There is some truth hidden in the above posts .
Through the years there have been making loads of variations on the P3A i make ... I even have one more in the house configured as headphone amplifier low power supply and 600ma bias
I get to notice each version since i've been also been mix matching parts and learn and understand the properties of each make, slower drivers /faster drivers , input capacitors , a variety also for vas , different miller capacitors regarding the make and the capacity, low voltage high voltage this diff the other diff and so on and on. Any variation name it and i have allready done it ....
I can verify that there is minor pros and cons between those variations and details like that will add or remove from the sonic signature ....Always you give something and you get something .
I can also verify that none of the variations was boring ....diferent may be but boring no ....and no by al means ...
So there is an END to all that because ok, after 15 years messing with the P3A i probably know it inside out ...This how far you will get without messing with the original circuit ....
Indeed i could keep the L10 in my house its a well made machine and my speakers loved the three times up power ( which i dont actually need )
OK then but this L10 cannot operate in night mode ...its completely dead !!!
Then this means that you need to have a second system obviously made with P3A smaller and more sensistive speakers to be able to realy enjoy music which i already have since girlfriend is well trained WAF is not a problem .....( look at picture 😉 )
So the Question is THEN WHAT ?
EFP amplifier i thik is too accurate and boring
Tubes is out of the question my machines should last for ever
Mosfets also since i never heard any mosfet that can outperform the P3a in terms of sound
then What ???
Remember that the standards are very very high
Through the years there have been making loads of variations on the P3A i make ... I even have one more in the house configured as headphone amplifier low power supply and 600ma bias
I get to notice each version since i've been also been mix matching parts and learn and understand the properties of each make, slower drivers /faster drivers , input capacitors , a variety also for vas , different miller capacitors regarding the make and the capacity, low voltage high voltage this diff the other diff and so on and on. Any variation name it and i have allready done it ....
I can verify that there is minor pros and cons between those variations and details like that will add or remove from the sonic signature ....Always you give something and you get something .
I can also verify that none of the variations was boring ....diferent may be but boring no ....and no by al means ...
So there is an END to all that because ok, after 15 years messing with the P3A i probably know it inside out ...This how far you will get without messing with the original circuit ....
Indeed i could keep the L10 in my house its a well made machine and my speakers loved the three times up power ( which i dont actually need )
OK then but this L10 cannot operate in night mode ...its completely dead !!!
Then this means that you need to have a second system obviously made with P3A smaller and more sensistive speakers to be able to realy enjoy music which i already have since girlfriend is well trained WAF is not a problem .....( look at picture 😉 )
So the Question is THEN WHAT ?
EFP amplifier i thik is too accurate and boring
Tubes is out of the question my machines should last for ever
Mosfets also since i never heard any mosfet that can outperform the P3a in terms of sound
then What ???
Remember that the standards are very very high
Attachments
Member
Joined 2009
Paid Member
Some interesting comments! - your girlfriend looks like a very good match to your audio passions...
I was thinking about some similar problems, where I have a k-horn speaker which benefits from my TGM8 power (based on P3a) driving the woofer but as a Class AB it maybe not the best option for the sensitive compression driver horn that takes care of 400Hz and up. I thought I would need a lower power amplifier for this, just like you mention for more sensitive speakers. Is Class AB still the right solution ? Should I consider my P3a derived TGM8 operating at lower power supply rails with Class A bias for the output stage ?
I was thinking about some similar problems, where I have a k-horn speaker which benefits from my TGM8 power (based on P3a) driving the woofer but as a Class AB it maybe not the best option for the sensitive compression driver horn that takes care of 400Hz and up. I thought I would need a lower power amplifier for this, just like you mention for more sensitive speakers. Is Class AB still the right solution ? Should I consider my P3a derived TGM8 operating at lower power supply rails with Class A bias for the output stage ?
I'm building another p3a and I'm out of 100pf caps.
Is it ok to use 330pf for C2?
What will change soundwise?
Is it ok to use 330pf for C2?
What will change soundwise?
Sakis congratulations for all this work you have done on p3a amp, an excellent amp in its simplicity, in my opinion. I have two questions:
1) About p37 preamp, do you prefer/use the one with symmetrical supply (p37 rev A) or the original p37 with single supply with your P3A? I have made both with junkbox components, could not say which is better, they both sounded good. It was not possible to have an A/B test, the second was made after i dismantled the first. I am thinking of making one of the two properly with good components, which is your preference?
