TPA3255 Reference Design Class D Amp with PFFB

[xrk971]

Can I use a Kerotherm Red sheet with this block?

Yes. Almost any silicone insulator pad will work as the heat flux is not a lot. Maybe 15w at most if playing full power.

 

[bucks bunny]

I have had a couple requests to provide this amp as monoblock PBTL. Has anyone done PBTL with amp? Wondering what your opinions and experiences are.

Me. Been there, done that - with my own pcb design

 

[xrk971]

Yes, how did it sound and was there any specific things we should be aware of to operate it as such?

 

[bucks bunny]

Yes, how did it sound and was there any specific things we should be aware of to operate it as such?

This is a look into the past and I will have to check my repositories. Generally I consider subjective sound anecdotes non-informative- including my own ones. So do not expect me to brag about its fantastic sound, I am wearing hearing aids btw for several years. Instead I will deliver some measurements that I did at that time - later on. I am sure some interesting aspect will show up.

 

[bucks bunny]

First of all my remarks on postfilter-feedback

 

[xrk971]

Nice work Bucks Bunny! Do you have schematics to show the exact implementation? The feedback capacitor is a great idea.

 

[TNT]

"A small capacitor tied from the output to the input..." - is this from the pins of the TPA chip?

//

 

[bucks bunny]

"A small capacitor tied from the output to the input..." - is this from the pins of the TPA chip?

//

Yes. Provided this input is driven by a certain series resistance - which is driven by lo-z opamp output. Series resistor and feedback capacitor form the hi-pass - i.e. differentialting feedback network. The low-z-drive - provided by the A(udio) F(ront) E(nd) - is mandatory, otherwise the hole thing will oscillate.

 

[bucks bunny]

You may look here, posting #32, as well: https://www.diyaudio.com/community/threads/tpa3255-oscillation-issues.393518/page-2

 

[xrk971]

Thank you, BB.

 

[Gaspar74]

Where can one buy this board and how much is it?

 

[Plott]

https://www.etsy.com/at/listing/755...34&click_sum=f998bd88&ref=shop_home_active_22

You may want to switch to your language or maybe you will be redirected automatically.
Hurry, only 7 Items left.

 

[xrk971]

Here are the new boards:

You might consider getting the BTSB Buffer to go with it. Provides SE or Bal input and selectable gains. Uses top of the line OPA1656 opamp and OPA1637 balanced line drivers. All top quality components.

 

[xrk971]

Testing units and all are passing and sound great. The build quality of this manufacturing house is exceptional.

I’m going to put together a “User’s startup guide” and a video to show how to hook up one of these amps.

 

[rhing]

Awesome! Thanks!

 

[turion64]

Hi X...1) are the cases used for Warp 1 available for purchase? and 2) I notice you didn't use any extra caps between the SMPS630-SO and the 3255. It's still advisable to do so to to avoid buss pumping, correct?

My apologies for posting my other questions in the other GB forum

Thanks

Pete

 

[xrk971]

I didn’t see the need for extra caps given the two 4700uF ones on the amp already plus the two pretty big ones on the SMPS630SO output. I never had an issue with bus pumping.

Cases available? You mean like Warp-1 chassis?

Unfortunately, those are only available for LSA Warp-1. If you look at the costs of the amp, SMPS, the BTSB buffer, chassis, connectors and hardware, you will see it is less expensive to buy the Warp-1 premade.

 

[turion64]

"Unfortunately, those are only available for LSA Warp-1. If you look at the costs of the amp, SMPS, the BTSB buffer, chassis, connectors and hardware, you will see it is less expensive to buy the Warp-1 premade."

Thanks..totally understandable X. I just did have the parts/components from other projects and never thought you'd have another GB for the amp.

Pete

 

[xrk971]

Here is the video on how to setup your TPA3255 amp module for the first time.

 

[xrk971]

Here is a diagram showing how to setup the DIP switches in case you want a different mode of operation. Note that Cstart can work in either position for stereo BTL. For 4 Ch SE output you need to install DC blocking caps where the Faston output tabs are located.

Here is a photo showing how to setup jumper resistors on the bottom and the small silkscreen error swap for R and C on the top side for those assembling the boards themselves: