Speaker hookup question
- Thread starter Northwinds
- Start date
Perry,
I am glad to see that someone is actually reading these old "owner's manuals" for the original Phase Linear 700's I recently posted.
The "snapping an popping sound" statement also appears in the 700B owner's manual on page 10.
Here are just a few observations.........
The original Phase Linear 700 owner's manual (Seattle Washington version) most likely was written at a time when the Phase 700 only had a total of (12) output transistors, and (4) drivers. Very few of the amps were made with only (12) output transistors.
This is more than likely the reason why the thermal cutouts occurs at 70 degrees C.
The later Edmonds Washington version was written when there were a total of (20) output transistors.
"Using a temperature sensitive crayon (Thermal Stik or equivalent) verify that cut out occurs between 80 and 95 degrees Centigrad".
NOTE: This comment also appears in the 700B owner's manual.
The Edmonds Washington (700) and Lynnwood Washington (700B) owner's manual have a number of things in common. Here are just a few:
Under "Operating Area", I thought it was interesting how they created a 4 ohm load by using (4) 16 ohm 15" woofers (JBL D-140, LE-15A or equivalent) and hooking them up in parallel.
Under "Operating Precautions To Observe During Testing".... "During a dead short, the output transistors experience stresses that are approximately three times those that occur during normal full output. Never short the output...."
NOTE:
The original Phase Linear 700 service manual on page 7 "Step 5" "....Short circuit the output terminals with a jumper, and drive the input of the amplifier at 20 Hz. Slowly increase the variac from 0 volts to 117 volts. Remove the short circuit jumper and verify that the amplifier resumes normal operation."
(Essentially the same statement is made in the 700/700B service manual "Prepared 6/76".)
The 700/700B service manual revised 2/81 on page 20 step 5.7 "Short circuit test. states: Drive the left channel with a 200 Hz signal at an output level of 53VRMS. Now short the output terminals with a jumper wire for 2 to 4 seconds. Remove the jumper wire and verify that the amplifier resumes normal operation. Repeat for the right channel".
MY COMMENT:
The way Dean taught me was this later method. That is to drive the amplifier at 200 Hz, at full output and then short the output. This is to verify proper operation of the protection circuit and identify any oscillations that may occur (and cure them per the service bulletin #7721) as well as to stress or identify (cause to fail) any weak or defective output transistors.
NOTE:
The transformers in both versions of the 700 owner's manual are listed as 2.5 kilowatts.
The 700B and 700 series two owner's and service manuals do not indicate how many kilowatts the transformer is.
Ed
I am glad to see that someone is actually reading these old "owner's manuals" for the original Phase Linear 700's I recently posted.
The "snapping an popping sound" statement also appears in the 700B owner's manual on page 10.
Here are just a few observations.........
The original Phase Linear 700 owner's manual (Seattle Washington version) most likely was written at a time when the Phase 700 only had a total of (12) output transistors, and (4) drivers. Very few of the amps were made with only (12) output transistors.
This is more than likely the reason why the thermal cutouts occurs at 70 degrees C.
The later Edmonds Washington version was written when there were a total of (20) output transistors.
"Using a temperature sensitive crayon (Thermal Stik or equivalent) verify that cut out occurs between 80 and 95 degrees Centigrad".
NOTE: This comment also appears in the 700B owner's manual.
The Edmonds Washington (700) and Lynnwood Washington (700B) owner's manual have a number of things in common. Here are just a few:
Under "Operating Area", I thought it was interesting how they created a 4 ohm load by using (4) 16 ohm 15" woofers (JBL D-140, LE-15A or equivalent) and hooking them up in parallel.
Under "Operating Precautions To Observe During Testing".... "During a dead short, the output transistors experience stresses that are approximately three times those that occur during normal full output. Never short the output...."
NOTE:
The original Phase Linear 700 service manual on page 7 "Step 5" "....Short circuit the output terminals with a jumper, and drive the input of the amplifier at 20 Hz. Slowly increase the variac from 0 volts to 117 volts. Remove the short circuit jumper and verify that the amplifier resumes normal operation."
(Essentially the same statement is made in the 700/700B service manual "Prepared 6/76".)
