CRC Power Supply (Class A amplifier)

[xrk971]

CBB is a Chinese film capacitor company. Actually very good quality and performace, despite the price. I have used in audio signal path even with good results. So as a bypass on a PSU, no problem.

Yes, you saw it correct qnty 100 x 0.1uF 100v film for $5.39:
https://www.aliexpress.com/item/100...250-v-104-100-nf-0-1-UF-feet/32800632205.html

For a Pass amp, follow the Pass F1 PSU schematic exactly if you want quoted performance on the amps to live up to expectations. I shouuld use 33,000uF 25v caps but I am actually making this for another amp that will need a 32v supply, and could not justify cost of 33,000uF 35v caps. So swap to 33,000uF caps and it should work well for Pass (25w) Class A amps. The snubbers you need to do yourself for your own setup - it varies. I took a wild guess and used what I have on hand.

 

[zman01]

Prasi,

Boards received, thanks!

 

[xrk971]

Tested CRC with Ranchu/Aksa quasi amp in semi Class A at 510mA bias. Connected my 96dB sensitive DT770-250 headphones and could not hear any hum. With inputs grounded no bias. Here it is in action doing power test on 25w 8R resistor load (gold resistor on heatsink being cooled by a fan). Meter shows 14.1vac or 25w into 8ohms.

 

[Project16]

Thank's xrk! It's cool these feedback!

 

[prasi]

Yep!, nice feedback x, hope someone else had a chance too in building this and a feedback would be useful.

Here is a somewhat useful sch that I made .

 

[cgraf]

Boards received

Hi Prasi
I received the boards! Thanks for a very fast shipping the VERY nice pcb quality. Highly appreciated

Best,
Christoph

 

[xrk971]

Yep!, nice feedback x, hope someone else had a chance too in building this and a feedback would be useful.

Here is a somewhat useful sch that I made .

You mean I am the first to actually build this?

 

[prasi]

You mean I am the first to actually build this?

No, I built it first for testing purpose, on a pilot batch of PCB.

 

[prasi]

Hi Christoph and the Zman01,
thanks for your confirmation. I appreciate it.
reg
Prasi

 

[xrk971]

Now in stereo with low ESR LC cap bank. Believe it or not this is being used as a very powerful headphone amp to drive up to 4w into 50ohms HiFiman HE-6.

 

[prasi]

GB-2 status update
aubmar (4 boards) ok, shipped
jkjkaufm (6 boards) ok, delivered
pesve (4 boards) ok, delivered
manniraj (4 boards) ok, delivered
outtek (4 boards) ok, shipped
Master Pain (2 boards) ok, delivered
bandol83 (4 boards) OK. shipped
prasi+friends (6 boards) ok
cgraf (2 boards), ok, delivered
baggerbole (4 boards), ok, delivered
zman01 (2 boards), ok, delivered
Johnny Canuck (2 boards), ok, shipped
AVWERK (4 boards), ok, shipped
Hui13 (2 boards), ok, shipped

 

[prasi]

Pl confirm if there have been any more deliveries from GB-1 list also.

 

[prasi]

GB-1 Status update

kindly update your pcb delivery here or just inform me through PM.

mcandmar (4 boards) ok, delivered
Project16 (2 boards) ok, delivered
Myint67 (6 board ) ok, delivered
gwrskien (10 boards) ok, delivered
asuslover (4 boards)ok, delivered
Morde (2 boards) ok, delivered
Ryssen (2 boards) ok, delivered
Marra (4 boards) ok, delivered
gnomcat (10 boards) ok, delivered
bloozestringer (4 boards) ok, delivered
bOTL (10 boards) ok, delivered
Prasi (2 boards) ok
emynet (2 boards)ok, delivered
Sadik (2 boards)ok, delivered

zrxshack (4 boards) ok, delivered
patriz (4 boards) ok , delivered
JJGB (6 boards) ok, delivered
rephil (10 boards)ok, delivered
mituisho (4 boards) ok, delivered
Pepperman (4 boards) ok, delivered
Nounouchet (4 boards) ok, delivered (can you believe it went to Canada and then came back to France!?, due to customs error.. salute to all postal departments)
Joca (4 boards) ok, shipped, (with customs, they need a proof of purchase)
883bkong(4 boards) ok, delivered
bk856er(2 boards) ok, delivered
quan (4 boards) ok, delivered
oceanpeak (8 boards) ok, shipped (pl confirm if you have received)

joshvi (4 boards) ok, delivered
TIC37 (4 boards)ok, delivered

gabbar (4 boards) ok delivered*
bogde (2 boards) ok, delivered
PauloPT (2 boards) ok, delivered
Algar_emi (2 boards) ok, shipped (pl confirm if you have received)
__________________
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https://sites.google.com/site/analogdesign1234/

 

[prasi]

This could be somewhat useful. It demonstrates the use of terminal blocks in place of faston connectors for V+, GND and V-

http://www.diyaudio.com/forums/anal...ti-tidu34-certified-design-3.html#post5059760

 

[manniraj]

I am planning to use these boards for my upcoming Sony Vfet2 kit build. Need the BOM parts list that I need to use for getting a +/-28v DC out (I think this is the required DC voltage for the Sony VFET pcbs. Also based on the cost will plan to build a dual mono CRC psu for this amp with 2 different toroidal transformers.

