P3A COMPARSION TABLE ( long .... )

[sakis]

P3A is my favourite amplifier of this class ... i have designed my own pcb ... did a few things on it ... and this become my favourite amplifier and a standard to listen for almost 3 years now together with a diy nearfield monitors 6.5" visaton +vifa ...

I repair give or take around 200 amplifiers per year so i thought since except scopes loads and generators i also want to listen to the amps i repair i normally hook them up to my system and listen from them a few hours

Since i have a few standards created from my setup while listening most of the time my amplifier from the same tuner ( same radio station ) the same cd player and for reference always the same music for more than three years now. In this post i would like to provide some information about the amplifiers i repair may be start some questions about them and listen to others opinions but as a base i will use my listening expirience from the P3...always regarding sound qualities and never power

P3A construction and set up
dual mono 250W trafo per channel 2x28AC
psu caps 2x10.000 mfd on board
MKT input cap 4.7 mfd bypassed with 100nf mika
350 pf silver mica input filter
LTP matched pair +thermal junction
VBE attached in pos driver
82pf styroflex miller cap for VAS
100 PF multileyer cap on the driver
multiturn
120ma biass
BD139-140 family for drivers +VAS ( philps )
outpouts are MJL1302A 3281A motorola originall ( zeck replacement sets )


i normally listen from a passive shunt relay source selector with Alps blue line 47K so most of my tests do not include crosstalk issues since this configuration is almost unbeatable and since i am in the comercial bussines and most of the amplifiers i repair are comercial Japanese amplifiers there is actually no point to try to compaire the one with the other ....

Questions are about sonics, colourations ,ends , how deep , how clear , how crisp, and goes on and on

Most of the amplifiers i repair include tone controls so still comparsion is not that fair but lets thing of defeat switches where ever they exist...

here is a few things i have to say for my amplifier as made that will be followed of a few scope readings and then i will start posting the things i have seen in the amplifiers i repair ...

I will try to post as many details possible about these amplifiers and feel free to email me i f you have any questions or schematic requests

the P3A as is together with the Visaton/ Vifa near filed monitors become a bit endy ...means that this set has absolutelly no problem to deliver low frequencies or high frequencies....Bass is plenty extending often to very low frequency without any problems without anything excecive , punchy and tight but delicate... midle and soundstage are very very present but extremelly balanced and vocals or strings are very pleasent with the slightest sign of distortion and with a lot of depth .... sound stage is so perfect that can provide the placing of the vocals on stage easilly ... now high is one of the most nice since no matter how many remain crystal clean and extremelly detailed at various types of music ...

i t seems that the particular setup will deliver exactly what the producer had in mind ...negatives are that the all system performance has slight U eq performance meaning that midle is a click lower ...but just a clik...

then again it seems that if you play a terrible production the amplifier will make it even worst ...that i cannot explain if right or wrong ...The impression i have is that the amplifier is way too free with no llimmitations of any kind and under this ...sounds logic

thanks for listening ...here we go ...scope readings

[sakis]

some more pictures

[wahab]

thanks for the tests under capacitive load, Sakis,
very insightful..

[osscar]

Thanks for the info! Nice amp. and good measurements (I like the notes)
Perhaps i will built P3A in future.
My country is getting warmer now - because of that I'm now switching from F5 to Leach, who also sounds quite good and very cool at normal listening levels!
Is it possible to get your PCB layout >?
Thank you.

[sakis]

Originally Posted by osscar

Thanks for the info! Nice amp. and good measurements (I like the notes)
Perhaps i will built P3A in future.
My country is getting warmer now - because of that I'm now switching from F5 to Leach, who also sounds quite good and very cool at normal listening levels!
Is it possible to get your PCB layout >?
Thank you.

Actually no ...and i am really sorry to say that since ROD is making pcb for his amplifiers ...yes the design is free for anyone to use but still i would do nothing to advertize rod's work against somebody else or provide a pcb against rod's bussines

I hope that you understand what i mean ... Though there extensive threads in the forum that discuss pcb construction for the P3A and you may get some information from there and make your own ...Eva a forum member provided way too may details on what will be proper ( or high tech ) pcb for this type of amplifier ...

Finally if you make your own you can have my opinion about it

i am sorry for that ...

kind regards sakis

[osscar]

Ok, no problem!

[sakis]

here is some info about ACCUPHASE E205

the particular amplifier has been repaired in the shop almost one year ago with the ony problem that had a rectifier blown ( no soft start circuit ) and the owner thinks that some kid was playing with it .

also found the output relays to be replaced and we did ...other than that seemed that no capacitor was to be replaced inside

after aworking year in a very dusty area due to house renovation selector switch needed cleaning

the particular amp doesnt use relays or shunts of any type ... just a simple selector swich ... the constructiona and quality of materials inside are so good and everything is placed so properly inside that there is no audible crosstalks

preamplifier section is perfect and tone defeat switch actually works ( its done with arelay at a proper area ) so yes if you cut the tones the machine is working perfectly and measures the same

actually its one of the very few that i can compaire to my unfair set up meaning that eventhough integraded amp its extremelly ultra quiet

better than the SANSUI AU 717 that i will recall as one of the same range

other than that a very sweet and accurate amplifier powerfull with wonderfull bandwidth and no serious colourations

here is some pictures

[Telstar]

Originally Posted by sakis

outpouts are MJL1302A 3281A motorola originall ( zeck replacement sets )

Got any of them for sale?
(what means "zeck replacement sets"?)

[sakis]

i used to work for a company that represented Zeck for a while i Athens ....PT series from Zeck was very good Pro amlifiers expensive and very stable

at the time we never had a blown zeck the owner of the company had asked Zeck to provide matched sets of transitors to have for any repairs

after the company went down for other reasons i got to keep many of these sets for a very low prize

i am not willing to give away at any prize anything that is original and has a tag 1302-3281 on ( i have original toshibas also ) totally i have arround 120 pairs more and i am going to use them to construct amplifiers for my own pleasure ....in the coming years i hope to live long enough to construct 100 amps ( more )

[wahab]

Originally Posted by sakis

i used to work for a company that represented Zeck for a while i Athens ....PT series from Zeck was very good Pro amlifiers expensive and very stable

)

Very serious maufacturer that is about 50 km
from where i currently live..
With my band, we used a set of PA 15/3 Mini
Proline speakers, and they never deceived us.