Depending on LED and intensity you will like. A 3K will yeild arround 8 mA. Its more a trial and error selection. You may want to test it with a pot to select a fix R.
BTW, those three boards just look marvelous, very nice work Steen😎 😎 😎
Eagerly waiting your test drive and reaction.
BTW, those three boards just look marvelous, very nice work Steen😎 😎 😎
Eagerly waiting your test drive and reaction.
Tony, that wont be long now😉 I will make the F2 this weekend, in another chassis, and hopefully get some boxes for the Corals finished too🙂 I intend to move the F2 into the other "casa" when they are ready🙂 Thanks for all😉
Steen😎
Tony, what do think is the best preamp for the F2? I am building the Bride of Zen to drive it😉 Considering all the input/output impedance kind of thing, is the Bride the best??
Steen😎
I had hoped NP would answer that😀
Steen😎
I had hoped NP would answer that😀
Member
Joined 2002
steenoe said:
Free is good 😀 I paid 100$ us for all 6 of mine 😀 illbe ordering more too. i need some.. i'm working on new mini a's SMD amp's
steenoe said:
That's a very personal question Steen, a matter of taste or synergy?As far as impedance to the amp I guess most preamps will do. Any pre having no more than about 2K output impedance should do a good job. The only concern is the input capacitance of the FET.
BOSOZ and other Pass type pre is kind of a shotgun that will drive most any load in my humble opinion.
Now personally I would prefer a tube type for this amp, my pick would be a well implemented Euridice. But for the time being I will drive it with my pet 417A.
😀
Thanks for the reply, Tony. I will just try the F2 with the 4 different preamps I have at the moment. None of them are with tubes, though. Maybe I should pay some more attention to the "Grounded grid" thread? Seems like there will be a GB.
Steen🙂
PS I didn't mean it in the taste/preference way, when asking for advice on preamp. I was just wondering if there were some special requierments for output impedance and so on
Steen🙂
PS I didn't mean it in the taste/preference way, when asking for advice on preamp. I was just wondering if there were some special requierments for output impedance and so on
steenoe said:
PS I didn't mean it in the taste/preference way, when asking for advice on preamp. I was just wondering if there were some special requierments for output impedance and so on
BOZ, NS10 or Choky's WOT (Euridice-if you wish
)with tubes you need that OPT to preserve speed at heavy loads ; I love tubes,but that's naked truth ,at least for me.
choky said:
BOZ, NS10 or Choky's WOT (Euridice-if you wish
with tubes you need that OPT to preserve speed at heavy loads ; I love tubes,but that's naked truth ,at least for me.
NS10 did also cross my mind but did not mention it.
If someone will clone the NS10 I will be interested.
Did you see this thread? Yes that NS10, is tempting😉
http://www.diyaudio.com/forums/showthread.php?s=&threadid=26003&perpage=10&pagenumber=1
Steen🙂
Edit, just saw you did, as I reached page 4😀
steenoe said:
Simple and tempting but needs care on implementation and component selection for an excellent clone. I saw some Naim upgrades using Zetex transistors, could be a good choice.😎
Naim pres always had Zetex transistors only. I have not seen any exception - maybe very old prototypes or the last generation (where you cannot look under the thermo-cap.
Finally I managed to finish the F2-clone. Its been up and running for a few days now and everything seems to work properly🙂 I have done a lot of listening the last few days😎 Let me tell you right away, that the amp sounds great😎 Also its the biggest 5 watt'er I ever had. I only have a pair of Coral Flat6-II to hook on to it and the F2 clone is absolutely enjoyable with those.
The sound is very, very pleasant indeed. When I hook up one of my "normal" amps to compare, it takes less than 1 song to get back to the F2 clone🙂 Its a dualmono amp with 2 500VA 2x25V trafos. The rectifiers are Stealth diodes, followed by 100.000uF Rifa's and some big Siemens MKV polyprops. (Just because I had 2 of those). Otherwise the circuit is built as Apassgears schematic and also on his boards, Thanks Tony🙂 The only change is that I used a 1M trimpot for R4 and had to use bigger wattage R13 which is 2 pcs 0,47r, 7 watts in series. You might get away with 2 pcs 5 watts but it runs hot. The amp is totally quiet, and the turn on thump is not worth to mention, on the Corals at least.