The 700/700B service manual revised 2/81 on page 20 step 5.7 "Short circuit test. states: Drive the left channel with a 200 Hz signal at an output level of 53VRMS. Now short the output terminals with a jumper wire for 2 to 4 seconds. Remove the jumper wire and verify that the amplifier resumes normal operation. Repeat for the right channel".
MY COMMENT:
The way Dean taught me was this later method. That is to drive the amplifier at 200 Hz, at full output and then short the output. This is to verify proper operation of the protection circuit and identify any oscillations that may occur (and cure them per the service bulletin #7721) as well as to stress or identify (cause to fail) any weak or defective output transistors.
NOTE:
The transformers in both versions of the 700 owner's manual are listed as 2.5 kilowatts.
The 700B and 700 series two owner's and service manuals do not indicate how many kilowatts the transformer is.
Ed
Last edited:
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Well, the jury is no longer sequestered. Don't just twist wires for 2 pairs of speakers together (even a bad assed WOPL). It WILL BLOW UP SOONER RATHER THAN LATER. Wire them correctly or sign the check brothers.
Hmmmm, complete set of outputs.... labor.... sweet...... i have a credit card payment due......
Hmmmm, complete set of outputs.... labor.... sweet...... i have a credit card payment due......
What do you think of this
Found this on a ebay listing today. I have no idea what he is talking about in undersizing speaker wire
16 AWG, Teflon Insulated, Stranded, Silver Plated Copper Wire.
TWISTED PAIR.
High Temp - Mil spec.
"PTFE Silver Plated Stranded Copper Wire" provides a dramatic improvement in sound quality for your loudspeakers - clearer sound, better sharper treble. Aged copper wire has terrible sound quality.
[FONT="]PURPLE AND YELLOW, 16 AWG, Internal speaker PTFE Insulated Silver Plated Stranded Copper Wire. 12 feet as twisted.
What I use this for and always find provides exquisite improvements to sound quality is internal speaker wiring upgrades. I can compare the sound quality of this wire to solid silver for 10% of the cost yielding 80 - 90% of the sound quality improvement.
Why remove copper wire from inside your loudspeakers? Copper oxidizes and forms a brown semi-conductor coating. Semiconductors are active circuits and copper oxide causes severe degrading of sound quality. While a new speaker can be clear and neutral sounding, after a few months oxygen in the air seeps into the wiring and the sound quality reduces, within a short time harshness and listener fatigue set in. Even worse, if there is any sulfur in the air from certain sheetrock products, local sulfur dioxide air pollution, etc. copper sulfide forms on the wire surface and will cause an awful harshness and severely unpleasant listener fatique.
16 AWG is perfect for mid-woofers, woofers in a 3-way or Sub-Woofers.
Do not oversize wire - ohms per hundred feet is not the bigger parameter of sound quality. - INDUCTANCE is and twisted pairs of modest wire guage have lower inductance. Also, the maximum frequency for 100% skin depth is 11KHz for 16AWG. And 16AWG has 22 maximuum Amps for chassis wiring.
I use 20AWG (27KHz) and 22 AWG (42KHz) for Tweeters.
Most A/V receivers are only 50 to 80 watts, despite claiming 100 watts plus, so larger wire is not needed. 100 watts of constant power (music is usually 1 to 5 watts at full volume with only intermittent higher draw) has only 3-1/2 amps with an 8 ohm speaker. In a 2-way speaker the tweeter uses a very small percentage of the power.
So just look at the crimps on the speaker terminals.
Copper wire? REPLACE IT!
When handling the wire, first: Wipe your hands with some rubbing alcohol to remove oil and skin acid. When removing teflon insulation pinch the strippers around carefully since teflon doesn't tear like PVC. NEVER touch a conductor. Seriously, I've seen fingerprints on aged copper pipes that standout from the brown oxide! If it needs to be twisted wear nitrile painters gloves (cheap and available at Lowes, Home Depot, Walmart, and any hardware store).
Remove the old solder first Solder the wires directly onto the speaker terminals with silver content electronics solder or for best sound use a Cardas Eutectic solder. Standard solder must be the 63/37 type only. Place the speaker in a way that any drip will not land on the speaker! Even better make a small shield of aluminum foil protecting the speaker from rosin smoke or splash.
