Assuming an appropriate rail voltage can you make a balanced power amplifier using a pair of class AB power amplifiers?
For example, I have an STK443-530 removed from a recycled chassis. If I am interested running some experiments can this be tried? Aside from the load currents and SOA issues the amplifiers don't really "know" that this experiment is being tried, right? (The two balanced signals fed to the left and right channels.)
I have several AVR transformers with both high and low voltage secondaries. I can use the low voltage secondaries intended for low impedance loads. The transformers are sized for 7 channel receivers.
Possible balanced sources include an E-MU 0404 USB, a homemade balanced output PCM1794 DAC and a modified ES9038Q2M with true I/V and filter modification (balanced).
I am not expecting any sort of stellar performance. I am more interested in learning and listening. I have the STK443-530 boards as well as various discrete Yamaha and Onkyo recycled 7 channel boards to experiment with.
Is this possible or is it fatally flawed?
For example, I have an STK443-530 removed from a recycled chassis. If I am interested running some experiments can this be tried? Aside from the load currents and SOA issues the amplifiers don't really "know" that this experiment is being tried, right? (The two balanced signals fed to the left and right channels.)
I have several AVR transformers with both high and low voltage secondaries. I can use the low voltage secondaries intended for low impedance loads. The transformers are sized for 7 channel receivers.
Possible balanced sources include an E-MU 0404 USB, a homemade balanced output PCM1794 DAC and a modified ES9038Q2M with true I/V and filter modification (balanced).
I am not expecting any sort of stellar performance. I am more interested in learning and listening. I have the STK443-530 boards as well as various discrete Yamaha and Onkyo recycled 7 channel boards to experiment with.
Is this possible or is it fatally flawed?
Attachments
See the ESP project here for some ideas:
Simplest Ever Bridging Adapter for Amplifiers
Also see his article
Trimode Amplifier Bridging
Simplest Ever Bridging Adapter for Amplifiers
Also see his article
Trimode Amplifier Bridging
The usual term for this is Bridged operation, or Bridge Tied Load.
As you note, each amplifier will see only half the impedance of the load, which means that if the amplifiers are suitable for low impedance loads, you can get maybe 4x as much power into the load for a given power supply voltage.
As you note, each amplifier will see only half the impedance of the load, which means that if the amplifiers are suitable for low impedance loads, you can get maybe 4x as much power into the load for a given power supply voltage.
According to the datasheet, the load is 8 ohms. Can you use a 16 ohm load (Bridging)?
Or you use a lower voltage supply and agree with the increase in THD.
Or you use a lower voltage supply and agree with the increase in THD.
I plan to use a lower voltage supply and the same peak output currents. (The transformer SecL voltage is roughly half the voltage of the SecH voltage.)
I do not need higher power (load current). I am simply interested in experimenting with a balanced amplifier driven by the balanced output of the DAC. (Both listening to and measuring the performance of the same amplifiers single ended and then balanced.)
I do not need higher power (load current). I am simply interested in experimenting with a balanced amplifier driven by the balanced output of the DAC. (Both listening to and measuring the performance of the same amplifiers single ended and then balanced.)
You will need amplifier halves that are stable at half the impedance of your actual load. Reducing the supply voltage is not sufficient and will not bring back the lost damping factor.
If your load is 8R, you will NEED amplifier halves rated for 4R single-ended operation otherwise it may be unstable, and it will definitely get hotter even with reduced supply voltage.
If your load is 8R, you will NEED amplifier halves rated for 4R single-ended operation otherwise it may be unstable, and it will definitely get hotter even with reduced supply voltage.
The Onkyo TX-SR504 has a damping factor of 60 at 8 Ohms 1 kHz.
The Yamaha HTR-5940 has a damping factor of 120 or more 20 Hz to 20 kHz 8 Ohms.
The particular receiver with the Sanyo STK443-530 has a damping factor of 60 at 8 Ohms 1 kHz.
So perhaps the Yamaha is the best bet to try this experiment. Right now I don't want to try modifying gain and stability to raise the damping factor.
The Yamaha HTR-5940 has a damping factor of 120 or more 20 Hz to 20 kHz 8 Ohms.
The particular receiver with the Sanyo STK443-530 has a damping factor of 60 at 8 Ohms 1 kHz.
So perhaps the Yamaha is the best bet to try this experiment. Right now I don't want to try modifying gain and stability to raise the damping factor.
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