| lordvader |
R5 trimmer ? But that'll be for the jfet, and I'm assuming have no impact on the ac current gain ...
I'll have a go with the 3 1ohm resistors first anyway, and if I can't get 50% current gain, then I'll replace the resistor.
I went a bit overboard with the caps and psu :)
The board caps are Nichicon KZ caps, with a jensen 4 pole for the output.
The PSU is dual mono, CLC thang (33000uf, 2.2mH, 33000uf), and should hopefully kick some butt (just better not be mine !). The transformers have dual 18V secondaries, so the voltage should be well within the ballpark.
I've yet to wire this thing up, as I want to finish off my pearl phono preamp first :) |
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| jameshillj |
Don't think the 50% thing is "fixed in stone" - can alter the sound a bit with less/more
May want to try Silmics for C2, C3 and C4 - I have some spares.
And the C9 can be a bit tricky - I'm using Phillips PP + Rifa styrene in series.
The 2.2mH chokes should be great (0.1R?)
All the best - amazing amp |
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| Ryssen |
| I am testing one chanel on my F3 amp.ItŽs playing just fine,but How should I adjust P2??:rolleyes: |
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| Ryssen |
Apart from the above question,..
The 2 channels are playing just fine with my portable flac player.
When connented to my DEQ 2496/DCX2496 I get distortion at low volume.Must be something with ground I think.One channel has 0,7v at input,am I sopposed to take the loadspeaker between +46v and - output?
The LU1014 has 0,6v on source..
Is there a layout/gerber file for the PCB so I can print it out when messauring? |
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| Ryssen |
| Sommething popped up..should the LU1014 be isolated from heatsink?Mine are not.. |
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| Zen Mod |
| quote: | Originally posted by Ryssen
Sommething popped up..should the LU1014 be isolated from heatsink?Mine are not.. |
:bigeyes: |
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| Ryssen |
I guess that surprising smiley means it should be...:clown:
It sounds good with my portable flacplayer..
IŽll isolate them tomorrow...:cool: :)
What about that P2,where to adjust/messaure?:bawling: |
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| Zen Mod |
| quote: | Originally posted by Ryssen
I guess that surprising smiley means it should be...:clown:
It sounds good with my portable flacplayer..
IŽll isolate them tomorrow...:cool: :)
What about that P2,where to adjust/messaure?:bawling: |
first thing first ; isolate them ........ |
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| Ryssen |
| quote: | | first thing first ; isolate them ........ |
Okay,that did it,plays fine after the DEQ2496,but a little low sensitivity,compared to my Symasym,cannot maXimaZe the F3.
I guess I could make a prestage with a 2sk389 in F3,thouts?
Anyway P1 is adjusted for half V+ at Q2,now what about P2?
IŽll throw in some pics later.. |
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| CeeVee |
Hi Ryssen,
What speakers are you using ?
F3 need sensitive speakers.
I've got an F3 and Symasym nearing completion but they are on the back burner until i finish my UGS preamp. |
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| Ryssen |
At the moment this cheap ones,they are 92db so theę are quite sensitive
http://www.xtz.se/produkt.php?allmant=true&produkt=49
until I finnish my diy speakers...
It is on the input I cannot maximize the F3,my DCx sends out max 4v and its no enough for the F3,at least not mine..:rolleyes: |
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| Ryssen |
Notice the small Symasym..;)
F3 needs an extra gainstage,if I can found a schema with jfets..
A schema with 1-2 fets are welcome..with + and - supply..Or should I go single supply as F3 is singlesupply??
And P2 still not adjusted..:rolleyes:
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| jameshillj |
Ryssen,
Sometimes things don't go according to plan (!) but with a 1v input, the amp should put out the equivalent of about 15W into 8R speakers (about 1.5Amps) which should be enough provided all things are assembled correctly, and you're not using one of those complicated big loss passive crossovers - remember, this amp doesn't require a speaker to have a "flat Z" (constant load) to function properly.
A possible source of trouble may be the amplifier's low input impedance that can sometimes cause the signal source such as a CD player to not deliver full output, and the addition of a simple buffer to the amp's input will solve this, such as the one described in Nelson's B1 project (on the First Watt site)
I would also check that your Jfets have survived the "chassis connection" - all the info that you require is on the F3 manual or on this thread - it's not a complicated amp if you go about in a systematic way and if I remember correctly, the R0 Cct diagram contains the various cct voltages to check that all is functioning correctly and especially around the Jfet.
