Vintage Phase Linear 400 Power Amplifier – Refurbished (On Ebay Now)
- Thread starter oldphaser
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I wonder what the method to his madness is then? If you say it's bad, I will take your word over his but he acts like he knows what he is talking about? I don't think it's smart to sell something or wire anything you don't know shit about. I wonder if the amp even sounds good let alone what will happen when the new owner decides to put the boots to it
I called and left a brief message with Steve Mantz. I am awaiting his reply.
In the meantime, I did a little more research and found some additional posts of his regarding Phase Linear using the name "MOER" on diyaaudio:
https://www.diyaudio.com/forums/solid-state/186493-phase-linear-oscillation-3.html
also take a look under P.L.F. post #36 at:
https://audiokarma.org/forums/index.php?threads/phase-linear-700-ii-recapping-and-more.484891/page-2
In the meantime, I did a little more research and found some additional posts of his regarding Phase Linear using the name "MOER" on diyaaudio:
https://www.diyaudio.com/forums/solid-state/186493-phase-linear-oscillation-3.html
also take a look under P.L.F. post #36 at:
https://audiokarma.org/forums/index.php?threads/phase-linear-700-ii-recapping-and-more.484891/page-2
Seems legit. He backed up all his component selections with specs and details of why he chose them. He also addressed the grounding issue I read about here on these amps.
Interesting build. 27,000mfd rail caps? Damn.
What are typical full comp WOPL 400 output specs? I wish he would have posted some 2ohm load test specs.
Interesting build. 27,000mfd rail caps? Damn.
What are typical full comp WOPL 400 output specs? I wish he would have posted some 2ohm load test specs.
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2ohm? He would have been toasting marshmallows. The amps can't take that abuse, not enough cooling surfaces, especially 4 fin models
The rail caps are not anything special, it does not make the amp put out more power, just stores more energy for dynamic passages. I think I was running a pair 16,500MFD in at least one of my 400s IIRC
The rail caps are not anything special, it does not make the amp put out more power, just stores more energy for dynamic passages. I think I was running a pair 16,500MFD in at least one of my 400s IIRC
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These are my comments on the Phase Linear 400s I just sold on Ebay. My name is Stephen Mantz and I own Zed Audio Corp (www.zedaudiocorp.com where you can read my history and see some of the restorations I have done). My primary business is now consulting and design for both the 12 volt and home audio industries. I shall now reply to each comment made.
One thing you will all read, is that when someone makes a silly or uninformed comment, I shall point them out in no uncertain terms. Constructive criticism is always welcome and I am happy to learn from others.
Gepetto: "Very bad choice" on what?
mondialfan: Yeah a 140v transistor woudn't be my choice etc etc. Never heard of voltage grading? Your guess is wrong as to my stash of "them stashed somewhere". If you have proof submit it, otherwise don't comment on things you know zero about.
Geegz: "MJ15003/4 bad choice or the TO-200's or both. Same comments as above and why is my choice of a TO-220 bias device bad? Would love to read your explanation.
Gepetto: You obviously no little about SOA curves and what they mean. "Negative SOA in this application" - frankly never heard of negative SOA but maybe you will teach me what it really is. My TO-220 bias device is rated at 180v (KEC2238A) and I would guess, yes I am really guessing here, that with a max of about 3.3v across the bias transistor, a 180v breakdown may just be OK, but just.
The Rebel: 2 ohm is a no go on these amps.
Northwinds: I never claimed that the amps pushed more sine wave power with larger caps but rather that under high level musical transients the rails will hold up better with larger capacitors, so yes nothing special as I did not claim anything special.
Gepetto: Again you know little about energy storage in power supplies.
mlucitt: Yes I know about White Oak Audio. What do they have to do with what I do?
Bradrock: The Marantz 15's modifications are completely different to what I do on Phase Linear amplifiers.
Geegz: No "Joe" had nothing to do with my design of these PCBs, they were done all by little 'ol me!
grapplesaw: Thanks for the sarcastic comment "A valiant attempt ". Please explain what bad research I did on component choices. Before you critisize make sure that you know what you are talking about. mm have you listened to my designs yet, even with the single fin mechanicals? I doubt it.
oldphaser: I just called the PCB "PL36" and not for any reason as to whether PL used ICs or discrete diff amps.
mlucitt: Yes apparantly I am still in business!
Northwinds: What is an "AK" member?
Northwinds: Blue is my favourite colour so I use blue solder mask on all my PCBs. Damping factor is easily measured if you have a high accuracy wide band AC voltmeter and I use my Audio Precisions to do this. Consider this: DF is defined as load impedance divided by the output impedance of the amplifier channel. So to get a claimed PL DF number of 1,000 with an 8 ohm load, the output impedance is 0.008 ohms. I have never been able to measure this on a stock PL400 even with their massive open loop gain and lots of NFB. My designs have local feedback loops and I keep the open loop at sane levels and I personally have zero interest in the actual DF #.
