End Millennium Pseudo-clone Amp

[Havenwood]

Hi, I build this pseudo-clone amplifier.

What do you think?

When I finish my function generator based in XR2206 I upload some pictures from my old oscilloscope.
The amplifier sound really good, Iq = 70mA and gain x10 (or 20dB).
I use hyper-common componets, like BC547/557, BD139/140 and TIP3055/2955 TO3P.

For minimize the noise, in a few days, I hope finish the VAS and input stage power supply. Use voltage doupler (i don´t want use another transformer) and capacitance multiplier, like various japaneses amplifiers.

Cheers

 

[lineup]

I like it.
Symmetrical input and VAS.
Triple Darlington output .. light load for the VAS. Easy to drive,

R17 and R18.
With 10k it makes the gain in VAS only x10 (10k/1k)
You could make them 100k.
Experiment. Because this will effect the THD dist.
You can even run without R17/R18. This is the normal for maximal gain.

 

[Havenwood]

Here is the positive Vreg, from the main transformer.
Voltage doupler + Capacitance Multiplier.

Rippley is very low under low load (100omhs). When I finish the function generetor, I test this PSU on the amplifier.

I´m working in the PCBs of all.

1N4148 = 1N4007 (in pspice is missing)
BF469 = BD139
BZX.... = Zener 24V

 

[Havenwood]

Hi, after read some threats, what is the impact to use cascode current source? only provides more Zout?

And Sziklai pair on input stage?
Anybody build some amplifier with CFP input stage?

 

[djk]

"You can even run without R17/R18. This is the normal for maximal gain. "

With no global feedback the gain would be a bit too high don't you think?

The first stage has a gain of about 6dB, the second stage about 20dB, 26dB is about the right gain for a hi-fi power amplifier.

 

[Havenwood]

I don´t measure Zout, but is valid use configuration to reduce Zout?