When amps are bridged, each amp "sees" half of the speaker impedance at its output. Therefore each amp will deliver its 4 Ohm output power when an 8 Ohm load is connected to the bridge.
If an amp delivers 300W into 4 Ohms, a bridge of two such amps will deliver 600W into 8 Ohms.
When your amplifiers are not rated for 2 Ohm loads (this is the case for both PA-300 and PA-600), you should not connect a 4 Ohm load to a bridged version.
This is of course simplified. Often you will see that the output power of a bridged version is not exactly twice the output power of each channel (at twice the load impedance), because the common power supply for both channels is too weak to supply two channels running at max.
If an amp delivers 300W into 4 Ohms, a bridge of two such amps will deliver 600W into 8 Ohms.
When your amplifiers are not rated for 2 Ohm loads (this is the case for both PA-300 and PA-600), you should not connect a 4 Ohm load to a bridged version.
This is of course simplified. Often you will see that the output power of a bridged version is not exactly twice the output power of each channel (at twice the load impedance), because the common power supply for both channels is too weak to supply two channels running at max.
Hi.
I have built PA300 and this is a fine amplifire.
but there is problem in my amp and I didn't know how can I do for this situation and I want to help me.
I test it with function generator with 20Hz to 20khz frequency.
But after 5khz(for instance 10khz) and high power the relay is cut off.but in this stage there is not any clipping and the output voltage is still low than 1khz frequency.in this frequency the output voltage is 27V.
but at 1khz and maximum power there is no any problem.so in this stage the output voltage is around 36V and it is more than the 10khz voltage output.
So in other High frequency for instance 20khz the output voltage would reduct to 20V and in this frequency at that voltage relay will cut off.
please help me about it.
thanks.
I have built PA300 and this is a fine amplifire.
but there is problem in my amp and I didn't know how can I do for this situation and I want to help me.
I test it with function generator with 20Hz to 20khz frequency.
But after 5khz(for instance 10khz) and high power the relay is cut off.but in this stage there is not any clipping and the output voltage is still low than 1khz frequency.in this frequency the output voltage is 27V.
but at 1khz and maximum power there is no any problem.so in this stage the output voltage is around 36V and it is more than the 10khz voltage output.
So in other High frequency for instance 20khz the output voltage would reduct to 20V and in this frequency at that voltage relay will cut off.
please help me about it.
thanks.
PA300/600
Hello, Bruce.
Thanks. Noted. For the capacity.
For PA.600, we were not sure of the pattern, according to Olivier.
We have rerouted PA.300 according routing logic note and added the extension PA.600. So we must review the resistors R41 e 42 for the rail 80 volts.
Thanks again.
Jacky
Hello, Bruce.
Thanks. Noted. For the capacity.
For PA.600, we were not sure of the pattern, according to Olivier.
We have rerouted PA.300 according routing logic note and added the extension PA.600. So we must review the resistors R41 e 42 for the rail 80 volts.
Thanks again.
Jacky
Hello, Bruce.
Thanks for your advice.
In fact, the printed circuit has been redrawn to miniaturize as much as possible. This is the copy according to PA.300 Elektor. Later, we came across the pattern of Mr. Olivier.
In Pa.600 We just increased the numbers of transistors. and changed the resistances to hold +/- 90 volts. We will start building. We'll keep you posted. Thank you so much.
Best regard.
Jacky.Tanski
Ps:
We also built the Titan, which works perfectly.
Make too, the broom, which works great!
Found transistors by recycling old electronic equipment.
Thanks for your advice.
In fact, the printed circuit has been redrawn to miniaturize as much as possible. This is the copy according to PA.300 Elektor. Later, we came across the pattern of Mr. Olivier.
In Pa.600 We just increased the numbers of transistors. and changed the resistances to hold +/- 90 volts. We will start building. We'll keep you posted. Thank you so much.
Best regard.
Jacky.Tanski
Ps:
We also built the Titan, which works perfectly.
Make too, the broom, which works great!
Found transistors by recycling old electronic equipment.
PA300/600
That's what we are trying to build. for now, this is just the study. We left Astx and Quasi.
A big thank you to them. You are a great source of inspiration for us. We are not specialists. but we do our best
There is a lot of enthusiasm for the handymen in Emmaus village. We recover parts by recycling discarded electronic devices.
Note:
This allows us to hold out against the misery that surrounds us and repression against yellow vests.
That's what we are trying to build. for now, this is just the study. We left Astx and Quasi.
A big thank you to them. You are a great source of inspiration for us. We are not specialists. but we do our best
There is a lot of enthusiasm for the handymen in Emmaus village. We recover parts by recycling discarded electronic devices.
