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- Halfbiass...Electron Herder and Backass Woof
Phase Linear and Pink Floyd
- Thread starter laatsch55
- Start date
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- Jan 14, 2011
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- 74,244
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- Gillette, Wyo.
- Tagline
- Halfbiass...Electron Herder and Backass Woof
- Joined
- Nov 1, 2014
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- 3,246
- Location
- Gaston, SC
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- Victim of the record bug since age five
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- Sep 9, 2012
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- 419
- Location
- Poland, Warsaw (Central Europe)
- Tagline
- I love BIG amplifiers!
- Joined
- Sep 9, 2012
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- 419
- Location
- Poland, Warsaw (Central Europe)
- Tagline
- I love BIG amplifiers!
PL700B and no cooling fan can become a danger...
[...] About Phase linear? Well, all the years, everyone called them everything already mentioned here. I never really had much experience with them, except that I knew many guys who loved PL! In the early 1990,s I was working several clubs on Miami Beach as a DJ! One club, always had gear that looked like it came straight from an Audio Rummage sale. I went to work one thursday evening, i was one of three DJ,s for that night, and when I got to the club the tech was all excited, he had a Phase LINEAR 700B, and he was going to show me how this thing puts a Crown to bed! He was a PL freak. The 700B was driving a pair of JBL 2225H woofers in the booth monitor system, and it didn't sound bad, definitely had some oomph to it. I was the 3rd DJ in the nights lineup, and the 2nd DJ was playing, and pushing the booth monitors hard. We were in the booth around 1AM, and all of a sudden, one 2225 made a loud cracking noise, and I watched that woofers dust cap literally shoot off the cone, and a burst of flame and sparks fly out from the gap area. Like a muzzle flash from a rifle! The amp went to heaven, the 2225 burned to death, and I was going on at 1:30AM with NO monitors! [...]
source: http://www.audioheritage.org/vbulletin/showthread.php?25317-Phase-Linear-700
[...] About Phase linear? Well, all the years, everyone called them everything already mentioned here. I never really had much experience with them, except that I knew many guys who loved PL! In the early 1990,s I was working several clubs on Miami Beach as a DJ! One club, always had gear that looked like it came straight from an Audio Rummage sale. I went to work one thursday evening, i was one of three DJ,s for that night, and when I got to the club the tech was all excited, he had a Phase LINEAR 700B, and he was going to show me how this thing puts a Crown to bed! He was a PL freak. The 700B was driving a pair of JBL 2225H woofers in the booth monitor system, and it didn't sound bad, definitely had some oomph to it. I was the 3rd DJ in the nights lineup, and the 2nd DJ was playing, and pushing the booth monitors hard. We were in the booth around 1AM, and all of a sudden, one 2225 made a loud cracking noise, and I watched that woofers dust cap literally shoot off the cone, and a burst of flame and sparks fly out from the gap area. Like a muzzle flash from a rifle! The amp went to heaven, the 2225 burned to death, and I was going on at 1:30AM with NO monitors! [...]
source: http://www.audioheritage.org/vbulletin/showthread.php?25317-Phase-Linear-700
- Joined
- Sep 9, 2012
- Messages
- 419
- Location
- Poland, Warsaw (Central Europe)
- Tagline
- I love BIG amplifiers!
V&I limits on output of Pink Floyd PL700
[…] Figure 5.24 (attached) shows a practical limiter used on one of the first of the high power, high performance amplifiers that was made for high-end domestic use, but was also adopted by Pink Floyd and others as the sound was so much better than the industrial power amplifiers they had been having to use (back in 1972-3) to get enough power. Over 15 years, the Phase Linear 700 was used for the many bands who hired systems from Britannia Row Productions.
Turning to the circuit, CCB and CCE show two locations for compensation capaci- tors where parasitic HF oscillation caused by positive feedback at RF, and other instabilities respectively, may be slugged − in this or any of the preceding limiter circuits. Notice the voltage sensing is not from the rails, but from 0v (a cleaner place that gives the inverse information) through the diode and resistor array, to give the dashed section down to G again, at high voltages. Note also the relatively elaborate control of the limiter’s ‘attack and release’ response with the 47μF, 1.5nF and 220pF capacitors.
[…] In 1972, Robert Carver, then president of Phase Linear Corporation, published a paper [56] outlining Phase Linear’s research into sonic differences between power amplifiers. This was by way of explaining why his company had launched a model producing what seemed an outrageous 350 watts/ch. Back then, it was described as a ‘700 watt’ amplifier by adding-together the power capability both channels, or else by citing ‘peak’ power.
Re-appraising power
In his 1972 paper, Carver cites a series of measurements which drive home a fact that was then less well known than it should be: that the ‘loudness’ capability of a power amplifier can be substantially affected by the supply rails’ regulation and voltage. This is at least one way in which, for a given loudspeaker, the highest undistorted sound level (whether experienced or measured) doesn’t necessarily fol- low the amplifier’s continuous rated power.
PSU dynamics
Carver noted that this was particularly true if the amplifier’s power supply was fairly ‘soft’, i.e. one exhibiting significant voltage sag on continuous drive, thanks to an undersized transformer, or reservoir capacitors. For example, an amplifier rated for a continuous 100 watts (into 8 ohms) with a badly soggy supply dropping from +65v to +45v on load, could sound louder on music passages, than a 200 watt amplifier (again into 8 ohms), with tightly regulated rails of + 57v. Although Bob Carver wasn’t the first person to stumble across the effect, judging by what he implemented, he clearly glimpsed consequences that others didn’t. Subsequently, the effect was recognised as ‘dynamic headroom’.
Dynamic headroom
For domestic Hi-Fi in the US, the IHF (Inst. of Hi-Fidelity) defined dynamic head- room nearly two decades ago, in their IHF 202 specification. It’s the maximum average (or short term ‘rms’) power available for just 20mS every 500mS, beyond the rated continuous power. Sometimes it’s called ‘burst power’. Since 1987, there’s been documentary evidence [57] of something amplifier designers and audiophiles have long suspected: That music’s peak SPL requirements can extend in bursts to 300mS and beyond, with a 20% duty cycle, ie. lengthy transient bursts can recur every 1 to 2 seconds. […]
source: https://books.google.pl/books?id=-5...gh Performance Audio Power Amplifiers&f=false
[…] Figure 5.24 (attached) shows a practical limiter used on one of the first of the high power, high performance amplifiers that was made for high-end domestic use, but was also adopted by Pink Floyd and others as the sound was so much better than the industrial power amplifiers they had been having to use (back in 1972-3) to get enough power. Over 15 years, the Phase Linear 700 was used for the many bands who hired systems from Britannia Row Productions.
Turning to the circuit, CCB and CCE show two locations for compensation capaci- tors where parasitic HF oscillation caused by positive feedback at RF, and other instabilities respectively, may be slugged − in this or any of the preceding limiter circuits. Notice the voltage sensing is not from the rails, but from 0v (a cleaner place that gives the inverse information) through the diode and resistor array, to give the dashed section down to G again, at high voltages. Note also the relatively elaborate control of the limiter’s ‘attack and release’ response with the 47μF, 1.5nF and 220pF capacitors.
[…] In 1972, Robert Carver, then president of Phase Linear Corporation, published a paper [56] outlining Phase Linear’s research into sonic differences between power amplifiers. This was by way of explaining why his company had launched a model producing what seemed an outrageous 350 watts/ch. Back then, it was described as a ‘700 watt’ amplifier by adding-together the power capability both channels, or else by citing ‘peak’ power.
Re-appraising power
In his 1972 paper, Carver cites a series of measurements which drive home a fact that was then less well known than it should be: that the ‘loudness’ capability of a power amplifier can be substantially affected by the supply rails’ regulation and voltage. This is at least one way in which, for a given loudspeaker, the highest undistorted sound level (whether experienced or measured) doesn’t necessarily fol- low the amplifier’s continuous rated power.
PSU dynamics
Carver noted that this was particularly true if the amplifier’s power supply was fairly ‘soft’, i.e. one exhibiting significant voltage sag on continuous drive, thanks to an undersized transformer, or reservoir capacitors. For example, an amplifier rated for a continuous 100 watts (into 8 ohms) with a badly soggy supply dropping from +65v to +45v on load, could sound louder on music passages, than a 200 watt amplifier (again into 8 ohms), with tightly regulated rails of + 57v. Although Bob Carver wasn’t the first person to stumble across the effect, judging by what he implemented, he clearly glimpsed consequences that others didn’t. Subsequently, the effect was recognised as ‘dynamic headroom’.
Dynamic headroom
For domestic Hi-Fi in the US, the IHF (Inst. of Hi-Fidelity) defined dynamic head- room nearly two decades ago, in their IHF 202 specification. It’s the maximum average (or short term ‘rms’) power available for just 20mS every 500mS, beyond the rated continuous power. Sometimes it’s called ‘burst power’. Since 1987, there’s been documentary evidence [57] of something amplifier designers and audiophiles have long suspected: That music’s peak SPL requirements can extend in bursts to 300mS and beyond, with a 20% duty cycle, ie. lengthy transient bursts can recur every 1 to 2 seconds. […]
source: https://books.google.pl/books?id=-5...gh Performance Audio Power Amplifiers&f=false
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- Joined
- Mar 18, 2013
- Messages
- 7,550
- Location
- Coventry, CT
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- Fondler errrr... fan of all Nav's avatars
- Joined
- Mar 18, 2013
- Messages
- 7,550
- Location
- Coventry, CT
- Tagline
- Fondler errrr... fan of all Nav's avatars
- Joined
- Jan 14, 2011
- Messages
- 74,244
- Location
- Gillette, Wyo.
- Tagline
- Halfbiass...Electron Herder and Backass Woof
Purple Phase Linear 700 Front Panel
The purple 700 Phase Linear is owned by Darrel Fisher. Darrel installed sound systems in a number of discos back in the day.
