This may be an OK amp if you don't push it. I used to drive Dalquist DQ10's with mine and it was not a good match. The dahlquists eat power and I used to pop fuses in them constantly when I turned it up. Then after about a year later and my second repair the tech recommended a Macintosh MC2200. The year was 1980. I decided to buy the Mac. Till this day 29yrs later I have never blown a fuse in the speakers and have NEVER had an amp failure since I bought the Mac and have pusher it longer and harder for the last 29.

Super true reproduction in sound,seperation, and high and mid.

2 channels, but that's all they had back then.

I had now idea. It just looked cool. It came with an Onkyo Preamp, Pioneer SR-750 parametric EQ, a Technics auto reverse cassette deck, and a tired turntable. It took time to "work" all the sliders and knobs to "get the dust out". I set it up with my Polk Audio speakers, they could not handel it. Then i connected them to my "other book shelf speakers" KLM which have a great high mid sound. No need for any more bass. The result was mesmerizing. It blew away my newer Yamaha amps sound. Now i connect it to my $40.00 MP3 player. Which of coarse, does not have the super true responce of my 80's vinyl. Which i will never abandon. Either way, the sound is a lesson in Audio and Visual education. Seperation in channels, clear distinction in instruments. I had no idea what i was missing out from my recordings on. I have only hit 75 watts because of the ungodly output. My neighbors are so ready to drop a sound bomb on me. Except i don't play my music past 8:00 P.M. plus the genre of music is so diverse they don't know what to hate. Yes it does WARM up. but if it is good enough for the WHO it's good enough for my gettoplex. Last amp i saw on sale on ebay got $336.00.
I would be an idiot to let it go for any price.Vintage rules.

Similar Products Used:

Marantz 7725, Yamaha, Denon.

Timeless brushed aluminum faceplate
LED wattage meters
"Tube-like" midrange and smoothness
Giant transformer
Power
Giant heat sinks

Small power cord
Accessibility to speaker binding posts when using large guage wire

The Phase Linear 400 Series II is one of the finest amps ever created. My dad purchased this amp for about $500 in 1975 and it has worked perfectly ever since. Until a few weeks ago, this amp was hooked up through a vintage mixer to a mid-end CD player and high quality JBL studio monitors. It sounded good, but I was sure that it could sound better. Recently, I acquired a flagship Sony CDP-705ES CD player with outboard transformer and variable audio output. This allowed me to hook the Phase Linear 400 directly to the CD player's variable audio output allowing for a simple set-up with an amp, cd player and speakers; a configuration rarely encountered in audio systems. The speakers I am using are KEF 103/4 Reference towers, also vintage, but incredible sounding. I am biwiring the speakers using two single sets of Audioquest Bedrock cable, and JPS labs interconnects. Unfortunately, the Phase doesn't accept aftermarket AC cords, or I might consider upgrading that too.
When I finally finished hooking this beauty up, I popped in a Verve copy of Ella and Louis. From the moment the first notes were sung, I was astounded- I had never heard this amp sound quite so sweet! The soundstage and imaging were unbelievable...they placed Ella pinpoint at the center of the room, the speakers practically disappeared. The smooth midrange of this amp was only accentuated by the KEF's UNi-Q drivers, at times I forgot that I was listening to solid state. I continued to play a variety of material on this amp, and it performed perfectly with all of it. Ranging from rock, classical, jazz, folk, and even some ukelele, this amp delivered effortless, encapsulating sound that I listened to for hours.When I brought my dad over to hear his "baby" sing in a set up as clean as this, he couldn't wipe the smile off his face. We listened to MFSL version of Dark Side of the Moon... I only wanted to play a few tracks but we ended up starting from the beginning and listening to it in its entirety. This thing just kept singing.
In the darkness of the living room, the sound seemed to eminate from some point in the center of the room, but all that we could do was sit back and watch the red wattage LEDs dance to the beat of the songs. Astonishingly, we never peaked over 10 watts of power consumption, although the amp is capable of 200 per channel into 8 ohms (and these are 4 ohm speakers)!
This amp could easily drive any speakers out there, and can usually be found at pretty good price. At about 20 lbs, the transformer on this thing is huge! I hope to keep it around for a while, as I don't think it can be beat at anywhere near the price. For the lucky man who gets one of these handed down to him: hold on to it, you will experience years of great listening from a legendary piece of equiptment.

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The current system consists of
Phase Linear 400 mkII
KEF 103/4 Reference Series
Sony CDP-705ES

Sounds comparable to
vintage Audio Research tube gear
The closest sound that I have recently heard to this unit is from the Pathos Acoustics Classic One mkii hybrid integrated amp.

When compared to the Crown IC-150 pre-amp and DC-300 power amps of the era....none.

Let's start with the 400 power amp...decent sound quality....very poor quality of engineering. Allow me to elaborate:

1. Too little heat sink area.
2. Power supply not centrally located making moving and mounting extremely difficult.
3. When 'THE WHO' used them in 1972 or 1973 the anps actually burst into flames on stage! This earned them the name 'FLAME LINEAR'.