Note:
This allows us to hold out against the misery that surrounds us and repression against yellow vests.
Attachments
Hello, Toni.
Thank you for the small message.
Exactly, we wanted to write to you. You have been faster than us, laughs!
Your concept is great, sincerely. We were looking for a way to make a universal box for our amplifiers. Thanks to you we had the light!
Little explanation:
The charity Emmaüs has 250 people. Rather old age. I am 62 years old. We take care of the poor, the sick of people broken by life. The region where we are located is very rich. So the people of the region give us everything electronic.
We repair, we polish, in short we restore, then we sell at very low prices for those who are not very fortunate. This is especially true for computers, télévision and HiFi. What is not repairable, we recover the components piece by piece, we test them and we reuse them for us. We have hundreds of amplifiers, Harman-Kardon, Pionner, even accuphase, that's saying !.
There is no question of trade here. Our generation sums or HiFi wanted to say something. The old school somehow. We do everything on Autocad. We build and equip the people of the village. The HiFi is for us a way to forget all this misery.
That's it for the little story.
Thanks again, Toni, your work is great and inspires us.
Jacky
Ps:
A Harman-Kardon amplifier repaired plus Davis speakers.
We mail you our request on another message.
Thank you for the small message.
Exactly, we wanted to write to you. You have been faster than us, laughs!
Your concept is great, sincerely. We were looking for a way to make a universal box for our amplifiers. Thanks to you we had the light!
Little explanation:
The charity Emmaüs has 250 people. Rather old age. I am 62 years old. We take care of the poor, the sick of people broken by life. The region where we are located is very rich. So the people of the region give us everything electronic.
We repair, we polish, in short we restore, then we sell at very low prices for those who are not very fortunate. This is especially true for computers, télévision and HiFi. What is not repairable, we recover the components piece by piece, we test them and we reuse them for us. We have hundreds of amplifiers, Harman-Kardon, Pionner, even accuphase, that's saying !.
There is no question of trade here. Our generation sums or HiFi wanted to say something. The old school somehow. We do everything on Autocad. We build and equip the people of the village. The HiFi is for us a way to forget all this misery.
That's it for the little story.
Thanks again, Toni, your work is great and inspires us.
Jacky
Ps:
A Harman-Kardon amplifier repaired plus Davis speakers.
We mail you our request on another message.
Attachments
Re, Toni.
Would it be possible to have the other cards of your amplifier.
Protection, input circuit. We do not really know how to play the four amplifiers together. We have watched well on the Internet, but the solutions do not speak to us! Just the PDFs, as you understand, one has the habit of routing everything on Autocad, laughs!
Thanks again for the little message, Toni.
Jacky.
Ps:
Harman-Kardon being routed on Autocad.
Would it be possible to have the other cards of your amplifier.
Protection, input circuit. We do not really know how to play the four amplifiers together. We have watched well on the Internet, but the solutions do not speak to us! Just the PDFs, as you understand, one has the habit of routing everything on Autocad, laughs!
Thanks again for the little message, Toni.
Jacky.
Ps:
Harman-Kardon being routed on Autocad.
Attachments
Sir Oliver may i know the value of resistor in PA 600 R121 AND R122 THANK YOU IN Advance sir god bless
Schematic, gerbers, dxf files (and also pcbs at factory costs + shipping) of all housekeeping circuits and firmware (mcu controller, relay-board, helper supply, backplane ...) are available on request for all people which are building my amplifier designs on a non commercial basis. Your NGO organization may fulfill these conditions too. Maybe you want to send me a PM or an email to discuss details.
BR, Toni
Hi,
may I ask why this ELEKTOR PA 300 shouldn't be good for HiFi? Is it due to it's input opamp? Is it due to it's age? I know from the article that ELEKTOR themselves told us so, but the data they published aren't that bad at all?!?
Of course I'd nowadays prefer power devices of the MJ21xxx family over the MJ15003/04 originals...
Best regards!
may I ask why this ELEKTOR PA 300 shouldn't be good for HiFi? Is it due to it's input opamp? Is it due to it's age? I know from the article that ELEKTOR themselves told us so, but the data they published aren't that bad at all?!?
Of course I'd nowadays prefer power devices of the MJ21xxx family over the MJ15003/04 originals...
Best regards!
PA300/600
Hello, Kay.
Sorry, I went to sea to recover refugees. the sea campaign to last a long time. To answer. The Pa 300 works great for HiFi without problems. The NE5534 is used worldwide in half of the audio circuits on the planet, laughs!
