Phase Linear 400 Amp

[A.wayne]

I ran them with the C100 cap bank and yes , its audio , one mans euphoria is another's anathema , Sonics aside we had issues with the pl400, 700, stability issues , smoke and fire issues...

This is also reflected by resale prices today compare PL PRICES To those of a 416 with c100 backpak ...

 

[A.wayne]

Don,

Agree on the complicated parts count of the 416 , we eventually replaced them with the 4b's , but never really had any issue's with the 416's , if memory serves me , it was due to a supply issue from Dynaco and moving on to the next "new" thing ....

 

[DonH50]

That matches my memory -- I think Dynaco (and many others) had problems obtaining transistors. The places I worked did not cary Dynaco thouhg I saw a lot of them; I am trying to remember if I ever actually worked on a 416 and do not think so (except to mod a few). It was relatively rare but had quite a following, like many things Dynaco. I never cared for the ST-120 (I think that was the model, lower power, reliability problems, harsh sound and high noise).

I had endless problems with my PL700 but the 700B seemed better. I do not recall any problems with the PL400; I am sure there were a few (long time ago). Maybe we got lucky...

Some of the early transistor designs had horrible reliability, and their tendency to have output Q's run away and short the supply rails to the speaker terminals was a pretty undesirable feature, IMO. - Don


p.s. The C100 was part of the reason a friend and I added a huge outboard cap bank to a Hafler 220 with very good results; we were surprised at how much better the bass became with the extra charge storage.

 

[rbbert]

My memory must be foggy ....

I remembered them as being unreliable , nonload tolerant beasties with sonics easily bested by others of the day, a Dyna 416 would walk all over any PL Product of the day and then there was Sansui's BA5000, MARANTZ M500, HK Citation 16, BGW, Pioneer Spec Series and Bryston's 4b....

To name a few .....

The reliability of the 400 was excellent; you may be letting the notoriously poor reliability of the 700 cloud your memory. I don't think the Bryston 4b was around back in '75 (at least in the USA), although I could be wrong. I did replace my PL400 with the Citation 16, but I can't say I remember much of a sonic difference.

 

[goldeneraguy]

I ran them with the C100 cap bank and yes , its audio , one mans euphoria is another's anathema , Sonics aside we had issues with the pl400, 700, stability issues , smoke and fire issues...

This is also reflected by resale prices today compare PL PRICES To those of a 416 with c100 backpak ...

I never had a problem with the PL 400 and mated to the PL 200 I found the combo excellent at the time.
After I parted with the 200 things were not the same.I decided to get the big Hafler for my Apt Holman.
I thought the PL combo to be better.

 

[Bill Hart]

I had a PL 700 (original), did a lot of systems with the 400 (I sold the stuff back in '73) and listened to those in a few friends' systems as well; I also owned a Dyna 400 new (factory built, not a kit). I think the PL 400 was the best sounding of the 3. The PL 700 (original) was the least reliable. I don't remember the Dyna being bad sounding, I remember the big selling point in the day was the 'DynaGuard' thing. Which I didn't really use....

 

[DonH50]

The Dynaco soft-clipping circuit got mixed reviews but I suspect few actually heard it (or knew if they did) in operation.

 

[A.wayne]

The reliability of the 400 was excellent; you may be letting the notoriously poor reliability of the 700 cloud your memory. I don't think the Bryston 4b was around back in '75 (at least in the USA), although I could be wrong. I did replace my PL400 with the Citation 16, but I can't say I remember much of a sonic difference.

It was 78 when we switched to 4B's and yes PL400 had issues, well unless you played them softly ....

 

[A.wayne]

I had a PL 700 (original), did a lot of systems with the 400 (I sold the stuff back in '73) and listened to those in a few friends' systems as well; I also owned a Dyna 400 new (factory built, not a kit). I think the PL 400 was the best sounding of the 3. The PL 700 (original) was the least reliable. I don't remember the Dyna being bad sounding, I remember the big selling point in the day was the 'DynaGuard' thing. Which I didn't really use....

The 416 was a different beast and put Dyna in with the big bwoys , with their C100 extra cap pak , nothing like a 400 ... In fact we had issues with our 4B's with noise after awhile, Bryston was real stingy with the caps, even when we requested bigger caps , they would tell us not necessary, we ended up sending them back every 2 yrs for re-cap under warranty ..

They still would'nt up the size .... great warranty .....

 

[Atmasphere]

Another amp from that period that was an impressive transistor amp (although not as powerful) was the SouthWest Technical Products (SWTP) Tiger. It was offered as a kit but easily took the PL400 to task as long as power was not the variable.

I encountered an HK Citation 2, which I rebuilt as it was in desperate condition; on my speakers (Fulton J modular, this was the late 70s) there was no contest and that was the end of use of the PL400, SWTP, Citation 11 and a few others. Never looked back.

A lot depends on the speakers being used! It is incorrect to assume that any amplifier can drive all loads correctly.

 

[A.wayne]

Agree , back then as now life begins at 2 ohm ..

 

[mep]

The PL 400 Series 2 will play as loudly as your ears can tolerate on moderate impedance speakers. The two that I own have worked flawlessly. And no, they don't have the grounded to the center of the earth bass that the KSA-250 does, but their bass is damn good. I find the PL 400 Series 2 amps to be in the "Jack be Nimble, Jack be Quick" category.

 

[MarinJim]

I miss my meters.

 

[mep]

I miss my meters.

I like the LED meters on the Series 2 amps. The meters give you the visual impression of speed.

 

[A.wayne]

I miss my meters.

I miss all meters and worse Pre's that actually did something ....

 

[Tonepub]

Got a 400 in here a while back to do a vintage article. Not a bad amp at all. Kind of grainy overall. Don't think I'd say it gave any of the modern amps any threat, and in comparison to the ARC D-79 that I had back in the 80's and again in the 90's not even close. (grabbed a friends' D-79 in mint condition for a quick comparison) I think JV likes to wax poetic about things he thinks he remembers from 30 years ago...

I think a lot of us gravitated to the PL 400 and 700 back then was the dynamics we weren't getting from a lot of the common amps of the day in the 35-60 watt range. Certainly an important part of music. The Phase Linear amps offered that excitement that made me crave big amplifiers to this day.

Not a bad trip down memory lane for a few hundred bucks though.

It's kind of like saying a 79 Kawasaki KZ1000 is a better bike than a new ZX-10. Great memories and still fun, but not better.

Now that Krell KSA-50 we just got in, that was pretty impressive in comparison to current products....

 

[mep]

Was the 400 you had for a listen the original version with the VU meters or the Series 2 with the LED meters?

 

[Tonepub]

Both, actually....

Not that much different.

 

[mep]

For the money you can buy them for, they are damn good amps. Having owned many ARC amps over the years, I would certainly take the PL over most of the old ones for sure. You alluded to the KSA 50 possibly giving newer amps a run for the money. I have a KSA-250 that has been back to Krell to be repaired, recapped, and brought up to spec and it is very special amp IMO. I'm pretty sure you could spend far more and receive far less in sound quality.

 

[MarinJim]

I don't know why no one has mentioned the designer, Bob Carver. But I moved on to SAE during the '80's, and then on to the new owner Of Theta, Morris Kessler from SEA and ATI. I think he knows what he is doing.