Now on to the 4000 pre-amp:

1. Too many gimmicks.
2. Too many circuit boards too close together and not secured on the top allowing them to touch, putting the amp into overdrive and killing your tweeters.

I bought a 4000/400 combo in 1984 from a friend at work. He said it did not work so he let it go for $50.00! You read that right. The amp sounded ok but the prer-amp had a mid frequency noise and when two boards touched it drove the power amp into clipping and killed both tweters in my L-100/A JBL's. I bought some fiber-glass sheet and installed it between all boards and the amps did ok after that.

Sold it for $500.00 and bought a Crown SL-2, POWER-LINE 3 and Boston Accustic A-400's for $450.00.

In the end it was not a bad deal for me.

Customer Service

N/A

Similar Products Used:

Crown SL-2 pre-amp
Crown Power-Line 3 and Power Line 4 power amps
Crown DC 300A-SERIESII power amps

Soundstage depth if paired with good speakers
Detail if teamed with good preamp
Bags of power

Crappy power cord, but hey, it's old school

Over the years I have heard a lot of negative reviews about many of the Phase Linear product, and definitely some for good reason.
I've also owned many, many other amps, mostly a lot more expensive that I won't name just so as not to cause any emotional injury, that didn't sound half as good.
I have also owned Carver amps, such as M1.0t, M4.0t, Silver t, as well as others and this 400 Series II blows all the Carvers away big time in the sound quality category.
I've always found the transfer function style far too rolled off and uninteresting sounding for my liking, as if B.C. went just a little to far trying to make it sound tube-like, whatever that might be...but that's another long story as I also own a complete tube system which is highly detailed and anything but bloated and dull as many refer "tube-like" as.
Anyway, so far I have found this unit to have bags of power, very detailed and deep soundstage, with just enough warmth so you could listen forever without ear drums drying out, cracking and bursting into flames, but lots of detail, deep soundstage, and great vocal presentation.
I bought this not long ago, and had a lot of hesitations, but dangit, I love the way it looks and always a sucker for the vintage stuff. Glad I didn't change my mind. I know I probably paid more than it's worth, but rather pay more for a perfect one, that a little less for crap-O-la.
No hums, no speaker hiss, no turn off thumps, just works fantastic for an antique.
This unit is mega-old and never been worked on, yet the DC offset is still right on spec and never been adjusted. Not many amps can boast that....well my mint Hafler still does, but not much really can when they get ancient.
Anyway, I know I've built this up pretty good, and don't get me wrong, it isn't the best there is or even close, but it sure is decent for the money and if you have a reasonable budget, don't want to sacrifice above average sound for muscle-bound power, this is one choice to look for if you can find one that's been looked after.

Customer Service

none to be had other than independants

Similar Products Used:

Hafler 220
Hafler 500
Conrad Johnson 250-please, not even close
Adcom 555 - better than the CJ
Yamaha
Carver - quite a few and none as good
Sonic Frontiers....mmmm...nope these are better
Bryston..(any)..ok I suppose in durability and power but far to clinical and dry

POWER
Detail, not brash
Deep soundstage
Warmish vocals
Good looks

Crappy power cord, but hey, it's old school

Over the years I have heard a lot of negative reviews about many of the Phase Linear product, and definitely some for good reason.
I have owned many Carver amps, such as M1.0t, M4.0t, Silver t, as well as others and this 400 Series II blows all the Carvers away big time in the sound quality category.
I've always found the transfer function style far too rolled off and uninteresting sounding for my liking, as if B.C. went just a little to far trying to make it sound tube-like, whatever that might be...but that's another long story as I also own a complete tube system which is highly detailed and anything but bloated and dull as many refer "tube-like" as.
Anyway, so far I have found this unit to have bags of power, very detailed and deep soundstage, with just enough warmth so you could listen forever without ear drums drying out and cracking, but lots of detail and great vocal presnetation.
No hums, no speaker hiss, no turn off thumps, just works fantastic for an antique.
I've also owned many, many other amps, mostly a lot more expensive that I won't name just so as not to cause any emotional injury, that didn't sound half as good.
This unit is mega-old and never been worked on, yet the DC offset is still right on spec and never been adjusted. Not many amps can boast that....well my mint Hafler still does, but not much really can.
Anyway, I know I've built this up pretty good, and don't get me wrong, it isn't the best there is or even close, but it sure is decent for the money and if you have a small budget, want power but above average sound, this is one choice to look for if it's been looked after.

Customer Service

Little to no chance of that!

Similar Products Used:

B&K - far too warm
Carver - paleeeeze
Conrad Johnson solid state - not even close!
Adcom - better than same priced CJ by a long shot
Denon - about the same quality sound, just different
Pioneer
Yamaha - highly under rated
Bryston - better than their stuff of the same year and probably even NRB (too clinical)
Marantz - again, in the same league, just different sound
Sonic Frontiers - mmmm...no not as good as this stuff

POWERFUL and LOUD
Can take Direct hit by Lightning
need I say more!!!!
!!!!

