F5 power amplifier

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umut1001 said:
there is no hum when i connect it to sound card..there is only a little music..emu sound card is a balanced card..i lost my mp3 player..i dont have any other source right now


No hum when connected to player - sounds like inputs dont have a shunt resistor.

The low-output - I have done the same thing before. Turned out one of the speaker terminals was touching the chassis. I would do the continuity test on the signal path...Make sure that inputs and outputs are isolated correctly.
 
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umut1001 said:
there is no hum when i connect it to sound card..there is only a little music..emu sound card is a balanced card..i lost my mp3 player..i dont have any other source right now


did you converted your emu output to unbalanced ?

I bet that's culprit

edit :

to make my self more clear - you need to connect output from emu card in unbalanced manner .

I'm not familiar with your card - does it have sort of XLR connectors ?

in that case , tie 1&3 marked pins on XLR cable connector ; that;s gnd
pin No.2 is hot
 
No bias current on my F5

rdk845 said:
please help a newbie... I have made one up with p to p using the Juma's lay out. I have reduced the P1 and P2 value to minimum . .....
Originally posted by cviller
Now try to crank up the resistance on P1 and P2 - this should give you some current through R11 and R12, but be careful......
I'm having problem with my F5 having bias currents. Now I have taken out the channels from heat sink and slowsly increased the P1 and P2. But I don't see the voltage more than ~100mA. The voltage across the P2 never goes higher than ~3.2V even when I go the way up in N-channel part, while across P1 I can get higher than 4.2V. In both channels I can't get more than 0.1V across R11 and R12. I have replaced all transistors in N parts, and there is no change. Could anyone please let me know how I can go around finding the culprit? Thanks!
 
labjr said:
Is the hum louder than the music is when you plug it into the input? Then the problem may be your source.


EUVL said:
> i used 2sk1530 and sj201. bias is 1,5a and i see 2,83volts on r3 and r4..

The Toshibas have about 2.5V Vgs at 1A, so the 2.8 you see is about normal. I assume you are using 0R47 for source resistor.


Patrick


now i connected the f5 amp to the speaker output of my denon pma495 r amp(denon amp has 70watt output for 4ohms) with a 13,6uf(paralel of 2x6,8uf) mkp coupling capacitor..i am surprised..amp is now playing loudly and very well :D there is no hum buzz or sth like that :D :D i didnt understand..what is the input voltage of f5 amp?..i think i need a very high gain preamp :smash: :smash:
 
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umut1001 said:






now i connected the f5 amp to the speaker output of my denon pma495 r amp(denon amp has 70watt output for 4ohms) with a 13,6uf(paralel of 2x6,8uf) mkp coupling capacitor..i am surprised..amp is now playing loudly and very well :D there is no hum buzz or sth like that :D :D i didnt understand..what is the input voltage of f5 amp?..i think i need a very high gain preamp :smash: :smash:


did you read what I wrote as Re - few posts above ?

you need few V for full blast from F5 , not speaker level from amp !
 
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Re: Chokes

danny_66 said:
Hello,
For the PS I'm thinking of a CLC
Browsing in the RS components I find some cheap common mode chokes of 10mH, 5A
http://be02.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=4890419
Can these chokes be used in the PS for an F5 ? One coil of the choke in series with the + supply and the other coil in series with the - supply.
Regards,
Danny


they're 5A just for AC current ;
what you need here are chokes for DC - mucho different animals ...
 
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umut1001 said:
yes of course i read it.an f5 amp must play with few voltages.but my amp doesnt play with few voltage..i didnt understand..but now it is playing very good with amp output :D ..i didnt understand the problem..


you probably tried balanced output from your EMU card - to connect to F5 , which is equipped with unbalanced input .

what you need is to connect balanced feed in unbalanced manner .

I wrote you how , suspecting that you have XLR connectors on EMU side