Great advise thanks!
Do you have any experience to set up the bias ?
The trimpot must be the shorted 0R or the largest value for start? Also I will use the resistor in parallel with the trimpot for fine adjustment .
I do not want to set in the middle because that can be a big mistake .
Greets
Do you have any experience to set up the bias ?
The trimpot must be the shorted 0R or the largest value for start? Also I will use the resistor in parallel with the trimpot for fine adjustment .
I do not want to set in the middle because that can be a big mistake .
Greets
It was carefully explained not very long back
But I know such detail are easily overlooked when scimming through a thread
Connect ohmmeter to the paralel resistor and adjust pot down until resistance/impedance stops falling
Then it should be safe to power it up
Intentionally it might be supposed to be a better starting point, rather than just setting pot at zero, which might result in lots of adjusting before anything happens
At least that was my understanding
A bit further back theres also good explanations how to calculate bias fore certain classA power in various impedances
btw, regarding bias adjustment
Its a very good thing to ALWAYS remember which way to turn trim pot
Write it down
Maybe even keep a diary on all your adjustments, dc, notice of heatsink temperature, sound etc
When doing careful trimming its very important to know which way to turn, rather than just start out trying, and turn the wrong way
Thats one way to find the sweet spot, without difficult measurements
But I know such detail are easily overlooked when scimming through a thread
Connect ohmmeter to the paralel resistor and adjust pot down until resistance/impedance stops falling
Then it should be safe to power it up
Intentionally it might be supposed to be a better starting point, rather than just setting pot at zero, which might result in lots of adjusting before anything happens
At least that was my understanding
A bit further back theres also good explanations how to calculate bias fore certain classA power in various impedances
btw, regarding bias adjustment
Its a very good thing to ALWAYS remember which way to turn trim pot
Write it down
Maybe even keep a diary on all your adjustments, dc, notice of heatsink temperature, sound etc
When doing careful trimming its very important to know which way to turn, rather than just start out trying, and turn the wrong way
Thats one way to find the sweet spot, without difficult measurements
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Thank you Thinitus
How you wrote the tread is long and when I don't know exactly were to look for the right answer after one-two hours reading it is very easy to go over the answer what I'm looking for .
In the beginning I read every day but after a while gave up , now I started to read again but mostly the new posts . I'm seriously interested to build a X type high power F5.
I think I will print out your advise before I loose it .
I don't know if you are interested on the X verizon ? Only one question left before I start work on the PC board layout .
I do not see the Ground neither the simplified F5X verizon neither on the Patric schematic !
There is no power Ground so were I connect the signal Ground ?
With out the amp sure not working .
Thanks one more time
Greets
How you wrote the tread is long and when I don't know exactly were to look for the right answer after one-two hours reading it is very easy to go over the answer what I'm looking for .
In the beginning I read every day but after a while gave up , now I started to read again but mostly the new posts . I'm seriously interested to build a X type high power F5.
I think I will print out your advise before I loose it .
I don't know if you are interested on the X verizon ? Only one question left before I start work on the PC board layout .
I do not see the Ground neither the simplified F5X verizon neither on the Patric schematic !
There is no power Ground so were I connect the signal Ground ?
With out the amp sure not working .
Thanks one more time
Greets
Take your time
Read more
Study all relevant Pass articles and FirstWatt amps manuals
No point in rushing into it
Seems to me you still have too many unsolved issues, and we cant answer it all at once
Fore one, dont over estimate your heatsinks
Im not even sure about my own F5
But one is certain
I have spent the needed money to buy 1meter 300x80mm, to be cut in 4
That I couldnt resist, after getting ok price offer
I have a friend who will help with grinding/milling the base 100% smoothly planed
Trafos next
But which, I cant decide
Size, IE, C-core, toroid ?
Lots of things to think about
But Im in no hurry, that I have learned
Read more
Study all relevant Pass articles and FirstWatt amps manuals
No point in rushing into it
Seems to me you still have too many unsolved issues, and we cant answer it all at once
Fore one, dont over estimate your heatsinks
Im not even sure about my own F5
But one is certain
I have spent the needed money to buy 1meter 300x80mm, to be cut in 4
That I couldnt resist, after getting ok price offer
I have a friend who will help with grinding/milling the base 100% smoothly planed
Trafos next
But which, I cant decide
Size, IE, C-core, toroid ?
Lots of things to think about
But Im in no hurry, that I have learned
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Hello
About transformer , out my 20 years experience I would advise go with a good quality toroidal transformer . Or use two for dual mono verizon.
