Active Bi-amp PCB

[saheb11123]

With the amount of work and hassle for regulation, its better to either get a traffo with your desired windings or get get separates. Also why are regulating them?

unregualted supply will do just fine, just rectify and leave them be. Only regulate for the pre circuits, ie, the active low and high pass.

 

[aniruddha82]

afaik, regulated supply improves sound quality this is what I have read from other forums about regulated PS.

 

[omishra]

afaik, regulated supply improves sound quality this is what I have read from other forums about regulated PS.

That is true. But we generally use unregulated power supply for power amplifier. Regulator add impedance to power supply rail. It is not good because it affect current pulling by load. Amplifier may sound thin or shrill. Power rail noise is generally removed from power amplifier design using CCS and local filters.
Preamplifier needs cleanest power supply.

 

[aniruddha82]

That is true. But we generally use unregulated power supply for power amplifier. Regulator add impedance to power supply rail. It is not good because it affect current pulling by load. Amplifier may sound thin or shrill. Power rail noise is generally removed from power amplifier design using CCS and local filters.
Preamplifier needs cleanest power supply.

Do you mean there will be HF noise because of regulators?

 

[omishra]

Do you mean there will be HF noise because of regulators?

No HF noise but less BASS definition and sharp HF which is artifact of high impedance in PS.

 

[aniruddha82]

No HF noise but less BASS definition and sharp HF which is artifact of high impedance in PS.

can this be solved by adding huge capacitors after regulator?

Building an LM3886 Gainclone chip amp with a regulated power supply (PSU).
I was inspired for regulated supply after checking "the results" section of above link

and the below link also
PA100 DIY 2x LM3886 in parallel gainclone audio amplifier

 

[avesbilal]

Is it good idea to use regulated PS for HF and M-F power amp and use unregulated PS for LF power Amp?

As I read that most of music is in HF and MF, we will get better SQ by using regulated PS and I believe it doesn't matter much LF to have regulated PS

 

[omishra]

Building an LM3886 Gainclone chip amp with a regulated power supply (PSU).
I was inspired for regulated supply after checking "the results" section of above link

and the below link also
PA100 DIY 2x LM3886 in parallel gainclone audio amplifier

See those links already have very less capacitance. If you are willing to put multiple of 10,000uF per rail then keep it at the output of regulator. Generally if such a high capacitance used then regulator is not required. Still nobody stops you.

 

[aniruddha82]

See those links already have very less capacitance. If you are willing to put multiple of 10,000uF per rail then keep it at the output of regulator. Generally if such a high capacitance used then regulator is not required. Still nobody stops you.

It is getting confusing now.

 

[omishra]

It is getting confusing now.

In short, more capacitance is must required for power amplifier. All chip amp has property PSRR. Regulator is optional. Regulator does not replace requirement of capacitance.

Preamplifier must have regulated clean power supply.

 

[keith_correa]

Since you are building power amps, forget about the pre-amp PS for now. Go ahead and build the Regulated PS from Pedja Rojic or Carlos FM from the decdun website. It has worked well for many - maybe it will work well for you too.

 

[omishra]

Since you are building power amps, forget about the pre-amp PS for now. Go ahead and build the Regulated PS from Pedja Rojic or Carlos FM from the decdun website. It has worked well for many - maybe it will work well for you too.

I thought he is keeping active crossover on same pcb. Correct me if i understood wrong.

 

[keith_correa]

I thought he is keeping active crossover on same pcb. Correct me if i understood wrong.

Yes, but if he is going the regulated route - it should work there too, right?

 

[omishra]

Yes, but if he is going the regulated route - it should work there too, right?

I did not understand this question.
IMO regulated power supply for power amplifier makes it clean but thin sounding and less emphasis on bass. Body of vocal vanishes. But more capacitor at the output of regulator remove this tinny ness from sound.
Preamplifier on the other hand has low current requirement and does not need large capacitor but needs regulator. Its sound signature does not change with low or high capacitor in ps. Only noise level improve with good regulator. Thus sound too improve.
Supplying same regulated power supply to preamplifier and power amplifier needs isolations for current reservoirs(RC decoupling), so that cross talk does not happen. Power amplifier is current hungry and preamplifier easily affected with shared power supply variation due to power amplifier.

 

[keith_correa]

So we have multiple things to consider here:

1. Regulated PS for power amp: He intends building this PS based on Pedja Rojic or Carlos FM's designs - those are tried and tested by many for the gainclones so IMO he should try them out. If I remember correctly, Linuxguru even powered his MyRef variant with an SMPS with no difference in SQ.

2. Regulated PS for pre-amp: Like you correctly said, a regulated PS will work for the pre-amplifier so no problem here.

3. Sharing the same PS for both the pre & power amp. No comment from me on this - you know more than me so if you say it's going to be a problem the OP should consider the pro's and con's of this before taking a decision.

 

[aniruddha82]

IMO regulated power supply for power amplifier makes it clean but thin sounding and less emphasis on bass. Body of vocal vanishes.

Is it because regulator is not able to provide enough current for bass or some other reason? If the reason is current then please note I plan to use 2 x LM338 which can provide 5 Amp continuous each which should be sufficient for 2 LM3886.

 

[omishra]

Is it because regulator is not able to provide enough current for bass or some other reason? If the reason is current then please note I plan to use 2 x LM338 which can provide 5 Amp continuous each which should be sufficient for 2 LM3886.

Yes its instant current requirement.

 

[aniruddha82]

Yes its instant current requirement.

Ok, understood. Do you have schematic where you faced this problem? Also, which IC did you used?

 

[omishra]

I faced problems within class A amplifiers, class AB push pull and in TA2022 based amplifiers. No particular.

 

[aniruddha82]

I faced problems within class A amplifiers, class AB push pull and in TA2022 based amplifiers. No particular.

Thanks for the info. which regulator did you used?