DIY F2 clone

I am new to this forum, so apologies if the answer to this question has been worn out, but I am interested in building an F2 clone. Dick Olsher is mandating use of the F2 to power the Eminence woofer in his Basszilla speaker and I can't afford the store-bought version.

Has the Reverend Pass released the necessary circuit information to now make a DIY clone possible? If so, where does one find it? If not, is there some timetable?
 
first watt f1 f2

First Watt is a "kitchen-table" effort by Nelson Pass. First Watt builds very simple high quality, low power audio amplifiers intended for use with sensitive loudspeaker drivers.

These amplifiers are hand-built by Pass and are available in very limited quantities. Each design is a different exploration into high quality at low power.
At the end of the sales cycle of new product, the schematics and technical details of each design will be posted for the benefit of the "DIY" community.

As you can see from this quote of FAQ at http://www.firstwatt.com/faq.htm
the promise we can trust in is:
... there will be, in time technical details of each design
... but not until The End of sales cycle of new product.

As what I can understand, Nelson may correct me, this means details are public for F1 now.
As F2 is now a new product, for sale. Like is F3.
And we have to wait patiently some time for more detailed info of F2 and F3.

Or sign up for to be a lucky buyer of an exemplar of F2!


What we can download now, by the generosity of Mr. Pass is at this download page:
http://www.firstwatt.com/downloads.htm

Manuals:
F1 Owner's Manual
F2 Owner's Manual
F3 Owner's Manual
Aleph J Owner's Manual

:cool: F1 Service Manual :cool:

F1 Review by Jon Ver Halen of Lowther American.

Articles:
Current Source Crossover Filters
Current Source Amplifiers and Sensitive / Full-Range Drivers
.

For details of an amplifier we look for Service Manual
as for service there would mostly be a schematic needed.


regards
lineup
 
Hi Scott, welcome to the Pass forum:) Yep we backengineered the F2. Mr. Pass said it was pretty close to the factory amp.
The development is mainly in this thread:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=57515&perpage=10&pagenumber=1
And this thread contains loads of good information and some examples of finished amps.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=60800&perpage=10&highlight=&pagenumber=1
Apassgear and I worked together on a boardlayout that is confirmed functional.
Good luck and happy building:)

Steen:cool:
 
F2 Clone Delight

Delighted to learn that some folks have already been developing F2 clones. And the "tomorrow" announcement from Mr. Pass about official circuit availability, while suitably cryptic to afford him the necessary wiggle room (been there, done that), is gratifying.

Seeing as what little skill I have is in speaker building and wiring up tube amps, I'm going to need all the help I can get to assemble an F2 clone. The operative word here is "assemble," as there's no way in hell I could actually build one from a schematic. So for those who are planning to whip together clone F2 circuit boards, power supplies, heat sinks et al, I hope you can be persuaded (with suitable incentives) to make extras enabling the electronics impaired to assemble something that won't turn into molten aluminum when switched on.

Here's hoping tomorrow arrives soon...
 
The one and only
Joined 2001
Paid Member
I use 3 watt resistors, and the lowest value I have in stock
are .33 (now used up) and the .47 ohm from Panasonic, which
is their lowest value. So parallel/series resistors are examples
where I want a lower value than .47 or more dissipation than
a watt or so.
 
The one and only
Joined 2001
Paid Member
BTW, this question has been asked before and will inevitably
be asked here - "Why the .33 ohm resistors, inductor, and
10 uF cap?"

The .33 ohm resistors are inductive wirewounds, and the
inductor in the schematic represents that. When I laid the
board out, I anticipated a large capacitor in the decoupling,
but it didn't work out best that way, and I ended up trimming
the values against the following square wave at 10 KHz:
 

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The one and only
Joined 2001
Paid Member
Netlist said:
I'm I right if I recognise a ZenV2 current source? I presume a variant with two IRFP240's would work as well?

I imagine so, although I did not try it. Note the 15,000 uF
cap in the current source charging circuit. An amplifier of this
low wattage will be paired with delicate drivers, and
avoiding turn-on thump is a priority.

:cool:
 
Nelson Pass said:
Here we go
:cool:

Thanks Nelson Pass
Many girls and boys will be very happy
... like getting an early X-mas gift

I attach the image of your schematic
for those who want to take a quick look,
without download of original PDF

lineup
------------------------------------------------------------------------
this image, as all 'pass-materials', is now put with all the rest of my collection in folder C:/My Documents/Nelson Pass

I have separate folders, for like 60-70 other audio persons and diyaudio members, too.
Including one folder for 'lineup circuits and stuff', I have manage to find in this forum + world wide web

;)
Attachment:
First-watt-f2-sch.png
 

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