The "Stock" Balanced F5 lives!
I fired up the "Stock" Balanced F5 channel I built tonight for the first time. I used an 2 x 18V 400 VA toroid, it's what I have for the moment.
I biased it to what I think is 2A (.180V on the 0R18 resistor and .220V on the 0R22 resistor. Is this 1A or 2A?). The heat sink settled at about 28C above room temperature. Biasing was trivially simple. In fact, this channel seemed to like being biased more than the other F5 designs I've experimented with.
Next came the sound test. I played the same two songs for this amp as I did for my Balanced Cascoded F5 (with IRFP outputs). Jet "Are You Gonna Be My Girl" and Professor Longhair "Tipitina". Once again, I was shocked. I have to say, I never really believe one can hear subtle differences on different nights with different equipment, but I heard differences. The Toshiba outputs seemed less edgy on the highs. Both amps are well defined at the top, but the IRFP outputs seem almost "too detailed" if that's possible. The Toshibas were definitely easier to listen to. I can't really say much about the bass. My listening set up is less than ideal at the moment - a single FF85K jury-rigged into a Logitech housing.
Obviously, I'd like to run the side by side "Stock" Balanced F5 vs Balanced Cascoded F5 - both though the Toshiba outputs. I need to modify the cascoded version to use the Toshiba outputs. That should just take a day or so. Then the head to head.
My next real slug of time is going to be spent making my OB speakers. It's impossible to do any substantial testing on my family of F5 amps without better speakers.
While the Toshiba outputs seem promising, I really need to do more critical testing to say which is better (obviously, in my opinion). Also, while I know conventional wisdom is that cascoding the inputs doesn't make a difference, I cannot say what the effect of cascoding is at this point. I need to run the experiment in a more controlled fashion. I also want to run down the differences between Balanced F5 and standard F5 cascoded. I'll test all the permutations against each other.
Finally, I strongly encourage anyone who's been sitting on the sidelines to jump in and build. The build to date has been trivial - essentially its the same as two regular F5s. I used NPs F5 PS design with an 18V 400VA toroid, his CL-60 NTC thermistors, and 72000uf (split 36000 - 36000) in a CRC per channel. So far, there's been no thumps, dimming lights, or hum from the channel - just music. As I said in my other thread, my biggest error to date was waiting to build.
Feel free to PM me if you want my PCB layout (based on Juma's F5) or any other general advice.
I fired up the "Stock" Balanced F5 channel I built tonight for the first time. I used an 2 x 18V 400 VA toroid, it's what I have for the moment.
I biased it to what I think is 2A (.180V on the 0R18 resistor and .220V on the 0R22 resistor. Is this 1A or 2A?). The heat sink settled at about 28C above room temperature. Biasing was trivially simple. In fact, this channel seemed to like being biased more than the other F5 designs I've experimented with.
Next came the sound test. I played the same two songs for this amp as I did for my Balanced Cascoded F5 (with IRFP outputs). Jet "Are You Gonna Be My Girl" and Professor Longhair "Tipitina". Once again, I was shocked. I have to say, I never really believe one can hear subtle differences on different nights with different equipment, but I heard differences. The Toshiba outputs seemed less edgy on the highs. Both amps are well defined at the top, but the IRFP outputs seem almost "too detailed" if that's possible. The Toshibas were definitely easier to listen to. I can't really say much about the bass. My listening set up is less than ideal at the moment - a single FF85K jury-rigged into a Logitech housing.
Obviously, I'd like to run the side by side "Stock" Balanced F5 vs Balanced Cascoded F5 - both though the Toshiba outputs. I need to modify the cascoded version to use the Toshiba outputs. That should just take a day or so. Then the head to head.
My next real slug of time is going to be spent making my OB speakers. It's impossible to do any substantial testing on my family of F5 amps without better speakers.
While the Toshiba outputs seem promising, I really need to do more critical testing to say which is better (obviously, in my opinion). Also, while I know conventional wisdom is that cascoding the inputs doesn't make a difference, I cannot say what the effect of cascoding is at this point. I need to run the experiment in a more controlled fashion. I also want to run down the differences between Balanced F5 and standard F5 cascoded. I'll test all the permutations against each other.
Finally, I strongly encourage anyone who's been sitting on the sidelines to jump in and build. The build to date has been trivial - essentially its the same as two regular F5s. I used NPs F5 PS design with an 18V 400VA toroid, his CL-60 NTC thermistors, and 72000uf (split 36000 - 36000) in a CRC per channel. So far, there's been no thumps, dimming lights, or hum from the channel - just music. As I said in my other thread, my biggest error to date was waiting to build.
