Pumpkin preamp - ordered by Steen , official making thread

hershann said:
substitute with film cap

Better any cap across a rectifier diode than no cap, stuff like distortion figures and tolerance don't mean sheet for diode damping.
Cheapo cookybookie says better add some ceramics on the next orderlist, Z/X/NPo ceramics are superior to any film as rectifier bypass and cost mucho less.
(esoteric pric-picks an NPo/COG, 3.9pF-100nF)
 
jacco vermeulen said:


Better any cap across a rectifier diode than no cap, stuff like distortion figures and tolerance don't mean sheet for diode damping.
Cheapo cookybookie says better add some ceramics on the next orderlist, Z/X/NPo ceramics are superior to any film as rectifier bypass and cost mucho less.
(esoteric pric-picks an NPo/COG, 3.9pF-100nF)

Is it true for any kind od Rect.-Diode?
Shotky, Soft recovery, ultrafast etc...?

Manu

Je commande?
 
Very high efficiency speakers. . .

While waiting with eager anticipation for the Pumpkin/Shunty boards, I've been collecting parts out of my junk boxes, and figuring out what I need to order. However, I'm thinking that I may not need the truly manly voltage swing of the Pumpy/Shunty into the F4 with my 106db/w/m DIY Edgarhorns. . .

I've followed the threads on "how" to lower output, but what is stumping me is "how much" I ought to be considering -- I don't want to be running the volume control just cracked open. A pot can be touchy enough, and with stepped attenuators I've found that it is *always* one click to soft, the next click too loud. . . 😱

I currently run the Edgars with a Brenneman cathode follower tube integrated with a whopping 10 wpc, and usually never have the volume control more than 1/4 open.

Suggestions? 😎

It would be nice to have a volume control with very fine control down where I actually use it, and I don't care if it makes 6dB steps at full volume, 'cause it never gets close to that high!

Thanks for your time -- and thanks for the most interesting and entertaining DIY threads I've ever come across. 🙂 :cheers:

Steve Z
near Libby, Montana USA
 
Re: Very high efficiency speakers. . .

zettelsm said:
While waiting with eager anticipation for the Pumpkin/Shunty boards, I've been collecting parts out of my junk boxes, and figuring out what I need to order. However, I'm thinking that I may not need the truly manly voltage swing of the Pumpy/Shunty into the F4 with my 106db/w/m DIY Edgarhorns. . .

I've followed the threads on "how" to lower output, but what is stumping me is "how much" I ought to be considering -- I don't want to be running the volume control just cracked open. A pot can be touchy enough, and with stepped attenuators I've found that it is *always* one click to soft, the next click too loud. . . 😱

I currently run the Edgars with a Brenneman cathode follower tube integrated with a whopping 10 wpc, and usually never have the volume control more than 1/4 open.

Suggestions? 😎

It would be nice to have a volume control with very fine control down where I actually use it, and I don't care if it makes 6dB steps at full volume, 'cause it never gets close to that high!

Thanks for your time -- and thanks for the most interesting and entertaining DIY threads I've ever come across. 🙂 :cheers:

Steve Z
near Libby, Montana USA


did you downloaded Cook Book ?

http://czsr_bac.on.neobee.net/The Pumpkin & Shunty.pdf


just say -yey or ney , and I'll answer , or will not ........

:rofl:

edit :

it's really not important did you downloaded it ; what is important - did you read it ?

:devily:
 
jacco vermeulen said:
Naah, pass.

I think that I need a copy of that edition!!
Here is my Bible 'till now: "Il Cucchiaio D'argento"
"The Silver spoon" Is by far the most sold Cook Book in Italy!!
Since 1950, when it was issued for the first time, it has been a firm stable at every wedding in Italy!!! Tell me about it😀 I simply love Italian cooking😎 Italian style cooking, rock's... Take that my fellow Italians....🙂
Oh and to keep on track, the Pumpkin simply sounds great!

🙂
 
Cookbook/gain question

Yes, I did download and read the Cookbook, (and I thought it was a great thing for you to do). I believe I understand the "how to" part of lowering the gain/voltage swing of Pumpy. But maybe I missed something. I've had the flu for the last couple of days and haven't been in my right mind. :xeye:

What I am not sure about is "how much" to lower the gain. Or perhaps I don't need to lower it at all. I don't mind using the lower part of the pot or stepped attenuator, so long as I have enough control over small adjustments without always hunting and being too loud or too soft.

:dead:

I tried a a well-thought-of Chinese 2A3 integrated amp a while ago with my DIY Edgarhorns, and besides being unacceptably noisy, it was too loud at the third click of the stepped attenuator. :hot:

So maybe all I need to do is figure out the right range of potentiometer. I remember reading that a lower value is theoretically better for performance

Am I barking up the wrong tree? 😕

Feel free to heap ridicule on my head!

Steve Z
Libby, MT USA
 
Re: PS

zettelsm said:
Yes, I did download and read the Cookbook, (and I thought it was a great thing for you to do). I believe I understand the "how to" part of lowering the gain/voltage swing of Pumpy. But maybe I missed something. I've had the flu for the last couple of days and haven't been in my right mind. :xeye:

What I am not sure about is "how much" to lower the gain. Or perhaps I don't need to lower it at all. I don't mind using the lower part of the pot or stepped attenuator, so long as I have enough control over small adjustments without always hunting and being too loud or too soft.

:dead:

I tried a a well-thought-of Chinese 2A3 integrated amp a while ago with my DIY Edgarhorns, and besides being unacceptably noisy, it was too loud at the third click of the stepped attenuator. :hot:

So maybe all I need to do is figure out the right range of potentiometer. I remember reading that a lower value is theoretically better for performance

Am I barking up the wrong tree? 😕

Feel free to heap ridicule on my head!

Steve Z
Libby, MT USA


zettelsm said:
Oh yeah, I will now go back and read through the Cookbook again and the selected posts I've saved. . .

Steve Z

Pumpie:


just use it in 5x gain mode ;

that means 10K in line with gates and 47K in feedback path ;

in case that you feel too small gain , just increase 47K

in any case - that drek is /will be yours , so you can do whatever you want ............. except neg gain ........... ( without meaning on phase ) :devilr: