• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Phase Linear 400 vs. Pio Spec-4 vs. 700M etc.

theblackknight

theblackknight

Mikes off! No recording!
Lately, I have been interested in vintage power amps(even though I dont have any).

I was wondering your opinions of each of these, their SQ, BQ, pos's and neg's, etc.

I recently "discovered" Phase Linear gear. I have to say, the looks are as cool as hell!!!:thmbsp: :thmbsp: :tresbon:
The back are kind of different though, they dont go back very far at all in depth, this is one thing which I really ??? about. All the stuff is exposed on the back of the amp.:scratch2:


Here is a small list of compareable ~150wpc power amps from the 70's. Please tell me which other ones I am missing. I am just wondering about your opinions about each.

Phase Linear 400
Accuphase P-300
Pioneer Spec-4
Kenwood 700M
Rotel RB-2000
Sansui BA-2000
Marantz 510M
Yamaha B-2
Setton BS-5500
Crown DC-300
Kenwood L-07M
Kenwood L-07mkII
 
Register to hide this ad
I don't have hands-on experience with these amps (other than turning the knobs on PL pre-amps in the Speakerlab listening rooms back in the 1970's) .

..but I thought I'd pass on a site with alot of good technical details on the Phase Linear line hosted by one of the 1970's employees, if you haven't seen this: http://www.hometown.aol.com/PhaseTek/
 
To the best of my knowledge, the Phase Linear 4000 is a preamp. There is a Phase Linear 400, which is their 200WPC amp. Judging by the rest of your post, I'm guessing this is what you are asking about.

Not being deep and exposed is not a problem in my opinion. If I remember correctly, the transformer and heatsinks are mounted on the back of the 'housing' thus reducing the components that would be inside. You don't need much space to hold a couple power supply caps and driver boards. The Crown DC-300 is very similar in thought (though missing from your list). Having the heatsinks on the outside is smarter than putting them inside a box.

Sorry can't comment on any of the amps you ask about. I have had experience with the Phase Linear 700B and 400. The larger Advents sounded quite nice with either.
 
Henry: Here are some more.

Rotel RB-5000
Kenwood L-09M
Pioneer Spec 2, 4. 1 is a preamp
Sansui BA-3000, BA-5000
 
Phase Linear made two common amps, the 400 (~200WPC) and 700 (~350WPC) series. Both are similar in design.

House de Kris is right, they put the transformer, output transistors, and heatsinks out in the open to make for a smaller package and better cooling. The 400 got its heatsink upgraded along the way since the original was a little undersized for heavy use.

I'm only a recent PL 400 owner, but it seems like a nice amp. It's incredibly easy to work on, one of the big reasons I traded for one. PL's designs get a lot of result out of a pretty simple layout. A downside to this is that if something fails to tends to fail dramatically, but from everything I've heard the reports of PL malfunctions are greatly exaggerated.

I know your title was probably a misprint, but you can't use an amp without a preamp. The 4000 series of preamps are just as good as, possibly better than, their amplifiers. Really sweet stuff. Not as easy to work on, though.

Edit: Oh yeah, just a note. I completely lost interest in monster receivers after owning one (Marantz 2600, close to the ultimate TOTL) for a few years now. It's huge, it's heavy, and it's all in one box. I'm getting more and more into seperates because of how flexible everything is. Change the preamp, change the tuner, move stuff around on a shelf, etc. Easier to fix, too.
 
That was pretty much SAE's heyday. Bunch of power amps in the 120 watts+ category - Mark III/A/C/CM, Mark XXIII, Mark XXIV, 2300, 2400, 2400L, 2500, 2600, etc.

David
 
SoCal Sam said:
Henry: Here are some more.

Rotel RB-5000
Kenwood L-09M
Pioneer Spec 2, 4. 1 is a preamp
Sansui BA-3000, BA-5000
Click to expand...
The Rotel RB-5000 was 500wpc.

Im making a list of ~150wpc amps. Thanks though.:thmbsp: :thmbsp:

Also, sorry about the PL misprint. I meant to say 400.:yes:

***Moderator Response: Thread Title Fixed***
 
Last edited by a moderator:
My dad had one of the first PL 400 amps, running a pair of SAE Mk XII speakers. Great sound, but if run into low-impedance loads, they had an unfortunate tendency to become very hot and unstable.

I think, but don't know, that it's because the heatsinks are just single sheets of aluminum that stick out in back of the small body of the amp, and there isn't quite enough cooling capacity in that design.

I was only in high school, and my dad was the stereo nut, but what I recall from that time is that the PL700 and 400 were the first popular high-wattage amps. All the others came later and had the opportunity to "perfect" their designs once Carver showed it could be done and that there was a big market. My childhood recollections can't be relied on, so does anyone know the actual history?
 
One thing I remember is they were called "flame linear" because if the were run hard they would literally shoot flames as they they failed........
 
Negotiableterms said:
... they had an unfortunate tendency to become very hot and unstable.

I think, but don't know, that it's because the heatsinks are just single sheets of aluminum that stick out in back of the small body of the amp, and there isn't quite enough cooling capacity in that design.
Click to expand...

I recall the nickname for the amps was "Flame Linear" - don't know for sure if that was earned or not :D
 
I'm not the one who should be posting this, but I'm here right now... Because they were some of the first affordable high-watt amps they got widespread and heavy use professionally. They were meant for home stereo, not racked ten at a time cranking out bass for Grateful Dead shows. Lots of overuse combined with a rather light design led to failures, and the negative reputation. Once those outputs started overheating things go downhill, fast. The models custom tailored for pro use were beefed up and had better cooling.

They're not the most bulletproof amp out there, but in normal use (and with proper attention paid to PL-specific issues during repair) I don't think there's any serious problem. And no one's ever faulted them for their sound.
 
I used 4 of the 400's to push 4 Bose 901's back in the 70's.I had them running mono,one into each speaker.They run hot.But Boy could they make those 901's sing.
 
In the late 70's early 80's all the local R&R bands had racks of 400's. I worked at a pro sound shop that sold them. Put a 4" muffin fan blowing on them and they'd hold up to PA use. We also supported the xfmr by extending one of the mounting bolts that aligned with a bracket in the rack.
 
brown13 said:
One thing I remember is they were called "flame linear" because if the were run hard they would literally shoot flames as they they failed........
Click to expand...

The comment about some folks of old referring to them as flame linears is true to the extent that it was in fact a rival company of Clair Brothers that started the comment. When Carver first provided the 700 power amplifier as a commercial offering, Clair Brothers actually contracted for a 'commercial version' to be built and provided to them. It was beefed up to handle the enormous load of providing 'stadium wide rock sound' for hours on end, throughout an entire tour, tour after tour. The rival company used stock home versions to provide the same sonics without contract and ended up with problems, reacting with calling them 'flame linears' due to the fact that they burnt them up. No shooting flames occurred, I assure you. Audio Analyst contracted for a commercial version as well and had no problem with their version at the Olympcs in Montreal whereas Phase Linear powered the entire complex. Driving 4 to 1.5 loads they must be cooled with a muffin fan naturally, however, handle it without stress and with complete stability. I have owned dozens of them and still have seven in regular use driving demanding Infinity loads and have never had a single issue or failure.

Vito

Vito
 
Yes, with the 700 and 400 it's all about transferring the heat, if you do that , zero problems and thumping sound. Cooling fans good.
 
You must log in or register to reply here.
Back
Top Bottom