Vintage HiFi Audio Forum

Audio Discussion => DIY => Topic started by: OldiesButGoodies on June 04, 2016, 08:30:08 PM

Title: Phase Linear 400 Refurbishing Project
Post by: OldiesButGoodies on June 04, 2016, 08:30:08 PM
Creating a thread to store pictures from my slowly unfolding Phase Linear 400 refurb. 

As purchased:

(https://c4.staticflickr.com/8/7105/27401168515_5c796fa0b1_k.jpg) (https://flic.kr/p/HKm9KV)Untitled (https://flic.kr/p/HKm9KV) by Jose Sifontes (https://www.flickr.com/photos/jsifontes/), on Flickr

One of the power supply can caps was shorted so I replaced them with a slightly higher value and voltage set of caps (from 5900 uf to 6800 uf):

(https://c5.staticflickr.com/8/7029/27367473596_fc32ac611f_k.jpg) (https://flic.kr/p/HGnsr3)Untitled (https://flic.kr/p/HGnsr3) by Jose Sifontes (https://www.flickr.com/photos/jsifontes/), on Flickr

The new cans are smaller and do not use screw terminals,  so had to use a rubber spacer to retain the original mount and adapt O terminals so the original Phase Linear wiring was not affected:

(https://c4.staticflickr.com/8/7302/27393647931_ac2547063f_k.jpg) (https://flic.kr/p/HJFB9F)Untitled (https://flic.kr/p/HJFB9F) by Jose Sifontes (https://www.flickr.com/photos/jsifontes/), on Flickr

Also added bypass caps per OCCD's suggestion:

(https://c2.staticflickr.com/8/7296/27393644921_5cbd810b02_k.jpg) (https://flic.kr/p/HJFAfM)Untitled (https://flic.kr/p/HJFAfM) by Jose Sifontes (https://www.flickr.com/photos/jsifontes/), on Flickr

I bought all the caps to redo the driver board:

(https://c6.staticflickr.com/8/7133/27393643541_3da78260ad_h.jpg) (https://flic.kr/p/HJFzQZ)Untitled (https://flic.kr/p/HJFzQZ) by Jose Sifontes (https://www.flickr.com/photos/jsifontes/), on Flickr

But it sounds so good as-is that I am thinking of not doing anything to that board for now (if not broken,  don't fix it..)

Next is the install of the blue-LED mod  and the speaker protection relays (neither has arrived).   And finding a Phase Linear 2000 to pair it up with. 

Will post pics after that as well. 

 :)

OBG


Title: Re: Phase Linear 400 Refurbishing Project
Post by: F1nut on June 04, 2016, 09:09:57 PM
Looks fine so far. I like the wood cabinet.

I'm sure you meant 5900uF, right?
Title: Re: Phase Linear 400 Refurbishing Project
Post by: OldiesButGoodies on June 04, 2016, 09:28:43 PM
Looks fine so far. I like the wood cabinet.

I'm sure you meant 5900uF, right?

Yes! corrected that typo...  Thanks for the + feedback Jesse.

Reg,

OBG
Title: Re: Phase Linear 400 Refurbishing Project
Post by: Kingman on June 05, 2016, 05:51:48 AM
What led you to try a Phase Linear Pepe?
Title: Re: Phase Linear 400 Refurbishing Project
Post by: OldiesButGoodies on June 05, 2016, 09:34:40 AM
This Phase Linear 400 showed up on Clist locally at a good price,  so I snatched it.  I want to have a second system so I thought I could use this as the starting point. Never owned a pre-Carver Carver product and I liked the fact that it came with a wood case in good shape.  Happy so far - just afraid to use it with the big speakers until the relay is installed!
Title: Re: Phase Linear 400 Refurbishing Project
Post by: Kingman on June 05, 2016, 09:51:22 AM
I'm listening to my Dual 500 right now...they are great amps and the bad rap they have acquired is undeserved...most were ran in professional applications and abused to the max!
Title: Re: Phase Linear 400 Refurbishing Project
Post by: papabearjew on June 06, 2016, 01:17:27 AM
One mod you should do that was never done to mine is the speaker protection mod like White Oak offers. Every time I shut it off I held my breath for the very loud shut down thump that went through your speakers. I think that mod also protects your speakers from the straight DC issue they're known for. I still have to have my PL400 looked at to see what damage I caused to it. You may want to look online and see some photos of it with the blue LEDs. I like the natural color that they came with better. It keeps with the  vintage heritage of the amp. They do offer LEDs in natural colors. My opinion of course.
Title: Re: Phase Linear 400 Refurbishing Project
Post by: OldiesButGoodies on June 06, 2016, 08:44:33 AM
Hey PBJ -

