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PeeCeeBee V4 GB!

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shaan

shaan

Member
Joined 2009
coolnose said:
Hi All,

sorry to stupidly ask here but I got lost in the several iterations of the amp..

Could anyone kindly link me to the latest iteration with 1 OT-pair only ? Would PCB's for that still be available ?

Thanks in advance,

Max
Click to expand...

Hi Max.

The latest/final is Revision 2. Schematic - Rev2 Schema, and layout Rev2 Layout

I have boards, but am out of home and will be back by 10 October. I can ship afterwards.

Thanks
shaan
 
C

coolnose

Member
Joined 2009
Thanks Shaan,

I read 1.95V for the greens and 1.80V, I will give it a shotas is, voltage drop seems high to me, it's standard Lite-On LED, nothing fancy.

4 more PeeCeeBee built, transistors reversed as I am using 2N5401/2N5551.
 

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shaan

shaan

Member
Joined 2009
coolnose said:
Shaan,

could you kindly confirm I can implement the "F5"-style P3 as you suggested in the V3 thread ?

I don't expect the modified FB network to make any change in this regard, does it ?

Thanks in advance,

Max
Click to expand...

Hi Max.

In a high global feedback amp such as v4, when you mess up the balance of AC feedback in the two halves, you get way more higher order harmonics like h6,7,8 along with lower order ones like h2,3,4 than in a low global feedback amp such as f5. To keep the higher harmonics under acceptable levels you will need to increase the bias to 1A or more and by then it has become a full fledged class A amp. If you can give it good amount of heatsinking then the asymmetry may bring up some of that "warmth" that p3 receives much praise for. However, I doubt it's worth all the effort as I did test it a year ago and found the non-p3 class AB v4 sound closer to my liking.

To unbalance the feedback, just replace one of the two 100R resistors in the feedback node with 82R or 68R(for more loss of balance).
 
E

electrix

Member
Joined 2003
Are the 2SK1058/2SJ162 fake?

One thing that is a dead giveaway as to whether a MOSFET is lateral or vertical is to compare the pinouts. Lateral MOSFETs have the source pin in the centre, while vertical types invariably have the centre pin as the drain. Many fake lateral MOSFETs are re-badged vertical devices (typically HEXFETs), so source and drain are in the wrong places and the amp will provide close to a dead short across the power supply via the intrinsic body diodes.
Click to expand...
This is a quote from Elliot Sound
and here is the datasheets for EXICON lateral Mosfets
http://www.exicon.info/PDFs/ecx10n20.pdf
 
Z

zebulo

Member
Joined 2014
Hello Shaan
here is my interpretation of your Peeceebee V4
2x24v 250va and 70000µF for each I know it's too much but I had them in the drawers!
it is true that the mod rev1 lacked bass but it had a beautiful sound image, silky and nervous at the same time
the rev2 with 47p, 220p is better it has lost nothing of its silky nervous image but with the bass and more in the face;) it's good and also a little too much for my ears, for my taste.
on your advice today I change 68p, 330p and I will listen like this while expecting new 47p, 220p of good cality mica to make the difference, but anyway I am happy with this new amp, even at low volune it loses nothing of its musical quality that's what I ask for a good amp
thank you Mr. Shaan, see you soon
 
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