it's pure class A operation, what factors I don't know. I do know that distortion levels in most class A/B amps are at inaudible levels, often less than tenths of a percent.
I remember buying a "class A" headphone amp a couple of decades ago and was so disappointed that it didn't sound any better and perhaps worse that I returned it.
Edited by Theresa - 1/9/13 at 1:16pm
post #15360 of 17194
Quote:
Originally Posted by kbarnes701 View Post

I have an ageing but glorious two channel Class A amp - 50 watts of pure class A - in my music system. It serves as a room heater too! wink.gif But is so silky smooth.... I prefer a slightly more 'laid back' presentation for music and this amp and my old but good speakers give me exactly that. For movies I prefer a much more ruthless transparency to the source.

Class A can be intoxicating when done right. I have a Nelson Pass era Threshold SA/4e 100 watt per channel pure class A amp that I bought in the early 90's. I've used it with Thiel 3.6's ever since and it has given me goosebumps while listening to well recorded music many times since. Good music reproduced just right should give you goosebumps from time to time. Power amp technology hasn't changed much in the last 20 years...a good power amp from the 90's is still a good power amp in the 21st century.

The only small limitation I have had with that amp and the Thiels is with home theater applications...Those Thiels really need more power than 100 watts per channel when doing really powerful movie soundtracks. No problem though, I can quickly switch to a pair of XPA-1's when I feel more power is required.
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