I twist the wires by clamping them to a table and hand braid them, then I attach a drill to get two twists per inch, LET IT HOLD FOR A MINUTE THEN BACK IT OFF SO IT DOESN'T SNAG ON ITSELF. Twisted pair wiring has lowered inductance which reduces phase shift and treble decay.
I always love the improvement to a speaker's performance, clearer sound and naturally sharper treble.
I have other colors for sale, message me for an eBay # and that will be less for shipping.
[/FONT]
Found this on a ebay listing today. I have no idea what he is talking about in undersizing speaker wire
16 AWG, Teflon Insulated, Stranded, Silver Plated Copper Wire.
TWISTED PAIR.
High Temp - Mil spec.
"PTFE Silver Plated Stranded Copper Wire" provides a dramatic improvement in sound quality for your loudspeakers - clearer sound, better sharper treble. Aged copper wire has terrible sound quality.
[FONT="]PURPLE AND YELLOW, 16 AWG, Internal speaker PTFE Insulated Silver Plated Stranded Copper Wire. 12 feet as twisted.
What I use this for and always find provides exquisite improvements to sound quality is internal speaker wiring upgrades. I can compare the sound quality of this wire to solid silver for 10% of the cost yielding 80 - 90% of the sound quality improvement.
Why remove copper wire from inside your loudspeakers? Copper oxidizes and forms a brown semi-conductor coating. Semiconductors are active circuits and copper oxide causes severe degrading of sound quality. While a new speaker can be clear and neutral sounding, after a few months oxygen in the air seeps into the wiring and the sound quality reduces, within a short time harshness and listener fatigue set in. Even worse, if there is any sulfur in the air from certain sheetrock products, local sulfur dioxide air pollution, etc. copper sulfide forms on the wire surface and will cause an awful harshness and severely unpleasant listener fatique.
16 AWG is perfect for mid-woofers, woofers in a 3-way or Sub-Woofers.
Do not oversize wire - ohms per hundred feet is not the bigger parameter of sound quality. - INDUCTANCE is and twisted pairs of modest wire guage have lower inductance. Also, the maximum frequency for 100% skin depth is 11KHz for 16AWG. And 16AWG has 22 maximuum Amps for chassis wiring.
I use 20AWG (27KHz) and 22 AWG (42KHz) for Tweeters.
Most A/V receivers are only 50 to 80 watts, despite claiming 100 watts plus, so larger wire is not needed. 100 watts of constant power (music is usually 1 to 5 watts at full volume with only intermittent higher draw) has only 3-1/2 amps with an 8 ohm speaker. In a 2-way speaker the tweeter uses a very small percentage of the power.
So just look at the crimps on the speaker terminals.
Copper wire? REPLACE IT!
When handling the wire, first: Wipe your hands with some rubbing alcohol to remove oil and skin acid. When removing teflon insulation pinch the strippers around carefully since teflon doesn't tear like PVC. NEVER touch a conductor. Seriously, I've seen fingerprints on aged copper pipes that standout from the brown oxide! If it needs to be twisted wear nitrile painters gloves (cheap and available at Lowes, Home Depot, Walmart, and any hardware store).
Remove the old solder first Solder the wires directly onto the speaker terminals with silver content electronics solder or for best sound use a Cardas Eutectic solder. Standard solder must be the 63/37 type only. Place the speaker in a way that any drip will not land on the speaker! Even better make a small shield of aluminum foil protecting the speaker from rosin smoke or splash.
I twist the wires by clamping them to a table and hand braid them, then I attach a drill to get two twists per inch, LET IT HOLD FOR A MINUTE THEN BACK IT OFF SO IT DOESN'T SNAG ON ITSELF. Twisted pair wiring has lowered inductance which reduces phase shift and treble decay.
I always love the improvement to a speaker's performance, clearer sound and naturally sharper treble.
I have other colors for sale, message me for an eBay # and that will be less for shipping.
