F5 power amplifier

[Ryssen]

Ryssen, I love the unconventional wood chassis!

Thanks!

 

[labjr]

I like the wood too. Does that heatsink run hot?

 

[Ryssen]

Does that heatsink run hot?

Can touch 10-15seconds.
Stein2 how hot is yours?

 

[Ryssen]

The power consumtion for the 2 channels is 160 watt.

 

[woodturner-fran]

Stein2 - the motor run caps are the last ones in the PS right? Did you try the amp with and without them?


Fran

 

[stein2]

Stein2 - the motor run caps are the last ones in the PS right? Did you try the amp with and without them?


Fran

About heat: I could sleep on it, pleasantly warm, not hot

The amp was initially built without MR caps, tested and I found it works just fine, the addition of MR caps and removing the 0.1R series resistors in the PSU makes things even better. Faster and even more "corpulent"... Everyone should try it

 

[bobodioulasso]

About heat: I could sleep on it, pleasantly warm, not hot

Nice work, Stein.Where did you get these nice heatsinks?

 

[slr 5000]

hi all
ive noticed that q3 and q4 are different in the tech diy parts list and the fig 6 schematic on mr pass site

eg fig 6 schematic says q3 =irfp9240 and q4 =irfp240

tech diy says the oposite q3 = irfp 240 etc


even in nelsons article they are swapped .eg. it is mentiond in the article that q3=irfp240 and q4= irfp9240

where as the fig 6 schematic in his article shows them opposite q3 irfp9240 and q4 irfp 240

which are the correct positions im confused !!!

 

[bobodioulasso]

q3=9240
q4=240

 

[slr 5000]

thanks mate much appreciated
so the fig 6 schematic is correct then

cheers from sheafer

 

[slr 5000]

sorry to be a pain guys
i just realised ive got the fairchild parts not irf
so q3 is fqa19n20c and q4 is fqa 12p20c correct?
is there much difference between the irf and fairchild devices

is one better than the other or are they same/same
what does nelson reccomend

thanks in advance
regards sheafer

 

[bobodioulasso]

With this common source topology, the P channel mosfet is situated on the positive supply side.
Fairchilds are the best here, but IRFs work fine too.

 

[jackinnj]

With this common source topology, the P channel mosfet is situated on the positive supply side.
Fairchilds are the best here, but IRFs work fine too.

I wouldn't say that the Fairchilds are necessarily "best" -- they don't suffer from a kink in the curve so the sound is reported to be a bit faster and more clinical than the IRF/Vishay devices. The FSC devices were a bit hard to get initially, so I put them in with the kits but either flavor is fine.

I've used both, but am considering selling off my F5 prototype boards and going back to the F4.

For anyone who's wondering where there "stuff" is -- I have been experiencing delays of up to 6 weeks on "Priority Mail Small Flat Rate Box" to the UK. Pretty intolerable. I don't know whether they are opening up and examining for customs.

 

[Peter Daniel]

sorry to be a pain guys
i just realised ive got the fairchild parts not irf
so q3 is fqa19n20c and q4 is fqa 12p20c correct?
is there much difference between the irf and fairchild devices

is one better than the other or are they same/same
what does nelson reccomend

thanks in advance
regards sheafer

There was an error in BOM I posted in GB thread, that was not my BOM and I didn't spot it as I was using IRFs. Here's the correction: http://www.diyaudio.com/forums/showthread.php?postid=1794930#post1794930

This is what Nelson says: http://www.diyaudio.com/forums/showthread.php?postid=1725328#post1725328

 

[woodturner-fran]

Less cross atlantic trade I reckon so they are waiting to fill a container. Bet thats the reason for the delay.

Fran

 

[samoloko]

stein2 can you post a closer picture of your PSU - I would like to know how are you did gnd wiring
with so much capacitance how you are starting up - with soft start or cl-60 what value fuse you use

 

[jackinnj]

Less cross atlantic trade I reckon so they are waiting to fill a container. Bet thats the reason for the delay.

Fran

Things are getting to Netherlands, Norway, Sweden and France without too much delay. Packages to Germany are being opened for inspection which really holds them up. Everything going to Italy has to be sent "Registered" which takes forever.

 

[Ryssen]

After listening about an hour on F5(before I had the F3).
And with the 6,5" (The brown ones):

There was with F3 a lack of bas,but with F5 there where more tighter bass..
I have sub 2.And there is air to..
Will listen more now.

 

[samoloko]

DO NOT put your main Audio Ground on the wire/trace/plate between the smoothing caps.
Instead place the main Audio Ground near the midpoint of all the points that need to be referenced to it.
Then connect the PSU Zero volts between the smoothing caps to this Audio Ground.
Also, connect the PSU Zero volts to the chassis using a disconnecting network.

Hi Andrew
would you please advise proper way to do ground wiring to this pcb
http://www.diyaudio.com/forums/attachment.php?s=&postid=1771389&stamp=1236867942
as you see the pcb has two gnd Input pads which actually Is one thin gnd point (the signal and power ground are same)
thx

 

[AndrewT]

as you see the pcb has two gnd Input pads which actually Is one thin gnd point (the signal and power ground are same)

Hi,
there is no power ground, nor speaker return, nor output Zobel return.
Nothing returns to the PCB to contaminate the signal ground.

There is only a signal ground. Look at it. It takes a signal from R1, R2 & R10, nothing else.