If you just think about a bit all the Pass amps mostly uses toroid's .But I can be wrong .
Yes you right . There is no need to rush . There are some basic question I don't know the answer right now .
Of course if I never start to do something it will be never be done that is also true .
I only can get answer from those people who already has some experience with the F5 X amplifier or from the Master if He has time .
One think I'm sure I will have to calculate some resistors due to the multiple output mosfet .
My heat sink (the enclosure) about 25kg when the cover and the front and the back on it . If I would have heat problem always possible to reduce the bias a bit .
But how I already wrote I have a Aleph X . Before I powered up I was worried about the size of heat sink . After start to use I realised it is over sized . That is never a problem.
I just modified my old layout I took out the cascode .
My PC board layout was made with the paint program in my computer so when I print it out the size a bit bigger .
I hope some expert guy will be so kind to help or give some further advise .
Also I read and read to learn more how you wrote .
I try to learn from the past mistakes .
Thank you one more time .
Greets
About transformer , out my 20 years experience I would advise go with a good quality toroidal transformer . Or use two for dual mono verizon.
If you just think about a bit all the Pass amps mostly uses toroid's .But I can be wrong .
Yes you right . There is no need to rush . There are some basic question I don't know the answer right now .
Of course if I never start to do something it will be never be done that is also true .
I only can get answer from those people who already has some experience with the F5 X amplifier or from the Master if He has time .
One think I'm sure I will have to calculate some resistors due to the multiple output mosfet .
My heat sink (the enclosure) about 25kg when the cover and the front and the back on it . If I would have heat problem always possible to reduce the bias a bit .
But how I already wrote I have a Aleph X . Before I powered up I was worried about the size of heat sink . After start to use I realised it is over sized . That is never a problem.
I just modified my old layout I took out the cascode .
My PC board layout was made with the paint program in my computer so when I print it out the size a bit bigger .
I hope some expert guy will be so kind to help or give some further advise .
Also I read and read to learn more how you wrote .
I try to learn from the past mistakes .
Thank you one more time .
Greets
Yes, indeed
You have a lot to learn about trafos too
I dont know why people persist to believe that toroids are the best
But they surely are the most available, and cheapest, and easy to fit in and mount
My friend, I have 40 years of experience, and Im still just scratching the surface of the level of knowledge in here
I feel like a complete beginner with everything
The more you learn, the more you realise how little you know
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... the beer bottles are intended for proper cooling of the output devices, if anything goes wrong
Correct & very sensitive! (Four output devices - four bottles)
Otherwise, congrats & cheers to myne Nachbarn!
"There is no power Ground so were I connect the signal Ground ?"
To enter a symetrical amp you need a symetrical preamp output.
There is no signal ground. The outside part of the cable is a screen only. It can be connected to plus, minus or 0 volts PSU.
Anyway.. IRFP devices are not expensive. You could buy some, build 4 stock F5 modules, evrything is in the PDF, then you could easily experiment with different arrangements; bridged, parallel, Xed, or even simply four channels.
Or are your laterals even matched?
To enter a symetrical amp you need a symetrical preamp output.
There is no signal ground. The outside part of the cable is a screen only. It can be connected to plus, minus or 0 volts PSU.
Anyway.. IRFP devices are not expensive. You could buy some, build 4 stock F5 modules, evrything is in the PDF, then you could easily experiment with different arrangements; bridged, parallel, Xed, or even simply four channels.
Or are your laterals even matched?
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Hello
Yes my mosfets are matched ! Also have 24VDC rail power supp .
So I must use multiple power mosfet for the X verizon .
I can design the PC board lay out that is not a problem .
My question if we take a look at the original F5 schematic R10 , R1,R2 all three resistor connected to the ground .
If I look at the simplified F5X schematic there is no ground at all ? For the input it has to be some type of ground . But also it is possible to connect to the power supp ground .I'm not sure .
Are you sure none of those resistors goes to the ground ?
If these question clear I could go on and make my PC boards .
I only interested in the X topology since I have a Aleph X and I'd like it so much .
Thanks for your help
Greets
Yes my mosfets are matched ! Also have 24VDC rail power supp .
So I must use multiple power mosfet for the X verizon .
I can design the PC board lay out that is not a problem .
My question if we take a look at the original F5 schematic R10 , R1,R2 all three resistor connected to the ground .
If I look at the simplified F5X schematic there is no ground at all ? For the input it has to be some type of ground . But also it is possible to connect to the power supp ground .I'm not sure .
