Imo, based upon what has been heard here on not my amp, but one that has had a range of different things tried on it, including PS arrangements and parts, various resistors and dorking with the way power is fed to the front end, wire and other parts - it is pretty easy to make the F5 go from somewhat dull and mushy to ultra clean and sparkly. This is with the same Fairchild outputs. The Tosh's have yet to be tried, and also this is without the limiters and with the thermistors (iirc)... also the bias seems to effect it as well.
All in all, a fine juggling act, on the highwire, while standing on one foot... ymmv.
_-_-bear
All in all, a fine juggling act, on the highwire, while standing on one foot... ymmv.
_-_-bear
Well,just removed limiters and thermistors,NOW it's on a bright side,ultra clean and dynamic,because i removed -3db lpad from tweeter during previous tests...I'm sure when i put back that resistor ,system will be balanced,VERY detailed and analytical.I guess this is the true F5. Will try toshibas some day...
Oh and biasing... i remember Nelson said-you have to find sweet spot,otherwise it can be fat (bass) ,i feel that it fatens just crossed over 1.3A i think,will need to play a little more.
Oh and biasing... i remember Nelson said-you have to find sweet spot,otherwise it can be fat (bass) ,i feel that it fatens just crossed over 1.3A i think,will need to play a little more.
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I know and that was kinda what I was referring to. But it seems like the crowd wants a step by step recipe...
Very interesting , fix this , change that , bias up , bias down , resistor left , resistor right , thermistors in thermistors out, sound good, sound bad , plenty highs , no highs , i will help a little , go figure out a lot , yaddy, yada
Nothing like being born with complete F5 knowledge ..........
I agree with EUVL, I was just being sarcastic. Modifying a schematics is not a simple thing and you need to know kinda what you are doing, but if you don't you'll just need to learn a lot more.
This forum has people from the whole spectrum from newbies to seasoned electronics veterans, so we end up with this problem all the time. If you don't want to learn, then don't expect be able to replicate EUVL's results. It requires trial and error to tune a circuit, so if you don't want to do that, then stick to the mainstream designs. The stock F5 is great and I am sure that most unsuccessful variations documented here are due to execution rather than the circuit itself.
This forum has people from the whole spectrum from newbies to seasoned electronics veterans, so we end up with this problem all the time. If you don't want to learn, then don't expect be able to replicate EUVL's results. It requires trial and error to tune a circuit, so if you don't want to do that, then stick to the mainstream designs. The stock F5 is great and I am sure that most unsuccessful variations documented here are due to execution rather than the circuit itself.
i'm not so long here,but i guess i've never seen and i hope will never see Nelson post like
-dig it yourself!
With that kind of approach,Pass thread would never born here...Because without Nelson support none F5 were built with errors or without.
I would understand "dig it yourself" only by comercial interests.Which,sadly, are very usual here
BTW i respect authors rights,like EUVL.I would never request PCB or something from him.And I've seen its balanced schematics.So he shares it ,but refuses to share (teach) info about how it works? Is it so hard? Meaning he is typing DIY already and we all DIY one way or another...
At last,why do i buy Toshibas and tried them first? Well my bad...
Peace
-dig it yourself!
With that kind of approach,Pass thread would never born here...Because without Nelson support none F5 were built with errors or without.
I would understand "dig it yourself" only by comercial interests.Which,sadly, are very usual here
BTW i respect authors rights,like EUVL.I would never request PCB or something from him.And I've seen its balanced schematics.So he shares it ,but refuses to share (teach) info about how it works? Is it so hard? Meaning he is typing DIY already and we all DIY one way or another...
At last,why do i buy Toshibas and tried them first? Well my bad...
Peace
a) There is a difference between DIY and dig it yourself.
b) The changes required for the Toshibas have been explained in details years ago.
If you are too lazy to search the F5 thread, then don't blame me for not willing to repeat.
There are people who have built the X-version without asking me one question, and are fully happy with the results.
Again that is fully documented in the F5 thread.
I don't owe anyone to publish or explain anything.
People just take things for granted and not even be grateful.
I have better thing to do. Good night.
Patrick
b) The changes required for the Toshibas have been explained in details years ago.
If you are too lazy to search the F5 thread, then don't blame me for not willing to repeat.
There are people who have built the X-version without asking me one question, and are fully happy with the results.
Again that is fully documented in the F5 thread.
I don't owe anyone to publish or explain anything.
People just take things for granted and not even be grateful.
I have better thing to do. Good night.
Patrick
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Since I started this thread, perhaps I can be of help here... the thrust of this thread is two things: how the F5 sounds, and what changes or differences in the circuit or parts may be effecting the sound.
Mostly, the how-to-build and what the circuit elements do, as well as how to use different brand output Mosfets is discussed in some detail in the original F5 thread.
There was a lengthy discussion on the balanced (X5?) as Patrick said, some time ago, but not in this thread - I think in the original F5 thread. It's worth reading.
After that, if you still have questions there are two good choices:
- post a specific question, cite the exact schematic (the post number)
- privately PM or email an appropriate member who might be able to help you
For some readers the schematic is self-explanatory, for others it gets the idea across, and for many it requires additional reading, exploration and maybe even the use of a "SPICE" type simulator to see what does what... or maybe even building the circuit breadboard style...
markofka, you might not realize it, but in a long and complex thread like this one (and the main F5 thread) many contributors do not want to keep repeating the same things over and over, and readers who have spent the time to search or read the threads also do not want to go back over things that have already been discussed in detail.
So maybe if specific questions were asked in the appropriate thread, or maybe even in a new thread were posted you might get back useful information?
