PeeCeeBee

Hi friends. Here goes the PeeCeeBee V1.1 PDFs.

Happy building!!!

shaan
 

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Superb @ Shaan... Wish these layouts were uploaded earlier ... lol. Right Now i am Working on Another 2 Projects .. Cresecndo ME and Bryston. I had yesterday received the SKs (Toshiba Mosfets) for Crescendo. And Now i have to Itch the Boards, Drill, Component Assembly, Make Enclosure for Crescendo ... lot of work there.
 
To those who would like to know what changed in the V1.1 layout from V1, here are some details.

> smaller size, 2" x 2.5"
> correct pin spacing and orientation
> miller compensation
> symmetrical zobel at output
> larger PS decouple caps
> better component placement
> no input capacitor
> much better and easier offset trimming with small plastic trimpots

Cheers.
shaan
 
Hi,

Yes V2 is the dual-FET one. The input cap has been omitted in all three versions btw.

I have prepared a simple PS board that that will have TO220 diode bridge, 2x 10000uF 1.2" diameter caps and 1x 0.1uF per rail, bleeder resistor, 2x supply headers per rail and 4x ground headers on 70micron copper. It doesn't have a speaker protection, yet. Learning how to implement one.

Thanks for the reply,The reason I asked for that PSU was cause it's a cap multiplier and regulated both. This works best (at least according to me). So would be great to try.

I had used Cap multiplier PSU in Tube pre and results were very very satisfying,hence my prefrence.

Also I have already built a stereo Amp from Mr.Mile's AX14 and thought would use this PSU for that as well.

There seems a load of dedicated speaker protection boards available on the net, mostly 1237 based. Do you think these are good?

Yes should work fine.Anything which protects accidental shorting of the speaker wires or thermal overrun or over heat etc.

Will be looking forward to the assembled boards of V2 and its results.What are PSU criterion for the V2 Dual mosfet version ? What's max voltage and current ( I have to order the transformer,hence want to know before hand), Whats the power of the V2 @ 8Ohm with the max PSU.

Also Shaan whats the price of the mosfet from where you buy ? Am yet to check here in Bangalore,But if it's cheaper there perphaps I can ask you to add them along with the PCB.


Finally if its not a problem or an issue can you please let me know how does they sound ?? Like I mentioned above have already built AX-14 ( 2pairs of 1943/5200 per channel)and Am pretty happy with that but want to know will this dual mosfet version will sound better or equal or whatever.

Regards.
 
Hi,



Thanks for the reply,The reason I asked for that PSU was cause it's a cap multiplier and regulated both. This works best (at least according to me). So would be great to try.

I had used Cap multiplier PSU in Tube pre and results were very very satisfying,hence my prefrence.

Also I have already built a stereo Amp from Mr.Mile's AX14 and thought would use this PSU for that as well.



Yes should work fine.Anything which protects accidental shorting of the speaker wires or thermal overrun or over heat etc.

Will be looking forward to the assembled boards of V2 and its results.What are PSU criterion for the V2 Dual mosfet version ? What's max voltage and current ( I have to order the transformer,hence want to know before hand), Whats the power of the V2 @ 8Ohm with the max PSU.

Also Shaan whats the price of the mosfet from where you buy ? Am yet to check here in Bangalore,But if it's cheaper there perphaps I can ask you to add them along with the PCB.


Finally if its not a problem or an issue can you please let me know how does they sound ?? Like I mentioned above have already built AX-14 ( 2pairs of 1943/5200 per channel)and Am pretty happy with that but want to know will this dual mosfet version will sound better or equal or whatever.

Regards.

Hi SG.

I agree a regulated cap-multiplier is the best choice, however it is not essential IMO.

Thanks for the suggestions I will look into the protection circuit.

For V2 boards a 400VA 40V-0-40V toroid (+/-56V rectified) per channel will do. Power at 8ohm is 160W.

The MOSFETs are available for Rs.250/- a piece.

.......

Now, the sound.

My main system is totally PeeCeeBee V1 based and after 2years of living with it I still can't find the next better thing soundwise. The sound is open, clean and transparent in their production without fatigue and the tested V1.1 board has the same quality with much lower noise/hum.

Cheers.
shaan
 
Hi Shaan,i see that you add compansation caps to all of your new versions .
Is the compensation nessecery?
My test didn't show this.
You want a more safe amplifier?

Hi thimios.

Yes all boards have pads for compensation capacitor.
Necessary? NO!
Good to have provision for? YES.
Reason - Flexibility. :cool:

Many people have asked for bare boards and while the PeeCeeBee is happy with only a zobel at its output, a few of the cases may demand compensation due to whatever reason which I can't probe from my home. Besides, the new boards run okay with the comp. caps.

I thank you again for those tests, a worthwhile addition to this thread. How about you run a couple of the V1.1 layout amps through some tough tests like before. It might surprise you again! :D

edit: ps. those caps don't affect sound quality in this amp so no worries. ;)
 
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Coming next - clipping and slew performance.

Here are some traces of the V1.1 PeeCeeBee. All tests done with 10R resistive load and +/-30V PS, zobel disconnected, 100pF at input and Cdom installed.

Pic 1 - 1KHz response
Pic 2 - 1KHz moderate clipping
Pic 3 - 1KHz high clipping
Pic 4 - 16KHz 80nS rise time input squarewave measured at 25VPP output.

As you can see, no sign of overshoot, rail sticking or other ill behavior. Slew rate is about 60V/uS. This is normal with compensation and input HF filtering.

This concludes my tests on the V1.1.
Distortion performance can be found here Post#1900

Coming next - V2.
stay tuned! :D
 

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The populated V2.

Assembling was easier than I expected, and the assembled board looked also somewhat better than expected.

FET legs bent at 5mm from case and that's it. The VAS trannies are standing instead of lying because I like them that way (and because I have only metal washers now.) :eek:

Anyways, nice huh?
 

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