Most of all of the amplifiers Darrel owns have been gone through by me at one time or another approximately 10 years ago including the purple 700.
All of the amps (that weren't already fully comp amps) have been converted into a fully complementary output using PL36 pc boards with MJ15024 and MJ15025 output transistors.
By the way, Darrel is a huge Phase Linear fan and would like to build a million watt Phase Linear system, in an effort to establish a new Guinness World Record. Any donations of Phase Linear amps would be greatly appreciated by Darrel.
http://www.discomusic.com/clubs-more/3845_0_6_0_C/
https://www.flickr.com/people/74759855@N03/
http://www.discomusic.com/clubs-more/9432_0_6_0_C/
https://www.facebook.com/Star-sound-and-light-207318029306340/?ref=stream
https://groups.yahoo.com/neo/groups/Satanism101EList/conversations/topics/1163
From what I have heard only (1) or (2) purple 700's were ever built. Perhaps as prototypes for Heil Sound.
Phase Linear however did build approximately (50) purple Phase Linear 400's for Heil Sound.
http://web.archive.org/web/20040225045145/http://hometown.aol.com/phasetek/heil400.jpg
http://repforums.prosoundweb.com/index.php/topic,25656.60.html
https://en.wikipedia.org/wiki/Bob_Heil
Please check out Mike Chafee's comments about 3/4 of the way down the page:
https://www.gearslutz.com/board/so-much-gear-so-little-time/144137-phase-linear.html
Ed
The purple 700 Phase Linear is owned by Darrel Fisher. Darrel installed sound systems in a number of discos back in the day.
Most of all of the amplifiers Darrel owns have been gone through by me at one time or another approximately 10 years ago including the purple 700.
All of the amps (that weren't already fully comp amps) have been converted into a fully complementary output using PL36 pc boards with MJ15024 and MJ15025 output transistors.
By the way, Darrel is a huge Phase Linear fan and would like to build a million watt Phase Linear system, in an effort to establish a new Guinness World Record. Any donations of Phase Linear amps would be greatly appreciated by Darrel.
http://www.discomusic.com/clubs-more/3845_0_6_0_C/
https://www.flickr.com/people/74759855@N03/
http://www.discomusic.com/clubs-more/9432_0_6_0_C/
https://www.facebook.com/Star-sound-and-light-207318029306340/?ref=stream
https://groups.yahoo.com/neo/groups/Satanism101EList/conversations/topics/1163
From what I have heard only (1) or (2) purple 700's were ever built. Perhaps as prototypes for Heil Sound.
Phase Linear however did build approximately (50) purple Phase Linear 400's for Heil Sound.
http://web.archive.org/web/20040225045145/http://hometown.aol.com/phasetek/heil400.jpg
http://repforums.prosoundweb.com/index.php/topic,25656.60.html
https://en.wikipedia.org/wiki/Bob_Heil
Please check out Mike Chafee's comments about 3/4 of the way down the page:
https://www.gearslutz.com/board/so-much-gear-so-little-time/144137-phase-linear.html
Ed
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- 74,244
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- Gillette, Wyo.
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- Halfbiass...Electron Herder and Backass Woof
PHASE LINEAR & BOB CARVER HISTORY
I have been asked many times to put down into words all that I know about Phase Linear and Bob Carver.
Needless to say, I believe it would be a fascinating story. Not all is known about Bob Carver yet.
Even those that have known him for 50+ years don't know all the details.
By the way, here is a question many of you will not know the answer to. What was Bob's name at birth? What was his name when he attended college? What was his name when he entered the military? (Lee you are excluded from this since I already told you the answers)
By the way, The Absolute Sound is coming out with their second coffee table book:
"Illustrated History of High End Audio Volume Two Electronics" $129.95. Due to come out by the end of this month.
......starting on page 71 Robert W. (Bob) Carver: Phase Linear, Carver Corporation,Sunfire, Bob Carver Corporation
Dean Nissen and I met with Bob Carver (in August) and provided him with photos and stories that he in turn passed onto Robert Harley (the editor). Dean and I are anxious to see if we will be given any created for the photos we provided.
https://store.theabsolutesound.com/
Ed
I have been asked many times to put down into words all that I know about Phase Linear and Bob Carver.
Needless to say, I believe it would be a fascinating story. Not all is known about Bob Carver yet.
Even those that have known him for 50+ years don't know all the details.
By the way, here is a question many of you will not know the answer to. What was Bob's name at birth? What was his name when he attended college? What was his name when he entered the military? (Lee you are excluded from this since I already told you the answers)
By the way, The Absolute Sound is coming out with their second coffee table book:
"Illustrated History of High End Audio Volume Two Electronics" $129.95. Due to come out by the end of this month.
......starting on page 71 Robert W. (Bob) Carver: Phase Linear, Carver Corporation,Sunfire, Bob Carver Corporation
Dean Nissen and I met with Bob Carver (in August) and provided him with photos and stories that he in turn passed onto Robert Harley (the editor). Dean and I are anxious to see if we will be given any created for the photos we provided.
https://store.theabsolutesound.com/
Ed
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