Banned
Joined 2002
Kooka & Billbo:
A single channel tube pre-amp?? Using dual 12au7 for balanced input??
Noticing that Kooka's board above has provisions for three full wave bridge rectifiers ... ?? is all that required for a single channel ??
Or am I mis-reading the board layout and this is a dual channel circuit??
Anyway, I could very easily be persuaded to get enough boards and parts for two complete, two channel pre-amps (2 boards or 4?).
(Oops, just spotted the double gain variable resistors indicating two channels per board.)
(Also, can or should the 12ax7 be used as substitute??)
Got schematics?
A single channel tube pre-amp?? Using dual 12au7 for balanced input??
Noticing that Kooka's board above has provisions for three full wave bridge rectifiers ... ?? is all that required for a single channel ??
Or am I mis-reading the board layout and this is a dual channel circuit??
Anyway, I could very easily be persuaded to get enough boards and parts for two complete, two channel pre-amps (2 boards or 4?).
(Oops, just spotted the double gain variable resistors indicating two channels per board.)
(Also, can or should the 12ax7 be used as substitute??)
Got schematics?
FastEddy said:Kooka & Billbo:
A single channel tube pre-amp?? Using dual 12au7 for balanced input??
Noticing that Kooka's board above has provisions for three full wave bridge rectifiers ... ?? is all that required for a single channel ??
Or am I mis-reading the board layout and this is a dual channel circuit??
Anyway, I could very easily be persuaded to get enough boards and parts for two complete, two channel pre-amps (2 boards or 4?).
(Oops, just spotted the double gain variable resistors indicating two channels per board.)
(Also, can or should the 12ax7 be used as substitute??)
Got schematics?
Yes, 2 channels.
Banned
Joined 2002
FastEddy said:Kooka & Billbo:
A single channel tube pre-amp?? Using dual 12au7 for balanced input??
Noticing that Kooka's board above has provisions for three full wave bridge rectifiers ... ?? is all that required for a single channel ??
Or am I mis-reading the board layout and this is a dual channel circuit??
Anyway, I could very easily be persuaded to get enough boards and parts for two complete, two channel pre-amps (2 boards or 4?).
(Oops, just spotted the double gain variable resistors indicating two channels per board.)
(Also, can or should the 12ax7 be used as substitute??)
Got schematics?
Opps, I nissed your question about the 12ax7. I would not use them since they would have too much gain and would not work very linear like 6sn7. The board is designed for working with 6sn7 and those would be the best tubes for it.
Yes!! I want it ... please enter my request for:
(2) Two Channel Tube pre-amp circuit boards.
Costs =TBD ? plus shipping in North America. (PayPal or company check?)
Preliminary Documentation (to be edited as project progresses):
Prototype image: http://www.diyaudio.com/forums/attachment.php?s=&postid=1076311&stamp=1165587976
PCB w/ silk screen parts layout: http://www.diyaudio.com/forums/attachment.php?s=&postid=1075771&stamp=1165526525
Begin of construction thread: http://www.diyaudio.com/forums/showthread.php?s=&threadid=91800
... A Dual Channel Valve Pre-Amp for chip amps (Class-D, Gainclone type, power MOSFET, etc.). I intend to couple one finished two channel valve pre-amp board to my NX150 dual mono-block power amp along with a modest effects controller of some kind (to be determined). The purpose would be to provide a two channel input gain control & signal pre-amplification for guitar, unpowered microphone or line level effects generatior.
Guesstimate of bill of materials (draft rev. 0.9 = to be edited):
1 .. The circuit board
2 .. 12au7 Valves (vacuum tubes, new or pre tested)
2 .. PCB upright mount sockets for 12u7 valve
4 ... 4700 uF electrolytic capacitors, polarized, 35 volt? (recommendations?)
2 ... 47 uF (?) electrolytic caps, polarized, 100 volt? (recommendations?)
8 ... 2.2 uF (?) electrolytic (or plastic?) snubbing caps, 35 or 100 volt? (recommondations)
12 ... 1n4001 (?) diodes for 2 low current/voltage bridge rectifiers (& signal control/voltage reference?)
1 ... Zener diode for voltage reference (? value ?)
4 ... 1n4004 (?) diodes for 1 high current/voltage bridge rectifiers
5 ... PCB mount compression termination blocks / off board power (3) & RCA output (2).
