F4 power amplifier

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#621
The biggest difference is the more elaborate volume control,
rendered in discretes instead of surface mount, more inputs,
separation of digital control and the two channels, and we make
the technicians wash their hands before they touch them.

😎
 
#622
tnx Papa,as always............

please- be sure to pour few glasses from me.....when you arrive at
AR2 's (Simovic......crazy photographer) place .......... 😉

I suppose that this is most important :

Nelson Pass said:
...................................... and we make
the technicians wash their hands before they touch them.

😎
Click to expand...


:devilr:
 
#625
lykkedk said:
Hi.

I am currius if someone have a pcblayout, which fit for the R0 4/17/07 ? - There is some issue with the 'IN' connection etc... ?

Also i would be very pleased, if someone could explain how much 'preamp' it would take to drive the f4 in a full balanced dual-mono block (4 pcb's + 2 torrids 2x18v 500VA).
It's not that i did not read this thread, and the 'mate for f4' thread also, but there is so much talk about voltage-swing / db-gain etc... that i am a bit confused.

I had been listening to the f4 at Steenoe's placed (I also mentioned this earlier in this thread), and i am in no doubt, that this amplifier sounds very veery good, and that i really would like to build one myself. I through have a slight feeling, that i would have a problem with my speaker/preamp setup, which was discussed in the 'mate for f4 thread' too...

Well, i have not so much acknogledge about the db / voltage-sving things, so please be gentle, if someone would try to explain this to me ! :cannotbe:

Jesper
Click to expand...

Hi Jesper. As far as I remember you have a X-BosoZ? Did you try to raise the gain? Try to increase R18 and R19 on this sch. to 80k-100k. That will give you all the gain you need. 100K is 19dB gain in theory, but its much better to just try it out😉

"First build then ask"
Click to expand...
I really like that one😎

Steen🙂
 

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#626
Nelson Pass said:
If you built it yourself, you can always scale the gain and power
supply up to get what you need.

😎
Click to expand...


According to the service manual of the Aleph L , the gain can be adjusted by changing the value of the input resistor(s) 47K gives 0dB gain, 22K 6dB, and 10K 12db. With 5K we will get 22dB and I guess it would be too much. Or not?
With 7K5 will we get about 18db? Must be "just jake" to drive the F4? Can I go for it?

- What would be the effect of upping the supply voltage (to 70V may be) ?
:xeye: Yes yes i should try... and see the result . But I just would like to understand what I do.

Thx in advance
Manuel
 
#627
Steenoe :

Hi Jesper. As far as I remember you have a X-BosoZ? Did you try to raise the gain? Try to increase R18 and R19 on this sch. to 80k-100k. That will give you all the gain you need. 100K is 19dB gain in theory, but its much better to just try it out
Click to expand...

Sorry about that, its a 'normal' old fashion bosoz running unbalanced right now.. 😉

Well my bosoz is with 124ohm (13,5db in my setup) for maxium gain, but somehow i feel, it's not enough, that's why i asked if the x1 delivered the stuff somehow differently ?

Maybe i will take a closer look, at the aleph p 1,7, which seem's' like a bit more heavy, than my bosoz, and i think i could use my +rail from my bosoz to test it.

Jesper.
 
#631
Ok then... I will try it out, whitin the next few day's guys 😉 ... My only consern is, that the 124 ohm resistor is a seriel-resistor connected to a 500ohm potmeter, which i allready disconnected a long time ago.
But right now i am busy designing and etching a pcb for an 11vdc psu for my dac. :xeye:

Jesper 😉
 
#639
Done. 🙂

Since the search engine can't seem to find two-letter words like 'F4' it's almost impossible to find this thread unless you type the whole thread name.
Just bookmark it if you want to keep this reference for later use.

/Hugo
 
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