Hi Jacco ,
that is a great cookbook ,
from a very good cook .
He created such things like
Peach Melba unsw. .
But his style is not that simple
as the Einstein Thing .
Happy cooking !
Jürgen
that is a great cookbook ,
from a very good cook .
He created such things like
Peach Melba unsw. .
But his style is not that simple
as the Einstein Thing .
Happy cooking !
Jürgen
Re: Re: PS
R5/R1 and R6/R3 to 4.7/1 and since R5 & R6 are decreased by 1/2, C1 & C2 are increased by 2X. . . (I did really read the Cookbook -- 101 Ways to Cook Serbian Pumpkin)
After posting my question about potentiometer range, it occurred to me that I could try a couple of cheap stereo log pots in ranges 10K, 25K, 100K and see what I like best before spending $$ for a four-channel. I even have a couple of old ALPS square stereo pots around here somewhere -- and they are Blue! 😀
Thank you,
Steve Z
Zen Mod said:
Pumpie:
just use it in 5x gain mode ;
that means 10K in line with gates and 47K in feedback path ;
in case that you feel too small gain , just increase 47K
in any case - that drek is /will be yours , so you can do whatever you want ............. except neg gain ........... ( without meaning on phase )
R5/R1 and R6/R3 to 4.7/1 and since R5 & R6 are decreased by 1/2, C1 & C2 are increased by 2X. . . (I did really read the Cookbook -- 101 Ways to Cook Serbian Pumpkin)
After posting my question about potentiometer range, it occurred to me that I could try a couple of cheap stereo log pots in ranges 10K, 25K, 100K and see what I like best before spending $$ for a four-channel. I even have a couple of old ALPS square stereo pots around here somewhere -- and they are Blue! 😀
Thank you,
Steve Z
Hi Jacco ,
is that switch on Escoffier ?
( like switch on Bach ?)
Jacco , enjoy the cooking !
Greetings
Jürgen
is that switch on Escoffier ?
( like switch on Bach ?)
Jacco , enjoy the cooking !
Greetings
Jürgen
Re: Re: Re: PS
sorry if I missundestood your question.........
anyway - value of pot will not have effect on gain , at least if you are in range of 10 - 100 K ; in any case - stay in lower range of pot value , if you can .......... it's just more convenient blahblah
zettelsm said:
sorry if I missundestood your question.........
anyway - value of pot will not have effect on gain , at least if you are in range of 10 - 100 K ; in any case - stay in lower range of pot value , if you can .......... it's just more convenient blahblah
I wasn't clear what I was asking, Choky.
I was wondering -- with my very sensitive speakers -- if:
1. I should decrease gain, or,
2. If there is a value of potentiometer that will avoid having all the working range at the bottom, and that will prevent that working range of adjustment -- from too soft to too loud -- being too small.
Or maybe even,
3. Both.
But, after thinking about it last night between bouts of hugging the bucket with the flu, I decided what I should do is leave gain alone at first, and play with some different value pots instead to see if I can get what I want. No sense crippling the F4 by choosing Pumpy gain so low that F4 cannot achieve full output.
Even though I probably listen with milliwatts going to the horns, it would be nice to have the whole 25 wpc available for headroom for transients. Or to listen to my system when I am visiting my neighbor down the road
You're absolutely right -- it's my Pumpy and I can do anything I want! 😀
Thanks for your time and trouble.
Steve Z
I was wondering -- with my very sensitive speakers -- if:
1. I should decrease gain, or,
2. If there is a value of potentiometer that will avoid having all the working range at the bottom, and that will prevent that working range of adjustment -- from too soft to too loud -- being too small.
Or maybe even,
3. Both.
But, after thinking about it last night between bouts of hugging the bucket with the flu, I decided what I should do is leave gain alone at first, and play with some different value pots instead to see if I can get what I want. No sense crippling the F4 by choosing Pumpy gain so low that F4 cannot achieve full output.
Even though I probably listen with milliwatts going to the horns, it would be nice to have the whole 25 wpc available for headroom for transients. Or to listen to my system when I am visiting my neighbor down the road
You're absolutely right -- it's my Pumpy and I can do anything I want! 😀
Thanks for your time and trouble.
Steve Z
zettelsm said:I wasn't clear what I was asking, Choky.
I was wondering -- with my very sensitive speakers -- if:
1. I should decrease gain, or,
2. If there is a value of potentiometer that will avoid having all the working range at the bottom, and that will prevent that working range of adjustment -- from too soft to too loud -- being too small.
Or maybe even,
3. Both.
But, after thinking about it last night between bouts of hugging the bucket with the flu, I decided what I should do is leave gain alone at first, and play with some different value pots instead to see if I can get what I want. No sense crippling the F4 by choosing Pumpy gain so low that F4 cannot achieve full output.
Even though I probably listen with milliwatts going to the horns, it would be nice to have the whole 25 wpc available for headroom for transients. Or to listen to my system when I am visiting my neighbor down the road
You're absolutely right -- it's my Pumpy and I can do anything I want! 😀
Thanks for your time and trouble.
