Xmas Amp - Dibya's TDA7293 by Jhofland

[Dibya]

Hi joensd,

I will not bother much about drop out voltage rather about noise.These Active bridge have very low noise and fast recovery time. I called them Sci-Fi because of their price. Definitely will love to use them too. More over that PSU is overkill for TDA7293, This chip has a 75db PSSR. It will be useful for Class A amplifier.

I personally like Vishay VS-HFA08TB60-M3 as it has very fast recovery time but it is at the same time , soft recovery type.

 

[xrk971]

Has anyone looked at these cheap active or “ideal” diodes? I wonder if two could be used for a half wave bridge? There are many variants out there and they are made for solar cell battery charging. Low RDSon.

US $3.73 11％ Off | 15A Ideal Diode Solar Panel / Battery Charging Anti Reverse Irrigation Module batteries Charger backwash protection 5V 12v dc A
15A Ideal Diode Solar Panel / Battery Charging Anti Reverse Irrigation Module batteries Charger backwash protection 5V 12v dc A| | - AliExpress

US $3.34 12％ Off | 15A Solar Panel Battery Charging Ideal Diode Anti Reverse Irrigation charger Constant current module dc DC4-28V 5v 12v
15A Solar Panel Battery Charging Ideal Diode Anti Reverse Irrigation charger Constant current module dc DC4 28V 5v 12v|Replacement Parts & Accessories| - AliExpress

Some are rather large high current affairs and not so cheap, but 50A diode worh mV of dropout is very good.

US $11.45 19％ Off | diymore 50A Solar Panel Battery Charging High Power Positive Voltage Ideal Diode Controller Anti Reverse Irrigation Protection
diymore 50A Solar Panel Battery Charging High Power Positive Voltage Ideal Diode Controller Anti Reverse Irrigation Protection|Instrument Parts & Accessories| - AliExpress

Monolithic 12v 5A from Analog Devices:
LTC4358 Datasheet and Product Info | Analog Devices

 

[nautibuoy]

More over that PSU is overkill...

That seems to cover a lot of our activities on DIY Audio 😉

More over that PSU... ...will be useful for Class A amplifier.

That's what the other Prasi CRC boards will be used for.

 

[Kokanee]

I will probably use Keratherm on these (because I have some). Are the ceramic pads used, the 1mm or 0.635mm thickness ?. Is heat sink grease also used behind these ?.

Thanks for the help,

Myles

 

[Vunce]

Hi Myles,

The ones I use are 1mm thick. I did not use thermal goop for this build simply because I have installed/uninstalled the amp modules several times. But, for a final build I would always use goop between the device/insulator and insulator/heatsink.

 

[DarpMalone]

Ughhh. Just seeing this. It looks great xrk971. Might you be doing another run?

 

[Kokanee]

Thanks Vunce. Happy New Year

MM

 

[1883]

Hi Everyone,
Here is some PSU option,
Feel free to use your own design.

Another Psu Designed by Owner of Chipamp.com in Past:
(This was my first PSU)
Chipamp power supply – (mis) Adventures in Hi-Fi

BOM is under $30

Basic PSU:-
D1: KBPC3502 ( Select the package you want to use)
CX: https://www.mouser.com/ProductDetail/Panasonic/ECW-FE2J474KA/?qs=wYonFgBYHKkV/7JwdBfsaA==
CR: https://www.mouser.com/ProductDetai...EpiMZZMukHu%2BjC5l7YYQBV/jCy/7T3hj5t4%2BfqBA=
RC: https://www.mouser.in/ProductDetail/KOA-Speer/MO2CT631R222J/?qs=qJYTfuAnAfoxfBoTkFFvDw==
Choose Whether You like Proto Board or Point to Point
Bom is under $22 ,
Schematic: basicpsu — ImgBB

XRK971 CRC PSU:-
https://www.etsy.com/in-en/listing/820063565/all-cees-class-ab-psu?ref=shop_home_active_4

Emerald PSU: (Not for Commercial Use) [Its bit of a overkill]
C1 to C20: 2200uf 50v ( Any low ESR from good brand like Nichicon)
CXD: Panasonic ECW-FE2W474QA
Diode Capacitor : Panasonic ECW-FE2W474QA
D1 to D8 :Vishay VS-HFA08TB60-M3
As for resistors, Use KOA Metal Oxide one
Schematic: https://ibb.co/bQ37VWp

Gainclone PSU by MR.Carlos:
http://www.decdun.me.uk/gainclonesnub.html

https://www.hifiocean.biz/products/classic-power-supply-pcb

 

[xrk971]

Ughhh. Just seeing this. It looks great xrk971. Might you be doing another run?

