|
|||||||
| Home | Forums | Rules | Articles | diyAudio Store | Blogs | Gallery | Wiki | Register | Donations | FAQ | Calendar | Mark Forums Read |
| Chip Amps Amplifiers based on integrated circuits |
  |
|
|
|
Please consider donating to help us continue to serve you.
Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving |
 |
|
|
Thread Tools |
24th November 2020, 12:39 PM
|
#1 |
|
diyAudio Member
Join Date: Dec 2015
Location: south east asia
|
How to parallel multiple power amps?
Each paralleled amp equates the voltage of its resistor to be equal to the master's resistor. By this the output current is multiplied here by four. the main amp sees the load as Rload×4. The load sees the impedance of the main amp as Z/4. Hayk Last edited by kokoriantz; 25th November 2020 at 10:23 PM. |
|
|
24th November 2020, 11:47 PM
|
#3 |
|
diyAudio Member
Join Date: Dec 2015
Location: south east asia
|
On simulator it does work in perfection with a gain of unity.
Bellow is the transient for 10khz 10v Last edited by kokoriantz; 24th November 2020 at 11:54 PM. |
|
|
|
25th November 2020, 12:32 AM
|
#5 |
|
diyAudio Member
Join Date: Dec 2015
Location: south east asia
|
Parallel bridge configuration is widely used to get high power amplifiers by using small chips. The LM1875 gives its best with 8 ohms 15 watts only.
Bellow is the impedance that sees the main driving amplifier. To note that the simulating model doesn't have inductive component of the output impedance, it is fixed for simplicity to 0.1 ohms. This why the high frequency impedance falling to 0.5 ohm is wrong. Last edited by kokoriantz; 25th November 2020 at 12:36 AM. |
|
|
|
25th November 2020, 05:50 AM
|
#7 |
|
diyAudio Member
Join Date: Dec 2015
Location: south east asia
|
I appreciate your attention about the subject.
The datasheet also precise that it is loaded 2k. The open loop gain depends greatly with the load. The datasheet also precise that with one ohms in series, it is stable with any capacitive load. In other words, the OLG with one ohm gets considerably reduced to remain stable. How about loading 0.22 ohms! The OLG decreases by far by 10 fold to be stable at unity gain. If an amplifier still oscillate, to feedback by 1k resistor and shunt the inputs by 100 ohms. The gain decreases by ten fold. See applied by Mooly The LM1875 for best After testing on simulator, it is the positive feedback is the reason of stability. Last edited by kokoriantz; 25th November 2020 at 06:09 AM. |
|
|
|
25th November 2020, 06:22 AM
|
#8 |
|
diyAudio Member
Join Date: Dec 2015
Location: south east asia
|
This is response as unity follower with 0.22 ohm. Is stable but this is not reason of stability. The load if not zero is receiving feedback, I don't know yet how.
|
|
|
|
25th November 2020, 06:59 AM
|
#9 |
|
diyAudio Member
Join Date: Dec 2015
Location: south east asia
|
The stability is perfect but very well damped. This is modeled with not non inductive resistors worst case and adjusted for perfect stability. Last edited by kokoriantz; 25th November 2020 at 07:10 AM. |
|
|
|
25th November 2020, 07:43 AM
|
#10 |
|
diyAudio Member
Join Date: Sep 2001
Location: Melbourne, Australia
|
Hayk,
Is this needed? Rowlands has marketed amps with multiple chips, at high cost, and others had done this with HP amps too. HD |
|
|
|
| Thread Tools | |
|
|
Similar Threads
|
||||
| Thread | Thread Starter | Forum | Replies | Last Post |
| Multiple PAM8403 in parallel (same power supply) | demiansmith | Chip Amps | 8 | 1st September 2020 11:36 AM |
| Whats the Main Purpose of Using Multiple Low Power Transistors in Parallel? | escksu | Power Supplies | 11 | 18th July 2020 05:15 PM |
| Parallel opamp: an extreme audiophile amplifier made of parallel multibrand op-amps | GianlucaG | Chip Amps | 24 | 30th November 2018 11:21 AM |
| 5.1 with multiple T-amps + pre amps??? | adamzx3 | Everything Else | 15 | 5th December 2008 06:28 AM |
| Parallel amps & Parallel Voice coils? | officeboy | Multi-Way | 7 | 26th May 2004 08:12 PM |
| New To Site? | Need Help? |