3 ... TO3 Transistors (? value / number ?)
4 ... small signal transistors (? value / number ?)
handful ... various metal film resistors and various PCB mount plastic caps.
unknown ... additional PCB mounted parts (any surface mounted parts?)
4 ... PCB mount standoffs = hole location TBD.
? ... ??
1 ... manual and documentation= to be determined. (I have several web domains where PDF files could be placed for convinent download.)
Let's build 'em ...
My test bed setup: ( http://3dotaudio.com/ampics.html & http://aussieamplifiers.com )
(2) Two Channel Tube pre-amp circuit boards.
Costs =TBD ? plus shipping in North America. (PayPal or company check?)
Preliminary Documentation (to be edited as project progresses):
Prototype image: http://www.diyaudio.com/forums/attachment.php?s=&postid=1076311&stamp=1165587976
PCB w/ silk screen parts layout: http://www.diyaudio.com/forums/attachment.php?s=&postid=1075771&stamp=1165526525
Begin of construction thread: http://www.diyaudio.com/forums/showthread.php?s=&threadid=91800
... A Dual Channel Valve Pre-Amp for chip amps (Class-D, Gainclone type, power MOSFET, etc.). I intend to couple one finished two channel valve pre-amp board to my NX150 dual mono-block power amp along with a modest effects controller of some kind (to be determined). The purpose would be to provide a two channel input gain control & signal pre-amplification for guitar, unpowered microphone or line level effects generatior.
Guesstimate of bill of materials (draft rev. 0.9 = to be edited):
1 .. The circuit board
2 .. 12au7 Valves (vacuum tubes, new or pre tested)
2 .. PCB upright mount sockets for 12u7 valve
4 ... 4700 uF electrolytic capacitors, polarized, 35 volt? (recommendations?)
2 ... 47 uF (?) electrolytic caps, polarized, 100 volt? (recommendations?)
8 ... 2.2 uF (?) electrolytic (or plastic?) snubbing caps, 35 or 100 volt? (recommondations)
12 ... 1n4001 (?) diodes for 2 low current/voltage bridge rectifiers (& signal control/voltage reference?)
1 ... Zener diode for voltage reference (? value ?)
4 ... 1n4004 (?) diodes for 1 high current/voltage bridge rectifiers
5 ... PCB mount compression termination blocks / off board power (3) & RCA output (2).
3 ... TO3 Transistors (? value / number ?)
4 ... small signal transistors (? value / number ?)
handful ... various metal film resistors and various PCB mount plastic caps.
unknown ... additional PCB mounted parts (any surface mounted parts?)
4 ... PCB mount standoffs = hole location TBD.
? ... ??
1 ... manual and documentation= to be determined. (I have several web domains where PDF files could be placed for convinent download.)
Let's build 'em ...
My test bed setup: ( http://3dotaudio.com/ampics.html & http://aussieamplifiers.com )
FastEddy said:Yes!! I want it ... please enter my request for:
(2) Two Channel Tube pre-amp circuit boards.
Costs =TBD ? plus shipping in North America. (PayPal or company check?)
Preliminary Documentation (to be edited as project progresses):
Prototype image: http://www.diyaudio.com/forums/attachment.php?s=&postid=1076311&stamp=1165587976
PCB w/ silk screen parts layout: http://www.diyaudio.com/forums/attachment.php?s=&postid=1075771&stamp=1165526525
Begin of construction thread: http://www.diyaudio.com/forums/showthread.php?s=&threadid=91800
... A Dual Channel Valve Pre-Amp for chip amps (Class-D, Gainclone type, power MOSFET, etc.). I intend to couple one finished two channel valve pre-amp board to my NX150 dual mono-block power amp along with a modest effects controller of some kind (to be determined). The purpose would be to provide a two channel input gain control & signal pre-amplification for guitar, unpowered microphone or line level effects generatior.
Guesstimate of bill of materials (draft rev. 0.9 = to be edited):
1 .. The circuit board
2 .. 12au7 Valves (vacuum tubes, new or pre tested)
2 .. PCB upright mount sockets for 12u7 valve
4 ... 4700 uF electrolytic capacitors, polarized, 35 volt? (recommendations?)
2 ... 47 uF (?) electrolytic caps, polarized, 100 volt? (recommendations?)
