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Discussion Starter #1
1. Product:

Pair of Linear Power 952IQ amps

2. Specs:

Rated at 12.5v

47.5w x 2 @ 4 ohms
95w x 1 @ 4 ohms

0.05% THD @ 20-20khz
2-ohm stereo stable

Underrated of course

3. Description/Condition:

Pair of very nice Linear Power 952iq amplifiers. Fantastic SQ, hand made in the U.S.A, and renown Linear Power quality. These would be awesome for a front stage or to power a pair of mids bridged. These amps are marked as made on July 31, 1991 with sequential serial numbers: 33759 and 33760. Cosmetically, they are in great shape. I took pictures of the main flaws to the best of my ability, but from a few feet away, they look amazing. Mechanically, they work beautifully. They are unmodified and have not been repaired from my knowledge and from what I can see; gut pics are included. A video of each demonstrating that they are in working condition is provided in the next post. The back has velcro attached from their previous mounting.

4. Price: :

$155 + shipping each


5. Pictures:



 

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Nice. Very nice.

Take a good look at those gut pics. They look like some kids science project yet they are some of the most well regarded amps ever made. A pretty board means nothing.
 

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Nice. Very nice.

Take a good look at those gut pics. They look like some kids science project yet they are some of the most well regarded amps ever made. A pretty board means nothing.
Companies spend too much time thinking about the asthetics few people see. I think it might also cost less running board traces than point to point wiring as well in the mass market scheme of things. I have a 2502IQ and 2.2HV in my car right now. They aren't the most powerful I've used, but they do sound ridiculously nice.
 

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Discussion Starter #7
Nice. Very nice.

Take a good look at those gut pics. They look like some kids science project yet they are some of the most well regarded amps ever made. A pretty board means nothing.


Companies spend too much time thinking about the asthetics few people see. I think it might also cost less running board traces than point to point wiring as well in the mass market scheme of things. I have a 2502IQ and 2.2HV in my car right now. They aren't the most powerful I've used, but they do sound ridiculously nice.
Thanks fellas. I agree, these little guys sound phenomenal and look so clean. If I weren't short on cash, I would try picking up more LP amps and swap out my whole system.
 

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Those numbers don't add up. Normally bridged at 4 ohms gets between 3-4 times the power of 4 ohm stereo operation...

Any idea what the actual power output might be? The pair of them might make a damn good setup for my front stage lol
 

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LPs are always rated @ 12V, so they're often WELL underrated.
 

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I know they're underrated, but normally bridged into 4 ohms is listed at twice the 2 ohm power, not twice the 4 ohm power. I just wanted to be sure that was bridged into 4 ohm power listed, not bridged into 8 ohm power.
 

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Per LP specs @ Linear Power Inc. - For The Love Of Music

952 /952IQ

4Ohm Stereo: 47.5W x2 RMS
THD20-20khz:0.050%
4Ohm Bridged: 95 Watts
Max Output: 190 Watts
Damping Factor 4/2Ohm: >133
Channel Separation: 70 dB
Slew Rate: 8V/mSec
SNR: 95 dB
Fuse Required: 15 Amps
2Ohm Stereo/4Ohm Bridged Operatio: Yes
Internally Bridgeable: Yes
 

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Hmm... I wonder how underrated it is. 15 amp fuse means 216 max watts at 14.4 volts. It's gotta put out 120 watts at max RMS. Pretty good for an amp where someone can fit one under each seat to have a stealthy install of a powerful front stage :)
 

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Discussion Starter #13
I know they're underrated, but normally bridged into 4 ohms is listed at twice the 2 ohm power, not twice the 4 ohm power. I just wanted to be sure that was bridged into 4 ohm power listed, not bridged into 8 ohm power.
In all honesties, the ratings confused me too. If I had to make a guess, I would put the bridged output power @ 4ohms somewhere from 150-200w, but there's no way for me to really tell without the proper testing equipment. All I know is that that these guys sound fantastic for what they're supposedly rated at.
 

