Very clean transparent sound. Detailed, airy delivery with a big sound stage. Bass is very tight and controlled and the amp has great dynamics.

Chassis is very unusual and off balance. Stacking of gear is not possible unless you buy or build a cabinet.

I've owned 2 Phase Linear 400 type 2 amps and currently own a Carver C-500, which is almost identical.

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Lots of power Clean sound

30 years old, so there are undoubtedly improvements in technology since then

Need suggestions for a new Preamp to go with my Phase Linear 400....I have had my Phase Linear 400 and Bose 901 II speakers as a combination for 30 years (back in my younger days I listened to LOUD music and this combination can deliver it, albeit with some comprimises with the 901's--I realize these are not the favorite speakers for audiophiles). I've had two preamps and am now needing a third. The current preamp that I am using is an Adcom GFP-555. The on-off switch is broken and the volume control when it is on low delivers more sound to one speaker than the other. I've tested this with separate sets of speakers, so I'm fairly sure it is not the speakers. I'm an avid eBay user and want to buy an affordable used preamp. My question is whether there are any suggestions for a good preamp to go with my Phase/Bose combination given that so many people still seem to be into the Phase 400?

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Adcom GFP-555

Them best sounding amplifier ever made with brute force & enough bang to embarrass an amp almost twice the power and 18 years newer? I can't say enough good about em.

The only thing that can be said here is the Chassis is an obviously serious weak point and its hard to believe that the design engineers didn't correct this after they knew Sound companys were using them. They have to be put on shelves in racks then bolted in so they are tight against the shelf. Not even a little bit of play in the support under the unit. The Chassis will crack at the rack ears in short order.

I'm a live sound guy and never write in to these things but when it comes to Phase Linear 700 (any series) I get going. These are the best sounding amplifiers ever made in my opinion, I used to laugh at a competeing sound company using Crown DC 300's, their rig sounded dull, lifeless, flat, horrible speaker control if any at all - just a huge sloppy mess. With the Phase Linear's our system could do a place 4 times as big with clean, tight, high fidelity. We embarrassed those guys big time. (We had the same sized system cabinet for cabinet) The owner of the other company used to call them Flame Linears. I used to tell him I've never blown a speaker or an amp and if they do I can fix em. Your Crowns may never blow up but they sound like ass and there's nothing you can do about it! Now on to the newest shoot out. I put a 700B that I got for a friend up against a Crest 8001 at a rehearsal studio. One channel of Crest against one channel of 700B on a the PA system in their big room. When I asked him which had better highs, better lows, and which one sounds like it has more power? The Phase 700B easily Kicked it's ass. The Crest is rated at 1100 watts at 4 ohms - the Phase rated at 700 watts at 4 ohms. The Phase sounded like it had more power - and it did! sound that way. The point here is they are better sounding than even "big guns" touring amps. A friend of mine says, "I haven't heard "LOUD" since people stopped using Phase Linears" (meaning in concert sound systems) He also said that "If they were still made - that's all I'd buy". There is a trick to biasing them that a friend showed me which works brilliantly and seems to result in a incredibly stable cool running amp. Anyone wanting to get rid of any "Flame Linears" to buy more Crown, QSC, or Crest amps - send em my way - I'll buy every one as long as the chassis metal isn't torn or face plate gouged out badly. I've got 22 or 23 of them and I'd buy 200 more and will as soon as I find em. After all these are what Clair Brothers used for years - launching them to the biggest sound company on the planet. Since they stopped (probably due to the unavailability of more) their systems don't have the Rich High Fidelity and pure open clarity they used to when using the Phase Linears. Many people I know agree with me on this last statement.

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SAE 2600 amplifiers. The second best sounding amplifier of all time and very close second The Phase has better top end fidelity / slightly more open high frequency

clean earth shakeing power

none

I got my Phase Linear 700B about 10 years ago and have been on the lookout for another one. Just last week I got my ahnds on a great one bought origionally by a friend's father it came with the box and manuals. The amps are driveing 4 Bose 901's with a AR 250 watt 12 inch sub and I love clean loud music and this setup really delivers.

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nothing in this class but I have been a stereofile for 20 years

lots of power, rated for 200 watts/ch but compaired to todays ratings its 400 watts/ch. Very sexy looking.

PURPLE PEOPLE SPEAKER EATER!! Runs hot!

I have a phase 400 which was blowen up by my dad in the early 80's and sat around for years on the shelf. The driver board was totally smoked and needed to be replaced. I went on ebay to buy another one for parts and it has become an addiction. I now own 5 of them, I love everything about the amp, looks, power, and yes it runs hotter then a fire cracker but if your going to pound the crap out of it put a fan on it!! I have owned dozens of different amps in the past and for the money you cant beat it!! I repaired the 400 and before I hooked them up to my speaker system( 4 15" ev forse and altec 511e horns with 292-16 drivers with a set of jbl bullets) I wanted to make sure the amp was in perfect working condition so I hooked it up to a pair of orian dual voice coil subs, when both coils on each speaker are in paralle drops the load down to 2 ohms ( becasue they are car speakers) I pounded this amp for at least 2 hours to make sure it was ok and yes it ran as "hot like the gates of hell" as one fella stated earlyer but did not quit!!! THATS IMPRESSIVE to me, Ive seen lots of amps cut out with just a 4 ohm load! And the nick name my dad gave the amp was " purple people speaker eater" because yes if it blows, it takes your speakers with it!! Im not as defined in sound qauality as some of you guys out there, but I do know whats good and this phase is good. My brother has a pair of 700's series 2 and he beats the crap out of them! I find the series 1's much more attractive, the VU meters with the back ground lights dimming to be bass notes really dos something for me. I have a sansui au11000 intagrated amp which I use as a preamp and with my altec horns man when you get the right song on, tears come to my eyes!! Its beautiful!!! I have owned a sansui ba5000, crown 300, heflar 600, nikko 450, luxman, etc and for the money nothing touches the 400 phase linear. Im thinking on bridging them and running them one per channel! 600 watts rms at 8 ohm! it is not recommended to have any less then a 8 ohm load when bridged so I read at a web sight. But Im sure its not recommended to run at 2 ohms either which I already know it can do with out a problem!! If your not a beleaver, go and buy one!

