hi there!
first I must say that my english isn't very well, but I try to do my best.
In the moment I'm assembling a F5 circuit (2xmono in one case).
The PCB's for the amplifier are here now (they are from this site- and VEEERY NICE ones!), and my power supplies are ready, too.
the components I used:
- 2x300VA transformator with both 2x18V/8,13A
- 2x28 capacitors each with 4700µF/35V for the DC-side
- one huge heatsink (450x300x50mm or 17,7"x11,81"x1,97") for the mosfets
now I have the following ideas:
- the heatsink is the top from the case
- the sides will be made with wood (to match the loudspeakers)
- for the front I want to use brown plexiglass
- the back will be made with 10mm aluminium to take all the connectors
now I've seen here in the forum, that most of you place the heatsinks on the sides of the case. do you think using the heatsink as top would be ok, too?
can I use CAT5-cables for wiring the in/outputs of the amp?
(or what would you choose, if its gonna be a "cheap"-build? 😛)
do I need any shields for the AC-side? (one of you did, the others didn't)
AAAAND one very silly question, but I'm a bloody newbie:
what preamp should I build when using a simple CD-player or cassette-deck? Is it possible to use the amp without any preamp?
I thought I would go for the balanced zen line stage...
oooh I've got sooo many questions and read a lot about the F5's here in the forum... but it's not so easy finding the answers- because there are so MANY answers...
thanks for reading this, maybe you can answer a few of this questions...
best regards,
matthias from bavaria...
first I must say that my english isn't very well, but I try to do my best.
In the moment I'm assembling a F5 circuit (2xmono in one case).
The PCB's for the amplifier are here now (they are from this site- and VEEERY NICE ones!), and my power supplies are ready, too.
the components I used:
- 2x300VA transformator with both 2x18V/8,13A
- 2x28 capacitors each with 4700µF/35V for the DC-side
- one huge heatsink (450x300x50mm or 17,7"x11,81"x1,97") for the mosfets
now I have the following ideas:
- the heatsink is the top from the case
- the sides will be made with wood (to match the loudspeakers)
- for the front I want to use brown plexiglass
- the back will be made with 10mm aluminium to take all the connectors
now I've seen here in the forum, that most of you place the heatsinks on the sides of the case. do you think using the heatsink as top would be ok, too?
can I use CAT5-cables for wiring the in/outputs of the amp?
(or what would you choose, if its gonna be a "cheap"-build? 😛)
do I need any shields for the AC-side? (one of you did, the others didn't)
AAAAND one very silly question, but I'm a bloody newbie:
what preamp should I build when using a simple CD-player or cassette-deck? Is it possible to use the amp without any preamp?
I thought I would go for the balanced zen line stage...
oooh I've got sooo many questions and read a lot about the F5's here in the forum... but it's not so easy finding the answers- because there are so MANY answers...
thanks for reading this, maybe you can answer a few of this questions...
best regards,
matthias from bavaria...
The main issue with the heat sinks on top of the case is air circulation. The center of the heat sinks will be hotter than the edges. Only testing can tell you if horizontal sinks will provide adequate cooling. A fan set up to blow gently across your sinks will improve the cooling tremendously.
If you can keep your AC side far enough from teh signal side you don't need shielding. It won't hurt though.
Cat-5 pairs would be adequate for input signal wiring. You would need many multiples to adequately handle the output and DC power wiring. Get a bit of 12 gauge hookup wire for output and rails wiring. Over here the big box hardware stores have small quantities. Car stereo stores usually carry heavy wire, too.
Keep it Pass - a B1 would be a good choice if you need a buffer after your CD player. Unless your CD player has balanced outputs you don't need a balanced preamp.
Enjoy your project
If you can keep your AC side far enough from teh signal side you don't need shielding. It won't hurt though.
Cat-5 pairs would be adequate for input signal wiring. You would need many multiples to adequately handle the output and DC power wiring. Get a bit of 12 gauge hookup wire for output and rails wiring. Over here the big box hardware stores have small quantities. Car stereo stores usually carry heavy wire, too.
Keep it Pass - a B1 would be a good choice if you need a buffer after your CD player. Unless your CD player has balanced outputs you don't need a balanced preamp.