The speakers are connected to the amps output and the 0Volt (or central ground point) as usual, except the terminals are marked in reverse - it's a current gain amp
At low levels, this amp is excellent, particularly as you've added the choke into the power supply - I have used the amp to drive my AKG701 headphones (64R load) with excellent results with very soft and occassionally extremely loud volumes. No problems.
Hope this may be useful ... |
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| Ryssen |
| quote: | | A possible source of trouble may be the amplifier's low input impedance that can sometimes cause the signal source such as a CD player to not deliver full output, and the addition of a simple buffer to the amp's input will solve this |
That might be the case,I willtry to connect my brute force tube pre inbeetwen and se how it goes.My portable flacplayer can drive it from the eaphones jack.
| quote: | | I would also check that your Jfets have survived the "chassis connection" |
Yes they did,but 1 Q2 died,so its replaced.
I have not seen anywhere how to set up P2,maybee iŽll read it again.
Edit:with the tube stage it plays loud as it should without dist.
Guess I have to carry the oscilloscope dowstairs to se how much signal it neds.. |
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| Ryssen |
My "brute force" tube head/prestage must output 10-12v P-P before F3 beginns to dist so I can hear the dist.
So a 3-4 amplification is neded.
Any one can suggest a simple,good one with jfet? |
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| Ryssen |
tested with my tube preamp and it works okay.
So I will implement the JiSbOS with some gain..3-4 times gain.:) |
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| Zen Mod |
| quote: | Originally posted by Ryssen
tested with my tube preamp and it works okay.
So I will implement the JiSbOS with some gain..3-4 times gain.:) |
combine Jfet BOZ and B1 ............ |
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| Ryssen |
| quote: | | combine Jfet BOZ and B1 ............ |
Ehummm,your putting me on deep water there...
My skills is the limiting factor..
Original the JISBOS is a buffer,I just have to change 1 resistor to get some gain. |
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| Zen Mod |
| quote: | Originally posted by Ryssen
Ehummm,your putting me on deep water there...
My skills is the limiting factor..
Original the JISBOS is a buffer,I just have to change 1 resistor to get some gain. |
point me to JISBOS ..... ? |
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| Ryssen |
Hmm,yes he did..
Is it R6/R1+1=gain? |
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| Zen Mod |
| quote: | Originally posted by Ryssen
Hmm,yes he did..
Is it R6/R1+1=gain? |
:clown:
it's already written pretty clear ....... |
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| Ryssen |
| quote: | | it's already written pretty clear ....... |
Yes...;)
BTW maybee the JIABOS is a litte overkill with its TO220 output transistors as preamp? |
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| chrismercurio |
I admit to not reading the entire thread.
Are there any F3 boards left?
Thank you,
Chris |
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| chrismercurio |
Okay. No reply....so I read the whole thread.
I will post a WTB in the "Trading Post".
Chris |
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| Ryssen |
| Got it right after changing one jfet and one mosfet,but still it neads at least 2 more gain for the DCX to drive it to the max.There a guy in Sweden working on it.(Ludo,thanks) |
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| lordvader |
It's alive !!!
I finshed the assembly this evening, and fired the sucker up !!!
I was petrified ! Worried that I'll blow my speakers. Worried that I'd missed something and see the thing go up in smoke. Worried that it'll be a hum machine, or noise noise noise.
None of that :)
I turned it on, no hum ! Attached a preamp, and turned it to max, no noise !!!
Attached a source (after lowering the volume :) ), and music !!!!!
I was ecstatic ! I've spent probably a year or so collecting parts for this thing. Three months or more building it (baby steps, didn't want to rush this one !), and it all paid off !!!
Pictures to come (in my haste, there are no photos of it dissassembled), but I've still got to drill and attach the front panel (10mm alumminium !).
:D :D :D :D :D :D
DIY is ******* awesome !!!!! |
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| Variac |
Congratulations!
Hey you guys, I friend is making an F3/V9 .
He has the Peter V9 circuit board. Is there a parts list cross reference
listing what F3 components replace what V9 component or maybe more clearly expressed , is there a parts list for the F3 with the parts numbered to correspond to the parts on the V9 ?
