TPA3255 Reference Design Class D Amp with PFFB

[xrk971]

I wanted this to be one of the first products I highlight in my new forum. This amp started as a GB in this thread.

TPA3255 Reference Design Class D Amp GB

There was a second GB here:

XRK RTR TPA3255 Reference class D Amp GB2

What can I say, this is a superb sounding amp. Quiet, powerful, dynamic, non fatiguing, low distortion.

JPS64 created a masterpiece with his signature symmetry, via stitched ground planes, and ultra short high current traces. The board is 2mm thick, 2oz copper, ENIG finish. Assembled in California using premium genuine Mouser-sourced BOM. Each amp is individually tested on an Audio Precision test stand at the factory and then sound quality tested by myself before shipping.

Many people have assembled this amp into a nice chassis and everyone loves the sound. With the right PSU, the amp has the distinction of being the quietest amp I have built. You cannot tell it is on with ear pressed to the speaker cone. Just silence.

I hope folks will share their builds here. Or feel free to ask technical questions.

Redjr made on of the nicest implementations. More here.

Vunce made an awesome build with a linear PSU with an LT4320 Ideal bridge rectifier amp on a plank here:

For best results, this amp should be paired with the BTSB balanced buffer which provides selectable gains (0dB/6dB/14dB/20dB) SE or Bal input and SE and Bal output. Since the TPA3255 with PFFB only has 15dB gain, it needs a preamp with about 14dB of gain in order to play music to its maximum levels. The BTSB is a superb preamp design by Jhofland. It started as a GB in this thread. Here is the panel mount version of the BTSB:

Those of you who know me, know that I hate casework (chassis building). This most of my amps are “plank” amps. Amps on a plank of wood. Only the most special and deserving of amps get a chassis. Well this amp is one of those amps. More to come...

Edit Jan 31, 2023: video on how to setup and connect your amp module for the first time.

 

[xrk971]

Hi Folks,
Just wanted to let everyone know about an exciting collaboration between XRKAudio and Living Sounds Audio. LSA will be producing a commercial amplifier with the RTR TPA3255 as the OEM core along with the BTSB Panel Mount input buffer. All of this will be in a nicely made custom CNC’d aluminum chassis. All genuine Mouser BOM and premium components like Viborg binding posts.

Here are some renders and an initial prototype of the production line unit.

We still need to tidy up the internal wiring - but it’s getting there:

 

[Octavia]

looks very very nice

 

[Cardone]

Very nice device and neatly made

 

[xrk971]

Hey thanks, guys. Some more progress photos. You can see this is not vapor ware anymore. These are not the correct binding posts. I spec’d premium solid copper with anodized aluminum knobs like in the renders. But wiring is a bit neater and buttons, switches and LEDs are connected.

Some neat details like dual 18ga silicone RC race car wires for the speaker outputs for extra low impedance. Also silicone wire is used for power from SMPS to the amp.

The BTSB buffer is the best there is and provides auto switching detection of RCA or XLR with XLR being dominant.

 

[xrk971]

The first production unit has been delivered and it looks and sounds stunning!

Some sound clips of the First Sound test playing on my Rockville speakers.

First Sound of new Warp-1 Amp! - YouTube

Watermelon Man - Warp-1 amp test - YouTube

 

[Cardone]

The case has become very good and neatly constructed ...
Good work....
Thanks for the pictures....

 

[xrk971]

Thank you. The case is really nicely made. 6mm thick top and bottom panels feel substantial and side panels are 4.75mm thick. The satin finish powder coated paint is really beautiful to see and touch. It’s a nice weighty feeling amp when you pick it up.

 

[xrk971]

Thermal transfer blocks for this amp will be available in my shop soon. Lets you use 10mm stand-off for proper stack up height with 0.5mm to 1.0mm silicone insulator sheet between chassis and block.

 

[xrk971]

A review of the Warp-1 amp just came out on TONE magazine.

REVIEW – The LSA Warp 1 Power Amplifier – Reviews | TONEAudio MAGAZINE

 

[CBRworm]

Thermal transfer blocks for this amp will be available in my shop soon. Lets you use 10mm stand-off for proper stack up height with 0.5mm to 1.0mm silicone insulator sheet between chassis and block.

Cool - I look forward to seeing them.

 

[xrk971]

Here is the listing for the thermal block.

Heat Transfer Spacer for RTR TPA3255 Amp | Etsy

 

[CBRworm]

Thanks, I just ordered one. I'm sure it will be much better than what I cobbled together.

 

[xrk971]

Let me know how it works. I find it very simple to use. Just add 1mm thick GPU cooler silicone insulator sheets and 10mm standoffs for the perfect stack height.

 

[RichiNL]

What a nice amp. I have been reading some reviews in the mean time and it seems to be a stunning piece. I have contacted Walter @ Underwoodhifi to see if he can ship one to The Netherlands as I am keen on comparing it to my Purifi EVAL1. Did you by any chance compare your design with the Purifi EVAL1?

BR,
Richard

 

[xrk971]

Hi Richard,
No, I have not tested or listened to it against a Purifi. You might listen review by Thomas & Stereo where he says it does some things better than VTV amp with dual Purifi modules. Mostly it’s in the bass slam and midrange of the Warp-1 which gives the amp more enjoyment.

 

[RichiNL]

Thank you for your quick reply! I will watch his review (again). 😁

 

[RichiNL]

And just ordered one from Walter. I am keen to compare it to my Purifi EVAL1 to see how it works with our Dynaudio Contour S 3.4 LE speakers.

BR,
Richard

 

[xrk971]

Great! Thanks for buying it. I know you will like it.

 

[RichiNL]

Well, the LSA Warp 1 has been delivered and it is playing!