Enjoy your project
hi BobEllis!
thanks for your answer! ok, I have to learn MAAAANY things, I think. the cd-player doesn't have balanced output- it's a normal one which has got 2 chinch outputs for left/right.
can I use this one FIRST WATT B1 as preamp? it isn't balanced, so must be the right one?
the cooling I have to test, ok. 🙂
wiring shouldn't be a big issue then, I will go exactly for your tip!
thanks a lot!
matthias
thanks for your answer! ok, I have to learn MAAAANY things, I think. the cd-player doesn't have balanced output- it's a normal one which has got 2 chinch outputs for left/right.
can I use this one FIRST WATT B1 as preamp? it isn't balanced, so must be the right one?
the cooling I have to test, ok. 🙂
wiring shouldn't be a big issue then, I will go exactly for your tip!
thanks a lot!
matthias
Matthias: If you post some pics of your heat sink (and other parts) perhaps someone can suggest a layout that has better natural convection cooling than fins on top....?
Consider the heatsink on one side with the fins running top to bottom. The toroid could be mounted vertically to make a very slim tall build, could look very nice.
The F5 does not have much gain. I have seen people complain that it doesn't go loud enough. So, it would better to build a preamp with some gain rather than building the B1-preamp, which is just a unity gain buffer. Don't get me wrong, the B1 is awesome, I use it everyday, but it is not a good match for the F5. Bride of Zen or the JBOZ (search diyaudio) are good options.
Another option may be the BA-3 front end. You can even get PCBs on diyaudio.
Another option may be the BA-3 front end. You can even get PCBs on diyaudio.
hi there and thanks for the answers! 🙂
ok, I try to build a tower-designed case with heatsinks on every side.
If I want to use the BA-3 as preamp for my F5, how can I adjust the volume then? I surfed through the forum search function, but there are so many answers and posts and threads and... I'm a bloody newbie.
I bought this potentiometer 100K stereo 24 step potentiometer ladder volume control | eBay .
Is it possible to use it with the BA-3 and if so, where should it sit in the circuit?
PS: pictures are coming soon, in the moment I'm missing a few parts...
best regards,
matthias
ok, I try to build a tower-designed case with heatsinks on every side.
If I want to use the BA-3 as preamp for my F5, how can I adjust the volume then? I surfed through the forum search function, but there are so many answers and posts and threads and... I'm a bloody newbie.
I bought this potentiometer 100K stereo 24 step potentiometer ladder volume control | eBay .
Is it possible to use it with the BA-3 and if so, where should it sit in the circuit?
PS: pictures are coming soon, in the moment I'm missing a few parts...
best regards,
matthias
If you are kicking around ideas about heatsink location and a wood-sided enclosure, you might want to scan my old thread:
http://www.diyaudio.com/forums/pass...-build-beautiful-music-different-drummer.html
http://www.diyaudio.com/forums/pass...-build-beautiful-music-different-drummer.html
@CanAm Man: stunning, absolutely stunning! nice- or how do you say here: fugly? 🙂
@Nelson (Papa?) Pass: Hmm, do you think, the B1 will do the job for a normal CD-player when I change the value from the resistors?
It's difficult to sort all those threads and infos, but it's very interesting and I will try to give my best! 🙂
THANKS A LOT!
best regards,
matthias
@Nelson (Papa?) Pass: Hmm, do you think, the B1 will do the job for a normal CD-player when I change the value from the resistors?
It's difficult to sort all those threads and infos, but it's very interesting and I will try to give my best! 🙂
THANKS A LOT!
best regards,
matthias
I have used the B1; DCB1; A Lightspeed type and a TVC volume control with the F5 driven by a CD player and all work extremely well. Not sure whether an other source would have enough output to be used without some extra gain though.
Have a look at
http://www.diyaudio.com/forums/pass-labs/125893-preamp-ideas-f5.html
The bjt version is very promising
http://www.diyaudio.com/forums/pass-labs/125893-preamp-ideas-f5.html
The bjt version is very promising
hi everyone!
long time since I visited the last time, but now it's time for an update.
one of the two F5-mono-amplifiers is build together, but I have a big problem.
If I fire it up, I can measure 24V+ and 24V- against the GND-point. so the power supply is fully functional, I think.