The first run is a giveaway of 50 boards. More amps you guys can make yourselves with the Gerbers or organize your own GB. We are working on refining the design so final design/layout not completely there yet. That’s why we do verification builds.

Maybe add your name to waiting list?

 

[Dibya]

Hi Everyone, Feel free to use your favorite preamp but use it since gain on this amp is very low.

Here are some of my favorite preamp,

XRK Audio PCA:
Bare PCBs for Pocket Class A Headphone Amplifier / Desktop / | Etsy

XRK Audio DCA:
SE Class A Desktop Amp PCB | Etsy

Geek MooseFET Preamplifier:
DIY Audio Projects Forum • MooseFET Preamplifier

XRK Audio Haikun DB on Yarra Preamp:
Hakuin DB for Yarra | Etsy

RJM Audio J-Mo Mk. II :-
RJM Audio - J-Mo Mk. II headphone amplifier

Dont care about distortion but want Tuby smoothness and warmth
Little Bear P5: https://www.ebay.com/itm/Little-Bea...507594?hash=item44180131ca:g:JSAAAOSw7ThUit5a
Little bear T7: Check out ebay for best deal

Price is not a problem so you want something pre built? Right Here You go
Loki by Schiit Audio
https://www.schiit.com/products/loki

If you want to see my preamp with OPA2134 , let me know.

Speaker Protection is essential , you can avoid if you wanna take risk. You can use your favorite one of course.

SSR Speaker Protection by XRK971:
Ready-to-Run (RTR) SSR DC Speaker Protection and Delay GB

Speaker Protection by 00940:
https://www.diyaudio.com/forums/chip-amps/321922-source-layout-lm3886-13.html#post5606986

ESP speaker Protection:
https://sound-au.com/project33.htm

 

[Dibya]

Power Supply Board – hifiocean

Those capacitors looks fishy to me. You can use it but one psu for each amp as capacitance is not enough.

 

[e_fortier]

Why are you saying that the gain of this amp is very low ?

On the schematic it’s a typical gain, shown as 27.7 (29dB), I don’t believe a Preamp is mandatory when using this amp. Was the overall design modified ?

Thanks
Eric

 

[Dibya]

Well 28db is kinda low in my opinion. 7293 sounds best with preamp.

 

[e_fortier]

Ok, I’m used to First Watt stuff with the usual gain around 15dB...

I currently have way too many projects before I get to this one so to be fair with other members please withdraw my name from the list. Thanks to the design team, this was a nice freebie.

BR,
Eric

 

[Dibya]

Of course you can use without a preamp , @e_fortier i hope you are not withdrawing due to preamp requirement.


@e_fortier which dac does you use?

 

[e_fortier]

Hi Dibya,

I already have a Preamp (the one designed by Geek) but I honestly have 12-13 projects to complete before I would get to that one. I already bought most of the components for the above projects so instead of consistently buying new stuff I’ve decided to actually work on them...lol

BR
Eric

 

[e_fortier]

MaxReboBand / 2 boards / USA
as8912 / 2 boards / USA
ahtllc / 2 boards / USA
dBel84 / 2 boards / USA *Cancelled *
Flamethrower1 /2 boards/ USA
Signal Lost / 2 boards / USA
diy.tiger / 2 boards / NZ
MShipmanPE/ 2 boards / USA
Angchuck / 2 boards / Singapore
Francois G / 2 boards / USA
Asuslover /2 boards /USA
Guerilla / 2 boards /Denmark * cancelled*
astromo / 2 boards / Australia
Kay Pirinha / 2 boards / Germany
pinkfloyd4ever/ 2 boards / USA * cancelled *
Sixto / 2 boards / USA
Tubesguy / 2 boards / USA
E_Fortier / 2 boards / Canada * cancelled *
Hicoco / 2 boards / France
Liva / 2 boards / Canada
Kokanee / 2 boards / Canada
chermann/ 2 boards / Austria
twocents/ 2 boards / USA
s610adam / 2 boards / USA
hochopeper/ 2 boards / Australia
1883 / 2 boards / USA
Jlevro / 2 boards / USA
nautibuoy / 2 boards / UK


As mentionned above I'm out so 1 free spot available.

 

[1883]

Please withdraw my name from the list

Please withdraw my name from the list, $600.00 stimulus check is a joke.

 

[twocents]

Please withdraw my name from the list, $600.00 stimulus check is a joke.

😕 what is this all about?

 

[Vunce]

Don’t mix politics with fun hobby stuff 😉