Thanks in advance.

 

[prasi]

Referring to the sch posted by me (post #285),
You could start with RS-CS-C2 default values.
Use MUR 1560 diodes
dont use the caps parallel to diodes (10nF)
you could try to get 33000uF 35V caps (2pin-10mm pitch/4pin-22.5mm pitch) from a known manufacturer (Rubycon/Nichicon) and get them from mouser/element14
CRC resistor could be 0.1-0.22ohm 5-7W, could even be 3W depending on amplifier current consumption (use ohms law).
2k2 to 6k8 1/2 W carbon/MFR for led resistor, LED could be any generic 5mm/3mm. bleeder could be 1k -3W MOR/MFR
use the o/p snubber as 0.1nF 100V and 10R 1/2 W MFR.

However it could be better to consult the amplifier designer for PSU caps requirement or go with amp builders opinion in that thread.
these are just generalized suggestions, people could use whatever suits their requirement and wallet.
Prasi
Also a soft start may be required depending upon transformer va and PSU caps. Rod Elliott's article on his website is good reading.

 

[aubmar]

GB-2 status update
aubmar (4 boards) ok, delivered
jkjkaufm (6 boards) ok, delivered
pesve (4 boards) ok, delivered
manniraj (4 boards) ok, delivered
outtek (4 boards) ok, shipped
Master Pain (2 boards) ok, delivered
bandol83 (4 boards) OK. shipped
prasi+friends (6 boards) ok
cgraf (2 boards), ok, delivered
baggerbole (4 boards), ok, delivered
zman01 (2 boards), ok, delivered
Johnny Canuck (2 boards), ok, shipped
AVWERK (4 boards), ok, shipped
Hui13 (2 boards), ok, shipped

Excellent Quality Boards, Thank you for all your work and assistance here!
Very much appreciated

 

[outtek]

GB-2 status update
aubmar (4 boards) ok, delivered
jkjkaufm (6 boards) ok, delivered
pesve (4 boards) ok, delivered
manniraj (4 boards) ok, delivered
outtek (4 boards) ok, shipped
Master Pain (2 boards) ok, delivered
bandol83 (4 boards) OK. shipped
prasi+friends (6 boards) ok
cgraf (2 boards), ok, delivered
baggerbole (4 boards), ok, delivered
zman01 (2 boards), ok, delivered
Johnny Canuck (2 boards), ok, shipped
AVWERK (4 boards), ok, shipped
Hui13 (2 boards), ok, shipped

Hi to all, the boards have arrived today, very good quality PCB, I appreciate the work put in the design, I will probably not use the power resistor because it will be only one per rail and if it gets hot I don't know how reliable it will be, other than that a good design. If any revision from you Prasi will be done please add two places per rail for these resistors.
Regards.

 

[prasi]

Hi to all, the boards have arrived today, very good quality PCB, I appreciate the work put in the design, I will probably not use the power resistor because it will be only one per rail and if it gets hot I don't know how reliable it will be, other than that a good design. If any revision from you Prasi will be done please add two places per rail for these resistors.
Regards.

Hi Outtek,
you could calculate the power resistor wattage if you know the current demand from amp.
Also you could piggy back the resistors (one on top of other) if you want to be safe. see XRK's build.

my 2c.

reg
Prasi

GB-2 status update
aubmar (4 boards) ok, delivered
jkjkaufm (6 boards) ok, delivered
pesve (4 boards) ok, delivered
manniraj (4 boards) ok, delivered
outtek (4 boards) ok, delivered
Master Pain (2 boards) ok, delivered
bandol83 (4 boards) OK. delivered
prasi+friends (6 boards) ok
cgraf (2 boards), ok, delivered
baggerbole (4 boards), ok, delivered
zman01 (2 boards), ok, delivered
Johnny Canuck (2 boards), ok, shipped
AVWERK (4 boards), ok, shipped
Hui13 (2 boards), ok, shipped

 

[outtek]

Hi Prasi, that would be a solution that I have considered allready , puttin a smaller one bellow and a 10w on top to solder all leads to the the PCB , in this case I would have to use something like a 0.47 ohms in parallel. I can find pretty easy smaller size at 10w and bigger at the same wattage. I have read that it is recomended to oversize this resistor and for what I would like it needs to be close to 20w the total wattage. Thanks.