Class D Amplifier

[vizeta]

I am kind of tending towards TPA3255. In parallel i was searching for a box to house it. I was looking for one to house the supply and amp board to gehter; should have a volume control space along with 4 channel selection switch. I have looked through many websites, not able to get the right one at decent price point. Appreciate any suggestions in this matter.

In case this helps https://www.hifivision.com/threads/my-dual-mono-ti-tpa3255evm-based-class-d-amplifier-build.69467/

 

[sunilmani]

In case this helps https://www.hifivision.com/threads/my-dual-mono-ti-tpa3255evm-based-class-d-amplifier-build.69467/

Thanks vizeta

I was reading up more on class D amplifiers and there were threads that said that one should use a linear power supply to power up a class D amplifier and that it make a huge difference as compared to a SMPS. Anyone had a first hand experience about this in our forum?

I have never made any amplifier with VU meter, so was planning to add in VU meter along with this one and an ALPS pot. Any pointers on where to source these from? I have found a few links on Ali Express for the same, but am not sure of the quality of these.
Pot Link -> link
VU Meter Link -> link

Also, what should be the pot value ? I would typically be connecting it to my DVD player, mobile, ipod and RasperBerryPi + DAC unit. Is there some way to calculate what should be the value of the dual pot ?

 

[sunilmani]

Finally my friend got me my Class D amplifier from the US.

Now i can get started with the assembling process.

 

[saikatbiswas82]

Finally my friend got me my Class D amplifier from the US.
View attachment 42467
Now i can get started with the assembling process.

Please let us know how does it sound. I think this is the EVM board. I recently had a chat with one OEM and according to them, SMPS would be better compared to LPSU for their TPA3255. Please test both the options and let us know your findings.

Please let us know if you are able to hear any hissing noise from tweeter.

One advice - please use better shielded interconnects. The ones you are using here are succeptable to noise.

 

[sunilmani]

I was just testing the board if it was working good in 2.0 configuration. In the final setup, these would not be the interconnects

 

[adas]

Please use a Smps , with LPSU you run the risk of over volting the chip and that definitely will kill the chip. I have designed amps around these chips and using smps doesn't effect the audio parameters.

 

[sound1]

I was reading up more on class D amplifiers and there were threads that said that one should use a linear power supply to power up a class D amplifier and that it make a huge difference as compared to a SMPS. Anyone had a first hand experience about this in our forum?

I found that to be true in my case. I tried out Connex Electronics SMPS800R with my classdaudio SDS250 and it sounded awful. Immediately (within 10 minutes) switched back to linear supply it came with and never looked back. Surely high end amps like Hypex would have no issues but budget class D amps are better served with liner supplies (unregulated) instead of SMPS, of course, in my humble opinion.

And oh, let me know if anyone wants to buy an audio grade 800 watts SMPS

 

[sound1]

Finally my friend got me my Class D amplifier from the US.

Now i can get started with the assembling process.

Congratulations!! Do let us know how it sounds

 

[sunilmani]

Please let us know how does it sound. I think this is the EVM board. I recently had a chat with one OEM and according to them, SMPS would be better compared to LPSU for their TPA3255. Please test both the options and let us know your findings.

I currently have a liner power supply. Ran the amplifier for just an hour and it sounded clean. I am yet to procure a SMPS.

Please let us know if you are able to hear any hissing noise from tweeter.

I checked in the following environment -
Audio source - Raspi/DAC, Mobile device
Power Source - 25v linear supply
Speakers - My test speakers built in house
There was no hissing sound from Tweeter. But again this is on my test speaker boxes that i literally rough up every now and then.

One advice - please use better shielded interconnects. The ones you are using here are susceptible to noise.

About the sound quality - My first reaction was that the bass was hollow; but as time is passing, the sound seems to be settling in. I am still in love with my gain clone amplifier (3886T) and i am finding its sound to be more sweeter (maybe i am biased) than this one. Will hear this one out for a few more days before switching back to my gain clones and would let you know.


VU Meter - Does anyone have any experience with VU meters? I have never integrated one and was planning to do so with this amplifier. Apprecaite any suggestions

 

[saikatbiswas82]

I currently have a liner power supply. Ran the amplifier for just an hour and it sounded clean. I am yet to procure a SMPS.

