Class D Amplifiers

[keith_correa]

Cap'n - give it more volts and it will [should?] sound better. Would be very interested in seeing how you encase it. BTW, Congratulations!

 

[iaudio]

Cap'n If I read right this one makes 125w into 8ohms. Thats a whole lotta power!

 

[spirovious]

Now Class D vs T20 ,a real grp test awaited.

 

[captrajesh]

Cap'n If I read right this one makes 125w into 8ohms. Thats a whole lotta power!

Yeah & 250W RMS into 4 ohms & a whopping 500W in bridged mode. My next is to drive a sub with 12" driver with this.

Now Class D vs T20 ,a real grp test awaited.

Hi Spiro

This one is a monster. Trust me, this will beat the T20 hollow.

Cap'n - give it more volts and it will [should?] sound better. Would be very interested in seeing how you encase it. BTW, Congratulations!

Hi Keith_correa,

Thank you for you advise & kind words. I'm planning to buy a 35V 300va Torodial transformer after I go back. Will keep you guys posted on the developments.

 

[murali_n]

Hi Keith_correa,

Thank you for you advise & kind words. I'm planning to buy a 35V 300va Torodial transformer after I go back. Will keep you guys posted on the developments.

Hi Capt Rajesh,

Congrats on your new buy. BTW I think the Power supply required for the amp reads 45 to 60 V. Pl. ensure from the User manual before ordering. I think Maxine will do a good job.

N.Murali

 

[captrajesh]

Hai Capt Rajesh,

Congrats on your new buy. BTW I think the Power supply required for the amp reads 45 to 60 V. Pl. ensure from the User manual before ordering. I think Maxine will do a good job.

N.Murali

Hi Murali,
Thanks for the advice & kind words. In my older posts I did mention that maxine doesn't supply toroidal. 35V secondary would result in around 50V DC.

 

[grubyhalo]

Yeah & 250W RMS into 4 ohms & a whopping 500W in bridged mode. My next is to drive a sub with 12" driver with this.



Hi Spiro

This one is a monster. Trust me, this will beat the T20 hollow.

Nice! Congrats Captain!

 

[captrajesh]

After long delay hoping to rectify my faulty digital camera which is not happening, I'm posting the pics of my Class D Amp & the associated gear in action taken with my phone camera.

The amp has now logged a few hours and has sufficiently broken in I guess.

The Bass which was previously like a lean sweet 16 year old girl has now become a well endowed brunette.

The mids have remained as sweet as before and the earlier roll off at the top has now a little more extension.

Listening to Santana, Dire Straits-Sultan of Swing were sooooo sugary sweeet.

I'm amazed at the capability of my speakers which are bringing out each and every nuance of the music that is digged out by the CDP Amp combo.

I'm eagerly scouting around for a decent casing and thereafter would like to add an exotic looking faceplate.

 

[grubyhalo]

And don't forget those cap upgrades, Cap'n! Are you going to post your impressions at the Circle as well? Looking forward to listening to these guys someday!

P.S: Interesting speakers you have there. Does it have 2 horn-loaded tweeters?

 

[Rajiv]

Hi Capt,

Those tweeters look like Pioneer/JVC Ribbon tweeters.They are very good tweeters.


Regards
Rajiv

 

[gobble]

You may want to place the EI transformer farther away, like 6 inches apart or use one shielded by a brass flux bands

For now try laying it horizontally so the flux radiates in a direction away from the rest of the circuits.

Cheers

 

[captrajesh]

And don't forget those cap upgrades, Cap'n!

II thought I'll change the tranny to torodial & see first. Thanks for the suggestion, i'll also try that. Which caps are you suggesting?

Are you going to post your impressions at the Circle as well?

Thanks for reminding me about the Audio Circle Richie, I must update there too. :thumbsup:

Looking forward to listening to these guys someday!

You are welcome anyday. Just give me a day's notice.

P.S: Interesting speakers you have there. Does it have 2 horn-loaded tweeters?

Those tweeters look like Pioneer/JVC Ribbon tweeters.They are very good tweeters.

I'm not sure guys, these were taken out from my old kenwood speakers.

You may want to place the EI transformer farther away, like 6 inches apart or use one shielded by a brass flux bands

For now try laying it horizontally so the flux radiates in a direction away from the rest of the circuits.

Thanks gobble, will surely consider that.

 

[grubyhalo]

II thought I'll change the tranny to torodial & see first. Thanks for the suggestion, i'll also try that. Which caps are you suggesting?



Thanks for reminding me about the Audio Circle Richie, I must update there too. :thumbsup:



You are welcome anyday. Just give me a day's notice.

