Re: Pumpkin Volume Control
I think that I covered that in Cook Book's addendum ......
anyway - either using input or output unbalanced - most convenient is to ground minus leg , and use positive leg as hot
use whatever attenuator or pot ( up to 50K) , but have that on mind - shunt attenuator ( as shown on that link ) have variable output/input impedance
for Pumpie that isn't problem,but for some sources can be .
edit :
if you choose pot ........ our friend at Dantimax (lookie lookie) have some interesting things
Algar_emi said:
I think that I covered that in Cook Book's addendum ......
anyway - either using input or output unbalanced - most convenient is to ground minus leg , and use positive leg as hot
use whatever attenuator or pot ( up to 50K) , but have that on mind - shunt attenuator ( as shown on that link ) have variable output/input impedance
for Pumpie that isn't problem,but for some sources can be .
edit :
if you choose pot ........ our friend at Dantimax (lookie lookie) have some interesting things
Dviswa, Sylvain :
This is a TKD pot.
http://www.tkd-corp.com/02_products/p_06rotary_f.html
I've ordered mine directly at TKD in Japan (mail).
But, I think there must be some Us-resellers for TKD-products.
There is a german one too :
http://www.thel-audioworld.de/bauteile/regler/Potis.htm
(Somewhat expensive. THEL claims they were custom-made (different log curve: "speziellen Audiokurve" 🙂, etc.), Though. Is it worth it? Don't know).
Manu
This is a TKD pot.
http://www.tkd-corp.com/02_products/p_06rotary_f.html
I've ordered mine directly at TKD in Japan (mail).
But, I think there must be some Us-resellers for TKD-products.
There is a german one too :
http://www.thel-audioworld.de/bauteile/regler/Potis.htm
(Somewhat expensive. THEL claims they were custom-made (different log curve: "speziellen Audiokurve" 🙂, etc.), Though. Is it worth it? Don't know).
Manu
Manu said:
Forget it, I wont publish anything.......Sad enough, this would be an even greater thing than the Pumpkin😉 Let the publishers publish the project, I am surely not gonna do it😀 What I can tell you, is that the guys did notice my favourite transistor!!! Namely the Toshiba 2SK369's....he-he Try and get your hands on some of those.... Inductors/2SK369's he-he..... start to compute
🙂
jacco vermeulen said:
besides Waflers .......... ( I still dunno whazzat )
all I can find ( ECA TDV 2002) about is that 163N isnogood above 18mHoomps , and that xconductance is pretty venerable - in range of 9mS
369 isnogood above 30mHoomps and xconductance is not so venerable ..... in range of 40mS
wackoo dutchie - send me all yours 369s , I'll match them for ya , and never send them back 😉
jacco vermeulen said:
dreky layzeer holder ............
regarding MA furnace - I have those TO3 oldies (135/50) , no more no less than 4 pairs , , nuff 170BL/V for matching, plenty BC variety instead of dreky TO92 Japs ......... ya can help me if you have
regarding best european tippies for rest of circ .......... me hate to chase jap fuses 
No likey new sets of OP pairs ?
what's wrong with plain K389 shtr on the input, why 170s ?
Take pick: original 2x A1145/C2705, or A1360/C3423. or fatter ones like A1306/C3298 if you nutz.
what's wrong with plain K389 shtr on the input, why 170s ?
Take pick: original 2x A1145/C2705, or A1360/C3423. or fatter ones like A1306/C3298 if you nutz.
jacco vermeulen said:
I have those mentioned ; it's sacrilege to let them sleep ,and they aren't worse than origigi ones , I presume
jacco vermeulen said:
I have mucho BL/V , but just few 389s
jacco vermeulen said:
I can't see that you mention any eu tippie .......
I only have 389ies and Jappies to send you, and...cough...small Phili's (if that's your strange thrill)
Get real, n-EU tippies for me, last nice ones i remember were 414/416Cs.
Get real, n-EU tippies for me, last nice ones i remember were 414/416Cs.
Zen Mod said:
If you can put up with th gr version, just let me know, I have plenty of those, unfortunately I only have 10 of the bl version, and Steen is also low on those v types, 7 as I recall.
Magura 🙂
Variac said:
It BETTER be scary good or a mod posse is comin' for ya-
That means me buying Cal a plane ticket! 😉
misrepresentation of preamp SF - scary factor- 10 yrs in the bin!
But seriously, you say about any pot up to 50k will work with the Punky. That sound unfussy and aggreeable - like it's father..
I'll soon be ordering resistors for a switched attenuator (not shunted)
Since it can be any value up to 50 is there a preference depending on the amp input impedance or somethin'? Listening to SY, (I'm gonna stop taking advice RIGHT after you give me some!) I made my F4 with 200k impedance so his drecky tube pre will be all that it can be! Gotta take advantage of those JFETs! Would that point to a particular pot impedence? Otherwise I'll probabbly go 20-25 K or some such for the thing....
variac
look here: http://tiny.pl/p4bs
if you prefer lower version (10K ,for instance - better - if your sources can handle ) - look for other items of seller
you can hardly make it cheaper
edit .......... my brain is choking , evidently ....... that's just two channel version ................. I can't remember does he 4 channel versions........ 😕
still - worth cheking
No big deal, i had some 1000uf/63V on the shelf and no others that would fit.
Just fun to tease the BG/GC/Tweak folks
Just fun to tease the BG/GC/Tweak folks
Can a Pumpkin run on a power supply of +30v/-30v?
If so, are there any changes needed to the components or setup? Or will that affect the linearality of the the Fets or have an adverse effect on the sound?
I do not need such a high gain anyway, thinking of going for a gain of 10 or less (probably 5-7) - will adjust the necessary resistors for those gain.
Asking because I have a regulated linear supply of +30V and -30V on hand.
her shann
If so, are there any changes needed to the components or setup? Or will that affect the linearality of the the Fets or have an adverse effect on the sound?
I do not need such a high gain anyway, thinking of going for a gain of 10 or less (probably 5-7) - will adjust the necessary resistors for those gain.
Asking because I have a regulated linear supply of +30V and -30V on hand.
her shann
hershann said:
naah - just go for it ;
in Cook Book you'll find everything you need to know about setting gain for your needs ;
just one note - and you'll probably note my words not as ones from seller , but .........
without shunt reg ( not just Shunty , any other decent shunt reg) Pumpkin is very decent preamp ;
with shunt reg - it's great preamp .
few volts up or down aren't so important .
Zen Mod said:
Zen Mod,
looks like I'll be going shunty then, I'll email you when I am ready to get the boards and matched transistors.
Say I use a 10k ohm pot, what's the input impedance of the pumkin if the attenuator is set to minimum?
her shann
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