Pumpkin preamp - ordered by Steen , official making thread

[Zen Mod]

Originally posted by lykkedk


Thank's man... Actually i just tried it.

If i feed with 2vac sine, then 30vac sine come's out unbalanced, with -out 'open'... with -out closed, it spitzz out 45vac sine... that's a big difference...

JUST don't understand why ??? but nevermind... it work's fine.
I make this unbal/bal selector, so that i got possibility to use with other amp's than my F4...

Jesper.

it's easy to understand - you always need two points to establish any voltage difference ;
with one leg open , you have gnd somewhere, but not really where it need to be ;

when you ground one of outputs ( you know - you can choose which leg you'll ground ) you have established both points , needed for current flow......

be careful - using with F4 oriented gain setting - with other amps

[carpenter]

Originally posted by Zen Mod



it's easy to understand - you always need two points to establish any voltage difference ;
with one leg open , you have gnd somewhere, but not really where it need to be ;

when you ground one of outputs ( you know - you can choose which leg you'll ground ) you have established both points , needed for current flow......

be careful - using with F4 oriented gain setting - with other amps

So, the pumpkin does single-ended out. I thought it might, but forgot where I read, or forgot to ask.

Just remember to ground one of the outputs. Check.

If this is supposed to be an inverting amp, do I gound the negative out?

[Zen Mod]

Originally posted by carpenter



So, the pumpkin does single-ended out. I thought it might, but forgot where I read, or forgot to ask.

Just remember to ground one of the outputs. Check.

If this is supposed to be an inverting amp, do I gound the negative out?

where is the fun if I tell you everything?



just imagine xformer instead of ; both prim and sec CT-ed .

[lykkedk]

it's easy to understand - you always need two points to establish any voltage difference ;
with one leg open , you have gnd somewhere, but not really where it need to be ;

Woow... ofcause ZenMod... easy to understand, i also know that about floating gnd, but didn't just think of it in this case. I don't know why, but sometimes it's difficult to me to understand thing's in other perspectives than the one's i used to work with...

This is a very good explanation ZenMod, thank you for that.

Jesper.

[Manu]

Sasha,
I wan't some of these hudgely hugly pcbs too.
Excitement not any more under control.
Pada li snijeg un srbiji like in Betsch?




Monkey face

[carpenter]

Originally posted by Zen Mod
just imagine xformer instead of ; both prim and sec CT-ed .

Yes, that's a great analogy.

But what trips me up is which secondary tap to use if I want inverting. We've got + and - inputs and probably only want a + out relative to ground. I think. So my mind tells me to ground the negative tap.

[lykkedk]

ZenMod:

be careful - using with F4 oriented gain setting - with other amps

Hmmm... Actually i am having BIG problem driving my LeachAmp with ... I must say that i never tried it before i attached my inputselector... hmmm donno right if that's the problem ... will learn more next few day's i guess ... it's irritating but fun too ....

I attached my LeachAmp... and the inputselector/pumpkin is a GIANT disortion machine.... GREEEAT hummming reallly great!

I haven't yet tried the with my dreky inputselector and my F4... btw.

Will tell, about problem in few day''s...

Carpenter:

But what trips me up is which secondary tap to use if I want inverting. We've got + and - inputs and probably only want a + out relative to ground. I think. So my mind tells me to ground the negative tap.

I am pretty sure, it dosent matter... but anyway i would choose to gnd the -out...

Jesper.

[carpenter]

Originally posted by lykkedk
....i would choose to gnd the -out...

Jesper.

Thanks for that. Even though I haven't a solid idea as to why, it just seems to make intuitive sense to have a + out relative to ground.

[Zen Mod]

Originally posted by Zen Mod



where is the fun if I tell you everything?



just imagine xformer instead of ; both prim and sec CT-ed .

Originally posted by carpenter



Yes, that's a great analogy.

But what trips me up is which secondary tap to use if I want inverting. We've got + and - inputs and probably only want a + out relative to ground. I think. So my mind tells me to ground the negative tap.

take literally what I wrote ;

if you want absolute phase in puritan way then ground + output and use - as main one .

[Zen Mod]

Originally posted by Manu
Sasha,
I wan't some of these hudgely hugly pcbs too.
Excitement not any more under control.
Pada li snijeg un srbiji like in Betsch?




Monkey face

it stopped in late afternoon ......... hehe

pada li snijeg in Betsch like in Batsch ......... ?

seems tha now it started again, but slowly ..........

today I Skyped a little with my friend AR2 in SF ........ he told me that he didn't saw snow in 7 or 8 years ......

your package will be sent tomorrow.....