Author Topic: PREROTICA... a tube preamp... (Read 54911 times)

JojoD818 · « **Reply #60 on:** Sep 28, 2004 at 03:13 PM »

Quote from: Garp on Sep 28, 2004 at 11:08 AM

Thanks very much Jojo! Now I only have to research how a CF is done.

Give me some time to find out where the heck is the schematic of that 12au7 CF that I used months ago, very effective and transparrent so easily integrated and will only use one dual triode tube.

Cheers!

JojoD818 · « **Reply #61 on:** Sep 28, 2004 at 03:15 PM »

Quote from: s2kov on Sep 28, 2004 at 01:52 PM

RCA Phonostage with lower B+

Sir ok yan, try mo na and balitaan mo kami. Konti lang naman pinagkaiba nyan sa ginawa ko except for the higher v+.

s2kov · « **Reply #62 on:** Sep 28, 2004 at 03:31 PM »

Mukhang ito na nga cguro kc the one you built will require me to have another x'former that has higher voltage....

Thanks....

arnoldc · « **Reply #63 on:** Sep 28, 2004 at 03:31 PM »

garp, you will still need a preamp even with the phonostage. so just sub a 250K ALPS instead of 100K and you save on the hassle of putting in another tube as CF.

but if you insist, here's a cathode follower for you

12AU7, plate at B+ of 250V, Rk = 20K, then put a cap (around 0.33uF) from 12AU7 cathode to output, then Rl = 100K (output to ground)

this gives a gain of .92, Zout of 441 ohms

s2kov · « **Reply #64 on:** Sep 28, 2004 at 03:41 PM »

In addition, Frank's phono needs to have 4.7uF x 10 or 22uF (polypropylene caps). Mukhang wala namang availabale na 22uF & 47uF na polyprop cap or else pieces of caps will be paralleled to cathode bypass. Dami nun!!!!

JojoD818 · « **Reply #65 on:** Sep 28, 2004 at 03:49 PM »

Quote from: arnoldc on Sep 28, 2004 at 03:31 PM

garp, you will still need a preamp even with the phonostage. so just sub a 250K ALPS instead of 100K and you save on the hassle of putting in another tube as CF.

but if you insist, here's a cathode follower for you

12AU7, plate at B+ of 250V, Rk = 20K, then put a cap (around 0.33uF) from 12AU7 cathode to output, then Rl = 100K (output to ground)

this gives a gain of .92, Zout of 441 ohms

ayan pala garp, may circuit na si arnoldc. good luck sir.

arnoldc · « **Reply #66 on:** Sep 28, 2004 at 03:51 PM »

andy, get solen. they have 22uF and 47uF or just use black gate.

s2kov · « **Reply #67 on:** Sep 28, 2004 at 03:55 PM »

black gate yung available kay mickey? hhmmmm.... dalawa na kayo ni frank nagsabi skin nyan.

Quote from: arnoldc on Sep 28, 2004 at 03:51 PM

andy, get solen. they have 22uF and 47uF or just use black gate.

arnoldc · « **Reply #68 on:** Sep 28, 2004 at 04:12 PM »

o gawa na!

may prototype chassis na ko for the fdegrove phono stage

konting sipag na lang

Garp · « **Reply #69 on:** Sep 28, 2004 at 04:18 PM »

Quote from: arnoldc on Sep 28, 2004 at 03:31 PM

garp, you will still need a preamp even with the phonostage. so just sub a 250K ALPS instead of 100K and you save on the hassle of putting in another tube as CF.

but if you insist, here's a cathode follower for you

12AU7, plate at B+ of 250V, Rk = 20K, then put a cap (around 0.33uF) from 12AU7 cathode to output, then Rl = 100K (output to ground)

this gives a gain of .92, Zout of 441 ohms

Thank you Arnold. If I'm going to add another tube I'll probably use it as a last resort unless I can't get anything simpler that can drive a 100K load. Here's another circuit that I found--am not sure though if it can drive 100k.

s2kov · « **Reply #70 on:** Sep 28, 2004 at 04:20 PM »

yung prototype ko antagal na dito, cge mamaya magbubutas na ko kahit paunti unti....

arnoldc · « **Reply #71 on:** Sep 28, 2004 at 04:31 PM »

garp, by just looking at Rl, which is 470K, it's no different

andy, dalawang butas lang yan! he he

s2kov · « **Reply #72 on:** Sep 28, 2004 at 04:53 PM »

palit na ko maliit yung dati eh....