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The amps are HIGH POWER not HIGH CURRENT. The rail voltage are higher at 4-ohm stereo (8-ohm mono) than at 2-ohm stereo (4-ohm mono) with taps set correctly. The rail voltage is pretty high also, higher than other 100watt amps.

The amps benefit the MOST AT 4-ohm stereo. Not only you pull less current you make same power as 2-ohm stereo but it will run cooler (thats even if they get hot, mine never got hot).

Think of it like the RIPS system JL uses on their amps. They produce same power at any impendance, but will pull more current at lower impendance.
 

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Discussion Starter #15
The amps are HIGH POWER not HIGH CURRENT. The rail voltage are higher at 4-ohm stereo (8-ohm mono) than at 2-ohm stereo (4-ohm mono) with taps set correctly. The rail voltage is pretty high also, higher than other 100watt amps.

The amps benefit the MOST AT 4-ohm stereo. Not only you pull less current you make same power as 2-ohm stereo but it will run cooler (thats even if they get hot, mine never got hot).

Think of it like the RIPS system JL uses on their amps. They produce same power at any impendance, but will pull more current at lower impendance.
Thanks for the info. As you can tell, I'm not well versed in the technical history of LP amps, I just go by what my ears tell me :cool:

Bump!
 

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Beautiful amps, great price if you ask me. I'll be keeping a watch to see if they are still available in the next week or two. (I'm sure they'll be gone by then, wish I had the money today!) Best of luck.
 

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I know they're underrated, but normally bridged into 4 ohms is listed at twice the 2 ohm power, not twice the 4 ohm power. I just wanted to be sure that was bridged into 4 ohm power listed, not bridged into 8 ohm power.
This is often mis-understood on Linear Power amplifiers, but if you will notice there are two sets of taps in the center of the circuit board around the transformer that are labeled 4 and 2 these are power supply jumper taps that change the internal rail voltage to the output stage. If you are running 2 ohms stereo or 4 ohm bridged (the taps should be set to the ones marked "2" for 2 ohm stereo, this is the same setting for 4 ohm bridged too) and the power supply taps are set correctly the internal voltage of the amplifier is dropped to allow for the higher current draw of the circiut into a lower impedance load. This allows the amplifier to keep its damping factor and headroom nearly the same as in the higher impedance load and to keep distortion down. The amp will draw more current, produce more heat due to the increase in current and the loss of voltage, and work less efficiently at the lower impedance load, it is always better to run the amplifier into the higher impedance stereo load of 4 ohms are 8 ohm bridged. High voltage makes just as much power as running an amp at low votlage into a high curent load generated by a low impedance load. We have always designed our amps for peak sound quality and reliability and longevity by making them high voltage amps, thats why they last 15, 20, 25 years and few fail and they still sound good and people still want them. Higher voltage creates more dynamic natural clean and responsive music, due to the fact that a higher voltage can respond more quickly than a lower voltage can under a high current condition, and it does it way more efficiently, this is why you see your bigg home appliances running off 220 volts instead of 110 volts, the same reason that factories run on 440 volts or higher or the power lines run at 44,000 votls or higher unitl they drop voltage thru a transfomer to run your home. It has a higher efficiency and less power loss over teh distance and wires. This theory still works in smal scale in consumer electronics.

The same reason that car manufacturers are looking into going to 36 or 48 volt electrical systems in cars, they can cut weight by using smaller wiring since the current load is reduced and still make the same power, they can also save money since less copper is needed. A 48 volt electrical system is 4 times as efficient than a 12 volt system, meaning it will produce that same power into a high impedance load or electrical circuit with 1/4 the current and 1/4 the heat generation. Car Audio is the one industry that most manufacturers have actually gone backwards on in efficiency and design. High Current is not the future, it is not even the best way to make power! Any electrical engineer will tell you it is the wrong way to design anything, you are working against yourself, the only ones that will tell you differently would be the ones trying to market you the high current device. Go outside our industry and ask questions and do research, don't take just the information of this community as the gospel, go find out, make an intelligent informed decision based on knowledge not emmotion or love of a brand name.