P1 and P2 were set to their minimum value, as required. one multimeter is between the output points to measure the DC drift there. with the other one I measured R3/R4 to set the required 4.2V. I was able to set these values, but couldn't measure more than 0,05V (= nothing) between R11/R12. so no power on the output-mosfets, I think?
the DC value between the output points drifted up to +714mV as more as I came to the right voltage values for R3/R4. P1 is on its maximum value.
what is wrong with my circuit? I have only minimal current on the power input of the amplifier. nothing gets warm or is smoking...
all the hard work with the case, and now this fail... 🙁
can you please help me?
THANKS! (and sorry for my bad english...)
matthias
long time since I visited the last time, but now it's time for an update.
one of the two F5-mono-amplifiers is build together, but I have a big problem.
If I fire it up, I can measure 24V+ and 24V- against the GND-point. so the power supply is fully functional, I think.
P1 and P2 were set to their minimum value, as required. one multimeter is between the output points to measure the DC drift there. with the other one I measured R3/R4 to set the required 4.2V. I was able to set these values, but couldn't measure more than 0,05V (= nothing) between R11/R12. so no power on the output-mosfets, I think?
the DC value between the output points drifted up to +714mV as more as I came to the right voltage values for R3/R4. P1 is on its maximum value.
what is wrong with my circuit? I have only minimal current on the power input of the amplifier. nothing gets warm or is smoking...
all the hard work with the case, and now this fail... 🙁
can you please help me?
THANKS! (and sorry for my bad english...)
matthias
Kein Problem!
Servus Matthias,
I had the same problem using a Chinese PCB for steric reasons--still am much endebted to Nelson.
So your power supply works and you get the right rail voltage. Fine!
Best to use three (3) multimeters:
1 for the DC offset
1 each for R11 and R12
Adjust the pots P1/P2 as described and slowly bring up the voltage across R11/R12 to 0.59V, you should get less than 10mV DC offset.
When I did this, I could only bring things up to something like 0.4V and ran out of pot. I then increased R3/R4 from 2k2 to twice that resistance 4k5 or something and now had enough play (ja, Spiel!) on the pots to bring things up to around 0.6V and, most important, keep DC offset at a minimum.
I now have two F5 monos and am BLOWN away by the sound -- obergeil!
BTW Started with Nelson's B-1 passive preamp and couldn't believe my ears, only then started off on my F-5 and now am sooo happy!!!
Next step is the BA-3 preamp with gain, so that I can really max out the 25W.
Du bist auf dem richtigen Weg, mach das -- es lohnt sich ungeheuer!
Viel Glück!
Peter
PS Thank you Pappa, indeed!
Servus Matthias,
I had the same problem using a Chinese PCB for steric reasons--still am much endebted to Nelson.
So your power supply works and you get the right rail voltage. Fine!
Best to use three (3) multimeters:
1 for the DC offset
1 each for R11 and R12
Adjust the pots P1/P2 as described and slowly bring up the voltage across R11/R12 to 0.59V, you should get less than 10mV DC offset.
When I did this, I could only bring things up to something like 0.4V and ran out of pot. I then increased R3/R4 from 2k2 to twice that resistance 4k5 or something and now had enough play (ja, Spiel!) on the pots to bring things up to around 0.6V and, most important, keep DC offset at a minimum.
I now have two F5 monos and am BLOWN away by the sound -- obergeil!
BTW Started with Nelson's B-1 passive preamp and couldn't believe my ears, only then started off on my F-5 and now am sooo happy!!!
Next step is the BA-3 preamp with gain, so that I can really max out the 25W.
Du bist auf dem richtigen Weg, mach das -- es lohnt sich ungeheuer!
Viel Glück!
Peter
PS Thank you Pappa, indeed!
Hallo Peter!
Thanks for your infos! 🙂
My PCB's are from CViller (or something like that, I can't look for the right name in the moment).
Do you think, changing R3/R4 will work on my circuit, too?
50mV through R11/R12 ist nearly nothing. (I think it was nothing, because of the cheap multimeter I used 😀)
This value was static through the "calibration process"...
I think I'll put a second 2K2 resistor in line to see if it helps.😉
best regards,
matthias
Thanks for your infos! 🙂
My PCB's are from CViller (or something like that, I can't look for the right name in the moment).
Do you think, changing R3/R4 will work on my circuit, too?
50mV through R11/R12 ist nearly nothing. (I think it was nothing, because of the cheap multimeter I used 😀)
This value was static through the "calibration process"...