Steve Z
I repeat - you;'ll have no influence on gain and noise , changing pot value ;
you must set gain for your needs ....... dynamic reserve is entirely different issue than gain of Pumpie........ that's dynamic reserve of F4 and Pumpie .........
imagine that you're riding whoompin' 1500mW in your spks , with Pumpie/F4 gain set to 68K/10K .........
in a moment - nasty ZM-like trumpet man just throw all his frustration ( his missus wasn't in mood - last month) , and you have in a moment whoompin' 4K mW in your spk ........
point is that Pumpie/F4 combo isn't surprised with 4K mW demand - neither Pumpie is clipping in input , or output , neither F4 is clipping .......
comprende?
😉
Zen Mod said:
Understood about gain and noise -- R5/R1 and R6/R3 only sets gain. Really!
Guess I am having a major conceptual error -- aka as "brain-fart"-- over how dynamic reserve is totally different issue from Pumpy gain. If Pumpy -- or any preamp -- does not have gain of about 14-15 then it won't drive F4 to full 25 wpc. At least, this is what I thought I understood from Mr. Pass and others on F4 thread. . .
Nice horn example -- is this where expression "horn-y" came from?
Not worried about clipping Pumpy or F4, but thought it desirable to achieve full voltage swing, even if it might not be used with this particular set of speakers.
Sorry -- I'm not usually so dense. Once upon a time I was actually trained in electrical and electronics theory. Too many years sitting in a Control Room watching pretty lights and pushing buttons. . .
Like I said, I can alway change R5/R1 and R6/R3 if the original setting doesn't work for me. Nice thing about DIY.
Steve Z
zettelsm said:
Understood about gain and noise -- R5/R1 and R6/R3 only sets gain. Really!
Guess I am having a major conceptual error -- aka as "brain-fart"-- over how dynamic reserve is totally different issue from Pumpy gain. If Pumpy -- or any preamp -- does not have gain of about 14-15 then it won't drive F4 to full 25 wpc. At least, this is what I thought I understood from Mr. Pass and others on F4 thread. . .
Nice horn example -- is this where expression "horn-y" came from?
Not worried about clipping Pumpy or F4, but thought it desirable to achieve full voltage swing, even if it might not be used with this particular set of speakers.
Sorry -- I'm not usually so dense. Once upon a time I was actually trained in electrical and electronics theory. Too many years sitting in a Control Room watching pretty lights and pushing buttons. . .
Like I said, I can alway change R5/R1 and R6/R3 if the original setting doesn't work for me. Nice thing about DIY.
Steve Z
What's the max output of the average DAC? 2V?
Say if I use a gain of 10 - this will give me +20V / -20V at pumpy output (assuming pot fully open). Single ended output will be +20V
Feeding this into F4 - will cause it to clip - because it's headroom is 18V (single ended)?
Hmmm - I guess whether it will clip or not eventually depends on the DAC (source) input.
Sorry - still learning!
thanks
her shann
hershann said:
Oops,
just re-read the F4 schematic - its +/- 23V at it's rail.
So with a 2V input - the gain of 10 for the pumpkin is just about right.
her shann
hershann said:
(Sound of hand slapping forehead)
Yes, of course! Thank you Her Shann. I had completely overlooked the contribution of the source to driving the F4
Sometimes I think I have an infinite capacity to overlook the obvious. . .
Thanks for clearing up that particular error for me.
Steve Z
Hey all,
I'm trying to build me own pumpkin and got some q's. Unfortunately junkbox style, so sk170' s and different psu. Psu voltages all check out and I've set currents according to cookbook. All component values according to schematic.
However voltage at output (before coupling cap) stays at a little less then positive rail. Cookbook says it should be at 0V, right? it seems i can't adjust it and have a little voltage to ground at input as well, no relative offset.
Now what to do and where to look? I already looked for schematic with currents and voltages in other thread but don't get the clue.
regards,
Joris
ps sorry to be OT but cooking sausages....
damn now they'r burnt... should cook one thing at a time, either sausages or fets.
I'm trying to build me own pumpkin and got some q's. Unfortunately junkbox style, so sk170' s and different psu. Psu voltages all check out and I've set currents according to cookbook. All component values according to schematic.
However voltage at output (before coupling cap) stays at a little less then positive rail. Cookbook says it should be at 0V, right? it seems i can't adjust it and have a little voltage to ground at input as well, no relative offset.
Now what to do and where to look? I already looked for schematic with currents and voltages in other thread but don't get the clue.
regards,
Joris
ps sorry to be OT but cooking sausages....
damn now they'r burnt... should cook one thing at a time, either sausages or fets.
Lookie lookie, clever -IN grounding for the SE inputs😱
Look for small solder blops at the headers...
🙂
Look for small solder blops at the headers...
🙂
Hi Steen ,
this is the shortest signal-path
with JT and Darwin that i have seen , very simple , very elegant !
Greetings
Jürgen
this is the shortest signal-path
with JT and Darwin that i have seen , very simple , very elegant !
Greetings
Jürgen
jazz said:
you don't have enough opened IRF9510s ;
goal is to have more voltage drop across R7 and R8 ; to achieve that :
you need either to increase current through LTP
or to increase slightly values of sayed resistors
What should I say, Clean job Steen
Please Bwana , you know I always need some explanations, even if its obvious for the most.
Manu
Greedy to learn
Please Bwana , you know I always need some explanations, even if its obvious for the most.
Manu
Greedy to learn
steenoe said:
that reminds me .......
steen - you tried chip susy preamp ....... ? ( if I remember that well)
what's difference comparing it to Pumpie ........ neglecting output swing issue ..
?