Pumpkin Preamp - Perfect for F4

Jump to Latest
lykkedk

lykkedk

Member
Joined 2002
HeHe... Success !

R1/R3 = 8,1Kohm ... R5/R6 = 147,5Kohm (VoltageGain ~x18)

~3v input / 50v out (balanced)
~1v input / 18v out (balanced)

Clipping appears, at approx. 4v input (Near 70v out !!!)
There is a problem, with uploading picture's right now, so please visit LINK

Remember to roll down site. :yes: :Pinoc:

ZenMod :worship: :worship: :worship:

Jesper.
 
Zen Mod

Zen Mod

Official Court Jester
Joined 2003
zenmod.in.rs/
Paid Member
lykkedk said:
HeHe... Success !

R1/R3 = 8,1Kohm ... R5/R6 = 147,5Kohm (VoltageGain ~x18)

~3v input / 50v out (balanced)
~1v input / 18v out (balanced)

Clipping appears, at approx. 4v input (Near 70v out !!!)
There is a problem, with uploading picture's right now, so please visit LINK

Remember to roll down site. :yes: :Pinoc:

ZenMod :worship: :worship: :worship:

Jesper.
Click to expand...

and sound?

even mono?

seems that you owe me six pack next year in your neighborhood , at European Burning Amp Weekend

:devilr:

ps. post pdf of your pcb to all greedy boyz with cookin' missus irons .................

:Popworm:
 
lykkedk

lykkedk

Member
Joined 2002
and sound?

even mono?

seems that you owe me six pack next year in your neighborhood , at European Burning Amp Weekend



ps. post pdf of your pcb to all greedy boyz with cookin' missus irons .................
Click to expand...

all will be done... maybee listning session soon.... next few day's i havent got that much time unfortunately :rolleyes: ...

European burning amp.... tell me more 'sixpackZenMod' :worship: :worship: :worship:

Jesper.
 
Zen Mod

Zen Mod

Official Court Jester
Joined 2003
zenmod.in.rs/
Paid Member
I hope that Magura will see them in flesh...........

they just arrived - first batch of main pcbs

reg pcbs are little ( :cuss: ) delayed ...........

anyway - just a quickie scan , my digi isn't near me ....

1/2
 

Attachments

  • scan1.jpg
    scan1.jpg
    84.5 KB · Views: 698
lykkedk

lykkedk

Member
Joined 2002
You ba...... - Mine pcb, look's foolish compared to your's :clown:

Anyway, today i tried hook'ed 1channel up with F4 (Balanced out 1channel aka' mono)... Let's say, the sound is amazing, simply asstunning, and very clear. First thing i noticed, was very much 'punch', something my setup likes very much.
This pre. is absolutely something different than other i had been listning too, in the good way :D. Well i am not telling more about this now, as everything isen't made finish yet. (pumpkin wasent even hot when listning, nor adjusted 100% either),
Anyway i had a quistion for you today too ZenMod :D

I had been lowering R1/R3 to 8,1K and R5/R6 is increased to 147,5K for giving gain at ~18 times. Is there a formula for calculating this, say if i want 30x i increase R5/R6 into 200K and decrease R1/R3 to 6,8K giving like ~29. Will it give more heat ? Will it make noise ? Should i not do it ?... What's to tell about this ?

Jesper.
 
Zen Mod

Zen Mod

Official Court Jester
Joined 2003
zenmod.in.rs/
Paid Member
lykkedk said:
You ba...... - Mine pcb, look's foolish compared to your's :clown:

Anyway, today i tried hook'ed 1channel up with F4 (Balanced out 1channel aka' mono)... Let's say, the sound is amazing, simply asstunning, and very clear. First thing i noticed, was very much 'punch', something my setup likes very much.
This pre. is absolutely something different than other i had been listning too, in the good way :D. Well i am not telling more about this now, as everything isen't made finish yet. (pumpkin wasent even hot when listning, nor adjusted 100% either),
Anyway i had a quistion for you today too ZenMod :D

I had been lowering R1/R3 to 8,1K and R5/R6 is increased to 147,5K for giving gain at ~18 times. Is there a formula for calculating this, say if i want 30x i increase R5/R6 into 200K and decrease R1/R3 to 6,8K giving like ~29. Will it give more heat ? Will it make noise ? Should i not do it ?... What's to tell about this ?