8 ... 2.2 uF (?) electrolytic (or plastic?) snubbing caps, 35 or 100 volt? (recommondations)
12 ... 1n4001 (?) diodes for 2 low current/voltage bridge rectifiers (& signal control/voltage reference?)
1 ... Zener diode for voltage reference (? value ?)
4 ... 1n4004 (?) diodes for 1 high current/voltage bridge rectifiers
5 ... PCB mount compression termination blocks / off board power (3) & RCA output (2).
3 ... TO3 Transistors (? value / number ?)
4 ... small signal transistors (? value / number ?)
handful ... various metal film resistors and various PCB mount plastic caps.
unknown ... additional PCB mounted parts (any surface mounted parts?)
4 ... PCB mount standoffs = hole location TBD.
? ... ??
1 ... manual and documentation= to be determined. (I have several web domains where PDF files could be placed for convinent download.)
Let's build 'em ...
My test bed setup: ( http://3dotaudio.com/ampics.html & http://aussieamplifiers.com )
Hi Eddy, my english is not perfect so it happens I miss some of your points.
I asked my friend if he can make some more boards and he told me yes but not before some 10/15 days. The price would be about 24 euros (expensive, but it is not his job and he makes them one by one...). Maybe, if someone else is interested I could calculate the shipping price to northamerica and send to you, so that you can send to the other guy/s.
I have the schematics on my other computer at the office and I will be able to post it on monday if you want it.
Banned
Joined 2002
I'll take two ...
" ... The price would be about 24 euros (expensive, but it is not his job and he makes them one by one...) ..."
Not really that expensive considering it looks just fine. ... besides the Euro is going to fall dramatically against the dollar shortly. E$24 ~= US$31 ... right?
Put me down for two boards = E$48.00 (US$62?). I imagine shipping from Europe to the US is about E$16 (US$20?) for the two baords ... right?
PayPal OK ? ... or do you (he?) want a US$ funds company check?
Thanks
" ... The price would be about 24 euros (expensive, but it is not his job and he makes them one by one...) ..."
Not really that expensive considering it looks just fine. ... besides the Euro is going to fall dramatically against the dollar shortly. E$24 ~= US$31 ... right?
Put me down for two boards = E$48.00 (US$62?). I imagine shipping from Europe to the US is about E$16 (US$20?) for the two baords ... right?
PayPal OK ? ... or do you (he?) want a US$ funds company check?
Thanks
" ... How much was it for a set of psu boards and set of aussie amplifier boards ? do you like them ? I have ordered stuff from anthony before and he is really good. ..."
Yes I like them. They sound very clear, plenty of guts in the base range. ... very subjective listening tests ... my old 'scope can't see any distortion at low levels, but clipping at high levels is rounded without significant harmonics, etc. ... a better test device might show more, but I'm too busy to buy more test equipment.
Order directly from Anthony Holton at aussieamplifiers.com ... A full set, 2 amp boards and 2 PS filter boards (PSU#2), shipped to the USA was about US$330 or so. I believe it is more than worth it !!
Yes I like them. They sound very clear, plenty of guts in the base range. ... very subjective listening tests ... my old 'scope can't see any distortion at low levels, but clipping at high levels is rounded without significant harmonics, etc. ... a better test device might show more, but I'm too busy to buy more test equipment.
Order directly from Anthony Holton at aussieamplifiers.com ... A full set, 2 amp boards and 2 PS filter boards (PSU#2), shipped to the USA was about US$330 or so. I believe it is more than worth it !!
Re: I'll take two ...
I guess you are right, and paypal is ok. I repeat boards will not be available before 10 days. If you confirm you want them I can immediately ask my friend to make them.
FastEddy said:" ... The price would be about 24 euros (expensive, but it is not his job and he makes them one by one...) ..."
Not really that expensive considering it looks just fine. ... besides the Euro is going to fall dramatically against the dollar shortly. E$24 ~= US$31 ... right?
Put me down for two boards = E$48.00 (US$62?). I imagine shipping from Europe to the US is about E$16 (US$20?) for the two baords ... right?
PayPal OK ? ... or do you (he?) want a US$ funds company check?
Thanks
I guess you are right, and paypal is ok. I repeat boards will not be available before 10 days. If you confirm you want them I can immediately ask my friend to make them.
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