I dont think the Corals Bass reflex's I have, are good enough for this amp and I would love to hook it up to something better. I am sure it would do just great, comparing how it sounds with those old speakers. I can listen to them all night😉 For now, I am looking forward to see the Service manual if it is put up on Firstwatt.com sometime. Just to see how close we got🙂
Here is a pic🙂
Steen😎
The sound is very, very pleasant indeed. When I hook up one of my "normal" amps to compare, it takes less than 1 song to get back to the F2 clone🙂 Its a dualmono amp with 2 500VA 2x25V trafos. The rectifiers are Stealth diodes, followed by 100.000uF Rifa's and some big Siemens MKV polyprops. (Just because I had 2 of those). Otherwise the circuit is built as Apassgears schematic and also on his boards, Thanks Tony🙂 The only change is that I used a 1M trimpot for R4 and had to use bigger wattage R13 which is 2 pcs 0,47r, 7 watts in series. You might get away with 2 pcs 5 watts but it runs hot. The amp is totally quiet, and the turn on thump is not worth to mention, on the Corals at least.
I dont think the Corals Bass reflex's I have, are good enough for this amp and I would love to hook it up to something better. I am sure it would do just great, comparing how it sounds with those old speakers. I can listen to them all night😉 For now, I am looking forward to see the Service manual if it is put up on Firstwatt.com sometime. Just to see how close we got🙂
Here is a pic🙂
Steen😎
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Stunning Amp Steen 😎 😎 😎
2x 100mf and 2x 500 VA, double mono, regulated supply, no feedback, my God, sure enough should sound as one of the best current source amps around.
Of course credit has to be given to NP for this design and sharing of details to build this F2 clone, thank you Nelson.
How about hooking the F2 with Nelson’s NS10? 😀
Beautiful work Steen you make me jealous in the good sense of the word. 🙂
2x 100mf and 2x 500 VA, double mono, regulated supply, no feedback, my God, sure enough should sound as one of the best current source amps around.
Of course credit has to be given to NP for this design and sharing of details to build this F2 clone, thank you Nelson.
How about hooking the F2 with Nelson’s NS10? 😀
Beautiful work Steen you make me jealous in the good sense of the word. 🙂
Thanks alot JH🙂 Its a club worth being a member of😉
Thank you Tony. I didnt want to skimp on anything🙂 I am really impressed about the way this amp plays music! I better invest in a pair of Lowthers😀 Those 5 watts does a great job, indeed. I have used the NS10 clone a lot and also a plain BoZ. Both preamps does it just nicely with this amp. I would have thought that the NS10 maybe wasnt the greatest thing for this amp, but I was wrong🙂 It sounds really great and drives the amp with ease😉
Yep you are right, a great thank you to Nelson Pass, for dropping those breadcrumps along the roadside😉 Now I really understand what you were talking about, with these current source amps 😎 I wonder how close this is to a real F2😀
Steen😎
Ps. I better weigh this amp, I am sure its over 40kg's 😀 Talk about a big 5 watt'er😀
Ps Ps Just in case you were in doubt, here are the blue headlights😀 😀
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steenoe said:
Closer than you may think, to put it mildly. A diy amp can be done (as yours) with no cost concerns. 😀 😀 😀
The best is yet to come, give it some more hours of burn-in 😉
I dont know what to do if it gets better than this😀
Here is one more pic, where you can see the board a bit better😀
Both boards works like a dream😉 If you want to update the schematic, you have to increase the value of R4. I think mine are adjusted to about 6-700K. And increase the wattage of R13 to 10watt's, they really runs hot
Steen🙂
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Hi Steen ,
very , very nice work !!
maybe i have a plan for a encloure for the corals
Enjoy the music !
Jürgen
very , very nice work !!
maybe i have a plan for a encloure for the corals
Enjoy the music !
Jürgen
Thanks a lot, Jurgen🙂
I would like to see those plans for the Corals. Feel free to mail them or post here😉 I am sure that these bass reflex boxes are not the optimum conditions for those drivers. I am considering several options after having heard this amp; either a Voight pipe for the Corals, or investing in a new pair of drivers and build some new boxes for them. Horns or mass loaded quarter wave?
Steen🙂
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