Should I call this pre-amp+ PDB a "SPLIF" Amp?

[mtlin12]

I built my DB-01 pre-amp few years ago, and I also built a 25W
0dB Power Diamond Buffer Amp two years ago.

Diamond Output buffer eats trannies (thermal)

Recently I want to combine the pre-amp and a new thermaltrack PDB circuit
to build another 50W non-total NFB amp, but I found this article:

Originally posted by rbroer
You might consider this:

http://www.altmann.haan.de/splif_page/#the%20feedback
(The ALTMANN "SPLIF" Amplifier Topology)

Is there anybody built a non feedback amplifier?? post #11

Comparing my pre-amp + the thermaL_track PDB, they are almost
the same, so should I call it another "SPLIF" ( SPLIT FEEDBACK ) AMP?

[mtlin12]

My new non-global NFB 50W power amp EU-50,

using my pre-amp module with +/-47V voltage regulator ( EU-01)

and two +/-37V supplied power diamond buffers.




And its circuit topology is just like a "SPLIF" amp for eliminating
some duplicate parts.

[Workhorse]

Hi MTlin,
Congratulations on your amp completion
How does it sound, does it have a specific sonic signature...
What about the low frequency response with this amp, whats the damping factor you obtained, does it fairly controls the speaker cone movement...

regards,
K a n w a r

[Greg Erskine]

hi mtlin12,

I'll jump in, I can't see any resemblance to the SPLIF. My understanding of SPLIF is it requires parallel output devices. One of the output pairs drives a ideal dummy load and this is used as feedback for the differential pair. The rest of the output devices drives the speakers as per normal. The idea is to avoid the distortion generated by driving the speakers from being in the feedback circuit.

Or I could be completely wrong.

regards

[mtlin12]

Hi Kanwar,

Long time no see,

Yesterday I brought my pre-amp and power-amp to a second-handed
audio store, tested with the Platinum Audio's trio a 4 OHM 86dB/W
loudspeaker which I was told being designed by Phil Jones.





I'm glad to tell you that all my friends love its sound. Fast speed,
powerful, low noise, low distortion, transparent, very detailed and live...

It is pure DC-coupling design, the offset and thermal problem are
very little, wide F.R. range around 0~500KHz -3dB, only the damping
factor I think is not very high, I guess not even 40.

[mtlin12]

Originally posted by Greg Erskine
hi mtlin12,

I'll jump in, I can't see any resemblance to the SPLIF. My understanding of SPLIF is it requires parallel output devices. One of the output pairs drives a ideal dummy load and this is used as feedback for the differential pair. The rest of the output devices drives the speakers as per normal. The idea is to avoid the distortion generated by driving the speakers from being in the feedback circuit.

Or I could be completely wrong.

regards

thank you Greg,

Yes, I know the SPLIF output devices should be paralleled, so My
second posted circuit topology is just as you mentioned, the DB
( my pre and headphone amp driver) does parallel with the 50W
x1 PDB (Power Diamond Buffer ).

And only the pre-amp ( with no load ) has split NFB, the PDB doesn't feedback any harmful signals.
The PDB can be just one or several output devices.

The reason I use this pre-amp with PDB is because there already
has a good quality high voltage shunt regulator on my EU-01 (as driver) PCB.

[Workhorse]

Hi Mtlin

I think your current amplification is very less[you might be using only double darlington EF stage]....

If you need higher damping than atleast use triple or Quad Emitter Follower Pipeline or use Mosfets which would enable even much higher damping factor....

K a n w a r

[mtlin12]

Actually I use triple darlington this time, 2N5401/5551, 2SB649A/2SD669A and of course
my favorite BJT SANKEN 2SA1216/2SC2922, so I think the current
gain would be no problem, my only concern is that I am not dare
to use lower than 0.1 OHM emitter resistor because every 0.01V
rise will cause 100mA stand-by current up.

This 0.1 OHM maybe the most problem of damping factor.

[mtlin12]

I had another circuit topology and power amp prototype made
last year, it was NFB from the 2nd VAS stage, not through the
headphone DB nor the Power DB, only it has no driver stage
voltage regulaor, but still sounds very clear tested with 107dB
KLIPSCH "Klipschorn Anniversary" which belongs to my friend.

[Pasul]

Do you have any picture of THD distortion of this amp?I like to see it.THX