Has anybody rebuilt a Phase Linear 400 ?.
Are mj15003/15004 suitable to use as outputs, and are any modifications required (for stability), or desired ?.
Thanks, Eric.
Are mj15003/15004 suitable to use as outputs, and are any modifications required (for stability), or desired ?.
Thanks, Eric.
PL400 rebuild
Hi
I have rebuilt many of these.
Do not use the MJ15003/4 devices as BVceo is only 140V. Use the MJ15024/5 complements instead. If a Series 1 amp you will only need the MJ15024 devices.
Stability is not a problem with these devices in this amp. I have made this change on 4 PL400s and my PL700B as well.
Good luck with your amp.
Hi
I have rebuilt many of these.
Do not use the MJ15003/4 devices as BVceo is only 140V. Use the MJ15024/5 complements instead. If a Series 1 amp you will only need the MJ15024 devices.
Stability is not a problem with these devices in this amp. I have made this change on 4 PL400s and my PL700B as well.
Good luck with your amp.
As I recall the 003/4 are a little slow. I would try the
MJ15022-27 types, which are faster and more rugged.
MJ15022-27 types, which are faster and more rugged.
Look at this URL
If you have not already turned this up on your own, take a look at:
http://hometown.aol.com/PhaseTek
If you have not already turned this up on your own, take a look at:
http://hometown.aol.com/PhaseTek
The PL400 runs on ±85V so you need a minimum of 170V rated part, the MJ15003/04 won't cut it.
The MJ15024 is OK for the 400, but use the MJ21194 for the 700, it runs on ±110V, SOA at 100V on the MJ21194 is 2X the MJ15024.
The MJ15024 is OK for the 400, but use the MJ21194 for the 700, it runs on ±110V, SOA at 100V on the MJ21194 is 2X the MJ15024.
I also decided on the MJ15024.. But where i'm having trouble is on the PreDriver.. Namely a suitable replacement for the RCA410.. I found a datasheet for it but cannot decide what are the most importent criteria for selecting a replacement.
Let me know if you need a schmatic.. I've got all the 400 series and service manuals for them. Hard to believe that there is 4 differant versions of this amp, all with little differances.
any assistance???? For your info.. Phase Linear recommended that the NEC 2sd555 be used for replacements. I decided against this as the MJ15024 is a Motorola Direct replacement, and costs $5.00/transistor less.
Let me know if you need a schmatic.. I've got all the 400 series and service manuals for them. Hard to believe that there is 4 differant versions of this amp, all with little differances.
any assistance???? For your info.. Phase Linear recommended that the NEC 2sd555 be used for replacements. I decided against this as the MJ15024 is a Motorola Direct replacement, and costs $5.00/transistor less.
Member
Joined 2002
I had a Phase Linear 400 Series Two power amp i loved it i also had the Pre-amp to match it too. Loved that thing.. I have a question though. Does any one have the schematic for the led read out. i haven't seen amp that did that .. i mean where it moved one Line at a time and not a streak of them adding up to all the lines being lit up It was cool at night i used it as a subwoofer amp because it was a grunter. i had a marants amp that drove my little speakers. I would like to build the display board a matching pair for my proects just for something to do. : o ) Man that amp had lots of power.. i wis i still had it.
OH PS I got mine free heh. till it died. and i could not relocate a old psu for it. but oh well.
Now i got nelson pass and NICE class a stuff. ( still working on. )
OH PS I got mine free heh. till it died. and i could not relocate a old psu for it. but oh well.
Now i got nelson pass and NICE class a stuff. ( still working on. )
I have 2 of them now and will be the power amps of my home theater.. Been picking them up along the way.. both have been smoked. but in the process of rebuilding them.
The led readout never appeared in any of the manuals i've got. so i'm sorry can't help. but check out http://sound.westhost.com/ he has some wonderful projects
The led readout never appeared in any of the manuals i've got. so i'm sorry can't help. but check out http://sound.westhost.com/ he has some wonderful projects
Member
Joined 2002
no i sent it to a guy that collected them and repaired them 2 years ago. At that time i didn't have time or patience to fix it.
For anyone looking for them.. I've got ORIGINAL RCA410 predrivers on order from a supplier.. Probably limited stock but i'm picking up what he has. Let me know if you need something.
A few modifications
For my PL-400 II, I would second the use of MJ21196 for the outputs, that is what I used when I did my upgrade.
For the drivers I used MJ15020's though I wonder if I could have just have well used MJ21196's instead? (any comments?)
