hello,
what do you think on this amp schematic?
it's original a phase linear pl 400.
i've here nearly the same but from a german company called solton. there it's sta800.
i've edited the schematic, so that it's like my amp here.
my question is if i could use mje 15031 for q11, q12 instead of these unknown 2sa116x? and if q10 and q5 could be a mje340 and q7 a mje350.
thx a lot
best regards
andreas
what do you think on this amp schematic?
it's original a phase linear pl 400.
i've here nearly the same but from a german company called solton. there it's sta800.
i've edited the schematic, so that it's like my amp here.
my question is if i could use mje 15031 for q11, q12 instead of these unknown 2sa116x? and if q10 and q5 could be a mje340 and q7 a mje350.
thx a lot
best regards
andreas
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AS per my experience u can use the above mentioned substitute of transistors very well, but need to change the baising accordingly. Simply rebais the amp with substituteed transistors
AS per my experience u can use the above mentioned substitute of transistors very well, but need to change the baising accordingly. Simply rebais the amp with substituteed transistors
rebias
thx a lot,
but how?
Itis enough to turn the bias-trimmer or did i have to change any values of some resistors? or something else?
thx
andreas
thx a lot,
but how?
Itis enough to turn the bias-trimmer or did i have to change any values of some resistors? or something else?
thx
andreas
You should be able to use the bias trimmer without any change to other components.... However I would recommend you to add a least one more set of output divices if you entend to run it as a 300W amp 😉
Seems like a death wish to run transistors at or above their maximum voltage ratings. They do make MJE15032/33 and MJ21193/94, the outputs are about the same cost, the drivers a few pennies more.
SOA folds back above 50V on MJ15003/04
SOA folds back above 50V on MJ15003/04
transistors
thx
i could also use the mj15022 or mj15024.
they have 200v and 250v max. at 250w
is this right?
best regards
andreas
thx
i could also use the mj15022 or mj15024.
they have 200v and 250v max. at 250w
is this right?
best regards
andreas
The MJ15022/24 are a fine part and can handle 160W at 80V
The PL700 runs at over 100V.
SOA of the MJ15022/24 at 100V is only 100W, a MJ21194 has 200W SOA at 100V
The SOA of a MJ15003 at 50V is 250W, the big Crown amps are all bridged and use this type of transistor.
The PL700 runs at over 100V.
SOA of the MJ15022/24 at 100V is only 100W, a MJ21194 has 200W SOA at 100V
The SOA of a MJ15003 at 50V is 250W, the big Crown amps are all bridged and use this type of transistor.
What is folding back?
You've given a voltage but shouldn't you also give a current.
Does it foldback @ 1ma or 10a's?
> what do you think on this amp schematic?
Very good for its time, over 25 years ago.
Buy LOTS of output devices. There should be twice as many in the amp. Also because it has no protection, you can fry the whole output stage and Q5 too. (Transistors always "protect" fuses.) Phase Linears were reliable in home use, but in commercial use were much less reliable than the Crowns.
The design is antique and it shows in the sound. Many of us who grew up on such amps like the PL sound. But the bootstrap ensures distortion at low level. This is largely masked by an obscene amount of overall feedback, but for stability the feedback is rolled-off inside the audio band and high frequency distortion tends to be high.
Still all in all, perhaps one of the best very-simple amps for this power level.
Very good for its time, over 25 years ago.
Buy LOTS of output devices. There should be twice as many in the amp. Also because it has no protection, you can fry the whole output stage and Q5 too. (Transistors always "protect" fuses.) Phase Linears were reliable in home use, but in commercial use were much less reliable than the Crowns.
The design is antique and it shows in the sound. Many of us who grew up on such amps like the PL sound. But the bootstrap ensures distortion at low level. This is largely masked by an obscene amount of overall feedback, but for stability the feedback is rolled-off inside the audio band and high frequency distortion tends to be high.
Still all in all, perhaps one of the best very-simple amps for this power level.
"What is folding back?
You've given a voltage but shouldn't you also give a current.
Does it foldback @ 1ma or 10a's?"
SOA is a power. It is not a straight line. It will start to bend, ie: fold back, at some voltage.
A MJ15003 starts to foldback at 50V, a 2N6259 at 100V.
At 50V they are both 250W parts.
At 100V one is 100W, the other is still 250W.
A MJ21194 is 200W at 100V.
You've given a voltage but shouldn't you also give a current.
Does it foldback @ 1ma or 10a's?"
SOA is a power. It is not a straight line. It will start to bend, ie: fold back, at some voltage.
A MJ15003 starts to foldback at 50V, a 2N6259 at 100V.
At 50V they are both 250W parts.
At 100V one is 100W, the other is still 250W.
A MJ21194 is 200W at 100V.
Curve, is that the what you are saying?
