Power Follower 99

[audiodesign]

Here some relative threads:

http://www.diyaudio.com/forums/solid-state/183263-pf-99-years-happines.html

http://www.diyaudio.com/forums/pass-labs/241166-need-suggestion-my-power-follower.html

http://www.diyaudio.com/forums/solid-state/3471-andrea-ciuffolis-power-follower.html

 

[audiodesign]

Here the new PCB and last schematic

I am producing some of this pcb to test it.

I think this circuit can give the best performances using on input MK132 Caddock or parallel out-phase metal 1% resistors.

The input capacitor should be Auricap, Z-Cap RED or better.

The output capacitor should be Jensen electr., Nichicon Super Through or BHC Slit Foil, no other choice.

 

[audiodesign]

I think the best solution as voltage stage is vacuum tube stage.

I prefer a single tube like D3a or 6C45.

D3A specifications in triode connection:
filament voltage: 6.3V
filament current: 315mA

Max plate voltage: 200v
Max plate dissipation: 4.2w
Max cathode current: 33mA
Plate resistance: 1.9Kohm
Amplification factor: : 77
Max resistance in grid circuit: 0.5Mohm

6C45 specifications:
filament voltage: 6.3V
filament current: 440mA

Max plate voltage: 150v <<<<< it is lower than D3a
Max plate dissipation: 7.8w
Max cathode current: 52mA
Plate resistance: 1.2Kohm
Amplification factor: 52 ±16 <<<<< selection is necessary
Max resistance in grid circuit: 0.15Mohm

Here the schematic and relative pcb to create a cheap and good power supply for the vacuum tube voltage stage.

It use a virtual battery operation on anodic like the Power Follower and a soft start for filaments.

For some single tube configurations follow this link:
- http://www.audiodesignguide.com/Ibridone/index.html
- http://www.audiodesignguide.com/Ibridone/index3.html

Soon I will update also this project.

 

[audiodesign]

Files

Here some files to produce the pcb and to make some simulations with LTspice.

Follow the first configuration simulated on 8 and 4 ohm load:

Vcc=40V
Ibias=3A
IRFP150
Pd=40 x 3A = 120W

Vin=19Vp => 13.5Vrms
Vout = 18.5Vp -> 13.1Vrms
Rload = 8ohm
THD = 1.5%
Pout=13.1*13.1/8 = 21.5W

Vin=12Vp => 8.5Vrms
Vout = 12Vp -> 8.5Vrms
Rload = 4ohm
THD = 2%
Pout=8.5*8.5/4 = 18W

 

[tiefbassuebertr]

Power Follower 99 as Pre-Amplifier for driving of four Power Amps

This is the best line preamp, which I know. It runs since 13 years without any trouble. Volume control parts are penny & giles, but in oil-filled and no longer available version.
There are no commercial product on the marked with better sound.
Current source = 1A, Supply voltage behind the MOSFET regulator (at the actually buffer stage) = 9 volts.
For looking the images go to
http://www.diyaudio.com/forums/digi...e-connectors-special-outline.html#post3723081

 

[audiodesign]

Now I have some pcb available of the PF99 and virtual battery for the vacuum tube pre-ampl

 

[audiodesignguide3]

Now there are available pcb and file to produce these.

It is possible use a new cheap and easy voltage stage using 6072 or 12AX7.

 

[tiefbassuebertr]

I have heard, that audio MOSFET's like 2SK1058 provide any benefit (against the IRF series) in a topology with gain - i. e. not a follower resp. buffer - a circuit like this:
http://mydiyhifi.blogspot.com/2010/05/class-2sk1058-mosfet-amplifier.html
http://diyaudioprojects.com/Solid/ZCA/ZCA.htm

For me the question is, whether this also applies to a power follower circuits like those from attachment and under this URL's:
https://sound-au.com/project83.htm
https://web.archive.org/web/20070221013533/http://home.zonnet.nl/tschrama/owndesign.html
http://web.archive.org/web/20061224142340/http://www.pha.inecnet.cz/macura/follower_e.html
https://web.archive.org/web/20090409161013/http://royalsound.sweb.cz/FOTKY/index.htm
https://www.diyaudio.com/community/threads/pavel-macuras-mosfet-power-follower.45460/page-2 (attached files post 27)

 

[Mark Tillotson]

ZZZZZ .... I dreamt of a world with no NFB. 😀

OS

Then you have to drive with your eyes shut!!

 

[analog_sa]

I have heard, that audio MOSFET's like 2SK1058 provide any benefit (against the IRF series) in a topology with gain - i. e. not a follower resp. buffer - a circuit like

If you are asking whether laterals sound better than verticals in a follower application i wouldn't be able to tell, haven't tried it. SITS certainly do.

But one thing is certain, laterals having much less transconductance than verticals will also have a lower damping factor in such a circuit.