F5 power amplifier

Nelson Pass

The one and only
Paid Member
2001-03-29 12:38 am
As many of you know, the F5 power amplifier design is done and is
merely awaiting delivery of the issue of AudioXpress which was
scheduled to be mailed April 10.

I feel that it's important to support AudioXpress, a magazine with
which I have a 35 year history, and which also serves as a
mainstay for the DIY comunity. Lately they have kindly printed
projects that I had already posted on the web, but I decided that
they deserve a little better than that.

Coincidentally, I had surgery of the 10th, and having apparently
survived, I am typing this from my bed.

Do not try to lift an XA200.5.

In any case, I know you're eager to get going and as soon as the
magazines arrive I hope that this thread will become a beehive of
activity. I have no doubt that members here will improve or at
least embellish the design.

Here's a copy of the simplified circuit.
 

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steenoe

Member
2004-03-23 10:43 am
Nelson Pass said:
As many of you know, the F5 power amplifier design is done and is
merely awaiting delivery of the issue of AudioXpress which was
scheduled to be mailed April 10.

I feel that it's important to support AudioXpress, a magazine with
which I have a 35 year history, and which also serves as a
mainstay for the DIY comunity. Lately they have kindly printed
projects that I had already posted on the web, but I decided that
they deserve a little better than that.

Coincidentally, I had surgery of the 10th, and having apparently
survived, I am typing this from my bed.

Do not try to lift an XA200.5.

In any case, I know you're eager to get going and as soon as the
magazines arrive I hope that this thread will become a beehive of
activity. I have no doubt that members here will improve or at
least embellish the design.

Here's a copy of the simplified circuit.

Thanks a lot, Nelson. Hope you recover fully, pretty soon.
Wow thats simple enough for a P2P build:cool:

:)
 

sandstorm33

Member
2006-09-19 4:47 pm
Nelson Pass said:
As many of you know, the F5 power amplifier design is done and is
merely awaiting delivery of the issue of AudioXpress which was
scheduled to be mailed April 10.

I feel that it's important to support AudioXpress, a magazine with
which I have a 35 year history, and which also serves as a
mainstay for the DIY comunity. Lately they have kindly printed
projects that I had already posted on the web, but I decided that
they deserve a little better than that.

Coincidentally, I had surgery of the 10th, and having apparently
survived, I am typing this from my bed.


Most certainly, GET WELL QUICKLY!!

I congratulate you on your loyalty to TAA publications . The Audio Amateur and its successors have provided ,through the years , a trustworthy platform for the best of the audio DIY minds. Recalling its 4 issues a year in the 70's,the articles it contained opened a whole new world to understanding and construction of top notch audio equipment . Your 1994 original ZEN article ranks as one of the classics. We all await the F5. Hopefully my copy will arrive this coming week!
 

Nelson Pass

The one and only
Paid Member
2001-03-29 12:38 am
Thanks very much.

However, I don't want this to become a best wishes thread, rather
it should focus on what I think will be an exciting little amplifier.

In case you haven't already seen the square wave....
 

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best wishes for the fast recovery, nelson!

it would be great if you could add a few words on what in particular you've wanted to achieve with F5, what's the sound philosophy behind, whom it is aimed for (what kind of speakers).

this is so distinctive about each of FW amps - a strong philosophy behind each and every of them. but one has to be careful where to apply them!
 

Nelson Pass

The one and only
Paid Member
2001-03-29 12:38 am
Blues said:
Isn't that circuit supposed to be Zv10? :xeye:

I suppose that ZV10 would have been the F4.

The Zen Variations were intended as single-stage amplifiers
(although ZV4 had a buffer).

The First Watt stuff is distinguished by being commercial product,
and is not limited to single stages.

14 years is a good long run for the Zen series. I may return to it
some time in the future, but I don't have a specific plans.
 

Nelson Pass

The one and only
Paid Member
2001-03-29 12:38 am
EUVL said:
All the best for a speedy recovery.

The simplified schematics looks familiar though ?

http://www.diyaudio.com/forums/showthread.php?threadid=59339

PS I think R4 should also be 600 ohm and not 0R47.

Such a smarty-pants. Yes, it's 600 ohms (it's correct in the not-
simplified schematic).

I had not seen the Profet schematic before - when the ads came out
I noted that it supposedly "all the benefits of a current source
and voltage source" and I didn't give it further attention.

An email correspondent some years ago also suggested this
topology, a CFP with voltage gain. If I could remember his name I
would have mentioned him. (who knows, maybe it was the Profet
guy...)

Anyway, it's been around for a while. When you read the F5 article,
you will see "The topology is familiar...". Selectronics has chosen to
bridge the circuit and settled on different values.

Given the differences in measured performance from "Chuck"
Hansen's review in AudioXpress, I suspect that they were using the
same kind of gun to shoot at a different target.