I checked in the following environment -
Audio source - Raspi/DAC, Mobile device
Power Source - 25v linear supply
Speakers - My test speakers built in house
There was no hissing sound from Tweeter. But again this is on my test speaker boxes that i literally rough up every now and then.


About the sound quality - My first reaction was that the bass was hollow; but as time is passing, the sound seems to be settling in. I am still in love with my gain clone amplifier (3886T) and i am finding its sound to be more sweeter (maybe i am biased) than this one. Will hear this one out for a few more days before switching back to my gain clones and would let you know.


VU Meter - Does anyone have any experience with VU meters? I have never integrated one and was planning to do so with this amplifier. Apprecaite any suggestions

Thanks for the update.

Regarding the comparison with your gainclone i must say chipamps are great sounding amps. I might be wrong but each and every amplifier adds a degree of distortion (in a good way) which we get used to. After a long listening we start to think - that particular sound signature to be the benchmark and start comparing everything else against it.

Will be waiting for your review after initial burn in. If you still miss the sweetness, I'd suggest you to try a tube preamp in chain.

You may check diyaudiocart/ebay/AliExpress for vu meters/drivers.

Happy Listening!

 

[surfatwork]

VU Meter - Does anyone have any experience with VU meters? I have never integrated one and was planning to do so with this amplifier. Apprecaite any suggestions

You can get nissei meters from audiocrafts. He can also sell you the driver boards, or you can roll your own - it's a simple circuit. Drive it from your speaker outs, not line level signals to prevent distortion.
Have included it on my Diy chassis below. You can see the Diy driver board (perfboard) in the second pic on the top left.

 

[sunilmani]

Since its a class D amplifier, the negative speaker terminal is not ground and cannot be made as common. That being the case, is there a way to connect the VU meter circuits to the output ?

 

[saikatbiswas82]

You can get nissei meters from audiocrafts. He can also sell you the driver boards, or you can roll your own - it's a simple circuit. Drive it from your speaker outs, not line level signals to prevent distortion.
Have included it on my Diy chassis below. You can see the Diy driver board (perfboard) in the second pic on the top left.

Very nice build

 

[sound1]

Thanks vizeta

I was reading up more on class D amplifiers and there were threads that said that one should use a linear power supply to power up a class D amplifier and that it make a huge difference as compared to a SMPS. Anyone had a first hand experience about this in our forum?

I have never made any amplifier with VU meter, so was planning to add in VU meter along with this one and an ALPS pot. Any pointers on where to source these from? I have found a few links on Ali Express for the same, but am not sure of the quality of these.
Pot Link -> link
VU Meter Link -> link

Also, what should be the pot value ? I would typically be connecting it to my DVD player, mobile, ipod and RasperBerryPi + DAC unit. Is there some way to calculate what should be the value of the dual pot ?

Well I do. I replaced the linear power supply that came with the amp with an 800 watt SMPS (I think the model was Connex Electronics SMPS800R). It sounded awful, sound was flat - just like listening with an under powered AVR. I still have that SMPS lying around somewhere...

 

[sunilmani]

I know it has been long. But life kept me busy . Finally i am planning on completing my class D amplifier. I am not liking the dry sound of a class D, so as suggested have started looking for a tube pre-amp to put inline. I have been reading up on forums and it seems that i cannot just go with specs . Appreciate any suggestions/recommendations for a tube pre-amplifier.

 

[FlaCharlie]

I am not liking the dry sound of a class D, so as suggested have started looking for a tube pre-amp to put inline. I have been reading up on forums and it seems that i cannot just go with specs . Appreciate any suggestions/recommendations for a tube pre-amplifier.

I'm mostly into tube amps but I do have a few Class D amps. One of them is the popular Aiyima A-07 which I've used with a couple of tube preamps - one that I built and one that I bought.

I call the preamp I built the Boogie Factor. I'm new here and mostly post over at Audio Karma in the US. I was going to add a link to a thread I posted about it there but I checked the rules and I see that I'm not allowed to do that.

If you want to search there for '1626 preamp' you'll find it. I use the same moniker there. If anyone is interested I'll be happy to post more info here directly including why I chose the 1626, pics, schematics etc.