Or is this true already?
Mark |
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| chrismercurio |
Mark,
How about a source for matched power jFets used in either???
I thought it would be cool to make one of these until I figured out that the transistors were made out of the rare metal unobtanium.
Sometimes I am too late to the party,
Chris |
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| mithomas |
Chris,
Check this out. This guy has 600 PowerJfets.
I have ordered a few. A buck two fifty each. Cheaper than most output tubes.
Maybe enough purchasers, assuming these are the real deal, can convince Peter to make some more boards.:D :D
http://www.diyaudio.com/forums/show...33&goto=newpost
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| jameshillj |
Unfortunately, he doesn't have time to sort them out so we'll have to get bigger numbers for matching. But at only US$2.50 ea, it's quite reasonable.
Makes me really appreciate the extraordinary job that Grey did with the Group buy. |
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| chrismercurio |
It is nice that he has the unobtanium Fet's. I'm going to start a tube amp soon and am redirecting my resources. I bought some efficient speakers so the call of the SET is strong.
Chris |
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| Marsfrogie |
| I would definately buy a couple of boards if he decided to proceed with a production run. |
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| Peter Daniel |
| There is no problem with more boards. If there is enough interest in 50pcs or so, I can run another production, same for F4 and PS boards. |
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| mithomas |
I would be in for Z9, F3 PCB set with power supply.
I would by another stereo set of F4's as well. I fried one channel pretty hard.:hot:
Shall we start another Wiki Page? |
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| Peter Daniel |
| Wiki page could be good idea. Zv9 is basically the same as F3, the latter would be preferred. |
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| mithomas |
I think I may have done this correctly -
Peter , you may want to review the original commentary and edit.
Others may want to add to this list.
We should only cross reference after a few agree that this is presentable and do-able. I would consider adding instructions if I felt more confident about the final visual outcome we want.
Mike
Anyways, here is the Wiki Link.
http://www.diyaudio.com/wiki/index....WattPCBReissues |
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| Variac |
| So Peter, or anyone else that knows- Are the F3 and V9 identical circuits with different value parts? Can I build my V9 boards as F3's with no modifications? |
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| JimT |
I would be interested in 2 F3/ZenV9 boards.
Jim |
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| twitchie |
I noticed that Digikey no longer carries 3W Panasonic (or any other brand) resistors under 10ohms now - has anyone else been able to find a source for the bigger resistors needed to build an F3?
I've been looking at my boards lately but cannot find the ones I need. |
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| chrismercurio |
I haven't looked in the catalog, but there is most likely a Dale/Vishay at Mouser. That's where I bought all the 3w I needed.
There is also Mills from Michael Percy... |
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| JimT |
Thanks for the wiki pointer, I'm in.
Jim |
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| Variac |
| quote: | | Unfortunately, he doesn't have time to sort them out so we'll have to get bigger numbers for matching. |
Do the power JFETs really have to be matched? There is only one per channel, no? |
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| Zen Mod |
| quote: | Originally posted by Variac
Do the power JFETs really have to be matched? ........ |
nope
;) |
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| Peter Daniel |
| I guess people are tempted to match, if they have too many;) |
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| jims |
Peter
For some reason, I can't seem to get to the wiki. Never had problems before. Can you put down for 2 power supply boards and 2 F3 pcbs?
Thanks
JimS |
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| mithomas |
| quote: | Originally posted by jims
Peter
For some reason, I can't seem to get to the wiki. Never had problems before. Can you put down for 2 power supply boards and 2 F3 pcbs?
Thanks
JimS |
Done, this is enough btw to build two amps, four channels.
Current count is 23 F3s, 13 F4's and about 45 PS boards. Not enough for an order yet. |
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| mithomas |
| quote: | Originally posted by twitchie
I noticed that Digikey no longer carries 3W Panasonic (or any other brand) resistors under 10ohms now - has anyone else been able to find a source for the bigger resistors needed to build an F3?
I've been looking at my boards lately but cannot find the ones I need. |
The bubble gum blue resistors are still around at Digikey.
They are listed under Metal Film now, which I think has changed.
P0.47W-3BK-ND
http://search.digikey.com/scripts/D...e=P0.47W-3BK-ND
1 ohmers.
http://search.digikey.com/scripts/D...me=P1.0W-3BK-ND
Happy Soldering. |
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