I would like to start on an F1J and assume I need appropriate board to do so. Is it possible to strait wire it without killing myself or seeing the magic smoke. I like the simplicity of some of the Peter Daniel amps. I am really looking forward to building my first amp and its nice to know there are people on this forum who tinker with these sort of things. 
Point-to-point wiring works great - just takes a little more
patience. Mine always look like train wrecks, but they run...
Spaghetti bowl is perhaps more accurate. Train wrecks tend to larger.
Mr pass you hvae truly made my day. I just read the F2 and F2J articles and i am stumped as to wich of the two i should build for my soon to be built full range speakers. It sounds like the F2 is the same type of amp with a slighlty somother/warmer tube like sound. Is this true or am i missing something? So many difficult choices. I love it!
What's up bill. Board making seems much more intimidating to me than this other stuff. I haven't really looked into it. Pcb's are so readily available it doesn't seem worth the trouble, but who knows. My long term plan is to build an F1J or F2J with a fullrange setup like the metronome, and an F5 with a speaker like the one we have been talking about. The F5 is easier to get ones hands on component wise, so I may have to start there and just see how the Metronome's sound with it. I will probably build the Metronome's first because the cost is less.
You have got it. I enjoyed the F2, but the F2 j-fet is definitely a favorite of mine. If you can source the j-fets, I would highly recommend this.
The J versions are upgrades and in the SWAP MEET section there are some for sale. I need to buy a pair in the near future as well.
http://www.diyaudio.com/forums/swap-meet/161455-pre-order-semisouth-sic-jfets-check-out-price.html
http://www.diyaudio.com/forums/swap-meet/161455-pre-order-semisouth-sic-jfets-check-out-price.html
Zhou have later thread about these ;
they're also much cheaper than in pre-order moment
http://www.diyaudio.com/forums/vendors-bazaar/164271-semisouth-sic-jfet-16-pc-shipping-now.html
they're also much cheaper than in pre-order moment
http://www.diyaudio.com/forums/vendors-bazaar/164271-semisouth-sic-jfet-16-pc-shipping-now.html
I am trying to decide, hehehe, which Pass amp to build for my system. I will be building a full range speaker with either Fostex 166en/206en, or suitable enclosure for alpair 10.2. Would love to go Lowther but insufficient $$$ considering all i want to do. I was looking to the F1 or F2 for the Fostex with F2 being favorite. i was thinking F5 for the Alpair because of lower efficiency. Any recommendations or advice? Will you help with value changes of components if go with F2J.
J adjustments
Here are the necessary changes to the original F2 circuitry:
The F2's that I have updated with the JFETs need the
following changes:
R6 = 47k
C1 = 10 uF
Z1 removed
The potentiometer must be re-adjusted for minimum
distortion at 4.5 watts (symmetric clipping) and readjusted
after an hour.
The distortion results are typically a reduction from about 1%
at 1 watt to .25%.
You can find this on p33 of the F2 clone thread:
http://www.diyaudio.com/forums/pass-labs/91168-diy-f2-clone-33.html#post2094956
Here are the necessary changes to the original F2 circuitry:
The F2's that I have updated with the JFETs need the
following changes:
R6 = 47k
C1 = 10 uF
Z1 removed
The potentiometer must be re-adjusted for minimum
distortion at 4.5 watts (symmetric clipping) and readjusted
after an hour.
The distortion results are typically a reduction from about 1%
at 1 watt to .25%.
You can find this on p33 of the F2 clone thread:
http://www.diyaudio.com/forums/pass-labs/91168-diy-f2-clone-33.html#post2094956
I happened upon this article while investigating the possibility of an OB speaker using fullrange driver plus a woofer.
The First Watt Model F1 Current Drive Power Amplifier Review By Dick Olsher
Although he is using his woofer in a box and not OB style, he seems to be saying that he was driving it with the F1. Is that possible? We are talking about a 600w RMS woofer. Also, how would this speaker respond to being current driven?
Alpair 12 Driver | Markaudio
The First Watt Model F1 Current Drive Power Amplifier Review By Dick Olsher
Although he is using his woofer in a box and not OB style, he seems to be saying that he was driving it with the F1. Is that possible? We are talking about a 600w RMS woofer. Also, how would this speaker respond to being current driven?
Alpair 12 Driver | Markaudio
I drove a woofer with an F2 way back, my first foray into Pass DIY, based on the Basszilla and Open Baffle stuff.
Sure worked. The speaker is 98db 1/watt, so it's going to produce noise. It's just going really loud will get your to distortion quicker.
The F2 I recommend wiring Point to Point. Easy wire up for begineers, cap on output, no offset, safe amp. Only concern is to keep those 1R resistors plenty of air, they cook!
Adding the JFet and parts changes, it's a lot 'cleaner' sounding, with sweet sounding mids and treble, compared to IRF240 output.
I have not wired up an F1J yet, but Generg user likes it. My guess is the F2J might sound a bit tamer, but only a guess.
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