You need a welded steel rack ie audio analysts style

In my opinon the Phase Linear 700 is the best amplifier in the world period!!!
in 1978 I purchased my First Phase Linear 700B From Pacific Stereo right out of boot camp in San Deigo it was a demo and was hooked up to the Infinity Quantum Line Source Speakers it Sounded incredidable so i bought it for what I had in my Pocket 600.00 in cash. But my love was sound Reinforcement When I got to Great Lakes Navel Training Center I bought another 700B and proceded to put them to use doing live music at the Helm Club with the Big Tips Band a local band From Millwauki Wisconson They had the Bran new 9440 A Altec Power amps $3400.00 each !!!!!!! I told them my Phase Linear 700B would blow those away by miles and they did but not befor they critisised them as the FLAME LINEARS So i Put navy slow Blow 20amp fuses out of the computer I was tech for. in the power supply (4) of them we never had another problem with them !!!they used those altecs 9440A at the Helm Club again because the Phase Linears Blew them away many other bands used the instead of the crown DC300 and 300A Power amps at Close Encounters Club nearby I own 4 Crown Power amps as well 3 PSA 2 1 K2 They a good amps but they dont come close to a Phase 700 I own Crest CA12 CA9 CA6 Blows them away as well I own QSC amps MX Series I cant say Enough about the Phase Linear 700 its the Best I own 21 of them once they got dropped 8 feet off a fork lift at the loading dock at Roadway trucking at the all of them worked except one 400 now that is something I thought they were totalled!!!!! So did the repair place!!! I did a sound set up at a castle at 10,000 feet and there was no heat no windows my phase linears stood up to the the abuse BISHOP CASTLE for 2 years the coldest minus 50 degrees F even direct hits by Lighting could not stop my Phase Linears 700s I belive it is my duty to build a Million watt Sound System With These amps With Help From Other Phase Linear Fans Through Out the World!!! 1000 Phase Linear 700s are Required for the system Remember Clair Brothers, Pink Floyd, Audio Analysts
the WHO All had Phase Linears 700s D-500 and 400s!!! lets bring LOUD back 719-738-3666 starsoundandlight.com

Similar Products Used:

Crest CA 12
Crown PSA2
Crown k2
Macro Tech 5000
MacroTech 10000
QSC MX 2000
Crest 8001

Clean, accurate and tight. Gobs of power. Real power. Not peak watts or dymanic or some other bogus classifications. Nothing replaces 1970 RMS watts. If you want to draw back the big woofers while still maintaining clean mids and highs, you need the numbers. Simple math.

None so far.

As far as the cult that seems to follow most, if not all the Phase Linear gear, I have to comment that is probably due in part to the fact that is just plain sounds good. I have a pair of 400's being pushed by a 4000, all series one gear, and it sounds fanastic. All of the units have undergone the usual reworking by Bill of Circle Stereo in Texas and perform flawlwssly. I don't know what some posters here are referring to by "Negative feedback" and it that just don't sound good. I am listening to the system as I type this. Very musical, nice headroom, clean without being shrill, balance bottom end, without thumping. Never any fatique no matter how long I listen to it. The old Phase gear, IMO, deserves to have a cult type following. I has earned its right to its place in the history books. The 4000 preamp is a real item in its own right. The Kenwood speakers, although not high end in cost, handle the gobs of watts well, should I choose to unleash them. However, even at levels where the meters are just bearly bumping a bit, it is clear and solid. So, two thumbs up for Bob Carver. Older is not always not as good. Just look at wine! Rock on!!

Similar Products Used:

None, in a class all by themselves.

Plenty of pure clean power. Very durable if used correctly(Do not bridge this amplifier!)8ohm load is perfect, You can run 4ohm loads, But there really is no need.

None that I have ever encountered. Phase linear 400's are widely available on ebaY. Well worth the money people get for them.

My Phase Linear 400 has been in my family since before I was born. It is completely original with no repairs ever done to it. Mine was manufactured in June of 1972 and is the 103rd unit made. The sound that comes out of it is unbelievable. I have it mated to a Crown IC-150 preamplifier and a set of Source Technologies speakers hand built in Connecticut. http://www.sourcetechspeakers.com Phase linear amplifiers are very hard to come by completely original and I consider myself extremely lucky to own one.

Similar Products Used:

Many over the years.

power,headroom

no on/off switch-i had to hook it up to a surge supply strip that has an on/off button,but it was no big deal

i love the power of the phase linear 400 series 2-also,it looks great with the large aluminum front maybe someone can help me-i am not sure where to set the input sensitivity controls on the front to get maximum benefit and cleanest sound also,i read a reply by cougar,and he said that his amp sounded much,much better after he made 3 upgrades to it: power supply,driver board,and in/out connectors does anyone know who does this type of work,and approx the cost? thanks much,ralphieboy

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rotel,luxman,yamaha