Feel free to PM me if you want my PCB layout (based on Juma's F5) or any other general advice.
Nice work. It is great to see some fearless amplifier building as Nelson would say.
I would not say cascoding the input does not make a difference, but whether or not you can hear the difference is a different story. It will also depend on how you implement the cascode eg voltages across jfets and current running through jfet etc.
The main reason for cascoding the F5 was to allow the use of voltages above 30V.
By the way check out my open baffle
I would not say cascoding the input does not make a difference, but whether or not you can hear the difference is a different story. It will also depend on how you implement the cascode eg voltages across jfets and current running through jfet etc.
The main reason for cascoding the F5 was to allow the use of voltages above 30V.
By the way check out my open baffle
With due respect, it is not difficult to build a working F5, or even a bridged one. Everyone can follow Nelson’s article, pick up some more info from the Pass forum, get a PCB from Peter Daniel, and there you go. You don’t even need to bother with all this matching stuff, degeneration trick, …., and what not. I am sure it will already sound very, very nice.
It is also not difficult to build a F5 or F5 balanced with ultra low distortion, even lower than the “standard” version. You just need to crank up the open loop gain, by e.g reduce the input stage bias by a factor of 4. This will lower the distortion by something like 10dB. That is if you like the sound of high feedback amps. You can even change all the transistors to BJTs, both input and output, swap the drain resistors for current source, …., like in the JLH Class A latest version. And it will still be a very nice sounding amplifier.
But to be able to build and tune one so as to attain a certain distortion spectrum or sonic signature and yet retain the overall low distortion figure requires a bit more understanding of basic amplifier circuitry and device characteristics, IMHO.
Of couse the best one can do is to build unlimited number of versions, do hours and hours of blind ABCD testing, … to find out which one sounds the best, to your ears. And Spice simulation is only as accurate as the device models one uses, which are not always 100% accurate. As an engineer, however, I have to agree with John Lindsley Hood that audio design and engineering is not a black art. Even simple hand calculations, or excel sheets will help a long way in weighing different design parameters so that one can converge quickly to an optimum, leaving only a limited number of varaiables to verify experimentally.
And this you can do all by yourself, without having to ask Nelson.
Patrick
It is also not difficult to build a F5 or F5 balanced with ultra low distortion, even lower than the “standard” version. You just need to crank up the open loop gain, by e.g reduce the input stage bias by a factor of 4. This will lower the distortion by something like 10dB. That is if you like the sound of high feedback amps. You can even change all the transistors to BJTs, both input and output, swap the drain resistors for current source, …., like in the JLH Class A latest version. And it will still be a very nice sounding amplifier.
But to be able to build and tune one so as to attain a certain distortion spectrum or sonic signature and yet retain the overall low distortion figure requires a bit more understanding of basic amplifier circuitry and device characteristics, IMHO.
Of couse the best one can do is to build unlimited number of versions, do hours and hours of blind ABCD testing, … to find out which one sounds the best, to your ears. And Spice simulation is only as accurate as the device models one uses, which are not always 100% accurate. As an engineer, however, I have to agree with John Lindsley Hood that audio design and engineering is not a black art. Even simple hand calculations, or excel sheets will help a long way in weighing different design parameters so that one can converge quickly to an optimum, leaving only a limited number of varaiables to verify experimentally.
And this you can do all by yourself, without having to ask Nelson.
Patrick
Trivial
There is a little chart of Ohm's Law formulas you need to post on the wall until you understand and memorize them. I'll get you started. E/R=I. That's Voltage(E), divided by Resistance, equals Current. ie; 0.18V/.18ohm = 1A
Trivial
I don't think this is the issue. I think the issue is that NYC is having trouble visualising the difference between series and parrallel parts of the circuit, which makes it difficult to determine the total bias
I think the problem is that NYCO is good at following a recipe, while not understanding why adding some salt can change the outcome.
While in this state of "lack of understanding", he seems to be unwilling to read and instead criticises the Members who came in to give advice when asked for it.
While in this state of "lack of understanding", he seems to be unwilling to read and instead criticises the Members who came in to give advice when asked for it.
