Pumpkin preamp - ordered by Steen , official making thread

[Blues]

Originally posted by Magura



Right, should we name you KK the second?


Magura

In some parts "Ch" is pronounced like "K". Can we call you "KoKy"?

[dviswa]

Originally posted by AR2
I did adjustment per Choky's instructions. I do not have F4 and wanted to drive my Aleph 30 so I needed to lower value for two resistors and voila!
AR2 [/B]

AR2,
I am not sure in understand, please explain.

Originally posted by AR2
I did had a brief listen at BAF but I wouldn't take that seriously. Now I had it set up and I had my X BOSOSZ to compare to. It is unbelievable difference. Do not take me wrong - I still like my X BOSOZ, but I was just speechless once I heard amount of top detail from Pumpkin. I was amazed how come that I didn't miss all that detail before? I do not know but it is like Pumpkin has opened whole another dimension on the top of the spectrum. It is very detailed and bright amp. When I say bright not in the negative way, and amazingly there is still very strong and deep bass.

My pumpkin is still based on make shift XBOSOZ power supply while I am waiting for Shanty boards. This pumpkin has special value! It was constructed by Choky, Anatech, Magura and myself. I am afraid to change it since it might loose its international flair.

There is a special shielded wire that Magura and Anatech called Wire from Hell, but they still succeeded in completing it for the BAF.
I will be trying different caps in output to see how it will affect sound. I would strongly advise to try this preamp for F4 or any other amp. It is just unrealistically good.
[/B]

That is one glowing rave

Dinesh

[RKH]

Hi Choky,
Any update on possible shipping dates?

Cheers,
Ryan

[Zen Mod]

Originally posted by dviswa

AR2,
I am not sure in understand, please explain.


....

matter of gain ;

see cookbook for assembly

[Zen Mod]

Originally posted by RKH
Hi Choky,
Any update on possible shipping dates?

Cheers,
Ryan

what's not sent 31.10. , it will be on Monday ; I think that your package is still in my workshop ( Haaland , you are ? ) .

I planned today , but didn't succeed because of everyday family issues

important is that I have all eeny weeny parts , that was PITA to find them in needed amount for matching purposes ;

for instance - LM336Z-2,5 you can find in gallons everywhere , but that's not the case with (for Pumpkin needed) LM336Z-5,0 ........... buying them from each vendor I know in greater amount than 20pcs is a dream ........

[RKH]

Originally posted by Zen Mod



what's not sent 31.10. , it will be on Monday ; I think that your package is still in my workshop ( Haaland , you are ? ) .

I planned today , but didn't succeed because of everyday family issues

Haaland, yes, that's me. Re: 'Everyday family issues" ... i hear ya' brother. No worries on this end.

Cheers for the reply.

Ryan

[lykkedk]

ZenMod, I know that you can't remember the open loop gain / close loop gain, of the circuit, but is it possible that it can be explained howto calculate it.

The thing ís, that maybe somebody want to increase the gain, which is 100k / 10k = 10x of 'standard' circuit (R1, R3, R5, R6) give's this gain. I increased the 100k(R5, R6) to 147,5k, and decreased the R1, R3 to 6,8k giving me approx. 20x of gain... eg. the swings around 40v with an input of 2v in my case.

I can't remember the excact, 'max' voltage which the F4 can handle... But if one look forward to attach, an not so gain-strong phonostage perhaps, giving out.. say 1v, the F4 will only be feeded with 10v on standard , and around 20v in my setup... If the F4 need's... let's say around 25-30v for full throttle, the thing is still missing something to drive it to the max.

I know, that all such adjustment's has a backside, but i hope you got my idea, to conclude the stuff in the revissed cooking-book, BUT this is just an idea i have.

My DAC, gives around 1,6v out, so i think my setting's on is perfect for that, giving around a voltageswing of 34v (16v on standard )...

Jesper.

[dviswa]

ZM, anybody,

C4/C5 & C11/C12 are the output caps, I know you have said use your fav. But, I do not have a "fav". I am thinking of using
Black Gate N 47mfd 50V available in partsconnexion for $10, bypassed with 1mfd Vishay MKP 416-420 available on Digikey for a buck.

Why 47mfd? Well, my pumpkin will also be doing double duty of a headphone amp. I thought a larger cap will help with lower impedance cans. Or is this not a good idea?

What do you guys think of this choice? Any other suggestions?

Thanks,
Dinesh

[steenoe]

Guys, you are bored..... Here is something to have you listen up..
Since this thread has my name printed on it, I thought that you might want to see one of my fav. flies::::-) he-he Here ya go, take a look at the sweeping flow, that this fly has........Makes you want to throw it into thew current...... I am sold, Greame is, the question is, are you???? Yep, I dressed it......;-)

Steen

[mpmarino]

Originally posted by steenoe
Guys, you are bored..... Here is something to have you listen up..
Since this thread has my name printed on it, I thought that you might want to see one of my fav. flies::::-) he-he Here ya go, take a look at the sweeping flow, that this fly has........Makes you want to throw it into thew current...... I am sold, Greame is, the question is, are you???? Yep, I dressed it......;-)

Steen

Whoooah! This, sir, is waaay OT! This has got to stop.

Nice fly.

Even nicer to see your post