JojoD818 · « **Reply #73 on:** Nov 09, 2004 at 08:56 PM »

JojoD818 · « **Reply #74 on:** Nov 09, 2004 at 08:57 PM »

Thanks!

iceman90a · « **Reply #75 on:** Nov 09, 2004 at 10:52 PM »

tapos na!

humanda kayo ngayon

H a n $ · « **Reply #76 on:** Nov 09, 2004 at 11:05 PM »

OO nga saw that last month na chop chop pa now finish na pala...

kid · « **Reply #77 on:** Nov 10, 2004 at 09:24 AM »

Naku!!! matinding SARS na naman ito

wag ng iparinig ito

joke lang

H a n $ · « **Reply #78 on:** Nov 10, 2004 at 10:08 AM »

Quote from: punk kid on Nov 10, 2004 at 09:24 AM

Naku!!! matinding SARS na naman ito wag ng iparinig ito joke lang

asan si senor wanderlust now your chance!!

Control · « **Reply #79 on:** Nov 10, 2004 at 10:16 AM »

Quote from: hans adriane on Nov 10, 2004 at 10:08 AM

asan si senor wanderlust now your chance!!

wow..malilito nito si senor wanderlust... beauty #1 ba o beauty no#2...

baka naman pareho..

JojoD818 · « **Reply #80 on:** Nov 10, 2004 at 10:50 AM »

Grabe, may nag shootout kaninang umaga, masyadong madugo ang pangyayari. Hindi ko nga alam kung nakuhanan ko ng pic. tsk tsk tsk.....

kid · « **Reply #81 on:** Nov 10, 2004 at 10:55 AM »

sino kaya ang may ari nito?

taga pinoydvd ba ito? o kwela boy ito? tingin nyo guys....

Control · « **Reply #82 on:** Nov 10, 2004 at 11:03 AM »

Quote from: JojoD818 on Nov 10, 2004 at 10:50 AM

Grabe, may nag shootout kaninang umaga, masyadong madugo ang pangyayari. Hindi ko nga alam kung nakuhanan ko ng pic. tsk tsk tsk.....

wow, Master Jojo...paki post naman yung mga highlights ng shootout..

kid · « **Reply #83 on:** Nov 10, 2004 at 11:09 AM »

tutoong shoot out yata yun pre......... holdaper vs. pulis

Masta Joe,

dalin mo sa nov. 27 yan para masintensyahan natin

Control · « **Reply #84 on:** Nov 10, 2004 at 11:22 AM »

Quote from: punk kid on Nov 10, 2004 at 11:09 AM

tutoong shoot out yata yun pre......... holdaper vs. pulis

Madugo nga yan..

JojoD818 · « **Reply #85 on:** Nov 10, 2004 at 11:34 AM »

Quote from: punk kid on Nov 10, 2004 at 11:09 AM

tutoong shoot out yata yun pre......... holdaper vs. pulis

Masta Joe,

dalin mo sa nov. 27 yan para masintensyahan natin

Totoong shootout nga ang nangyari, "The Assassin" at "The Law" nagharap kanina 5:30AM!

kid · « **Reply #86 on:** Nov 10, 2004 at 12:28 PM »

mga bagong talent mo pala yan sir, ang aga ng shoot out mo

who is the winner?

JojoD818 · « **Reply #87 on:** Nov 10, 2004 at 01:45 PM »

Naka NOS yun law, samantalang naka EH lang yun assassin, kawawa naman.

Kakainis, akin pa naman yun isa.

JojoD818 · « **Reply #88 on:** Nov 10, 2004 at 01:51 PM »

parang magkakarera itong dalawa na ito na nasat starting line....

wanderlust · « **Reply #89 on:** Nov 10, 2004 at 02:37 PM »

gaganda nyan sir ah! for sale ba yang isa nyan, im in the market pa naman for a preamp which is tube rectified? gusto ko yong nanalo ha, yong itim ba! ehehehe