This clash of the egos stuff is getting really, really old. I for one am sick and tired of seeing members trying to find info and crashing headlong into such childish attitudes. If you dont want to help, or think a member is undeserving, keep your mouth shut, would be my advice. If you do and can, it is much appreciated. I thought that was what this was all about, sharing of info, no? It never ceases to amaze me how brave people are on the internet, basically bullying new members whose life isnt all about audio, by conducting a real life, and audio is just a side passion.
Maybe I'm wrong, and this is just a place for know it alls to trade tales and entertain themselves by belittleing members with questions. While I guess this is a legitimate way for a forum to be, I hardly think it is appropriate here in the Pass forum, where one fine man, Nelson has decided to share all in a very professional and respectful way. Its probably worth thinking about the fact that Nelson has likely forgotten more than most of you know collectively.
Can't we all just play nice? I came here to learn to build an F-5. Done, with many members fine help, and it is deeply appreciated. Yes audio has been a lifelong passion for me, but not my job, which I have to conduct in order to fund such side passions. I can tell you, there are a lot of people out here wanting to build Nelson's designs, and wont ask questions? I've never had that problem, to ask is to learn. To know and not answer is your right, but hardly appropriate here.
Lastly, I believe I just read a post where a member suggested one figure it out them self and not bother Nelson with questions...I'm going back for a re read, hopefully I miss took the real point there....surely I did...if not, how dare you!
Russellc
If you do and can, it is much appreciated. I thought that was what this was all about, sharing of info, no? It never ceases to amaze me how brave people are on the internet, basically bullying new members whose life isnt all about audio, by conducting a real life, and audio is just a side passion.Maybe I'm wrong, and this is just a place for know it alls to trade tales and entertain themselves by belittleing members with questions. While I guess this is a legitimate way for a forum to be, I hardly think it is appropriate here in the Pass forum, where one fine man, Nelson has decided to share all in a very professional and respectful way. Its probably worth thinking about the fact that Nelson has likely forgotten more than most of you know collectively.
Can't we all just play nice? I came here to learn to build an F-5. Done, with many members fine help, and it is deeply appreciated. Yes audio has been a lifelong passion for me, but not my job, which I have to conduct in order to fund such side passions. I can tell you, there are a lot of people out here wanting to build Nelson's designs, and wont ask questions? I've never had that problem, to ask is to learn. To know and not answer is your right, but hardly appropriate here.
Lastly, I believe I just read a post where a member suggested one figure it out them self and not bother Nelson with questions...I'm going back for a re read, hopefully I miss took the real point there....surely I did...if not, how dare you!
Russellc
Not wrong
Lastly, I believe I just read a post where a member suggested one figure it out them self and not bother Nelson with questions...I'm going back for a re read, hopefully I miss took the real point there....surely I did...if not, how dare you!
Russellc
If you were referring to Patrick. Then I don't believe that is what he was suggesting. I think what he was suggesting, is that even numpties like myself can work this stuff out, all it takes is perseverance, study, and hands on.
Last edited:
Thank heavens, I have the utmost respect for him, EVUL, right? Sorry I was a little steamed. I had no problems when I requested help, and I build to learn, but the curve is steep if not your life's work, and without help, very steep. Thanks to all who helped me build the F-5, B-1, and hopefully the Pearl 2 and Aleph I'm collecting parts for. not to mention a balanced F-5, once they suss it out.
Russellc
Russellc
Last edited:
post948 - unbiased viewpoint ?
Hi Russel,
I have checked back through this thread to ensure that I was not involved in any of the "problems" perceived by NYCO and Russel.
I can confirm I did not take part in any advice giving, nor instruction, nor teaching of NYCO.
As such I have been watching this thread and the way it has developed and came here to offer my opinion on what I have seen happening.
My post947 has no need to defend any of my actions/statements, it is offered in a way that may allow some Members to stand back and review their own behaviours. In my view it is not biased.
I don't know what made you say that, I don't know what you hoped to achieve with that, I don't know who you are criticising.
But I do think you are wrong in stating what you did.
Hi Russel,
I have checked back through this thread to ensure that I was not involved in any of the "problems" perceived by NYCO and Russel.
I can confirm I did not take part in any advice giving, nor instruction, nor teaching of NYCO.
As such I have been watching this thread and the way it has developed and came here to offer my opinion on what I have seen happening.
My post947 has no need to defend any of my actions/statements, it is offered in a way that may allow some Members to stand back and review their own behaviours. In my view it is not biased.
I cannot see what gives Russel the right to express this view in public, even if he had evidence that supported NYCO's outburst.
