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Amplifier Modules and PCBs For Sale

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AlexScan

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Joined 2011
JLesterP said:
I think if we put a very good inductor on both PFFB and pre filter TPA3255 amps, the only advantage of PFFB is that the amp will be load invariant. I have some reservations about the PFFB version specially about the open load stability and increasing the value of opamp feedback and zobel caps which might make the amp sound more sensitive to the quality of caps used, but it's only my hunch. Anyone you know or read about has compared the sound of the two?
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No but I read some post from 360customs.de about PFFB sound, he prefer with it, for him the sound is more realistic and dynamic.
 
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AlexScan

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Joined 2011
JLesterP said:
On my V1.1 board, VER2923 actually fits, I just have to score out some of the ground plane on top and drill oval hole for VER2923's flat cable.

Also on V1.1, I replaced 12V regulator LM317 with LM2940.
V1.0 is still good though and very low noise despite the use of LM317.


I will convert and test the V1.1 into PFFB first (we can convert it by changing some values, zobel and by using protoboard for R_fb and C_fb parts), Once I tested it, I will facilitate the manufacturing of PFFB version, maybe it will be available before November.
Click to expand...

You can replace 12V regulator by LT3045, no ?

I have time to wait PFFB version Lester, I have some DIY project to finish before (my speakers and some amps)
 
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AlexScan

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My purpose is to make a better TPA3255 for lower price (the board from 360customs is more than 100euro... in kit...):

TPA3255 / TPA3251 / TPA3245 universel - un pour tous - #360customs

IMG_9021_1280.jpg


I see the inductors is 7µH in place of 10.. the THD is lower... but the output filter is modified ?

See the KYA tank cap, better than any chinese Lelon or Cheng caps... me I put Nippon Chemicon KZN or Rubycon ZLH...
 
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AlexScan

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Joined 2011
Another TPA3255 Hiend with PFFB, the RTR from XRXaudio:

TPA3255 Reference Design Class D Amp GB

783331d1569353432-tpa3255-reference-design-class-amp-gb-tpa3255-test-success-03-jpg


RTR TPA3255 Amplificateur de reference classe D | Etsy

This is a custom design by XRKaudio with layout by JPS64 based on the TI EVM board, but with improved layout and functionality.

Improvements include Filter Feedback Topology (PFFB) for lower distortion, a very tight distance from PVDD power input connector to TPA3255 input pins with narrow deviation plugs and loose plugs from Nichicon search localized.

An insulated connector On board the CNT for ground and chassis is also provided.

The amp has been tested and the sound quality is superb.

The background sound is essentially zero (cannot hear anything with ear pressed to the speaker cone).

Measurements with a noise baseline of around -125dB with no pictures of driving hum or audible hissing.

The THD measurements are 0.0011% at 10w and 0.00074% at 1w, exceeding the performance specified by Texas Instrument in their PFFB application note
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We can do the same for a reasonnable price Lester.. after that I can send to Amir from ASR forum a DIY finish amp with SMPS600RS for "official" measurement... for sure after that (if performance for the price is astonishing) your store will be taken by a storm !
 
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PFFB design is already done, I just have to verify PFFB using the incoming V1.1 board.

For the PFFB version I will change parts to following:
Tank capacitors: Nippon Chemicon 2200uf * 4
Output inductors: Codaca equivalent of VER2923

You can replace 12V regulator by LT3045, no ?
Click to expand...
No, too expensive :D I'll stick with LM2940. Should I throw in TLS205B0EJV?

15V regulator LM5010 from EVM was replaced by XL7015 (same 150kHz switching frequency) or should I remove it like 3e board?

V1.1 will be the budget version.
 

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Deleted member 148505

AlexScan said:
I see the inductors is 7µH in place of 10.. the THD is lower... but the output filter is modified ?

See the KYA tank cap, better than any chinese Lelon or Cheng caps... me I put Nippon Chemicon KZN or Rubycon ZLH...
Click to expand...

Lelon Taiwanese cap is actually decent, Cheng is garbage.

Output inductors are already hot at 53V DC voltage, putting 7µH will be worse, maybe if you use it on 36V rails, but you will trade off reserve headroom for small THD gains.
 
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AlexScan

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Joined 2011
JLesterP said:
Lelon Taiwanese cap is actually decent, Cheng is garbage.

Output inductors are already hot at 53V DC voltage, putting 7µH will be worse, maybe if you use it on 36V rails, but you will trade off reserve headroom for small THD gains.
Click to expand...

Yes Lelon is better than Cheng but nothing compare Nippon KZN... ripple and ESR is in "another world"...

Ok inductor must be too hot with 7µH...
 
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AlexScan

Member
Joined 2011
JLesterP said:
PFFB design is already done, I just have to verify PFFB using the incoming V1.1 board.

For the PFFB version I will change parts to following:
Tank capacitors: Nippon Chemicon 2200uf * 4
Output inductors: Codaca equivalent of VER2923

Good choice Lester... the input cap can be removable on tpa3255 ?