You can't have power without both current and voltage so you can't give a voltage describing something without an associated current if talking about power.
SOA curves are heat related not singularly voltage or current but both.
A 200w device driving a 16ohm load will achieve a much higher voltage out while staying inside it's SOA curve with a lower current then it would driving a 4 ohm load.
I don't understand your association. Could you explain it differently.
Reading a data sheet doesn't change the fact that soa curves are not only volts but both current and volts.
Soa curves in data sheets are a measure of max power vs heat the device is able to handle with no regard to load, which is not the case in the real world.
An mj15003 driving a 4 ohm resistor will hit around 7.5a before it's soa is reached but at 16 ohms such as 2 paralleled devices into 8 ohms will each hit just below 2.5a's at around 77 volts.
btw mj15003/04 are 140w devices at 100v
I don't belive you can just say a devices is not practical above a certain level if a qualifier is nessecary to make the described situation true.
Soa curves in data sheets are a measure of max power vs heat the device is able to handle with no regard to load, which is not the case in the real world.
An mj15003 driving a 4 ohm resistor will hit around 7.5a before it's soa is reached but at 16 ohms such as 2 paralleled devices into 8 ohms will each hit just below 2.5a's at around 77 volts.
btw mj15003/04 are 140w devices at 100v
I don't belive you can just say a devices is not practical above a certain level if a qualifier is nessecary to make the described situation true.
Easyamp,
I'm sorry you can't understand the data sheet.
The curve represents power, the VA product being constant until a certain voltage is reached.
Above this voltage the power begins to foldback, ie: is less.
Motorola published curves on the MJ15003 only show it to be 100W at 100V, the foldback begins at 50V.
Fig. 1 Active-Region Safe Operating Area
Page 3-501 Motorola Bipolar Power Transistor Device Data
DL111/D REV7
"I don't belive you can just say a devices is not practical above a certain level if a qualifier is nessecary to make the described situation true."
It's real simple. An amplifier driving a reactive load needs good safe are at the rail voltage it's running at.
Most plastic TIP stuff folds back at 30V, as does the old popular MJ802/4502 pair.
I recently threw away $25,000 worth of 2N6277.
250W, 50A, 30Mhz, 150V (180V CB)
Go look up the SOA and tell me why.
I'm sorry you can't understand the data sheet.
The curve represents power, the VA product being constant until a certain voltage is reached.
Above this voltage the power begins to foldback, ie: is less.
Motorola published curves on the MJ15003 only show it to be 100W at 100V, the foldback begins at 50V.
Fig. 1 Active-Region Safe Operating Area
Page 3-501 Motorola Bipolar Power Transistor Device Data
DL111/D REV7
"I don't belive you can just say a devices is not practical above a certain level if a qualifier is nessecary to make the described situation true."
It's real simple. An amplifier driving a reactive load needs good safe are at the rail voltage it's running at.
Most plastic TIP stuff folds back at 30V, as does the old popular MJ802/4502 pair.
I recently threw away $25,000 worth of 2N6277.
250W, 50A, 30Mhz, 150V (180V CB)
Go look up the SOA and tell me why.
This is because of heat the device is capable of internally dissapating (bonding/second breakdown) nothing else and is pretty much all the soa curve is based on, not an actuall load.
this certain voltage you speak of on an soa curve is only in reference to the heat the device is capable of dissapating before possible failure, not an actuall load.
The real world load variances on the transistor will not follow this absolute heat curve, and back to what I said before you can't give a voltage without current in respect to power, this is all I've been saying.
I now must assume that you are basing you statement on the soa curve's dive after 50v because of the secondary breakdown of the mj15003, but let me ask you this if, 5A's was 3A's would it still breakdown at 50v? This is all I'm saying. The secondary breakdown of the mj15003 is not fixed, but a result of VA so with a lower A the voltage limit of the sec brk goes up and can't be described individualy by voltage.
The mj15003 has a few diifferent data sheet out there some say 100w at 100v some say 140w at 100v.
I don't know, you may need professional help.
I'm wondering if a high power transistor such as the mj15003 is limited more by it's gain bandwidth product reaching an unstable level in a common negative feedback amplifier, then before its soa curve is a concern in a single output pair setup.
I've seen various amplifiers built using mj15003/04 combo and they seem to have low output ratings in view of there soa curve. Mr. slone's pro-60 in his audiophiles project sourcebook rated the amplifier at 60 watts. Is this just a cautious conservative rating with respect to the soa or the limited high frequency gain at levels?
I've seen various amplifiers built using mj15003/04 combo and they seem to have low output ratings in view of there soa curve. Mr. slone's pro-60 in his audiophiles project sourcebook rated the amplifier at 60 watts. Is this just a cautious conservative rating with respect to the soa or the limited high frequency gain at levels?
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