2)I have two separate enclosures for power amplifiers with power supplies , each one has PSU symmetrical +/- 45VDC (from 2x33VAC 660VA torroidal transformers). They have some other amplifier in them (working very well for 23 years). The PSU's are out of limits normally for P3A. Do you think that it is dangerous to use P3A with this PSU? What is your experience with so high voltages? My speakers are 8 Ohms nominal impedance, but I think they go down as low as 6 at certain frequencies. (Audio Spectrum S37 FE, I think you should know them since we are from the same country!).
1) About p37 preamp, do you prefer/use the one with symmetrical supply (p37 rev A) or the original p37 with single supply with your P3A? I have made both with junkbox components, could not say which is better, they both sounded good. It was not possible to have an A/B test, the second was made after i dismantled the first. I am thinking of making one of the two properly with good components, which is your preference?
2)I have two separate enclosures for power amplifiers with power supplies , each one has PSU symmetrical +/- 45VDC (from 2x33VAC 660VA torroidal transformers). They have some other amplifier in them (working very well for 23 years). The PSU's are out of limits normally for P3A. Do you think that it is dangerous to use P3A with this PSU? What is your experience with so high voltages? My speakers are 8 Ohms nominal impedance, but I think they go down as low as 6 at certain frequencies. (Audio Spectrum S37 FE, I think you should know them since we are from the same country!).
UP to 220pf will be fine and absolutely no more than that
should be ok.
have a look into post 1 in this thread:
...................
.........350 pf silver mica input filter
................
P3A has an excellent frequency response .... it is not realy important to tell how much ( since mine are going a bit higher than normal versions here and there ) which actually means having one amplifier that has a real bandwidth of 100K is useless unless you are a mouse or a dog .
Well this is not exactlly correct ...
For electronics engineer having one amp that has a bandwidth of 100K and stable first of all this is a sign of electric stability , and that is very important for an amplifier .
Second when amplifiers and speakers have extended bandwith even at that point this provides linearity in critical high frequency files above 10K where these files find a better path to develop ....
Yet again that is not magic and while one 1nf input capacitor may limit the bandwidth up to a point and destroy that extensive bandwidth that the P3A has
in the low frquency area where you have looooooong discussions about which input capacitor that has linearity even at signals of 10-18HZ you first have to wonder if your speaker is capable of that because most of the times they are not ....
So choise have to be wise ..... Overdesign doesnt help always
Kindest regards
Sakis
Well this is not exactlly correct ...
For electronics engineer having one amp that has a bandwidth of 100K and stable first of all this is a sign of electric stability , and that is very important for an amplifier .
Second when amplifiers and speakers have extended bandwith even at that point this provides linearity in critical high frequency files above 10K where these files find a better path to develop ....
Yet again that is not magic and while one 1nf input capacitor may limit the bandwidth up to a point and destroy that extensive bandwidth that the P3A has
in the low frquency area where you have looooooong discussions about which input capacitor that has linearity even at signals of 10-18HZ you first have to wonder if your speaker is capable of that because most of the times they are not ....
So choise have to be wise ..... Overdesign doesnt help always
Kindest regards
Sakis
Can you explain why?
1k+100p =1.5Mhz
1k+220p = 725Khz
1k+680p = 235Khz
1k+1000p = 160Khz(not recommended)
All far outside of the audio band.
Last edited:
Dear Sakis, have you ever tried Japanese Sanyo or Hitachi batwings for output P3A? I know you liked old Toshibas series.
Thank you Sakis. Probably it is a "no" then for 45VDC. Sometimes I listen real loud, or I like to have the option, anyway...
About P37 pre?Of course my question is marginally off topic. But I would appreciate an opinion from you...
About P37 pre?Of course my question is marginally off topic. But I would appreciate an opinion from you...
The 45VDC question was answered. I re-questioned about preamplifier. I expected the answer was sth like that about 45VDC. My P3A is working on +/- 25 VDC right now ( on relatively INsensitive speakers). Since I had enclosures and PSU 's for dual mono +- 45VDC, I thought perhaps I could "transplant" P3A to those boxes. But since I listen real loud sometimes, not. And my speakers are probably dipping below 8 Ohms on some frequencies. Sometime , a new PSU.