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Dean The Inevitable
Guest
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 Posted:
Wed Dec 15, 2004 6:36 am Post subject:
pre-amp? |
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Somewhere I came across a set of instructions for building a really
good-sounding pre-amp for very little money. There's some question,
however, as to whether this is a joke; I'm not in a position to judge.
Can anyone comment?
<start of instructions>
1 black hammond box to house the thing.
2 military grade (at very least... don't buy junk) sealed
potentiometers. (10k ohm)
4 RCA connectors (buy nice ones... Tiffany)
6 pieces of wire. GOOD wire... and make it solid core. *DO NOT* use
stranded wire, it sounds like shit.
The pin to the left on the pot is signal in. The pin to the right is
signal out. The center pin is ground. Solder the tip of the RCA
connector to the left pin on the pot. Since the RCA connectors are
mounted directly to the chassis, that is your ground. Solder that to
the center pin on the pot.
Close the box.
Plug your CD player in to the input jacks, the output goes directly to
the ins on your power amplifier.
<end of instructions>
Thanks in advance,
Dean
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Kalman Rubinson
Guest
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| Posted:
Wed Dec 15, 2004 6:36 am Post subject:
Re: pre-amp? |
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On 14 Dec 2004 17:41:50 -0800, dean_the_inevitable@hotmail.com (Dean
The Inevitable) wrote:
| Quote: | Somewhere I came across a set of instructions for building a really
good-sounding pre-amp for very little money. There's some question,
however, as to whether this is a joke; I'm not in a position to judge.
Can anyone comment?
|
Sure. It's not a preamp; it's a passive attenuator.
Kal |
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Arny Krueger
Guest
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| Posted:
Wed Dec 15, 2004 4:13 pm Post subject:
Re: pre-amp? |
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"Dean The Inevitable" <dean_the_inevitable@hotmail.com> wrote in
message news:c208271.0412141741.5f030874@posting.google.com
| Quote: | Somewhere I came across a set of instructions for building a really
good-sounding pre-amp for very little money. There's some question,
however, as to whether this is a joke; I'm not in a position to judge.
Can anyone comment?
start of instructions
1 black hammond box to house the thing.
|
Die cast boxes have their moments. It's all about look and feel to be sure.
| Quote: | 2 military grade (at very least... don't buy junk) sealed
potentiometers. (10k ohm)
|
These would be the classic AB-type J 2 watt potentiometers. Easy to find
with linear tapes (Jameco) harder to find with the more desirable audio
taper (Digikey http://dkc3.digikey.com/PDF/EU042/0673-0675.pdf ) hardest of
all to find in stereo audio taper. as close as I can come is part (RCV)
P304361-2 at http://www.surplussales.com/Potentiometers/Pots-6.html .Don't
know if it is linear or audio taper.
It's an open question whether 10K or 5K are more desirable here. Don't use
this kind of passive volume control to drive long pieces of shielded wire. 1
meter is OK.
| Quote: | 4 RCA connectors (buy nice ones... Tiffany)
|
Whatever. RCA connectors are a junk design, but we're stuck with them. Fancy
RCA connectors are just putting lipstick on a pig.
| Quote: | 6 pieces of wire. GOOD wire... and make it solid core. *DO NOT* use
stranded wire, it sounds like shit.
|
Horsefeathers.
| Quote: | The pin to the left on the pot is signal in. The pin to the right is
signal out. The center pin is ground. Solder the tip of the RCA
connector to the left pin on the pot. Since the RCA connectors are
mounted directly to the chassis, that is your ground. Solder that to
the center pin on the pot.
|
If you do it wrong, the volume decreases as you turn the knob clockwise.
| Quote: | Close the box.
Plug your CD player in to the input jacks, the output goes directly to
the ins on your power amplifier.
end of instructions
|
Been there, done that it works. For extra credit figure out how to add a
balance control. The most complex of these that I've built has two separate
volume control sections, and a switch to route either to the power amp.
Solves the problem of switching from the CD player to the tuner and having a
big jump in volume. |
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Dimitrios Tzortzakakis
Guest
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| Posted:
Fri Dec 17, 2004 6:13 pm Post subject:
Re: pre-amp? |
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In fact a good preamp needs very precise design and very accurate
manufacturing processes;especially when amplyfying a turntable where
amplifying must be according to the RIAA curve.The attenuator which you
describe is easy to construct, but offers no real amplifying;a real
amplifier needs precise componenets such as operational amplifiers etc.
--
Tzortzakakis Dimitri?s
major in electrical engineering, freelance electrician
FH von Iraklion-Kreta, freiberuflicher Elektriker
dimtzort AT otenet DOT gr
? "Dean The Inevitable" <dean_the_inevitable@hotmail.com> ?????? ??? ??????
news:c208271.0412141741.5f030874@posting.google.com...
| Quote: | Somewhere I came across a set of instructions for building a really
good-sounding pre-amp for very little money. There's some question,
however, as to whether this is a joke; I'm not in a position to judge.
Can anyone comment?
start of instructions
1 black hammond box to house the thing.
2 military grade (at very least... don't buy junk) sealed
potentiometers. (10k ohm)
4 RCA connectors (buy nice ones... Tiffany)
6 pieces of wire. GOOD wire... and make it solid core. *DO NOT* use
stranded wire, it sounds like shit.
The pin to the left on the pot is signal in. The pin to the right is
signal out. The center pin is ground. Solder the tip of the RCA
connector to the left pin on the pot. Since the RCA connectors are
mounted directly to the chassis, that is your ground. Solder that to
the center pin on the pot.
Close the box.
Plug your CD player in to the input jacks, the output goes directly to
the ins on your power amplifier.
end of instructions
Thanks in advance,
Dean |
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