I did look at the Oak Audio mod for speaker protection,  but found it a bit expensive at 100 for what is essentially a uPC1237 chip and some relays,  so I ordered it separately on ebay for a lot less (1/10th the price) and I am going with that.   Did notice a bit of a thump on shut off,  not too bad (I have heard much worse - I am looking at you, Melos equipment) and thought it would be taken care of by a ceramic cap by the power feed but not sure yet.  Come to think of it I could use the relays controlled by the 1237 for that as well,  just need to think it through a bit. 

On the meters - I ordered the blue LED kit.  Guilty,   I like the blue light (and I can barely see the needles dancing with the original lights).  I am trying my best to do everything in such a way that a future owner concerned with originality can reverse my work,  so along with the old can caps I will store the existing lighting board so it can be swapped back in.   

As I mentioned earlier,  I am surprised at how good this amp sounds for being a "budget audiophile amp" of the early seventies.

OBG
Title: Re: Phase Linear 400 Refurbishing Project
Post by: papabearjew on June 07, 2016, 12:47:18 AM
OBG sounds good
Title: Re: Phase Linear 400 Refurbishing Project
Post by: F1nut on June 07, 2016, 01:26:49 AM
OBG sounds good

Does he now?  :P
Title: Re: Phase Linear 400 Refurbishing Project
Post by: Kingman on June 07, 2016, 09:05:04 AM
OBG sounds good

Does he now?  :P
Sounds a little dull to me... :laugh:
Title: Re: Phase Linear 400 Refurbishing Project
Post by: OldiesButGoodies on June 07, 2016, 05:28:24 PM
And now I also have the Phase Linear 2000 pre to pair it up with...  Wil start working on the blue LED mod tonight. :P
Title: Re: Phase Linear 400 Refurbishing Project
Post by: OldiesButGoodies on June 07, 2016, 09:34:24 PM
This is an absurdly easy mod if you buy the kit from Oak Audio - very well done:

Before:

(https://c3.staticflickr.com/8/7167/27255843650_7c05751da7_b.jpg) (https://flic.kr/p/HwvjJN)Untitled (https://flic.kr/p/HwvjJN) by Jose Sifontes (https://www.flickr.com/photos/jsifontes/), on Flickr

Boards side by side:

(https://c1.staticflickr.com/8/7301/26922910104_f85a53f5d2_b.jpg) (https://flic.kr/p/H25Xcf)Untitled (https://flic.kr/p/H25Xcf) by Jose Sifontes (https://www.flickr.com/photos/jsifontes/), on Flickr

Installed:

(https://c8.staticflickr.com/8/7372/26923939783_e52b1d67ec_b.jpg) (https://flic.kr/p/H2behk)Untitled (https://flic.kr/p/H2behk) by Jose Sifontes (https://www.flickr.com/photos/jsifontes/), on Flickr

And lit up:

(https://c2.staticflickr.com/8/7318/27532298785_69a4c7eda6_b.jpg) (https://flic.kr/p/HWWedD)Untitled (https://flic.kr/p/HWWedD) by Jose Sifontes (https://www.flickr.com/photos/jsifontes/), on Flickr

I like the look.   :'(

OBG
Title: Re: Phase Linear 400 Refurbishing Project
Post by: MacGeek on June 08, 2016, 05:33:28 AM
Looking good.  There is just something about big blue meters.............
Title: Re: Phase Linear 400 Refurbishing Project
Post by: OldiesButGoodies on June 14, 2016, 04:05:26 PM
Minor mishap last night while recapping the control board - blew one of the fuses in search of a 12V signal (this thing has 80V all over the place) and the %$%$# fuse is that strange AGX size.  Instead of searching for a new fuse I am installing a regular size fuse holder and going on with life.   ::)

(https://c2.staticflickr.com/8/7410/27047443033_cdf4af6c8e_b.jpg) (https://flic.kr/p/Hd6duH)Untitled (https://flic.kr/p/Hd6duH) by Jose Sifontes (https://www.flickr.com/photos/jsifontes/), on Flickr
Title: Re: Phase Linear 400 Refurbishing Project
Post by: papabearjew on June 14, 2016, 08:07:58 PM
If you're talking about the 5 amp fuse in the odd size I have some I bought off eBay if that helps
Title: Re: Phase Linear 400 Refurbishing Project
Post by: OldiesButGoodies on June 14, 2016, 09:46:37 PM
A fuse holder and 34 painfully small caps later, the PL400 control board is done, and surprisingly, the amp still sounds great.   There is no consistency to the polarity of electrolytics on this board,   so you really have to follow the schematics or easier yet the PC board diagram,  which I am attaching below for reference in case anyone wants to do this recap job in the future:

PL400 Control Board
PC Board Layout:
(https://c3.staticflickr.com/8/7546/27400566570_5ae58c6e6b_b.jpg) (https://flic.kr/p/HKi4Py)Screen Shot 2016-06-14 at 9.33.55 PM (https://flic.kr/p/HKi4Py) by Jose Sifontes (https://www.flickr.com/photos/jsifontes/), on Flickr

Schematic:
(https://c2.staticflickr.com/8/7065/27604575281_78623eab6a_b.jpg) (https://flic.kr/p/J4jEv8)Screen Shot 2016-06-14 at 9.34.07 PM (https://flic.kr/p/J4jEv8) by Jose Sifontes (https://www.flickr.com/photos/jsifontes/), on Flickr

Parts List:
(https://c3.staticflickr.com/8/7476/27400566610_9f2f13330b_b.jpg) (https://flic.kr/p/HKi4Qf)Screen Shot 2016-06-14 at 9.34.26 PM (https://flic.kr/p/HKi4Qf) by Jose Sifontes (https://www.flickr.com/photos/jsifontes/), on Flickr

After recapping:
(https://c7.staticflickr.com/8/7095/27578054182_8262383612_b.jpg) (https://flic.kr/p/J1YJGN)Untitled (https://flic.kr/p/J1YJGN) by Jose Sifontes (https://www.flickr.com/photos/jsifontes/), on Flickr

Still works, sounding pretty good,  will test in the main system on the weekend, a tubes vs. old solid state comparo:
(https://c1.staticflickr.com/8/7454/27643833616_2ae52cb2e9_b.jpg) (https://flic.kr/p/J7MSCY)Untitled (https://flic.kr/p/J7MSCY) by Jose Sifontes (https://www.flickr.com/photos/jsifontes/), on Flickr

Still need to install the relay - that will be tomorrow:
(https://c7.staticflickr.com/8/7260/27379482190_889d306070_b.jpg) (https://flic.kr/p/HHr1aL)Untitled (https://flic.kr/p/HHr1aL) by Jose Sifontes (https://www.flickr.com/photos/jsifontes/), on Flickr

Then start work on the Phase Linear 2000 (which I hope will not need a full recapping):
(https://c6.staticflickr.com/8/7369/27583726021_84b8667b1d_b.jpg) (https://flic.kr/p/J2tNK8)Untitled (https://flic.kr/p/J2tNK8) by Jose Sifontes (https://www.flickr.com/photos/jsifontes/), on Flickr

Will keep you posted, thanks for looking.

OBG
Title: Re: Phase Linear 400 Refurbishing Project
Post by: OldiesButGoodies on June 14, 2016, 09:48:13 PM
If you're talking about the 5 amp fuse in the odd size I have some I bought off eBay if that helps

Thanks PBJ!  Ended up putting a regular-size fuse holder - which required some Dremel action - thanks for the offer though!
Title: Re: Phase Linear 400 Refurbishing Project
Post by: Kingman on June 15, 2016, 06:29:27 AM
Thanks for posting your progress and photos. There is just something special about these amps...the birth of high power!!! The 400 was the first high $ amp I ever heard and that Sound and vision have followed me my entire life!
Title: Re: Phase Linear 400 Refurbishing Project
Post by: papabearjew on June 15, 2016, 10:01:24 PM
OBG, nice photos. Not sure what's wrong with mine. I forgot it was on as all the meter lights are dead. While it was on I disconnected the interconnects to it from the preamp. Something got damaged as the 5 amp fuse blew right away. Obviously I'm hoping it's nothing major. BJ had already recapped it and put all new connectors on it. I was so pissed when I found it used AGX fuses. I had to order them on eBay. I think I paid about $6 for 5 of them
Title: Re: Phase Linear 400 Refurbishing Project
Post by: OldiesButGoodies on June 16, 2016, 08:49:57 AM
Ok - will take a look at it when BJ brings it (and the reel to reel)  over next Monday,  while my understanding of the innards is still fresh.  Take care,  Pepe