If the full PeeCeeBee circuit is used without omitting any components or stages then the high-bias performance may be better in some cases, though in my experiments I could not hear or measure any difference between 2A and 200mA bias. 🙂
Hi Gannaji
Thanks for your interest.
Not on the web in English but I have a complete description and step-by-step build manual in English. There is no kit yet but already built by 5 persons very satisfied with the sound. It can be built using an existing Pass clone F5 board from Ebay but requires to add circuitry on it thus not for beginner -if you are. It uses obsolete output mosfet but still available from reliable sources. Of course this is a class A amp thus proper heatsink is required... Just send me a message with your address if you want to give it a try.
The goal was to have one stage less than the VSSA (VSSA is the same as PeeCeeBee) but needing class A (as mentions Shaan) to obtain acceptable level of THD (3rd and 2nd harmonics only visible on scope). This design gives a similar general sound signature (current feed-back with great soundstage ) as the VSSA but also different enough to justify its existence since I prefer this one to the VSSA which I know very well for years....but this is only my personal preference of course...
Fab
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If the full PeeCeeBee circuit is used without omitting any components or stages then the high-bias performance may be better in some cases, though in my experiments I could not hear or measure any difference between 2A and 200mA bias. 🙂
Hi Shaan
Yes for the VSSA class A bias will not provide significant sound improvement but >=250ma bias per lateral mosfet is generally a good recognized level by many peoples.
Class A is more for simple design because it is required for THD consideration. If you have already experienced simple class A amplifier you may have noticed how natural they can sound at low and moderate volume for jazz and classical music...
However since my first design of "VSSA" (called this way by Lazycat) topology in 2012 I still enjoy its sound since it allows for a higher power amplifier when required...
The pcb layout is very important and your work seems to show that too thus please continue your contribution to diy 🙂
Fab
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Hello guys.
As already express before I'm looking for a simple, robust and low thd amp.
I have high hopes that peeceebee to be the one. so I have some p3a, p101, f5 and lm3886 amps. however i didn't had an acceptable test environment before.
So this weekend I spent debugging my cheap but reasonable good measurement setup.
the system I did came up was:
DAC: Behringer UCA202 using a usb isolator from adafruit.
ADC: steinberg ur12 - using the instrument input with gain at 75%.
load test for amp : 4ohms 50w resistor , 2way test speaker with a terrible passive crossover.
attenuation box : 10k potentiometer
3amp lab psu
software : RMAA Pro.
I after some handmade short cables the whole system is perform in consistent way.
So. I've been testing a F5, p3a and a LM3886 ( ebay kit ).
I'm just waiting for the PCBs and latmosfet to assemble a peeceebee and check how it
stand for the P3A and F5.
what I can say so far. P3A is ahead so far.
Thanks
As already express before I'm looking for a simple, robust and low thd amp.
I have high hopes that peeceebee to be the one. so I have some p3a, p101, f5 and lm3886 amps. however i didn't had an acceptable test environment before.
So this weekend I spent debugging my cheap but reasonable good measurement setup.
the system I did came up was:
DAC: Behringer UCA202 using a usb isolator from adafruit.
ADC: steinberg ur12 - using the instrument input with gain at 75%.
load test for amp : 4ohms 50w resistor , 2way test speaker with a terrible passive crossover.
attenuation box : 10k potentiometer
3amp lab psu
software : RMAA Pro.
I after some handmade short cables the whole system is perform in consistent way.
So. I've been testing a F5, p3a and a LM3886 ( ebay kit ).
I'm just waiting for the PCBs and latmosfet to assemble a peeceebee and check how it
stand for the P3A and F5.
what I can say so far. P3A is ahead so far.
Thanks
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I built vasa and p3a both. While vssa is very hi-fi and accurate sounding, I found p3a non fatiguing and something that one would listen to all day long. Planning to build peeceebee (already have shaan's PCBs v2 I think)..I am 100%, PeeCeeBee would sound as good and may be better.
Then on to aksa / ranchu quasi comp.
.
Just my subjective opinions.
Then on to aksa / ranchu quasi comp.
.
Just my subjective opinions.
I like LatMOS output amplifiers but P3A is my favorite BJT output amplifier. I find it sounding very pleasing to the ear, totally made for music.
Dear Shaan, I fully agree with You. To mention drawback of BJT CFP output stage - You can not go "into clipping" like You did nicely with VSSA! Because in CFP output would be so called "overshots" - or You have carefully modify P3A, to prevent output from saturation. So LatMOS is superrior over BJT CFP here 🙂
Hello
I realized version 1 & 5 of the USSA and this amplifier is really made for the beautiful sound.
You can see my version 5 just finished here:
http://www.diyaudio.com/forums/solid-state/96192-post-your-solid-state-pics-here-post5031437.html
🙂
Dear Shaan, I fully agree with You. To mention drawback of BJT CFP output stage - You can not go "into clipping" like You did nicely with VSSA! Because in CFP output would be so called "overshots" - or You have carefully modify P3A, to prevent output from saturation. So LatMOS is superrior over BJT CFP here 🙂
I'm from the opinion ( no hifi system should drive a amp to clipping ) and my audio system is designed to not to drive an amp into clipping.
I have a three way system with an active crossover, so my p3a will output a max of 6-15w on mid and high part of my system. all my tests are with a load test of ~6w.
So my goal is to replace the P3A with something considerable better and also needs to have
a very good cost benefit. I think a VSSA is will be the deal. So far I found that a F5 isn't a good deal for me.
ps. but I praise an amp that "clips" nicely. I just don't want it clipping any time 🙂
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Sometimes it could happen by accident (children, friend, etc.)
F5 - why was not good? Sound? Too big output impedance? Too hot? Cost is about the same.
Of course 🙂
I don't think this is the right place to talk about the F5. but essentially I decided to not go ahead with my F5 because it isn't very flexible. it has very high demands on Heatsinks.
psu, specific voltage on the transformers. and I wasn't able to notice a big improvement over
my p3a, actually the p3a looks like it has more control over the speakers.
So now I want check out the PeeCeeBee, because is a very simple amplifier, looks more stable than a P3A, has similar performance, no exotic parts.
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These are the prototypes of the new PeeCeeBee V4.0 for final testing. This is its last experimental phase so schematic is almost finalized. All will be published in a new thread when ready. There may even be a group buy for PCBs (if interest arises). 🙂