[/FONT]
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My (admittedly limited) experience suggests that these kinds of forum discussions are valuable insofar as the very knowledgeable folks here have given me the lay of the land information-wise. BUT--to really find which particular pair or set of power tubes sounds best in YOUR amp to YOUR ears, well, that's a tough one, especially if your amp must be manually biased.. his comment is here
Ultimately what I did was pay my tech for an hour's bench time and switch tubes out, on the fly, with him adjusting and re-adjusting the bias on each new set of power tubes (yes, with the amp chassis out of the amp--don't do it at home unless you're a pro) till I found the ones that pleased me most.
Was it worth it? To me, absolutely. I also learned something else firsthand that he had been telling me for years--the tonal differences between different power tubes FAR EXCEEDS any differences I've heard between pre-amp tubes. DRAMATIC changes in tone with power tubes properly adjusted for bias.
Ultimately what I did was pay my tech for an hour's bench time and switch tubes out, on the fly, with him adjusting and re-adjusting the bias on each new set of power tubes (yes, with the amp chassis out of the amp--don't do it at home unless you're a pro) till I found the ones that pleased me most.
Was it worth it? To me, absolutely. I also learned something else firsthand that he had been telling me for years--the tonal differences between different power tubes FAR EXCEEDS any differences I've heard between pre-amp tubes. DRAMATIC changes in tone with power tubes properly adjusted for bias.
Hello, all.
I'm a recent newbie to this forum - lurked for some time, and finally registered since I have an original Phase Linear 400 that I bought new in 1974.
Because I've not been a regular visitor, I had not seen this thread regarding speaker loading until today - seeing that it's almost three years old until vbnks resurrected it with his post about "tube preferences".
Coincidentally, I did see an earlier reference about "tubes" from WOPL Sniffer in this thread that linked to the amplifiedparts.com website - copied here:
"Read this: https://www.amplifiedparts.com/tech-corner/speaker-impedance-power-handling-and-wiring "
This copied link addresses speaker impedance relative to tube amplifiers - and driver impedance is very important for tube output circuits; so much so that tube amplifiers need output transformers for proper operation.
However, I did not know the Phase Linear amps were sensitive to lower speaker loads. Can they not handle 4-ohm loading? I actually have never driven my PL400 with two pair of speakers, but I have done this with several other power amplifiers. I presently have two pair of 8-ohm speakers in parallel on an older Carver amp, and I regularly use 8-ohm drivers in parallel on power amps with vehicle audio systems. In fact, I've heard of some amplifiers that can handle 2-ohm speaker loads. I consider parallel speaker loading to be normal for solid-state amplifiers, and most should handle it without problem.
Why the caution against wiring parallel speakers with the PL amps? Certainly it might require additional cooling, but with judicious listening levels I would think this is a normal setup for home audio. Are the PL amps that weak for current carrying capacity on the output devices?
Thanks,
John
I'm a recent newbie to this forum - lurked for some time, and finally registered since I have an original Phase Linear 400 that I bought new in 1974.
Because I've not been a regular visitor, I had not seen this thread regarding speaker loading until today - seeing that it's almost three years old until vbnks resurrected it with his post about "tube preferences".
Coincidentally, I did see an earlier reference about "tubes" from WOPL Sniffer in this thread that linked to the amplifiedparts.com website - copied here:
"Read this: https://www.amplifiedparts.com/tech-corner/speaker-impedance-power-handling-and-wiring "
This copied link addresses speaker impedance relative to tube amplifiers - and driver impedance is very important for tube output circuits; so much so that tube amplifiers need output transformers for proper operation.
However, I did not know the Phase Linear amps were sensitive to lower speaker loads. Can they not handle 4-ohm loading? I actually have never driven my PL400 with two pair of speakers, but I have done this with several other power amplifiers. I presently have two pair of 8-ohm speakers in parallel on an older Carver amp, and I regularly use 8-ohm drivers in parallel on power amps with vehicle audio systems. In fact, I've heard of some amplifiers that can handle 2-ohm speaker loads. I consider parallel speaker loading to be normal for solid-state amplifiers, and most should handle it without problem.
Why the caution against wiring parallel speakers with the PL amps? Certainly it might require additional cooling, but with judicious listening levels I would think this is a normal setup for home audio. Are the PL amps that weak for current carrying capacity on the output devices?
Thanks,
John