Btw, did you read the original article on the F5 on the First Watt site?? That explains a lot of how the basic circuit operates - which includes how the bias is generated - important to your question about the Toshiba devices.
_-_-bear
Mostly, the how-to-build and what the circuit elements do, as well as how to use different brand output Mosfets is discussed in some detail in the original F5 thread.
There was a lengthy discussion on the balanced (X5?) as Patrick said, some time ago, but not in this thread - I think in the original F5 thread. It's worth reading.
After that, if you still have questions there are two good choices:
- post a specific question, cite the exact schematic (the post number)
- privately PM or email an appropriate member who might be able to help you
For some readers the schematic is self-explanatory, for others it gets the idea across, and for many it requires additional reading, exploration and maybe even the use of a "SPICE" type simulator to see what does what... or maybe even building the circuit breadboard style...
markofka, you might not realize it, but in a long and complex thread like this one (and the main F5 thread) many contributors do not want to keep repeating the same things over and over, and readers who have spent the time to search or read the threads also do not want to go back over things that have already been discussed in detail.
So maybe if specific questions were asked in the appropriate thread, or maybe even in a new thread were posted you might get back useful information?
Btw, did you read the original article on the F5 on the First Watt site?? That explains a lot of how the basic circuit operates - which includes how the bias is generated - important to your question about the Toshiba devices.
_-_-bear
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Hello Cvillier ,
Completly understand , it's very difficult to be answering the same question over and over , when the answer is right there in the F5 thread , If only these lazy bastards would peruse all 50, 000 pages they would know that ...
Enhanced Print View helped me alot with this 50.000 pages! Plus ctrl-F
Hi,
Perhaps it is the recording that is at fault if things sound worse with improved resolution. I've found that good recordings sound even better while others are revealed as flawed.
Hi,
For those wondering about the 2SJ201/2SK1530's should look at EUVL's post#6503 in the main F5 thread.
Key points in case you are too lazy to look
To reduce Idss of the 2SJ74 JFet (Q2), increase the source resistor R2 from 10 to perhaps 15. To maintain a 1:5 ratio for R2 and feedback resistors (R6&R8) to 150ohm each or if using single resistor, 75R.
In Patrick's schematic of the F5-X he also altered the source resistors from 0.47ohm to 0.18 (R11 in single ended/NP version) and 0.22 (R12)
I've completed one channel with no value alterations and it works plenty fine
For those wondering about the 2SJ201/2SK1530's should look at EUVL's post#6503 in the main F5 thread.
Key points in case you are too lazy to look
To reduce Idss of the 2SJ74 JFet (Q2), increase the source resistor R2 from 10 to perhaps 15. To maintain a 1:5 ratio for R2 and feedback resistors (R6&R8) to 150ohm each or if using single resistor, 75R.
In Patrick's schematic of the F5-X he also altered the source resistors from 0.47ohm to 0.18 (R11 in single ended/NP version) and 0.22 (R12)
I've completed one channel with no value alterations and it works plenty fine
My friend tried different variations of F5(with fairchild irf and toshiba).He uses 25cm speakers.He noticed that 2sk1530/2sj201 sounds more balanced but a bit more loud and improper in bass.He uses single ended mode not balanced.I offered him to increase drain resistor of 2sj74 to 13ohms and increase feedback resistor to 75ohm total.He says Irf devices has magic in treble but toshibas does not.I do not know.He will listen 2 more days and decide what to do.
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Who played with feedback resistors? How it will affect SQ?
Meaning by increasing FB resistors gives = less feedback+more gain and a bit more distortion -answer is quite clear,but i really do not like to throw a lot of heat in the air since i use "standart" 2V cd player so additional gain would be usefull...
As i understood from EUVL tips for a start 75ohm wont be hurt
Meaning by increasing FB resistors gives = less feedback+more gain and a bit more distortion -answer is quite clear,but i really do not like to throw a lot of heat in the air since i use "standart" 2V cd player so additional gain would be usefull...
As i understood from EUVL tips for a start 75ohm wont be hurt
So F5 has 10 and 50 ohm at R2+R6. By formula R/R+1 we get F5 amplifies 6times.This time i just cut 2 of 4 100ohm resistors. This "extreme" way i get 11x amplifiing which are more than enough with my 2V standart player.Definately a party amp now.
As we increase feedback resistors,we get less feedback ,MORE distortion,less damping,more gain.I think Every one definately needs to play more with these values,depending on source,speakers,needs. I guess i try to decrease it a little.
Cant say how it plays as its playing only couple of minutes...
This is some kind of modification which frees those who have "hard" speakers or who dont want to build aditional preamp which is not neutral usual too...
As we increase feedback resistors,we get less feedback ,MORE distortion,less damping,more gain.I think Every one definately needs to play more with these values,depending on source,speakers,needs. I guess i try to decrease it a little.
Cant say how it plays as its playing only couple of minutes...
This is some kind of modification which frees those who have "hard" speakers or who dont want to build aditional preamp which is not neutral usual too...
the standard F5 with a gain of 6times needs ~2.45Vac to drive it to 27W maximum into 4r0.
Many CDP send a 0dBfs signal of 2.1Vac to 2.3Vac. You don't need a gain of 11times to overload the F5.
Try 150r//100r instead of single 100r for feedback.
You may find that the extra // resistor could be anywhere from 120r to 200r to drive the F5 into voltage clipping.
Many CDP send a 0dBfs signal of 2.1Vac to 2.3Vac. You don't need a gain of 11times to overload the F5.
Try 150r//100r instead of single 100r for feedback.
You may find that the extra // resistor could be anywhere from 120r to 200r to drive the F5 into voltage clipping.
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