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OLA and amp pairing?


kehern15

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Any suggestions for a good amp to use with the OLAs? From what I have read, an amp with at least 100wpc and a high dampening factor really makes these shine, can anyone recommend something in particular? I've been looking at the Crown DC 300A, but I'd like to stay under $200 if possible, vintage or new. Also preferably something that can handle a 4ohm load, as someday I hope to double stack the advents!

More background: I recently built a pair of Overnight Sensations speakers, and am very in love with them. But I was confused/surprised that they seemed to have a slightly deeper, more accurate bass when compared to the advents. I realized, with the help of a more "audiophile" friend cranking my amp, that I am underdriving the speakers currently. I have an Audiosource AMP-100 amp, at 50wpc. Great for the OS, but clearly not enough for the OLAs.

Also, what actually is a high dampening factor? From what I understand, it is a ratio measurment, and a bit subjective, but is there a good number to stay "above" when looking at amps to ensure that the Advents have tight, deep bass?

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I'm going to guess that amps that are good for the AR-3 and 3a would be suitable. Tom Tyson likes McIntosh, Crown, Bryston, Krell. I think the Crowns are the only ones within your budget. I'm currently using an Adcom 555 which gives plenty of power to the ARs.
There are also some inexpensive new amps from Crown and QSC that could fill the bill. The Crown XLS 1000 will deliver 350wpc for $279. I don't know the model numbers for QSC but try a google search.

OTOH, maybe it's the Advents. I had a pair that were supposed to be "keepers". Rebuilt the crossovers with all high-quality parts. But I found they did not hold a candle to AR-2ax's (both driven by a MAC4100).

btw--I've been thinking about building the OS myself. Glad to hear that you love them!

-Kent

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Speaking of Crown, this is an amazing deal at $199!

http://www.musiciansfriend.com/pro-audio/crown-x2000-stereo-2x450w-power-amp

Old school, reliable, professional AB amp design, also providing rca jacks, and banana jack speaker connection for home audio.

The thing is a boat anchor, but will more than do the job. 330w/ch into 8 ohms, 450/ch into 4 ohms...and bridgeable for 900w.

Roy

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I'm going to guess that amps that are good for the AR-3 and 3a would be suitable. Tom Tyson likes McIntosh, Crown, Bryston, Krell. I think the Crowns are the only ones within your budget. I'm currently using an Adcom 555 which gives plenty of power to the ARs.

There are also some inexpensive new amps from Crown and QSC that could fill the bill. The Crown XLS 1000 will deliver 350wpc for $279. I don't know the model numbers for QSC but try a google search.

OTOH, maybe it's the Advents. I had a pair that were supposed to be "keepers". Rebuilt the crossovers with all high-quality parts. But I found they did not hold a candle to AR-2ax's (both driven by a MAC4100).

btw--I've been thinking about building the OS myself. Glad to hear that you love them!

-Kent

Honestly after building the OS, I am uncertain I even want to keep the advents. I forgot how dated the tweeters are in the OLAs, the OS reminded me. The OS also throw out a ver big soundstage for their size, I was quite astounded the first time I listened to them! Going to try a new amp with the OLAs and if that doesn't help liven them up, I'll probably sell them. Hm if only I can afford some 3a's...

Speaking of Crown, this is an amazing deal at $199!

http://www.musiciansfriend.com/pro-audio/crown-x2000-stereo-2x450w-power-amp

Old school, reliable, professional AB amp design, also providing rca jacks, and banana jack speaker connection for home audio.

The thing is a boat anchor, but will more than do the job. 330w/ch into 8 ohms, 450/ch into 4 ohms...and bridgeable for 900w.

Roy

Wow, that seems like an amazing deal. Thank you very very much! Is there any benefit or drawback in using a "pro" amp versus a consumer model? Though that seems excellent, I read a bit that these amps can sound a bit harsh. I want to get the "best" possible amp for the advents, as if I don't like them after this...off to craigslist!

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Do some reading. On one site a guy said the sound was "tube-like." As always YMMV but it seems like a steal.

-Kent

PS: Apparently the X2000 is a re-badged Crown something-or-other made for Musician's Friend and Guitar Center. GC has the same deal:

http://www.guitarcenter.com/-i2670624.gc

See Post #8 here: http://techtalk.parts-express.com/showthread.php?243708-Price-Alert-Crown-X1000-X2000-X4000-on-sale-at-MF-and-GC

I may have to get one of these myself!

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Do some reading. On one site a guy said the sound was "tube-like." As always YMMV but it seems like a steal.

-Kent

...especially since shipping is included. I have this one as well as the "lower powered" (200w/300w/600w) version of this amp, and they are not harsh at all. The lower powered version (no longer available) went for $99 before the holidays!

The primary disadvantage is weight and size. Advantages include stability into low impedance and durabilty. These amps have been displaced by much lighter, switching-type power amps.

Roy

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What about the whole "damping factor" business? I read an explanation here http://www.crownaudio.com/media/pdf/amps/damping_factor.pdfand it says "all" Crown amps have a high damping factor but from what I see, not so much for the X2000.

Roy (and others)--do you have thoughts on this?

-Kent

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What about the whole "damping factor" business? I read an explanation here http://www.crownaudio.com/media/pdf/amps/damping_factor.pdfand it says "all" Crown amps have a high damping factor but from what I see, not so much for the X2000.

Roy (and others)--do you have thoughts on this?