This is important, the DCR of the speaker's coil is in series with the circuit and so even if the contact resistance of all connections and zero ohm wire and zero ohm amp output impedance the DF is still only 1.33. WHY you may ask, because the typical DCR of an 8 ohm driver is about 6 ohms and THIS IS IN SERIES WITH ANY OTHER IMPEDANCES INCLUDING THE AMP'S OUTPUT IMPEDANCE! So the effective DF is always about 1.33.
Geegz: So I added in 2 output transistors per channel. What will this achieve? Easy Geegz, I have improved the output stage's SOA by 25%, that's what I achieved, in addition I increased the effective Hfe of the output stage as each device now handles 25% less current and their Hfe increases at lower currents.
mondialfan: Test mules, testing for what?
laatsch55: I chose the MJ15003/4 devices because they work fine in PL400s. [a] I grade these for voltage breakdown and then for Hfe. I have used MJ15003/4 for over 35 years and there are not many which grade out less than 200v Vceo. Yes the MJ15024/5 do have a marginally better SOA but since I added the extra devices to the output stage, it is now safe with 4 ohm loads. The MJ15024/5 would not allow 2 ohm operation anyway as there is simply not enough power silicon to do this. However converting the output stage to a series configuration (drive board as well) would give an output stage with even better SOA as the devices are now only working on a +/-42.5v rail and their SOA's are nowhere near the ISB section of their SOA curves. Pretty much all my high end home designs use series output stages and anyone can take SOA curves and put them into a spreadsheet and compare.
As an example on a design I have just completed and using Toshiba 2SC5200/2SA1943 parts, with a +/-95v rail I need 12 up and 12 down for 2 ohm SOA when in parallel, BUT when in series can use 6 up and 6 down (3 in parallel in series with 3 in paralell on top and bottom of the O/P stage) for the exact same SOA/2 ohm job. That is the big advantage of series O/P stages. In addition I use a PFC switchmode design which has variable rail voltage so my effective SOA with typical program material is increased even further because the output stages "live" most of the time in the lower rail supply.
MarkWComer: The Toshiba drivers are TO3-P parts not TO-220. My TO-220 bias devices use the original hole from PL bias part.
One thing you will all read, is that when someone makes a silly or uninformed comment, I shall point them out in no uncertain terms. Constructive criticism is always welcome and I am happy to learn from others.
Gepetto: "Very bad choice" on what?
mondialfan: Yeah a 140v transistor woudn't be my choice etc etc. Never heard of voltage grading? Your guess is wrong as to my stash of "them stashed somewhere". If you have proof submit it, otherwise don't comment on things you know zero about.
Geegz: "MJ15003/4 bad choice or the TO-200's or both. Same comments as above and why is my choice of a TO-220 bias device bad? Would love to read your explanation.
Gepetto: You obviously no little about SOA curves and what they mean. "Negative SOA in this application" - frankly never heard of negative SOA but maybe you will teach me what it really is. My TO-220 bias device is rated at 180v (KEC2238A) and I would guess, yes I am really guessing here, that with a max of about 3.3v across the bias transistor, a 180v breakdown may just be OK, but just.
The Rebel: 2 ohm is a no go on these amps.
Northwinds: I never claimed that the amps pushed more sine wave power with larger caps but rather that under high level musical transients the rails will hold up better with larger capacitors, so yes nothing special as I did not claim anything special.
Gepetto: Again you know little about energy storage in power supplies.
mlucitt: Yes I know about White Oak Audio. What do they have to do with what I do?
Bradrock: The Marantz 15's modifications are completely different to what I do on Phase Linear amplifiers.
Geegz: No "Joe" had nothing to do with my design of these PCBs, they were done all by little 'ol me!
grapplesaw: Thanks for the sarcastic comment "A valiant attempt ". Please explain what bad research I did on component choices. Before you critisize make sure that you know what you are talking about. mm have you listened to my designs yet, even with the single fin mechanicals? I doubt it.
oldphaser: I just called the PCB "PL36" and not for any reason as to whether PL used ICs or discrete diff amps.
mlucitt: Yes apparantly I am still in business!
Northwinds: What is an "AK" member?