In our specifications we always list power with the power supply taps set in the correct positions for the load, which makes the amps look less powerful. You can run the amplifiers into a 2 ohm stereo load or 4 ohm bridged load without moving the taps from 4 to 2 inside the amp and the amp would increase power across the circuit just as any amp would, BUT this is not advised, recommended or put into print. As we have always built amps for sound quality as well as for high votlage NOT high current conditions. As in any amp running it into a lower impedance load (or with our amps with improper settings) will produce more power, but will also produce more distortion and heat and reduce the life of the amp, or any other amp for that matter, it is all about the mathematics and physics of the circuit.
 

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Discussion Starter #19
This is often mis-understood on Linear Power amplifiers, but if you will notice there are two sets of taps in the center of the circuit board around the transformer that are labeled 4 and 2 these are power supply jumper taps that change the internal rail voltage to the output stage. If you are running 2 ohms stereo or 4 ohm bridged (the taps should be set to the ones marked "2" for 2 ohm stereo, this is the same setting for 4 ohm bridged too) and the power supply taps are set correctly the internal voltage of the amplifier is dropped to allow for the higher current draw of the circiut into a lower impedance load. This allows the amplifier to keep its damping factor and headroom nearly the same as in the higher impedance load and to keep distortion down. The amp will draw more current, produce more heat due to the increase in current and the loss of voltage, and work less efficiently at the lower impedance load, it is always better to run the amplifier into the higher impedance stereo load of 4 ohms are 8 ohm bridged. High voltage makes just as much power as running an amp at low votlage into a high curent load generated by a low impedance load. We have always designed our amps for peak sound quality and reliability and longevity by making them high voltage amps, thats why they last 15, 20, 25 years and few fail and they still sound good and people still want them. Higher voltage creates more dynamic natural clean and responsive music, due to the fact that a higher voltage can respond more quickly than a lower voltage can under a high current condition, and it does it way more efficiently, this is why you see your bigg home appliances running off 220 volts instead of 110 volts, the same reason that factories run on 440 volts or higher or the power lines run at 44,000 votls or higher unitl they drop voltage thru a transfomer to run your home. It has a higher efficiency and less power loss over teh distance and wires. This theory still works in smal scale in consumer electronics.

The same reason that car manufacturers are looking into going to 36 or 48 volt electrical systems in cars, they can cut weight by using smaller wiring since the current load is reduced and still make the same power, they can also save money since less copper is needed. A 48 volt electrical system is 4 times as efficient than a 12 volt system, meaning it will produce that same power into a high impedance load or electrical circuit with 1/4 the current and 1/4 the heat generation. Car Audio is the one industry that most manufacturers have actually gone backwards on in efficiency and design. High Current is not the future, it is not even the best way to make power! Any electrical engineer will tell you it is the wrong way to design anything, you are working against yourself, the only ones that will tell you differently would be the ones trying to market you the high current device. Go outside our industry and ask questions and do research, don't take just the information of this community as the gospel, go find out, make an intelligent informed decision based on knowledge not emmotion or love of a brand name.

In our specifications we always list power with the power supply taps set in the correct positions for the load, which makes the amps look less powerful. You can run the amplifiers into a 2 ohm stereo load or 4 ohm bridged load without moving the taps from 4 to 2 inside the amp and the amp would increase power across the circuit just as any amp would, BUT this is not advised, recommended or put into print. As we have always built amps for sound quality as well as for high votlage NOT high current conditions. As in any amp running it into a lower impedance load (or with our amps with improper settings) will produce more power, but will also produce more distortion and heat and reduce the life of the amp, or any other amp for that matter, it is all about the mathematics and physics of the circuit.

Wow, I really appreciate you clearing that up for us. From my short experience with LP amps, I must say I'm highly impressed with the quality of these amps, even more so with the reliability that they've demonstrated for over 20 years now.

These guys are still for sale. Any offers? Trades? PM me if you have something in mind. I wouldn't mind trading for a Bitone.1 or MS-8.
 
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