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Old 23rd August 2012, 09:14 PM   #1
zzffnn is offline zzffnn  United States
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Default DIY FirstWatt F2 speaker amp

Thanks for checking. I do not usually come to this forum, but I am more active at Head-fi.org. Please see my profile there under the same user name, zzffnn.

I have the same listing in Headfi with photos, please see:
DIY FirstWatt F2 speaker amp-Perfect for XLR'ed K1000s, HE-6s or LCD-2s

Still not sure I will sell this F2, hence this is rather an interest check. The reason is: I have a new baby boy and a busy work/life, so I do not have much time to listen to music (have used this amp for less than 30 hrs). I would really miss this amp.

The limited commercial version of FirstWatt F2 is no longer available and the F2 was retailed for well over $1800. It was designed by the legendary designer Nelson Pass. Please read online about it. This is a rare current source amp without feedback.

This amp was originally made, with love, by a hobbyist (an established DIY'er as well) for his own enjoyment, and was not made for sale. The build quality shows this. Part cost / labor would be over $700 alone. The entire case / heat sink was made from scratch with real metal. The circuit board is nearly identical to the commercial version (PCB was limited and no longer available). The builder carefully made it according to Pass' DIY notes.

There are two additional modifications done for using with balanced headphones (I can include an banana to 4pin XLR adapter if you need):
1) a volume pot (IIRC, it is a RK27)
2) a ground loop breaker to kill noise. It totally eliminates noise in my 2 headphone settings: iPhone -> Objective 2 -> F2 -> LCD-2s and PreSonus Central Station dac/preamp -> F2 -> LCD-2s
It is still perfect for driving speakers. The sound is neutral with a slight hint of warmth. Not recommended for sensitive headphones as it would be an overkill.

I would not ship unless you can DIY to fix any potential minor damage by shipping (note the amp is 30 lbs). I can not DIY or help you if anything breaks. The original builder would kindly help if you cover shipping/parts/time, but I would avoid to bother him with minor repairs. Local pick up in Houston is welcome. No international shipping.

I paid $750 shipped for this amp. I am looking for $599, not including shipping and paypal fees, if any (shipping with UPS is around $50 within CONUS). Price is firm. Again its commercial version, which is nearly identical besides being prettier, retails for over $1800.

Shipping weight is 40 lbs. The box dimension is 21.00" x 19.00" x 16.00" (or 52 cm X 47 cm X 38 cm). Shipping cost was around $50 in Aug 2011. So I will charge $50 for shipping. If it cost less I will refund the difference; if it cost more I will cover the difference from my pocket. So total is $599 + 3% paypal fee + $50 shipping = $667.

I will pack the amp very well with foam all over (I shipped a heavier tube amp before, which got to the buyer 100% functional and intact). I am a bit of OCD when it comes to shipping so don't worry. Should not be a problem as all solder points have been re-checked and strengthened by the builder.
I am a well established Headfier with 62 positive feedback at Headfi (100% positive). I have lots of EBay feedback as well (100% positive), under user name zzffnn. I can be reached at zzffnn at hotmail dot com

My new feedbacks can be found here
http://www.head-fi.org/Eclassifieds/feedback/index/user_id/126562

Old feedbacks here:
zzffnn



Sorry I am very busy dad, so the following PM's will be respectfully ignored.

1) low ball offer
2) Non-Local buyer who can not DIY to fix potential shipping damage


PS: I would consider some partial trades (plus paypal) with ONLY the following items:


1) A Synology NAS DS-212j
2) A few 64GB micrSDXC cards
3) One or two 1-2TB SATA hard drives.
4) A set of Kleer wireless transmitter/receiver for Sleek earphones (e.g., SA6s or CT6s).
5) Maybe a set of Vsonic GR-07 or Panasonic HJE900, if the price is right.
6) One or two Sansa Clip+

Please note this F2 is NOT your average amp cloned by Tim Rawson by the way, although my offering price may be even lower than Rawson's. Rawson built for sale, while this F2 was built by an experienced DIY'er for his own enjoyment. This F2 uses the original PCB circuit design, while Rawson does not. Also Rawson's soldering and wiring is questionable at best. Experienced DIY'ers all know that Rawson is not well regarded in any DIY forums. I don't DIY, but I know that much to stay away from any Rawson's clone.

Thank you and have a great day.

