Tomorrow I will haul (yes haul because they are a backbreaking 132 lbs per channel) a pair of PL X600's, the first incarnation from 2000 or so.
I have e few questions regarding these amps.
After reading the Owners Manual (very witty and with loads of technical information like the Aleph series OM's) I do not understand that the XA-160 and X600 both consume 600 Watts, have the same hardware, get evenly hot but the XA160 can produce 160 Watts RMS of Class A power and the X600 "only" 40 Watts. So same temperature, same hardware, same AC current-draw but different biasconfiguration. Is the increased railvoltage to get 600 Watts out of this amp at 8 Ohms responsible solely for the diminished Class A portion?
Just curious because I know that meter won't move that much in real circumstances with 80 Watts Class A peak power.
Can I perform updates myself, like installing a new frontendboard and then calibrating the amp again?
Apart from the filtercaps, which are probably more than 20 years old, is there any part I should replace asap you know of? Or (a) part(s) that would the raise level of performance sounds wise relatively much?
After a lot of Threshold gear, this is my first Passlab so I'm a bit new in this field. I know PassLab evolves to .8 status nowadays but I can't afford these (yet) and I have powerhungry and non efficient Infinity's so I need a potent set of amplifiers.
Are these amps stable in 4 and 2 Ohms?
Thanks in advance.
I have e few questions regarding these amps.
After reading the Owners Manual (very witty and with loads of technical information like the Aleph series OM's) I do not understand that the XA-160 and X600 both consume 600 Watts, have the same hardware, get evenly hot but the XA160 can produce 160 Watts RMS of Class A power and the X600 "only" 40 Watts. So same temperature, same hardware, same AC current-draw but different biasconfiguration. Is the increased railvoltage to get 600 Watts out of this amp at 8 Ohms responsible solely for the diminished Class A portion?
Just curious because I know that meter won't move that much in real circumstances with 80 Watts Class A peak power.
Can I perform updates myself, like installing a new frontendboard and then calibrating the amp again?
Apart from the filtercaps, which are probably more than 20 years old, is there any part I should replace asap you know of? Or (a) part(s) that would the raise level of performance sounds wise relatively much?
After a lot of Threshold gear, this is my first Passlab so I'm a bit new in this field. I know PassLab evolves to .8 status nowadays but I can't afford these (yet) and I have powerhungry and non efficient Infinity's so I need a potent set of amplifiers.
Are these amps stable in 4 and 2 Ohms?
Thanks in advance.
@RobertS61 - It might be easier to share where you're getting some of your information re: the specs of the X600 and the XA-160(any postfix) amplifiers. Can you upload and/or link to the docs you're using, please. Highlight any portions you've used for your specs in your post.
I think you may be under some false assumptions / have some incorrect information about their operating properties. Once we're all on the same page with the same specs, some of the questions you're asking may answer themselves, or we can revise the questions to better fit the specs of the amps you're describing.
BTW - Congratulations on yet another set of marvelous vintage amplifiers!!!!!
I think you may be under some false assumptions / have some incorrect information about their operating properties. Once we're all on the same page with the same specs, some of the questions you're asking may answer themselves, or we can revise the questions to better fit the specs of the amps you're describing.
BTW - Congratulations on yet another set of marvelous vintage amplifiers!!!!!
Clear will do that and thanks.
From the X1000, X600 and X350 manual:
"The meter has been calibrated to reflect the 600 watts idle draw of the amplifier, which is about one-third full scale for the X1000 and X600, and one-half for the X350. The meter is intended as a general indicator of the status of the amplifier and has not been calibrated to reflect any particular values."
Specs X600:
Gain 30 dB
Freq. Response -0 dB at DC, -3 dB at 100 kHz
Power Output 600 watts maximum @ 1% THD, 1 kHz, 8 ohms
Distortion refer to accompanying distortion curve
Maximum Output Voltage plus, minus 105 volts
Maximum Output Current plus, minus 25 amps
Input Impedance 22 kohm balanced
Damping factor 60 ref 8 ohms nominal
Slew rate plus, minus 50 V/uS
Output Noise 500 uV unweighted 20-20 kHz
Random noise floor approximately 2 uV
Dynamic range 153 dB (random noise floor to peak output)
Balanced CMRR -85 dB @ 1 kHz (input common mode rejection ratio)
DC offset < 100 mv
Power Consumption 600 watts idle, 1800 watts maximum
Temperature 20 degrees C. above ambient typical
Dimensions 19 " W x 22" D x 10.5" H
Shipping Weight 150 lbs
From the X160 manual:
"You can position this amplifier anywhere you wish, but it must have
ventilation. We do not recommend placing it in enclosed cabinets
or small closets without means for air to circulate freely.
Stacking these power amplifiers directly upon each other is not recommended
for the same reason. This amplifier idles at approximately 550 watts,
the equivalent of a small hand held hair dryer. At idle most of that
energy is dissipated across the heat sinks, so the heat generated by
each XA160 is equivalent to a small hair dryer.
Specs:
Gain 26 dB
Freq. Response -3 dB at 1.5 Hz, -3 dB at 100 kHz
Power Output 160 watts max @ 1% THD, 1 kHz, 8 ohms
Maximum Output Voltage plus, minus approx. 30 volts
Maximum Output Current plus, minus approx. 7 amps
Input Impedance 22 kohm balanced 11 kohm unbalanced
Damping factor 30 ref @ 8 ohms nominal
Slew rate plus, minus 50 V/uS
Output Noise 300 uV unweighted 20-20 kHz
Balanced CMRR approx. -60 dB @ 1 kHz
DC offset < 100 mv
Power Consumption approx. 550 watts
Temperature 25 degrees C. above ambient at idle
Dimensions 19 “ W x 11.25” H x 22” D
Shipping Weight 150 lbs
Nice quirk of the XA160:
"The Pass Laboratories™ XA160 will deliver 160 watts rms into
8 Ohms of impedance.
This is the amplifiers class A limit, driving the XA160 harder or reducing the impedance of the load will not convey any additional power. Driving into a short will not convey any additional power. These are not design oversights or flaws in the XA160, but rather a condition of the very highly biased Class A
operation."
So as a consequence the meter on a operating XA160 will never move....
Single-ended configuration?
Comparison, I know these are the .5 specs but here also the X160.5 and 600.5 share the same hardware, weight, idling etc..:
https://www.diyaudio.com/forums/attachment.php?attachmentid=994248&stc=1&d=1635774341
Attachments
> The XA160 can produce 160 Watts RMS of Class A power and the X600 "only" 40 Watts.
> Is the increased railvoltage to get 600 Watts out of this amp at 8 Ohms responsible solely for the diminished Class A portion?
You already answered your own questions.
Assuming your numbers are correct, and they refer to 8R load.
160W rms into 8R means +/-51V output, and ~56V rails.
Class A bias at 0.5*I max = 3.2A.
Total dissipation = 360W per amplifier only
600W rms into 8R means +/-98V output, and ~105V rails.
For the same dissipation, I_bias = 1.7A.
So Class A power (limited by I_bias) is 46W.
So pretty close to the numbers you quoted.
Patrick
> Is the increased railvoltage to get 600 Watts out of this amp at 8 Ohms responsible solely for the diminished Class A portion?
You already answered your own questions.
Assuming your numbers are correct, and they refer to 8R load.
160W rms into 8R means +/-51V output, and ~56V rails.
Class A bias at 0.5*I max = 3.2A.
Total dissipation = 360W per amplifier only
600W rms into 8R means +/-98V output, and ~105V rails.
For the same dissipation, I_bias = 1.7A.
So Class A power (limited by I_bias) is 46W.
So pretty close to the numbers you quoted.
Patrick
Anyone who went through the process of designing Class A and Class AB would know straight away.
Cheers,
Patrick
Cheers,
Patrick
I apparently didn't 😛, but I've could have used my Class A calculator ...
What about that quirk that the XA160 can't deliver any power whatsoever over it's rated 160 Watts?
What about that quirk that the XA160 can't deliver any power whatsoever over it's rated 160 Watts?
From the X600 manual:
All the transistors in the product are power Mosfets, actually Hexfets from International
Rectifier and Harris. These are hyper-matched parts, with gate voltages matched to 0.5% andall devices taken from the same lot codes (made on the same wafer). Most of the front endtransistors, the current sources and cascode devices, are rated at 200 volts and 150 watts. We run them at about 2.5 watts each..."
Please help me out here.
Those Hexfets probably won't have any emitterresistors I reckon ...
https://www.diyaudio.com/forums/attachment.php?attachmentid=994274&stc=1&d=1635781447
All the transistors in the product are power Mosfets, actually Hexfets from International
Rectifier and Harris. These are hyper-matched parts, with gate voltages matched to 0.5% andall devices taken from the same lot codes (made on the same wafer). Most of the front endtransistors, the current sources and cascode devices, are rated at 200 volts and 150 watts. We run them at about 2.5 watts each..."
Please help me out here.
Those Hexfets probably won't have any emitterresistors I reckon ...
https://www.diyaudio.com/forums/attachment.php?attachmentid=994274&stc=1&d=1635781447
Attachments
XA160 is factory Aleph X
go figure ........ thingie unable to produce KlunK!
Yes that Klunk that keeps me await at night ....
Well the Aleph's were productions models I thought but I remember that the Aleph 1.2 couldn't be drive into AB either..
Can't reproduce it with the calculations I know.
Ohm's Law: Volt = Current times Resistance
and Power = Current(squared) times Resistance
Please elaborate.
This from the XA160 owners manual:
"The XA160 has a significant number of power supply filter
capacitors. These caps are used to create the unregulated output stage
rails at plus and minus 30 volts at 7 amps. RC filtering is used to
passively remove ripple from the supply rails."
The X600 owners manual:
"The X1000 has 8 computer grade (the old large style computer capacitor cans, not the new
dinky ones) capacitor cans at 25,000 uF and 75 volts each. These are used to create the
unregulated output stage rails at plus and minus 75 volts at 30 amps. The X600 and X350
have 6 of these capacitors, operated at slightly lower voltages."
So the amps are bridged?
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