I think I'll put a second 2K2 resistor in line to see if it helps.😉
best regards,
matthias
hi!
thank you for the tip with the 2k2 resistor! 🙂
now it works!
but I have a question to the voltage through R11/R12:
I'm not able to adjust on both 590mV.
Theres always an offset of 30mV. (changed multimeters to check differences between them and got the same result)
The offset on the output is 0mV, thats perfekt.
is it ok or not aceptable for the F5?
thanks!
matthias😉
thank you for the tip with the 2k2 resistor! 🙂
now it works!
but I have a question to the voltage through R11/R12:
I'm not able to adjust on both 590mV.
Theres always an offset of 30mV. (changed multimeters to check differences between them and got the same result)
The offset on the output is 0mV, thats perfekt.
is it ok or not aceptable for the F5?
thanks!
matthias😉
Good enough!
Lieber Matthias,
This is good enough for government work 🙂)
So you did not match the transistors to the last Hinterkommastelle, or whatever, don't sweat it! Lass es so!
The main issue to have as little as possible DC offset so not to fry the speakers!
Nu setzt Dich zurück und HÖR mal!
Now lay back and LISTEN to Nelson's fabulous design!
Alles Gute aus Boston,
Peter
Lieber Matthias,
This is good enough for government work 🙂)
So you did not match the transistors to the last Hinterkommastelle, or whatever, don't sweat it! Lass es so!
The main issue to have as little as possible DC offset so not to fry the speakers!
Nu setzt Dich zurück und HÖR mal!
Now lay back and LISTEN to Nelson's fabulous design!
Alles Gute aus Boston,
Peter
Hey Peter!
VIELEN DANK! 🙂
my only problem is: there's still one left, because I'm building it mono.
(photos are coming as soon as possible, today I think they are both ready to play!)
Viele Grüsse aus Schwandorf,
Matthias 😉
VIELEN DANK! 🙂
my only problem is: there's still one left, because I'm building it mono.
(photos are coming as soon as possible, today I think they are both ready to play!)
Viele Grüsse aus Schwandorf,
Matthias 😉
Hello everybody!
Both F5 mono's are ready to play since a few days. They sound absolutely fantastic!!!
It's a real warm sound, nice and clear, too.
But every time I switch them on and listen to music, they have to be adjusted a little bit.
There's always more than 600mV on one of the two rails on every F5 mono amplifier.
The offset on the output is drifting away, after a few hours of listening it is always about +8mV.
Then I turn the pots down a little bit, and everything seems to be ok until the next measuring after an hour.
After a few adjustments I now have to wait an hour or two until the offset is +3mV on both.
The first minutes after powering them on I have about 15-25mV offset on both.
The heatsinks are ok, not too hot (I could sit on them without any issues *g*).
My question: Is it ok, or is something wrong with my F5? (The first adjustment took about an hour or two, so they were really warm and burned in, too)
Here are two pictures of them, but they aren't finished yet. 😉
1. adjusting number one:
both while playing music sooooo nice (the right one with cables for measuring voltage through R11/R12)
the backside is the heatsink, so I decided to make two towers. 🙂
the sides and the fronts are waiting for CNC-machining (they are all 10mm aluminium) , and the cables for +/-24V will be mounted on the top for a nice and clean look.
Thank you!
Matthias
Both F5 mono's are ready to play since a few days. They sound absolutely fantastic!!!
It's a real warm sound, nice and clear, too.
But every time I switch them on and listen to music, they have to be adjusted a little bit.
There's always more than 600mV on one of the two rails on every F5 mono amplifier.
The offset on the output is drifting away, after a few hours of listening it is always about +8mV.
Then I turn the pots down a little bit, and everything seems to be ok until the next measuring after an hour.
After a few adjustments I now have to wait an hour or two until the offset is +3mV on both.
The first minutes after powering them on I have about 15-25mV offset on both.
The heatsinks are ok, not too hot (I could sit on them without any issues *g*).
My question: Is it ok, or is something wrong with my F5? (The first adjustment took about an hour or two, so they were really warm and burned in, too)
Here are two pictures of them, but they aren't finished yet. 😉
1. adjusting number one:
both while playing music sooooo nice (the right one with cables for measuring voltage through R11/R12)
the backside is the heatsink, so I decided to make two towers. 🙂
the sides and the fronts are waiting for CNC-machining (they are all 10mm aluminium) , and the cables for +/-24V will be mounted on the top for a nice and clean look.
Thank you!
Matthias
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