This is just a guess. The PS you've ordered has about 20000 uF, that's about 3300uF per cap X 6. I'd looks at something like 10000/12000 uF per cap as long as it fits the board. Apparently you have good options locally at Richie St. or check with suds who had a few for sale.

http://www.hifivision.com/hot-deals/9468-yamaha-10-000uf-capacitors.html#post128884

 

[captrajesh]

This is just a guess. The PS you've ordered has about 20000 uF, that's about 3300uF per cap X 6. I'd looks at something like 10000/12000 uF per cap as long as it fits the board. Apparently you have good options locally at Richie St. or check with suds who had a few for sale.

http://www.hifivision.com/hot-deals/9468-yamaha-10-000uf-capacitors.html#post128884

You are absolutely correct. But do you think I would need this higher capacity caps? I think the caps are required to supply instant current for transient loads.

I checked this amp with different kinds music and even in demanding passages, it works effortlessly. Considering this fact, is change to higher caps warranted?

What would be the tangible results? I appreciate your reply.

 

[gobble]

You are absolutely correct. But do you think I would need this higher capacity caps? I think the caps are required to supply instant current for transient loads.

I checked this amp with different kinds music and even in demanding passages, it works effortlessly. Considering this fact, is change to higher caps warranted?

What would be the tangible results? I appreciate your reply.

I would say - Wait 6 months until some deficiencies in SQ become more "imagined" or "apparent". Then think if a cap upgrade will resolve the issue and go ahead. Why try to fix something that does not sound broken?


Regards

 

[grubyhalo]

...But do you think I would need this higher capacity caps? I think the caps are required to supply instant current for transient loads.

...

What would be the tangible results? I appreciate your reply.

Ofcourse, you don't NEED higher capacity. But, if you go through the Class D modification thread, you'd see that the users do find improvements. If you could get 6 caps at about Rs.200 a pop, it would be a risk worth taking. Ofcourse, this is JMHO and as I've stated before I've not heard the amp first hand and I'm basing this reasoning on second-hand information.

 

[suri]

hi captrajesh -

wonderful job!

you have made - and it is my duty to listen to your creation - and i will soon be there.

regds suri

 

[captrajesh]

hi captrajesh -

wonderful job!

you have made

Hi Suri

Thank you very much. Actually, though it is already sounding good, I'm yet to finish the project as I'm scouting for a torodial and casing.

- and it is my duty to listen to your creation - and i will soon be there.

Thats a great news. Do let me know when are you reaching Chennai. It would be my pleasure to host you. Hope to treat you to some sweet music to elevate you (spirit)ually.

Regards


Rajesh

I'm not sure guys, these were taken out from my old kenwood speakers.

Hmm,
Don't know why I said that. Probably would've been spiritually elevated then. They are not horn loaded and not ribbon tweeters. They are paper cone tweeters.

I would say - Wait 6 months until some deficiencies in SQ become more "imagined" or "apparent". Then think if a cap upgrade will resolve the issue and go ahead. Why try to fix something that does not sound broken?

Thats what I also thought.

Ofcourse, you don't NEED higher capacity. But, if you go through the Class D modification thread, you'd see that the users do find improvements. If you could get 6 caps at about Rs.200 a pop, it would be a risk worth taking. Ofcourse, this is JMHO and as I've stated before I've not heard the amp first hand and I'm basing this reasoning on second-hand information.

Yes Richie
Even i read it. Lets see.

BTW, I've ordered the transformer from Miracle Electronic Devices, B'lore. Cost me Rs. 708 including shipping. The person from SV Tronics Chennai had quoted Rs. 2100. Don't know if he was planning to make it with silver wire.:indifferent14:

And yes, I've driven a Dainty 12" Passive subwoofer to see the result. This amp was not upto it. It really excels in mids, just like SETs but also has juice to produce realistic bass.

 

[mathewsyriac]

Hi all!!!!
And Hi!!! Capt. Rajesh sir...

Just joined today:yahoo:..
Interested in a lot of experiments with class D audio...

Actually i customized an 8-channel amp for my Creative X-Fi Platinum Sound Card and i use it to listen to movies and of course for music i prefer only 2 channel...

two days ago i had a chance to hook up CDA-254 Amplifier from class D on to my sound card... But the sound was very feeble:sad:
Compared to other sound cards, i believe that creative has got better output in terms of level and it can drive headphones well too... And when i wanted to drive my passive sub (Bridge mode), it was much feeble..

Does this kit really require a pre-Amp to boost up the signal???
My TDA7294 has got at-least 10 times more gain as per its standard datasheet circuit design...
I believe its only something to do with gain in CDA-254 Amplifier, and it can perform well.

The detail of sound was superb!!! But i was curious to test its limits in driving my 12" subwoofer....

 

[captrajesh]

Hi all!!!!
And Hi!!! Capt. Rajesh sir...

Just joined today:yahoo:..
Interested in a lot of experiments with class D audio...

Hi Mathew

Welcome to the HFV. Glad to see you here. Yes it was your sub that I was talking about. It was not upto it. As I said to you, the TI based kit would be better for the sub-woofer duty. Check out their website.

BTW, you are required to start a thread saying hello to everyone in the forum before making any posts.