-Kent

Kent,

I don't see any documentation to show the X2000 is somehow deficient compared to other amps in the damping factor department. Where did you get that information? Check out the damping factor specs of any decent amp, new or old, and see if there is a correlation between its reputation and its "published" specification for that parameter. For the most part it is a non-issue.

Roy

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The more I think about it, that Crown amp looks like overkill for me (power and price). The price is excellent, but as a student on a tight budget, I may just patiently wait for a decent vintage amp to pop up wherever for ~$50 if I get lucky. (I found my OLAs locally, with the correct refoam kit included for $100, and he drove it to me!).

I was looking a bit more into the amplifier that I have, and stumbled across this review: http://www.kenrockwell.com/audio/audiosource/amp-100.htm

Apparently the amp measures well, and has a high dampening factor. I do understand that it is a complex number with many variables (as the impedance fluctuates constantly due to the nature of music, gauge/length of interconnect wire used, and the resistance of the specific voice coil) I am just using it as a guideline, as to what amps to avoid (below 50).

So the question now becomes...are the speakers not being powered enough at 50wpc? Do you believe more are needed, or maybe I simply don't like their sound?

I also think that it may be due to my setup, maybe I am unknowingly causing interference, standing waves, who knows what. Attached is a picture of the set up, as well as a brief description of my room. The speakers are about 4.5 ft apart (woofer to woofer measurement), I sit about 8-9ft from them, they are about 9 inches from the back wall, and raised up on concrete blocks by 16 inches (putting the tweeters at ear level). The room itself is about 12 x 12 ft, with the left side opening to the dining room/kitchen/bedroom (it's a small space).

Any advice if my set up is wrong? Move speakers out, toe them in, my room is just too small, etc. I seem to lack any deep and accurate bass unless the amp is cranked up past the 12 o'clock position, which can get very loud (I don't mind...neighbor might...)

post-174223-0-72939700-1422864219_thumb.

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Any chance your OLAs are wired out of phase? A quick check would be to reverse the speaker wires on just one speaker and see if there is a difference. Also, you "could" have made a mistake during refoaming.

Ain't no way the OS's could have deeper and more accurate bass than the OLAs. Defies the laws of physics.

As I've written, I'm not a big OLA fan but something is wrong here....

Kent

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Any chance your OLAs are wired out of phase? A quick check would be to reverse the speaker wires on just one speaker and see if there is a difference. Also, you "could" have made a mistake during refoaming.

Ain't no way the OS's could have deeper and more accurate bass than the OLAs. Defies the laws of physics.

As I've written, I'm not a big OLA fan but something is wrong here....

Kent

Oh my god, you can revoke my audio enthusiast card right now. Damn things were wired out of phase... Also explains why when I got them up on cinder blocks, as I rewired them with thicker gauge wire, the bass response was significantly less. I've had them that way for weeks now. :/

Turns out, the amp is fine. Sure I need to pump it up to 12 o'clock to really get the woofers moving, but it still has a fair bit of headroom. May keep an eye out for a nice vintage amp anyway, but I'm happy once again. Significantly deeper and richer bass response.

Seriously though, I have restored those OLAs, built a pair of speakers, have read 3 books on speakers/audio...and then promptly wired them out of phase. Sigh.

Thanks for your help JKent!

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And here I was going to write that my original Advents can get really loud without distortion and with deep, satisfying bass with my 50 WPC Heathkit amps. I guess yours can too now.

:D

Doug

Yeah I really feel like a dunce now... :blink:

Damn things can shake the books off the shelf, neighbor must hate me. :D

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I have four Advent stacks in my quad system and, after disassembling and reassembling it one time, I thought it didn't sound quite right but I decided it was just me because I was sure I had everything correct after double checking all the connections and RCAs, etc.

Months later I had occassion to remove the main amp to replace the pilot lamp. Upon disconnecting the speaker cables, I was agast upon discovering I had the left and right reversed so, out of the four pairs of speakers, one was reversed which, of course, is why it didn't sound quite right. Ya think?

So, dunces "R" us.

:D

Doug

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I've been looking into getting a second pair of Advents to double stack them myself (maybe after I move out of this smaller place...could shake the whole house down with double advents!)

How are you liking them Doug? I was really interested to try, but then reading Zilch's analysis of all the interference that occurs when you double stack the Advents had me a bit worried. :unsure:

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I love them. Sometimes I am amazed at the sound and the original adage about Advents is true; they expose the quality of the equipment feeding them.

I don't have mine in the prescribed configuration either with the two tweeters together. I have both speakers upright and it seems there is less interference between the tweeters that way. In fact, that makes more sense to me. The farther apart the two tweeters, the more dispersed the wave propagation is by the time the soundwaves from one hit the other. WIth the two tweeters together the interference is going to be pretty much immediate.

Doug

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OK, it will be great to hear your impressions from experimenting with stacking when you get to it.

I have mine on the floor and so the tweeters in the upper sets are about ear level or just above for the chair I use. No shortage of high frequencies. Of course, with a quad system the aim is more for a room-filling sound rather than soundstage/imaging and all that. I have always loved it when you enter a room and the sound is "in the room" rather than from one end of it. It sure seems more real to me.

Doug

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Ah I see. I feel the same with my Advents right now, as my room is fairly small (14x14ft), so if they are even a bit loud you get that wonderful feeling of sound all around. Probably won't get a second set for a while, but I'll let you know! Have you ever seen a frequency response or any measurements with double stacked advents and the tweeters apart?

Speaking of, I can't find the thread of Zilch's measurements of the stacked advents?

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