F5 power amplifier

[fff0]

Hi Zen/ Magura,

Thanks for the input.
Can I know if I can feed F5 with +48v and 0v (gnd), will it work? no?

[bobodioulasso]

see post 4239

[cviller]

Originally Posted by umut1001

hi huseyin how are you..i wish you will draw a good pcb for us and we will group buy...

There are already 3 designs available, so unless you want to do it for the experience, I doubt there will be much action in such a gb.

Cviller: Gb: F5 Pcb
Peter Daniel: F5 pcb group buy...
suds: FirstWatt F3/ F5 Clone GB

[Zen Mod]

Originally Posted by fff0

.....
Can I know if I can feed F5 with +48v and 0v (gnd), will it work? no?

yeah - with so-called Quad arrangement of PSU

see what bobodioulasso wrote

[AndrewT]

if I were designing a CLC for an F5, I would use 6m8F//6m8F//6m8F as the first capacitor bank, then 180turns of 1.6mm diameter enameled copper on a 48mm air core former (700gms of copper) and then 15mF//15mF//15mF as the second stage capacitor bank.
Your two channels will require a minimum of 250mF and 3.1kg of copper. That is an expensive PSU. It will work for both the ClassA operation (1.3A bias) and for the ClassAB operation.
It will even work with a ClassAB amplifier (150W into 8r0) irrespective of the output stage bias.

[sekess]

Originally Posted by AndrewT

if I were designing a CLC for an F5, I would use 6m8F//6m8F//6m8F as the first capacitor bank, then 180turns of 1.6mm diameter enameled copper on a 48mm air core former (700gms of copper) and then 15mF//15mF//15mF as the second stage capacitor bank.
Your two channels will require a minimum of 250mF and 3.1kg of copper. That is an expensive PSU. It will work for both the ClassA operation (1.3A bias) and for the ClassAB operation.
It will even work with a ClassAB amplifier (150W into 8r0) irrespective of the output stage bias.

Hi AndrewT,
2 questions:

1. Is there a reason why you need so much more capacitance for a CLC as compared with a CRC?

2. In your example: "180turns of 1.6mm diameter enameled copper on a 48mm air core former " -- how many Henries does that come out to?

Thanks,
Steve

[umut1001]

hi Andrew..i dont know how to calculate the most reliable power supply for F5 amp..i have these materials

1-) 0-18 0-18 0-18 0-18 600VA toroidal transformer

2-)8x 25volts 47mf kendeil capacitors

3-)0.47 ohm 3watts dale resistors

would you say how to make the best supply and best noise reduction and how many resistors should i connect paralleled for it?thank you

[AndrewT]

Originally Posted by sekess

1. Is there a reason why you need so much more capacitance for a CLC as compared with a CRC?

2. In your example: "180turns of 1.6mm diameter enameled copper on a 48mm air core former " -- how many Henries does that come out to?

+-45mF is not a lot for a ClassA amp that can drive 4ohms into ClassAB.
I posted the air core inductor spreadsheet quite a while ago.
183Turns calculates to 2.0mH and has 0r34 resistance, but it's big. 14.3turns/layer, 12.9layers = 184Turns resulting in 89.2mm diameter and 22.9mm spool width, using 40m of wire.

2mH using 1.9mm wire gives 103mm diameter and uses more than a 1kg spool of wire.

[SalvationMen]

I just completed my F5. The value of resistor is according to reference on the passdiy web. However, when I adjusted the bias and output DC, I adjusted P1 and P2 to keep voltage of R11 around 0.6V. I noticed the value was changed all the time. It can't be fixed in a value. The output DC is in the same situation. What's wrong?

[Zen Mod]

you must have input grounded while adjusting bias ands offset