New-building of my F5

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troystg

troystg

Member
Joined 2004
Babowana

Babowana

Formerly "jh6you". R.I.P.
Joined 2006
aheadamp.com
Hi, JJ

R.E.M., First we take Manhattan :nod:

I like The Lilac Time, Bird on the wire :nod:

Tori Amos, Famous Blue Raincoat?
>>:smash:<<


Cheers,
 

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Babowana

Babowana

Formerly "jh6you". R.I.P.
Joined 2006
aheadamp.com
Papa, it was in the year 2002. Nevertheless, do you remember your this advice on how to measure the amount of negative feedback (The advice was about my X-amp of ZV2.)? Six years have passed, but I still do not understand this clearly. Could you kindly give me another simple and clear explanation?

The same way of measurement is okay also for F5?

Thanks.

>>:)<<
 

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Zen Mod

Zen Mod

Official Court Jester
Joined 2003
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Babowana said:
Papa, it was in the year 2002. Nevertheless, do you remember your this advice on how to measure the amount of negative feedback (The advice was about my X-amp of ZV2.)? Six years have passed, but I still do not understand this clearly. Could you kindly give me another simple and clear explanation?

The same way of measurement is okay also for F5?

Thanks.

>>:)<<
Click to expand...


as I see it :

connect amp to 8R resistive;

drive it with 600R generator ; measure gain of amp ; write it down as A1

then drive it with 10K generator ( even same as in case No.1 but with 10K in series ) ; measure gain of amp ; write it down as A2

then feedback of da amp is 20log(A1/A2)

simple , isn't it ?

when you're Santa , with snowy Stage Coach full with gadgets ......... and Brain

:rofl:

edit :

ya like Lou Reed - Sally can't dance album?

:hphones:
 
Gyuri

Gyuri

Member
Joined 2003
Well, Babo, I see it here Lou Reed. And what you believe his wife, Laurie Anderson her music? My hot favourite. She is a meteoric little lady.
My best wishes enclosed herewith:
Gyuri
I make my work in one of SEH Hungary firms recently otherwise. Beautiful big modern factory.
Samsung Electronics Hungary
 
Nelson Pass

Nelson Pass

The one and only
Joined 2001
Paid Member
Babowana said:
Papa, it was in the year 2002. Nevertheless, do you remember your this advice on how to measure the amount of negative feedback (The advice was about my X-amp of ZV2.)? Six years have passed, but I still do not understand this clearly. Could you kindly give me another simple and clear explanation?
Click to expand...

This circuit dependent. In the case of the F5 you can compare the differential
voltage between the Gates and the Sources of the JFETs to the output
voltage for a given load. Thumbnail calculation shows about 20 dB open loop
contributed by the JFETs and a comparable figure contributed by the Mosfets.

With a gain of 15 dB, this leaves you with approximately 25 dB of feedback.

:cool:
 
Babowana

Babowana

Formerly "jh6you". R.I.P.
Joined 2006
aheadamp.com
Nelson Pass said:


This circuit dependent. In the case of the F5 you can compare the differential voltage between the Gates and the Sources of the JFETs to the output voltage for a given load. Thumbnail calculation shows about 20 dB open loop contributed by the JFETs and a comparable figure contributed by the Mosfets.

With a gain of 15 dB, this leaves you with approximately 25 dB of feedback.

:cool:
Click to expand...


Thank you, Papa. It's very clear.


Cheers,

>>:)<<
 
Nelson Pass

Nelson Pass

The one and only
Joined 2001
Paid Member
umut1001 said:
hi Papa.. i have 2x20 volts 250watts(i think it is not very quality)ac transformer..is it possible to supply f5 with this transformer?.what is the max dc value of the amp?.i think i will put 1ohm 10watts resistor between bridge diode and transformer..what do you think about this?does it reduce the supply noise too?thanks
Click to expand...

It all depends on the quality of the transformer. If its a Plitron or
Avel, then it should work fine.

:cool:
 
L

Lesp

Member
Joined 2008
Hawthorne solo and the F5

Hello Mr Pass,
I'm very keen to build an F5 and I'm in on the group order for the PCB's,I also have the parts on order from Tech DIY. My question is do you think that the Hawthorne SI 15 inch coax speakers on open baffles would be compatable with the F5. They are about 96dB/1 watt/Metre so I think that they should be able to make good use of the first watt principal I guess I should have made this enquiry before ordering the parts. Your opinion would be most welcome.

Cheers,
Les.
 
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