Northwinds: Blue is my favourite colour so I use blue solder mask on all my PCBs. Damping factor is easily measured if you have a high accuracy wide band AC voltmeter and I use my Audio Precisions to do this. Consider this: DF is defined as load impedance divided by the output impedance of the amplifier channel. So to get a claimed PL DF number of 1,000 with an 8 ohm load, the output impedance is 0.008 ohms. I have never been able to measure this on a stock PL400 even with their massive open loop gain and lots of NFB. My designs have local feedback loops and I keep the open loop at sane levels and I personally have zero interest in the actual DF #.
This is important, the DCR of the speaker's coil is in series with the circuit and so even if the contact resistance of all connections and zero ohm wire and zero ohm amp output impedance the DF is still only 1.33. WHY you may ask, because the typical DCR of an 8 ohm driver is about 6 ohms and THIS IS IN SERIES WITH ANY OTHER IMPEDANCES INCLUDING THE AMP'S OUTPUT IMPEDANCE! So the effective DF is always about 1.33.
Geegz: So I added in 2 output transistors per channel. What will this achieve? Easy Geegz, I have improved the output stage's SOA by 25%, that's what I achieved, in addition I increased the effective Hfe of the output stage as each device now handles 25% less current and their Hfe increases at lower currents.
mondialfan: Test mules, testing for what?
laatsch55: I chose the MJ15003/4 devices because they work fine in PL400s. [a] I grade these for voltage breakdown and then for Hfe. I have used MJ15003/4 for over 35 years and there are not many which grade out less than 200v Vceo. Yes the MJ15024/5 do have a marginally better SOA but since I added the extra devices to the output stage, it is now safe with 4 ohm loads. The MJ15024/5 would not allow 2 ohm operation anyway as there is simply not enough power silicon to do this. However converting the output stage to a series configuration (drive board as well) would give an output stage with even better SOA as the devices are now only working on a +/-42.5v rail and their SOA's are nowhere near the ISB section of their SOA curves. Pretty much all my high end home designs use series output stages and anyone can take SOA curves and put them into a spreadsheet and compare.
As an example on a design I have just completed and using Toshiba 2SC5200/2SA1943 parts, with a +/-95v rail I need 12 up and 12 down for 2 ohm SOA when in parallel, BUT when in series can use 6 up and 6 down (3 in parallel in series with 3 in paralell on top and bottom of the O/P stage) for the exact same SOA/2 ohm job. That is the big advantage of series O/P stages. In addition I use a PFC switchmode design which has variable rail voltage so my effective SOA with typical program material is increased even further because the output stages "live" most of the time in the lower rail supply.
MarkWComer: The Toshiba drivers are TO3-P parts not TO-220. My TO-220 bias devices use the original hole from PL bias part.
Moer,
I'll comment on your grumbling about my posts.
"Yeah a 140v transistor wouldn't be my choice etc etc. Never heard of voltage grading?"
Please point us all to a major manufacturers data sheet that says "Its completely acceptable to exceed our max voltage ratings as long as you grade our devices for breakdown voltage first".
"Your guess is wrong as to my stash of "them stashed somewhere". If you have proof submit it, otherwise don't comment on things you know zero about." My guess was just that a guess and I think I freely admitted that, it wasn't a guilty verdict, all you had to say was wrong. This is a public forum I will continue to speculate, guess, estimate, freely think and comment on anything I like thank you,,, god.
"Test mules, testing for what?"
You posted many years ago like 2010 on DIYAUDIO about designing boards for PL amps and you inquired as to the interest there for the boards. It seemed like a decent "guess" that these amps may have been some sort of test mules for the boards you designed back then.
SERIOUSLY? These things bothered you??? If so you've got some thin skin partner. You'd think that someone with as many accomplishments as yourself over as many decades could care less about what a bunch of DIY'ers thinks about his work, but hey to each his own.
I'll comment on your grumbling about my posts.
"Yeah a 140v transistor wouldn't be my choice etc etc. Never heard of voltage grading?"
Please point us all to a major manufacturers data sheet that says "Its completely acceptable to exceed our max voltage ratings as long as you grade our devices for breakdown voltage first".
"Your guess is wrong as to my stash of "them stashed somewhere". If you have proof submit it, otherwise don't comment on things you know zero about." My guess was just that a guess and I think I freely admitted that, it wasn't a guilty verdict, all you had to say was wrong. This is a public forum I will continue to speculate, guess, estimate, freely think and comment on anything I like thank you,,, god.
"Test mules, testing for what?"
You posted many years ago like 2010 on DIYAUDIO about designing boards for PL amps and you inquired as to the interest there for the boards. It seemed like a decent "guess" that these amps may have been some sort of test mules for the boards you designed back then.
SERIOUSLY? These things bothered you??? If so you've got some thin skin partner. You'd think that someone with as many accomplishments as yourself over as many decades could care less about what a bunch of DIY'ers thinks about his work, but hey to each his own.