It's not the McIntosh circuits, but it's very good at the level of operation. The trick in fact would be to power the NE5534 with regulators like 78xx and 79xx. This makes it possible to lower the residual ripple very low and at the same time the background noise. Always better than the couple zener / resistance. Properly tuned and properly wired, the PA300 is a good amplifier. The circuit is quite universal. Easy to modify for greater power and the use of other power transistors.
Kay, sincere greetings. Jacky
Ps images of ongoing studies on the PA.300, 400, 600.
This is the exact copy of the Pa.300 Elektor. Except that the specific routing adapted to the ASTX system.
Hello, Kay.
Sorry, I went to sea to recover refugees. the sea campaign to last a long time. To answer. The Pa 300 works great for HiFi without problems. The NE5534 is used worldwide in half of the audio circuits on the planet, laughs!
It's not the McIntosh circuits, but it's very good at the level of operation. The trick in fact would be to power the NE5534 with regulators like 78xx and 79xx. This makes it possible to lower the residual ripple very low and at the same time the background noise. Always better than the couple zener / resistance. Properly tuned and properly wired, the PA300 is a good amplifier. The circuit is quite universal. Easy to modify for greater power and the use of other power transistors.
Kay, sincere greetings. Jacky
Ps images of ongoing studies on the PA.300, 400, 600.
This is the exact copy of the Pa.300 Elektor. Except that the specific routing adapted to the ASTX system.
Attachments
Thanks, Jacky, and an interesting modification!
I don't see how the TO3's are joined with the heatsinks, though. Maybe due to the rather small and hard to decipher drawings in your 2nd pic?
And if we'd think of the more recent MJ21193/21194/21195/21196 ring emitter devices instead of the ancient MJ15003/15004's, we'd also have TO-264 MJL or TO-247 MJW (almost) equivalents that surely would decrease PCB size and ease PCB routing and mechanical mounting as well.
Best regards!
I don't see how the TO3's are joined with the heatsinks, though. Maybe due to the rather small and hard to decipher drawings in your 2nd pic?
And if we'd think of the more recent MJ21193/21194/21195/21196 ring emitter devices instead of the ancient MJ15003/15004's, we'd also have TO-264 MJL or TO-247 MJW (almost) equivalents that surely would decrease PCB size and ease PCB routing and mechanical mounting as well.
Best regards!
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PA300/600
Hello, Kay.
Thank you for the answer.
Exactly. The To3 cases were the top. the system was very well designed. The new boxes are for the sake of economy. They take up as much space, if there are many pairs. See the images as an example. the pa.300 was designed on a 194x124 map of ours, 80x168, cool no! The Pa.300 is complete with full protection. Thermal, dc detect, clip etc! If we add the same protection on a map Top.3 pl congestion increases very quickly. See the map 226x70, without any protection. There is the Ips system, ops that separate the input circuit with the power. Ok, but I like the shortest links possible at the Pcb level.
Anyway you have to do with!, Laughs!
To return to Pa. The To3 are mounted on aluminum brackets, as Elektor originally see the attached drawing.
I have studies in progress with modern type Mjl transistors, but I have not finished routing the Pcb yet.
Sincerely, Kay
Jacky
Hello, Kay.
Thank you for the answer.
Exactly. The To3 cases were the top. the system was very well designed. The new boxes are for the sake of economy. They take up as much space, if there are many pairs. See the images as an example. the pa.300 was designed on a 194x124 map of ours, 80x168, cool no! The Pa.300 is complete with full protection. Thermal, dc detect, clip etc! If we add the same protection on a map Top.3 pl congestion increases very quickly. See the map 226x70, without any protection. There is the Ips system, ops that separate the input circuit with the power. Ok, but I like the shortest links possible at the Pcb level.
Anyway you have to do with!, Laughs!
To return to Pa. The To3 are mounted on aluminum brackets, as Elektor originally see the attached drawing.
I have studies in progress with modern type Mjl transistors, but I have not finished routing the Pcb yet.
Sincerely, Kay
Jacky
Attachments
This amp is 1978 basic design BGW 750B professional power amp, and very reliable after 40 years too
I cant complain anything !!!!
Build it and enjoy,.... but take Original 750B circuit design, not modified elektor circuit
I have redesign PA600 / BGW750B with NMOS output stage
can handle 100 V +/- with 1000W RMS @ 4 OHM
I cant complain anything !!!!
Build it and enjoy,.... but take Original 750B circuit design, not modified elektor circuit
I have redesign PA600 / BGW750B with NMOS output stage
can handle 100 V +/- with 1000W RMS @ 4 OHM
Attachments
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