Another little hack I did was replaced the LF356 with a BB-OPA604AP. Plus lowered the 10K input resistor to 4.7K.
It does sound better but the 20Khz THD I just could not get below .02%. At 100, 1K and 10K, THD was below my limit of .01%.
(all at one watt into 8 ohms).
For my PL-400 II, I would second the use of MJ21196 for the outputs, that is what I used when I did my upgrade.
For the drivers I used MJ15020's though I wonder if I could have just have well used MJ21196's instead? (any comments?)
Another little hack I did was replaced the LF356 with a BB-OPA604AP. Plus lowered the 10K input resistor to 4.7K.
It does sound better but the 20Khz THD I just could not get below .02%. At 100, 1K and 10K, THD was below my limit of .01%.
(all at one watt into 8 ohms).
Member
Joined 2002
Quote::::: Another little hack I did was replaced the LF356 with a BB-OPA604AP. Plus lowered the 10K input resistor to 4.7K.
You used a different op-amp i'm thinking about working on my x-overs witch use the LF-356's Does the op amps that you used compare.? are they faster/better..? i don't want to build my x-overs with slow older parts if i can help it..
You used a different op-amp i'm thinking about working on my x-overs witch use the LF-356's Does the op amps that you used compare.? are they faster/better..? i don't want to build my x-overs with slow older parts if i can help it..
I put sockets on the PCB where the opamp was and tried
LF-351
LF-356 (org)
BB OPA637AP
BB OPA134AP
OPA604AP
(I know people will complain about the sockets)
However, for my ears the OPA604AP sounded the best in a PL400-II. However, on this board there are many other opamps that people prefer. For my un-blind tests, I would try one opamp for a week then another the next week ... After a number of tries I decided on the OPA604. But then next year I may pop in another.
The fun of DIY equipment that can be modified🙂
LF-351
LF-356 (org)
BB OPA637AP
BB OPA134AP
OPA604AP
(I know people will complain about the sockets)
However, for my ears the OPA604AP sounded the best in a PL400-II. However, on this board there are many other opamps that people prefer. For my un-blind tests, I would try one opamp for a week then another the next week ... After a number of tries I decided on the OPA604. But then next year I may pop in another.
The fun of DIY equipment that can be modified🙂
Member
Joined 2002
well i was going to use lf-356's in this x-over.. should i use the ones that you used. ?
BB OPA637AP
BB OPA134AP
OPA604AP
http://24.69.72.2/view_photo.php?set_albumName=album18&id=xover1
BB OPA637AP
BB OPA134AP
OPA604AP
http://24.69.72.2/view_photo.php?set_albumName=album18&id=xover1
The BurrBrown Opamps are by far a better amp, The LF351 is a good amp but no where near the burrbrown OPA's.
The OPA134 is the ones i used a couple years ago.. Tried many in a Phase Linear 300 which shipped with the LF351, and found the OPA134 outperformed the LF in all fields. You can use the OPA134 as a direct replacement.
there is a OPA2134- 2op amp and a OPA4134 the four op am version.
Opamps were only in the PL36 boards of the Phase Linear 400.. And on the Phase Linear 300. All other 400's used descrete front ends.
The OPA134 is the ones i used a couple years ago.. Tried many in a Phase Linear 300 which shipped with the LF351, and found the OPA134 outperformed the LF in all fields. You can use the OPA134 as a direct replacement.
there is a OPA2134- 2op amp and a OPA4134 the four op am version.
Opamps were only in the PL36 boards of the Phase Linear 400.. And on the Phase Linear 300. All other 400's used descrete front ends.
Hello all,
I have this phase linear 400; It worked untill I accidently shorted the outlet on one channel; the amp proceeded to suck the cone in on one of my 12"ev and cook it.So it has been sitting for 3 years. It was made in 1974.
Now I am into diy and was considering using the power supply about 75v per rail. Are the sonics of this design worth resurecting for home stereo or is there a design where I can use this high voltage?🙂
I have this phase linear 400; It worked untill I accidently shorted the outlet on one channel; the amp proceeded to suck the cone in on one of my 12"ev and cook it.So it has been sitting for 3 years. It was made in 1974.
Now I am into diy and was considering using the power supply about 75v per rail. Are the sonics of this design worth resurecting for home stereo or is there a design where I can use this high voltage?🙂
It's nothing special.
I would consider fixing it and then letting it go down the road. If it looks good and works, it will bring a good price on eBay.
I would consider fixing it and then letting it go down the road. If it looks good and works, it will bring a good price on eBay.
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