It's very simple and uses relatively inexpensive tubes. While it wasn't designed specifically for use with SS or Class D it works well with them. I plan on making a couple of minor parts changes to optimize it further for use with Class D. If you're interested I can describe them.

I've also been playing around with the Nobsound E6 which caught my attention because it uses directly heated tubes. I also started a thread there about it which can be found by searching for 'Nobsound E6'.

If you read through that thread you'll see that quality control has been an issue with some of these. Most of the issues are related to the stock Chinese tubes being microphonic and in most all cases using the Russian version of the tube solves the issues. A few units seem to have issues that go beyond the tubes though.

So, if you're interested in these I'd suggest that you buy it from a vendor that allows free returns. Amazon does this in the US. Not sure if they sell in India or have the same return policy there if they do. Most owners use them with SS and Class D amps and seem to like them a lot. If you're not into DIY and don't want to spend a lot of money, these are cheap ($50 to $60 including shipping) and worth looking into.

Although I didn't build it, I also breadboarded a simple design that uses the 2P29L, which is a cousin of the 2J27L used in the E6. Either of these tubes could be used in this design with only minor changes to the schematic.

If anyone is interested just let me know and I can start a new thread about any of them.

 

[keith_correa]

If you want to search there for '1626 preamp' you'll find it. I use the same moniker there. If anyone is interested I'll be happy to post more info here directly including why I chose the 1626, pics, schematics etc.

If anyone is interested just let me know and I can start a new thread about any of them.

I for one, am interested and I'm sure many in here would be too so would appreciate it if you please go ahead.

 

[sunilmani]

I'm mostly into tube amps but I do have a few Class D amps. One of them is the popular Aiyima A-07 which I've used with a couple of tube preamps - one that I built and one that I bought.

I call the preamp I built the Boogie Factor. I'm new here and mostly post over at Audio Karma in the US. I was going to add a link to a thread I posted about it there but I checked the rules and I see that I'm not allowed to do that.

If you want to search there for '1626 preamp' you'll find it. I use the same moniker there. If anyone is interested I'll be happy to post more info here directly including why I chose the 1626, pics, schematics etc.

It's very simple and uses relatively inexpensive tubes. While it wasn't designed specifically for use with SS or Class D it works well with them. I plan on making a couple of minor parts changes to optimize it further for use with Class D. If you're interested I can describe them.

I've also been playing around with the Nobsound E6 which caught my attention because it uses directly heated tubes. I also started a thread there about it which can be found by searching for 'Nobsound E6'.

If you read through that thread you'll see that quality control has been an issue with some of these. Most of the issues are related to the stock Chinese tubes being microphonic and in most all cases using the Russian version of the tube solves the issues. A few units seem to have issues that go beyond the tubes though.

So, if you're interested in these I'd suggest that you buy it from a vendor that allows free returns. Amazon does this in the US. Not sure if they sell in India or have the same return policy there if they do. Most owners use them with SS and Class D amps and seem to like them a lot. If you're not into DIY and don't want to spend a lot of money, these are cheap ($50 to $60 including shipping) and worth looking into.

Although I didn't build it, I also breadboarded a simple design that uses the 2P29L, which is a cousin of the 2J27L used in the E6. Either of these tubes could be used in this design with only minor changes to the schematic.

If anyone is interested just let me know and I can start a new thread about any of them.

I for sure am interested. Appreciate if you can share more details.

 

[sunilmani]

I need some inputs here. I am pairing the 3255 class D amp with a meanwell smps (LRS-350-48) . I was just going through the specs and it reads AC inrush current is 60 Amps at 230V (cold start) . That is making me wonder about having a soft start board in place. Anyone else faced this issue ? If a softstart board is the solution, then appreciate any suggestions regarding the ones to go for.

 

[bobbyprajan]

I need some inputs here. I am pairing the 3255 class D amp with a meanwell smps (LRS-350-48) . I was just going through the specs and it reads AC inrush current is 60 Amps at 230V (cold start) . That is making me wonder about having a soft start board in place. Anyone else faced this issue ? If a softstart board is the solution, then appreciate any suggestions regarding the ones to go for.

I use the same evaluation board with LRS-350-48. Never had any issues of circuit breakers tripping or anything like that.

Soft start circuits are recommended for for transformers of more than 500VA. Not sure whether they are required in SMPS