Are you sure none of those resistors goes to the ground ?
If these question clear I could go on and make my PC boards .
I only interested in the X topology since I have a Aleph X and I'd like it so much .
Thanks for your help
Greets
There is no signal ground when symetrical connexion.
There are two wires for the signal the third one is a screen only .
If ou have a symetrical PSU, connect it to 0 volts .
There is no resistor connected to ground in Patrick Euvl schematic.
I would think of some serial input resistors though in the lay out.
With 24 volts rails (did you measure this with load?) i would keep the stock F5 values.
The only ones you could have to modify are R4 R5 but these are not critical as pots parallel them.
There are two wires for the signal the third one is a screen only .
If ou have a symetrical PSU, connect it to 0 volts .
There is no resistor connected to ground in Patrick Euvl schematic.
I would think of some serial input resistors though in the lay out.
With 24 volts rails (did you measure this with load?) i would keep the stock F5 values.
The only ones you could have to modify are R4 R5 but these are not critical as pots parallel them.
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Hello
I found many valuable information from the picture Symslow posted from his F5X .
I found the Cviller PC board and I did com pare the populated PC board and the bare board . Now I see wich components are there and wich ones aren't .
There is some signal ground because Symlow use the R10 which is 100K and goes to the ground . Even he use the R9 resistor 1K at the input .
Now all clear .
I will modify my layout .And I can go on to each the PC boards .Probably I will have to increase the 5W resistor values because I will use 3 par mosfet the rest remain the same how Patrick build it .
Thank you for your help .
Greets
I found many valuable information from the picture Symslow posted from his F5X .
I found the Cviller PC board and I did com pare the populated PC board and the bare board . Now I see wich components are there and wich ones aren't .
There is some signal ground because Symlow use the R10 which is 100K and goes to the ground . Even he use the R9 resistor 1K at the input .
Now all clear .
I will modify my layout .And I can go on to each the PC boards .Probably I will have to increase the 5W resistor values because I will use 3 par mosfet the rest remain the same how Patrick build it .
Thank you for your help .
Greets
EI core versus toroids
Hello,
A lot of people believe toroid core power transformers are superior to EI types in many ways, but you indicate a contrary belief. Could you share some of your experiences using EI cores transformer in your builds?
Regards,
David
Hello,
A lot of people believe toroid core power transformers are superior to EI types in many ways, but you indicate a contrary belief. Could you share some of your experiences using EI cores transformer in your builds?
Regards,
David
I wish I could give hard facts, but I cant
Actually I have never used EI trafos, only UI cores
UI cores are said to work like a marriage of C-core and toroid
The first contradiction about toroids happened many years ago when HAFLER entered the scene
Around here some people began to change the Hafler IE core to the new toroids, and believed it was a significant improvement
When I asked a guy about it he just said "why on earth would you wanna do that fore"
Got me thinking, but didnt do anything about it
I couldnt believe people would take such hazzle without a reason
Later on I have heard people with greater insight and knowledge claim that almost any other than toroids should be preferred
The only facts I belive to know are as follows
Toroids have huge powerup current(inrush current)
Other trafos have more "pleasant" powerup
Toroids are more sensitive to DC on the mains power, and other kinds of noise
What I do know is that you can build an amp with UI core that will pull the socks off many other amps
And probably with EI cores as well
I dont say that toroids are inferiour, not at all
Only that they arent superiour as many people believe them to be
The best toroids are probably really good stuff
Unfortunately many people go fore the cheapest ones, believing that only the price is different
Maybe its all about build quality, and nothing else
Yet again, theres always the risk of "buying tha cat in the sack"
To me, the only problem with any other trafo than toroids is that they are getting exceedingly hard to find, and expencive
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Absolutely the opposite in my country - EIs are easy to find, and get wound to custom specs and with every possible variation. Toroids are expensive to find.
Of course, R-, C- and UI-cores are impossible to find in this neck of the woods.
EIs have absolutely zero startup problems, but they have other issues, efficiency being one of them (dunno if that's so important for DIY'ers) and a high temperature rise (which is a real problem). I don't find issues with magnetic fields (plenty of distance) or with size and weight in the amps I've built, or even the DAC transformers I use.
I specify the transformers with interwinding shields and frame grounding lugs, and the manufacturer resin-dips the transformers (they smell disgusting for a few hours) to prevent any mechanical hum. Seems to work well....
And you have those lovely old trains too
I have thought about the heating issue
Wasnt sure about it tho
According to you it is a tendency
Should be considered if its an issue with classA drive
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