I don't know what made you say that, I don't know what you hoped to achieve with that, I don't know who you are criticising.
But I do think you are wrong in stating what you did.
Last edited:
Not pointing the finger at anyone here, but it did feel like people were ganging up on NYCONE.
3 posts in quick succession from different members all attacking the same individual.
Even if what is said is true, it does not mean it has to be said.
I think I can empathise with everyones view point here, but do we really want to drive out new members. I know I would feel intimidated if several different members all ganged up on me.
3 posts in quick succession from different members all attacking the same individual.
Even if what is said is true, it does not mean it has to be said.
I think I can empathise with everyones view point here, but do we really want to drive out new members. I know I would feel intimidated if several different members all ganged up on me.
> I sense some frustration.
> there is no need to kill the joy of enthusiastic new members.
I have no reason for either, and certainly no time. Nor is there clash of ego. Please read post #919. If there is any differences, there is only one in the approach to audio design and engineering.
But for those who have been waiting patiently on the sideline for months and see apparently no progress, they must be wondering why it is such a burden when a novice can knock one together in a week or two.
Only to them I owe an answer. Hence my previous post #943.
I can also inform you that we expect to have the PCB work done by the end of February, and we are planning prototyping and testing now. Whether we shall finish before end of June and publish all our results depends on how much time the team members can afford to devote to the project.
But once the PCBs are proven functional, and even before we finish the last 5% of circuit optimisation, we shall publish the schematics and associated documents (bill of materials, source, ...), etc so that people can start planning and sourcing components. That I expect to be around Easter.
Thanks to all who wait patiently and silently, and also your support through your many PMs,
Patrick
.
> there is no need to kill the joy of enthusiastic new members.
I have no reason for either, and certainly no time. Nor is there clash of ego. Please read post #919. If there is any differences, there is only one in the approach to audio design and engineering.
But for those who have been waiting patiently on the sideline for months and see apparently no progress, they must be wondering why it is such a burden when a novice can knock one together in a week or two.
Only to them I owe an answer. Hence my previous post #943.
I can also inform you that we expect to have the PCB work done by the end of February, and we are planning prototyping and testing now. Whether we shall finish before end of June and publish all our results depends on how much time the team members can afford to devote to the project.
But once the PCBs are proven functional, and even before we finish the last 5% of circuit optimisation, we shall publish the schematics and associated documents (bill of materials, source, ...), etc so that people can start planning and sourcing components. That I expect to be around Easter.
Thanks to all who wait patiently and silently, and also your support through your many PMs,
Patrick
.
Last edited:
I believe you. However the message was not congratulatory towards NYCOne.
Just Relax. I think you have already proven yourself many times, and when it comes to delivering a project you are a perfectionist. I am absolutely certain that others on the F5X builders list feel the same way.
Just in case there is confusion. That was a sincere complement.
Just Relax. I think you have already proven yourself many times, and when it comes to delivering a project you are a perfectionist. I am absolutely certain that others on the F5X builders list feel the same way.
Just in case there is confusion. That was a sincere complement.
> 1. Papa is working hard , to have fun all the time
> 2. he never post grumpy
> 3. he never post to show own superiority
Funny you said that.
In my previously mentioned PM to NYCOne a few months back, I openly admitted to him and I do not have the patience and the time to coach beginners, and I admire Nelson for his patience and his efforts.
If it makes you all happy, I can make a request to the moderators to split all my posts off this thread into a new thread call "F5X -- EUVL's approach". Then we can all happily go our separate ways, and each individual can decide for himself which approach to follow.
And Choky, I do not recall one occasion that I did not take you seriously.
Patrick
> 2. he never post grumpy
> 3. he never post to show own superiority
Funny you said that.
In my previously mentioned PM to NYCOne a few months back, I openly admitted to him and I do not have the patience and the time to coach beginners, and I admire Nelson for his patience and his efforts.
If it makes you all happy, I can make a request to the moderators to split all my posts off this thread into a new thread call "F5X -- EUVL's approach". Then we can all happily go our separate ways, and each individual can decide for himself which approach to follow.
And Choky, I do not recall one occasion that I did not take you seriously.
Patrick
I don't understand you. Can't you find joy in other people's joy. He did start the thread after all.
Maybe it is best to separate the threads. There are clearly two different stories to tell here.
my happiness isn't in any way or meaning - in your or anyone's loss or disturbance ;
this thread is still perfect , at least for me ;
even if somewhat too serious
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.