Jesper.
Click to expand...

well ......... I know that I'm Ba...... ( :clown: ) but just imaaaaagine how Ba..... Papa is .......... :rofl:

anyway- you can alter values of feedback loop to your choice ,thinking that (roughly!!!) input impedance is ~ value of your R1(R3) resistor and- most important - you can't go with CLG much near OLG without penalties ;

as I wrote before - I didn't measure OLG and I didn't remember what I calc on back of ....toilette paper ....... :clown: , but- in any case your Cathode Ray Oscilloscope will tell ya something about THD before you can hear with ears........

anyway - why you need astronomic input voltages in F4 ,stacked or not ......... are you deaf .......... or you try to PA kindergarten?

:clown:

edit:

:Pumpkin: is hottest when is in idling , doesn't matter what gain you set ; it's A class , ya remember?
 
lykkedk

lykkedk

Member
Joined 2002
anyway - why you need astronomic input voltages in F4 ,stacked or not ......... are you deaf .......... or you try to PA kindergarten?
Click to expand...

Hehe... yep, i live near such a thing!... Anyway i just want to drive the F4 to max, at approx. 1/2 volume.. But i see now, it's a stupid thing to do. End of that quistion :)

is hottest when is in idling , doesn't matter what gain you set ; it's A class , ya remember?
Click to expand...

I just throught that i was changing bias (stupid throught!).. It's clear to me, how it work's now thank's :)

BTW: Have you tested that +36/-36v regulator ? It's just that i made a simmulair one, with 6x6,8v zener = 40,8. Voltage is dropping to 35v with 1 channel hooked up (Maybee i will adjust zener to 42v later). I don't know how much it will lower more (if any) with 2channel's... Just to tell you (and not trying to be clever here :D). It proberly dosen't mean anything btw.

Jesper.
 
Zen Mod

Zen Mod

Official Court Jester
Joined 2003
zenmod.in.rs/
Paid Member
lykkedk said:


.........

BTW: Have you tested that +36/-36v regulator ? It's just that i made a simmulair one, with 6x6,8v zener = 40,8. Voltage is dropping to 35v with 1 channel hooked up (Maybee i will adjust zener to 42v later). I don't know how much it will lower more (if any) with 2channel's... Just to tell you (and not trying to be clever here :D). It proberly dosen't mean anything btw.

Jesper.
Click to expand...


why I need to test that silly thing- it's boiled water and remember that's just schematic ............ nobody can say that your specimen will work, if you drek something :devilr:

reg is reg- his role is to regulate voltage , in some boundaries ;

you probably made some mistake- in wiring or in approach....... have your xformer enough voltage and mA for task?

you must have firm input voltage in reg , to have firm output

btw- for reg of that sort , output voltage IS overall zenner string voltage MINUS Ugs ............

edit:

why switch to open source........ XP is free,too ............ :devilr:
 
Zen Mod

Zen Mod

Official Court Jester
Joined 2003
zenmod.in.rs/
Paid Member
lykkedk said:


.........

BTW: Have you tested that +36/-36v regulator ,,,,,,,,,,,,,,,,,
Click to expand...


like usual, I made mistake in hand-drawing - switched legs of 9610 .... I hope :clown: that now is OK ( lookie lookie at pic)


Magura said:


Ok, have you gotten a sixpack from him? Has Steen? I know I havn't!

.......So why do you keep helping him?


Magura ;)
Click to expand...

better like this than he start messin' around with phone calls :devilr:
 

Attachments

  • simple-pumpkin-regw.jpg
    simple-pumpkin-regw.jpg
    47 KB · Views: 618
You must log in or register to reply here.
Top Bottom