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
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
Attachments
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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.
)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.
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
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Service accuphase e 205
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
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
Attachments
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 )
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 )
a little off topic
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.
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.
service SAE A201 and P101
here some more just finished yesterday
its the A201 and the P101 from SAE ...
the ampifier needed a 110/230 conversion new trafo 600 W fitted inside most electrolytics replaced retuned idle and working just fine ...
as an ampifier and next to my set it seemed that the amplifier had less bandwidth than my set ...low ends was kinda limmited still clea and not that punchy but seemed to be a lack at the very low stages just about the same for high i got the feeling that wasnt that clean and kind of hissy or harshy trebles
original bias seemd also low but i didnt want to play anything other than the oiginal values ... the topology outputs and configurations reminds the 555 series from Adcom only adcom was by far better
-------------------------------------
preampifier was a box full of TTL and 80 electrolytics that all refused to work ...replace them all things got a lot better ...
as a buffer and a preampifier is exeptional ( let us not forget its an 1981 design ) it seems that there is no ability to drive long cables or anything that is just a bit capacitive with this preamp
even though there a load of ttl inside to perform all button controls the unit is very quiet and the phonh stage is amazing ...( the costuemr will not run it with a phono ...still the phono stage was tested and seemed to have amazing tollerance to various heads tested i dsay that was extremelly adoptive
id say that both amp and preamp are above average and nothing too amazing
here is a picture
here some more just finished yesterday
its the A201 and the P101 from SAE ...
the ampifier needed a 110/230 conversion new trafo 600 W fitted inside most electrolytics replaced retuned idle and working just fine ...
as an ampifier and next to my set it seemed that the amplifier had less bandwidth than my set ...low ends was kinda limmited still clea and not that punchy but seemed to be a lack at the very low stages just about the same for high i got the feeling that wasnt that clean and kind of hissy or harshy trebles
original bias seemd also low but i didnt want to play anything other than the oiginal values ... the topology outputs and configurations reminds the 555 series from Adcom only adcom was by far better
-------------------------------------
preampifier was a box full of TTL and 80 electrolytics that all refused to work ...replace them all things got a lot better ...
as a buffer and a preampifier is exeptional ( let us not forget its an 1981 design ) it seems that there is no ability to drive long cables or anything that is just a bit capacitive with this preamp
even though there a load of ttl inside to perform all button controls the unit is very quiet and the phonh stage is amazing ...( the costuemr will not run it with a phono ...still the phono stage was tested and seemed to have amazing tollerance to various heads tested i dsay that was extremelly adoptive
id say that both amp and preamp are above average and nothing too amazing
here is a picture
Attachments
sniff
maybe you'll sell me a built amp one day?
sure why not !!!! you can e mail me with full data name and so on an i will include you in my will ha ha ha ha ha ....
beyond jokes ...constract one on your own you will have all my help !!!!
a P3A for my son's bedroom ....
almost 1.5 year ago i have constructed a P3A for my wife so i wanted to see the effect of the sound while she was having the baby ... and then use the same system for the baby after it was born ...
The baby loves the sound ( i think ) so is my wife .... the problem was that the amplifier i builted was too big ...the amazing waf factor ... so i was asked to bulit some other version probably less power but for sure less size
here we go ..there some pictures of my new built ... but i have a small issue ...
that is a standard built uses original 1302+3281 in the out ,100pf silvermica for miller VAS and then 100 pf multileyer for the down driver ...other than that everything else is as seen on schematic
i ve been building in the past mostly with bd 139-140 and mJ15030-31 families
this time i used bd 829-830 i had some of them available and willing to try
i wasnt expecting a noticable diference but even though the bias is quiet low since size of the box and heatsink i didnt want to create high temperature inside still it plays by far better than the 139-140 or 15030-31
can anyone explain why ????
can any one double check this and provide an opinion ???
thanks sakis
almost 1.5 year ago i have constructed a P3A for my wife so i wanted to see the effect of the sound while she was having the baby ... and then use the same system for the baby after it was born ...
The baby loves the sound ( i think ) so is my wife .... the problem was that the amplifier i builted was too big ...the amazing waf factor ... so i was asked to bulit some other version probably less power but for sure less size
here we go ..there some pictures of my new built ... but i have a small issue ...
that is a standard built uses original 1302+3281 in the out ,100pf silvermica for miller VAS and then 100 pf multileyer for the down driver ...other than that everything else is as seen on schematic
i ve been building in the past mostly with bd 139-140 and mJ15030-31 families
this time i used bd 829-830 i had some of them available and willing to try
i wasnt expecting a noticable diference but even though the bias is quiet low since size of the box and heatsink i didnt want to create high temperature inside still it plays by far better than the 139-140 or 15030-31
can anyone explain why ????
can any one double check this and provide an opinion ???
thanks sakis
Attachments
Hi Sakis
The main difference between the BD829 and BD139/MJE15030 is the fT. The BD829 has a transition frequency of typically 250MHz, as opposed to 8MHz for a BD139.
It may be the higher speed of these devices which accounts for the sound difference. In what way would you say they sound better?
Regards,
Steve
well as i describe my approach for this amplifier and some time compared with the DX amplifier which i find very accurate and very precise my amplifier is a bit endy ....means that will represent with problems any signal at the ends ...low and high
now if you see the one that is made with BD139 series and the other was made with BD829-830 seems that everything is more bass is even more rich midle is more perfect but most of all seems that high are by far more clean and have a class A sweetness ...tybe style sound
the previous version i was listening to was biassed at 120 ma per board now this one is biassed almost to 1/4 of this bias and still plays better ...
i have to investigate this farther ...it seems that these driver rock !!!!
( hei do you like my enclosure ??? )
now if you see the one that is made with BD139 series and the other was made with BD829-830 seems that everything is more bass is even more rich midle is more perfect but most of all seems that high are by far more clean and have a class A sweetness ...tybe style sound
the previous version i was listening to was biassed at 120 ma per board now this one is biassed almost to 1/4 of this bias and still plays better ...
i have to investigate this farther ...it seems that these driver rock !!!!
( hei do you like my enclosure ??? )