P3A-More upgrades

[east electronics]

the only thing that i found in TTA and TTC parts is a long history of failure so in most cases these DO not exist in my systems and testings

 

[brian92fs]

Hi Sakis,
You have said several times that BD829/830 drivers paired with 2SA1302/2SC3281 output devices performs very well.

With the BD829/830 unavailable would you stick with the BD139/140 or MJE150xx series recommended by ESP or would something else be worth considering?

 

[brian92fs]

I see the the BD829/830 has a SMD equivalent in the BCP53/56 that is still available. Perhaps this is a viable alternative. Other than mounting it if using the ESP PCBs.

 

[Ranchu32]

KSA1220/KSC2690 are a good option and readily available from the usual places.

 

[east electronics]

Hi Sakis,
You have said several times that BD829/830 drivers paired with 2SA1302/2SC3281 output devices performs very well.

With the BD829/830 unavailable would you stick with the BD139/140 or MJE150xx series recommended by ESP or would something else be worth considering?

1306 was the original driver of the 1302 Green in color
MJ150xx no its not my choice they sound bad and dont pair with3281-1302

been working with a1837 and c4793 and i am very happy with those

 

[minoan_war]

measuring power

Hi, I'm trying to calculate the output power for my p3a mono amp, I got only 12vac with an 8ohm load (xformer is 22+22 3A -> +/-31VDC) I think is too low, does anyone knows why my output is low?

 

[Bone]

Drive it harder. Your input is too low.

 

[brian92fs]

22V secondary's should be you around 30Vdc after rectifier losses. A BJT output stage should be able to swing within 2 or 3 volts of the rails, which comes out to around 19V to 20V rms. This would give you 45W to 50W into 8 ohms. The gain of a P3a is about 27dB (or 22x). So to drive this to clipping you need 0.9 to 1.0 V rms of input signal.

Even with worst case transformer and mains regulation, you should still see at least 17Vrms on the output.

What is the VA rating of your transformer? You indicated 3 amps... If this is 3A per secondary, then it looks to be around 130VA. This might be too low if you're driving both channels to clipping. For 50W of output into 8 ohms, you'd get just under 2.5A per channel. If you're driving two channels, you might be reaching the limits of the transformer. Maybe try driving just one channel and see if it makes a difference.

 

[Vrystaat]

Just wait, Sakis will be here soon !

 

[brian92fs]

...the P3A master

 

[Zohaib Ahmad]

Long time ago I wanted to build this wonderful amplifier. I upload some photos of it..I
thank Stephie B., my friend, for helping me get original transistors for the input stage. Getting some old reciclying parts, at last! I finished the amp which differs from Rod Elliott's only by adding a current mirror to the differential pair collectors. I supplied the amp with +/-40, using C5200 and A1943 in the output stage, I left bias current at 30 mA for each transistor maybe bias is high but temperature through them kept normal. Rod does not recommend the Vbe multiplier is attached to the main heatsink since overcompesation can occur causing crossover distortion due to the complementary feedback pair or Sziklai pair used in the output stage. The sound is very good.

Hello There I Am Interested In This Amplifier Can U Provide original Schematic of This Amplifier????
I Want to build it

 

[jacques antoine]

ESP P3A

 

[Zohaib Ahmad]

ESP P3A

Thanks Man...

 

[Zohaib Ahmad]

ESP P3A

Can I Run This Amplifier On 35 0 35 AC???

 

[Ciro82]

Can I Run This Amplifier On 35 0 35 AC???

35Vac after rectifier would be something around 49Vdc ... IMHO too high

 

[Zohaib Ahmad]

measuring power

Hi, I'm trying to calculate the output power for my p3a mono amp, I got only 12vac with an 8ohm load (xformer is 22+22 3A -> +/-31VDC) I think is too low, does anyone knows why my output is low?

Bro Your Input DC Current Is Not Enough...

 

[Zohaib Ahmad]

35Vac after rectifier would be something around 49Vdc ... IMHO too high

Too High Will Give Maximum Peak

 

[alain98]

Every individual has different taste and distortion preferences. Amplifier can be in A class and still have high harmonic distortion. Some people prefer odd order harmonics over even order harmonics. Some people don't like crossover distortions but to me they are not that offensive.

I remember some 30+ years ago that in HiFi Choice magazine there was test of Audio Innovations tube amp (I think it was Audio Innovations 400 integrated). It was push pull EL84 based meaning that it had huge amounts of all kinds of distortions, both harmonic and crossover. The test results were: Lab - poor, Sound - excellent! Many solid state amps with great specs were unable to achieve Sound - excellent result.

Distortion performance of amp is highly overestimated in it's importance. Doug Self proved that Japanese high speed output transistors have lower distortion than American or European parts. Sakis too prefers the sound of P3A with Japanese high performance output transistors. But my own personal experience, from many DIY projects, is that I like the sound of low speed parts like TIP35/36C, MJL 2119x, etc., better .

Hi Ivan,
I am trying to understand solid state working amplifiers.
What kind of VAS transistors and drivers do you use and recommand with slow output transistors?

 

[TonyTecson]

I am trying to understand solid state working amplifiers.
What kind of VAS transistors and drivers do you use and recommand with slow output transistors?

the VAS has the highest voltage swing, and so murst have a very high Ft, transition frequency, and high hFE, look for trannies used in the color tv crt boards....

 

[ostripper]

TTA006/TTC011 = repackaged 2SC4783/A1837 1.5A instead of 2A .... perfect for a CFP/1 pair EF2/3.
For low voltage amps like a P3A , TTC/A004 - 1A would also do nicely. None of these are obsolete (I use em').
Outputs are usually the slowest on my EF2/3's , drivers are always as fast as I can source. 100Mhz Ft is good.
OS