Edit: I would like to edit the title to " DIY cloned FirstWatt F2 speaker amp" but can not edit title, so I leave it here

Click the image to open in full size.Click the image to open in full size.Click the image to open in full size.Click the image to open in full size.Click the image to open in full size.

Last edited by zzffnn; 24th August 2012 at 06:21 PM. Reason: corrected typo "usally". also attempted to edit thread title.
 
Old 23rd August 2012, 10:02 PM   #2
zzffnn is offline zzffnn  United States
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Somehow I can not see the photos I posted. Please refer to my Headfi thread for photos:
DIY FirstWatt F2 speaker amp-Perfect for XLR'ed K1000s, HE-6s or LCD-2s

Or simply email me at zzffnn at hotmail dot com

Thanks.
 
Old 24th August 2012, 12:35 AM   #3
john65b is offline john65b  United States
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With all due respect, I do not think you will find much interest on DIYAudio for a Rawson built Pass Amp. Do a site wide search and I think you will understand why.

Maybe a peek here -

F3 on ebay at $750GBP

Be good.
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Last edited by john65b; 24th August 2012 at 12:46 AM.
 
Old 24th August 2012, 01:53 AM   #4
zzffnn is offline zzffnn  United States
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I understood that Rawson-built clones are bad and illegal. What I am listing here was not built by Rawson. It was a DIY by a experienced member for himself.

I was merely saying that, look, my F2 was built much better, and is being listed for cheap.
 
Old 24th August 2012, 01:58 AM   #5
zzffnn is offline zzffnn  United States
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Or Are you suggest that I should use another name for the amp, instead of FirstWatt? Please suggest what to sue. I apologize as I did not know this. But again, it was not built by Rawson and not for profit. My F2 does have some custom work done, including ground loop breaker and RK27 volume pot, for headphone use.
 
Old 24th August 2012, 07:30 AM   #6
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I think your description and naming of this amp would pass muster with Mr. Pass, he actually stated in that post referred to above he does not mind the use of the series number (F1,2,etc) when it is combined with "clone"....in your case "DIY" is used which, in my mind, implies it is a Clone....just my two cents.
You clearly state it is not a Rawson built amp so I do not follow John65b's remarks as relevent to your ad.
If I wasn't gear heavy right now I would buy it at your price.....
 
Old 24th August 2012, 12:41 PM   #7
zzffnn is offline zzffnn  United States
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Thank you jmillerdoc.

You have to hold this amp in your hands to understand why I said it was built with love, not for profit.

The circuit board is identical to the commercial one,
soldering is clean and has been strengthened for shipping,
the entire enclosure and heat sink is DIY made of thick metal (hence 30lbs), and the builder has lots of DIY experience (for reference, this builder has made a F1 clone and >2 Beta22 amps).

Actually the builder did not even advertise for this amp, I was talking with him about going beyond Beta22, he said that he prefers F1 to Beta22 and F2. Then few days later this 30lb monster landed in my house.


If I do not have a 2 yr old running around a small house, I would have kept this lovely amp.
 
Old 24th August 2012, 04:39 PM   #8
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Is this one of the amps that has no voltage gain, just current? What type of power output does it have? I am completing a very nice build of an SE45 (solid silver secondaries from Electraprint) and have heard of using it in conjunction with one of the Pass amps that only has current gain....is this the one?
 
Old 24th August 2012, 05:05 PM   #9
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Quote:
Originally Posted by jmillerdoc View Post
Is this one of the amps that has no voltage gain, just current? What type of power output does it have? I am completing a very nice build of an SE45 (solid silver secondaries from Electraprint) and have heard of using it in conjunction with one of the Pass amps that only has current gain....is this the one?

Jeff: There are several First Watt amps that are current buffers, the F2 being one of them. The F4 also is a current amp (no voltage gain), and it appears that there are a few others.

http://firstwatt.com/pdf/prod_f2_man.pdf

FIRST WATT PRODUCTS
 
Old 24th August 2012, 05:15 PM   #10
zzffnn is offline zzffnn  United States
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Dear jmillerdoc,

Sorry I do not have enough knowledge to answer your questions. You would be better off to find the actual circuit drawing. I searched but could not find one.

Based on what I read (which I can not understand completely, being a Biology major), F2 has no voltage gain, just current gain. F1 is also a current source amp. I saw MOSFET in the F2, which could be the output device. Mr. Pass said in the F2 manual that it is a pure class A amp.
 

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