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sansui au11000, altec 511e, altec 292-16, electrovoice, jbl ,altec 604

Smooth, good bass, detailed, and lifelike.

none now.

I have had my Phase Linear 400 for over a year now I purchased it on Ebay for $100.00 it had a bad right channel had noise (meter would Peak). I repaired the channel and was surprised at how nice it sounded for a amp of over 24 years. I then decided to upgrade it, best descision I ever made. I uprgaded the power supply, driver board, and input output connectors. WOW! this amp really sounds great now, nothing like before. I have a very highly rated High End power amp in the $4500.00 range that I will not name that the Phase Linear now comes very very close to. I bought another one to upgrade also and have a pair for biamp configuration. The phase Linear is a fine power amp and great once upgraded.

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much clean power

needs big speakers and a good preamp

please excuse ma broken english , i`m german.i bought this amp after reading the reviews here. it realy works good on my revox symbol II speakers. much cleaner and powerfull than my revox b750 amp, wich i now use as a preamp. i think it`s in the same class as a revox b740 poweramp, wich`s price is much higher.

See article

See Article

Why does the Phase Linear Sound So Clean ? The Phase Linear audio amplifier utilizes electrical voltage induced waveforms to reproduce recorded sound. Analog technology allows the potential of unlimited voltage iterations (or variables) to achieve better accuracy. The equivalent to voltage iterations in the digital realm is bit rate. Bit rate refers to how many bits are used to reproduce each sample. Bit rate is theoretically unlimited as well but in most current hi-tech hardware it is limited to 24bit. Sample rate refers to how often per second a reproduction is captured from the source audio. The more samples the more realistic the sound theoretically. However in reality the human brain has perceptual limits. At certain level of quality people often can't tell good from better. This is why a well encoded Mp3 can sound as good as a much bigger wav file. (I won't even get into the fact that most audio playback hardware is limited in is ability to playback sound faithfully). Digital audio has reached 96khz recording technology, in fact 192khz is on the way. Digital audio still sounds harsher... Why? One of the weak links in digital audio is bit rate limitations. For example, in 8 bit audio, 8 bits are used to draw each sample. Imagine 8 bits drawing a wave form (or even a smiley face). Well that is a pretty jagged, harsh sounding wave (or smiley face). Obviously 8 is not enough. Currently 24 bit is the professional standard with 56bit on the way. 24bit resolution in current hardware implementation does not appear to equal the smoothness the best analogue recording equipment is capable of. So all digital audio needs to do is to continue to increase bit rate resolution capability, improve the bottom end, lower the cost of the components, and digital sound may eventually surpass even the best analog has right now. The demise of analog may be inevitable, but until then many top producers are using digital / analog hybrid systems to play it safe. Recording and /or editing in digital, and then using analog effects and mastering to warm things up. There are even digital effects that try to emulate that analog sound. An additional theory should be presented. Since most of us were raised on analog sound and perhaps we all have a slanted perspective. Just as people enjoy songs (some of them bad) that remind them of the great past moments they had, analog sound may be similarly sentimentally favored. When we hear well done 96khz 24bit sound it may in fact be better than the best analogue 1/2 inch tape master recording, however it is unfamiliar. That lack of familiarity causes us to say it sounds worse. Before we know it we have our pitch fork and torch in hand, and have joined the mob on the way to the Dracula's castle. Maybe digital audio is already better, who knows ? In any case even when it objectively really is better, expect analogue zealots like myself to still proliferate, and have the objectiveness to ask. Finally when it comes to using the ever present large back lit Phase Linear VU meters using a pointer dancing romantically on the front panel to attract a vintage audience to a new digital amplifier, they take on a new meaning. Rather than the term "VU" standing for the industry term "Volume Unit" a unit measure of sound, in digital applications these meters take on a new meaning "Virtually Useless". So, coupled with the increased cost of digital components, VU mechanical movement meters that are inaccurate (when used in digital applications), and the seemingly insatiable desire of today's audiophiles romantic involvement with traditional vintage warmth and bottom end sound, perhaps we have jumped the gun to soon and just need to slow down a bit or two.

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awesome power! i can barely get the meters to move before it shakes my living room! attractive front panel,beautiful vu meters. this amp rivals or exceeds amps costing much more today!

gets very hot! meters are slow even though they look nice!

i got a beautiful phase linear 700b on ebay. i had trouble with it at first. the right channel blew! but the repairman said the channel was fixed before using the wrong transistors! i got it fixed and im in love with it. it sounds as beautiful as it looks!

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Inaudible noise level, good power, no pots or switches to get dirty and generate noise, looks intimidating, rack-able.

Power supply and output transistor cooling fins get hotter than the fires of hell. If my room was not presently air conditioned I would not be comfortable running this thing for more than a few hours without adding more heat fins (a modifcation made by phase linear themselves on the second version of this amp) and getting a fan pointed at it.

Got it as a gift, from the original owner. I've build my stereo mostly from vintage sansui components, using a 9090 for the fronts, a 5000X for the rears, and a 5000A for center channel. However, this thing puts out so much clean power I'm sure I will find a use for it. Once I pick up a set of Bose 901's, I think its power will finally be put to best use.

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Sansui 9090 (Seems just as clean if you use the main ins, but a bit less power. Nice becase it will power 4 speakers at a time.)