No, too expensive :D I'll stick with LM2940. Should I throw in TLS205B0EJV?

I don't know, TLS205 is better ? ... why not TPS7A4700 ? ADP150 ?

15V regulator LM5010 from EVM was replaced by XL7015 (same 150kHz switching frequency) or should I remove it like 3e board?

3e audio remove it, why ? The TPA need 12v and 15v ?

V1.1 will be the budget version.

With Codaca CPD2320 the ratio price/performance may be very good !
Click to expand...
 
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danschy

Member
Joined 2015
AlexScan said:
....We can do the same for a reasonnable price Lester.. after that I can send to Amir from ASR forum a DIY finish amp with SMPS600RS for "official" measurement... for sure after that (if performance for the price is astonishing) your store will be taken by a storm !
Click to expand...

Amir sees a lot of variation in distortion vs frequency performance of Class D amps. It would be nice to see that measured for this amp. Attached is performance of the DIY amp using Hypex NC400 modules, one of the best he's tested so far (but very expensive). Blue curve is Hypex; red curve is a Class AB amp with poor performance.
 

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AlexScan

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Another interesting TPA3255 PBTL mono board:
TPA3255 - all about DIY, Discussion, Design etc.

He use CPQ4233 (the best big one inductor) and Nippon Chemicon KZN 1800µF Cap, see the schema and PCB attached.

He uses a pair of OPA1632 op-amps with a complete TI PFFB arrangement.

The bi-polar 12V power supplies are generated from a single supply input using Linear Tech's LTC3265 low noise bi-polar supply charge pump.

And +15V was regulated by LM5164.
 
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Deleted member 148505

AlexScan said:
Another chinese inductor builder:

Class D Inductors - Shen Zhen Powerhen Electronic Co Ltd

i don't know the quantities required and the price but eventualy you can contact them...

(The PH32A is one the best inductor i see, it too big for TPA3255 stereo bord but for a TPA3255 mono board he can match "easy")
Click to expand...
Looks like codaca is more 'decent' manufacturer compared to powerhen. I already contacted Codaca regarding VER2923 equivalent inductors, I'm getting 100pcs for the meantime, hopefully I can get it at half the price of VER2923 on mouser. They don't have reply yet for the pricing, they just asked how many inductors do I plan to get in the future, looks like 100pcs qty is small to them.

I will also buy VER2923-103KL from mouser to compare it to Codaca (at least on THD measurements from 2 identical TPA3255 modules)

AlexScan said:
Another interesting TPA3255 PBTL mono board:
TPA3255 - all about DIY, Discussion, Design etc.

He use CPQ4233 (the best big one inductor) and Nippon Chemicon KZN 1800µF Cap, see the schema and PCB attached.

He uses a pair of OPA1632 op-amps with a complete TI PFFB arrangement.

The bi-polar 12V power supplies are generated from a single supply input using Linear Tech's LTC3265 low noise bi-polar supply charge pump.

And +15V was regulated by LM5164.
Click to expand...

Yes I'm using that kind of inductor on my 1000W power amp (attached pic), it's around 14USD a piece from mouser.

I'm reading opamp thread from head-fi.org, they do like the OPA1692. It's only around 1.4USD/10pcs, i so I will be including it as default option on my PFFB build.

I also made the electro caps for opamps through hole so that it can be easily replaceable. I have lots of genuine 100uf 25V nichicon caps here and I will use it for opamp bypass caps. (attached pic)
 

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AlexScan

Member
Joined 2011
JLesterP said:
Looks like codaca is more 'decent' manufacturer compared to powerhen. I already contacted Codaca regarding VER2923 equivalent inductors, I'm getting 100pcs for the meantime, hopefully I can get it at half the price of VER2923 on mouser. They don't have reply yet for the pricing, they just asked how many inductors do I plan to get in the future, looks like 100pcs qty is small to them.

I will also buy VER2923-103KL from mouser to compare it to Codaca (at least on THD measurements from 2 identical TPA3255 modules)

Ok if codaca is better manufacturer and the price is half than coilcraft for the same performance, you win (good idea to measure two board with different inductor)

Yes I'm using that kind of inductor on my 1000W irs2092, it's around 14USD a piece from mouser.

I already see that Lester...

I'm reading opamp thread from head-fi.org, they do like the OPA1692. It's only around 1.4USD/10pcs, i so I will be including it as default option on my PFFB build.

Ok for OPA1692, i don't know if it's better than 1656 ...


I also made the electro caps for opamps through hole so that it can be easily replaceable. I have lots of genuine 100uf 25V nichicon caps here and I will use it for opamp bypass caps. (attached pic)

Ok, the caps are in the singal path before of after opamps ?
Click to expand...
 
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AlexScan

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Joined 2011
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AlexScan

Member
Joined 2011
And for better medium/treble performance it's possible to make esasily a TPA3245 board ? (according to PFFB datasheet the TPA3245 was better 6.67Khz THD)

For my semi-active speakers in construction the best combinaison for me it's TPA3255 PBTL for woofer and TPA3245 PBTL for medium/treble
 
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