Is there a good online source, for free schematics of phono preamps? I'd
like to build my own stereo preamp for copying high-quality LPs. I get too
much background hum from the phono preamp section of my solid-state
receiver, and I'd like something a bit better. I have plenty of experience
and lots of parts, the preferred preamp tube would probably be 6SN7 or 12AX7
/ 12AZ7 / etc, as I have plenty of these.
Anyone know some good links?
Thanks in advance.

Do you want to build a complete preamp or just the phono stage?
Gordon
"Chris F." wrote in message
...
Is there a good online source, for free schematics of phono preamps? I'd
like to build my own stereo preamp for copying high-quality LPs. I get too
much background hum from the phono preamp section of my solid-state
receiver, and I'd like something a bit better. I have plenty of experience
and lots of parts, the preferred preamp tube would probably be 6SN7 or
12AX7
/ 12AZ7 / etc, as I have plenty of these.
Anyone know some good links?
Thanks in advance.

"Chris F."


I get too much background hum from the phono preamp section of my
solid-state
receiver, and I'd like something a bit better ....


** The vast majority of SS phono preamps fitted to amps and receivers are
hum free and have very low noise - your unit is either faulty or bady set
up.

Building a phono preamp with tubes that can match a SS one for absence of
noise and hum NOT a trivial task.




.............. Phil

On Tue, 27 Jan 2004 12:05:09 +1100, "Phil Allison" wrote:


"Chris F."


I get too much background hum from the phono preamp section of my
solid-state
receiver, and I'd like something a bit better ....


** The vast majority of SS phono preamps fitted to amps and receivers are
hum free and have very low noise - your unit is either faulty or bady set
up.

Building a phono preamp with tubes that can match a SS one for absence of
noise and hum NOT a trivial task.




............. Phil



Phil is right, even my Techniks is quieter then the "custom phono pre amp" I last built, and I was proud of it having
-70db!

You should also check into problems with your record player or it's pickup. If that's the problem, a new pre amp won't
solve anything.

And really, if you have to ask how to build it, you aren't going to beat the manufacturers at their game...

Look at transcendentsound.com
There is a new kit there for sale.
I am going to buy one as soon as I recover
from my christmas expenses.

Building a phono preamp with tubes that can match a SS one for absence of
noise and hum NOT a trivial task.

This seems like a too simplistic statement.

For moving magnet cartridges
with outputs above 2.5 mV, a 12AX7 input tube and following
6SN7 gain tube can provide entirely adequate snr.

Many SS phono stages in many SS items have worse hum and noise
than some tube phono amps.

However, with a moving coil source,
where output is down to 0.1 mV,
it isn't easy to build *any* discrete component
amplifier which is free of noise and hum.
Usually a step up transformer has been used in the past
to over come such problems and allow the benefits of the MC sound quality to be
realised.

I am using a 2SK369 j-fet as an input device in cascode with a frame grid
pentode strapped as a triode, and the snr is OK for
direct connect to MC.
The j-fet has an input noise well below a 12AX7, or any other tube I know.
Keeping the noise levels low in tube amp stages after the fet input
is not difficult if the usual rules about fine power supplies,
screening, short leads, and earthing are followed.

Vinyl is a great medium for hi-fi, until
you hear the clicks, pops and naked track noise in the middle of quiet
classical recordings.
The amp noise can usually be made to be well
below the noise of an unmodulated vinyl groove.
This noise should be similar or lower to the background noise of the
recording venue, and tape and equipment noise in the recording
studio....
For rock and roll,
the vinyl and amp noise is less important.

Patrick Turner.

"Patrick Turner"

Building a phono preamp with tubes that can match a SS one for absence
of
noise and hum NOT a trivial task.

This seems like a too simplistic statement.


** Who gives a **** what "seems" to a vowed enemy of the truth like the
Turneroid.



For moving magnet cartridges
with outputs above 2.5 mV, a 12AX7 input tube and following
6SN7 gain tube can provide entirely adequate snr.


* Can you spot the embedded Turneroid fallacy ???

The weasel words "can" and "entirely adequate" render the claim
worthless.

The truth is that SS phono pre amps *will and do have* lower noise and
hum than tube versions.



Many SS phono stages in many SS items have worse hum and noise
than some tube phono amps.


** See the Turneroid fallacies here ??

Like finding maggots in piece of meat it revolts the mind.




.............. Phil

Chris F. wrote:

Is there a good online source, for free schematics of phono preamps? I'd
like to build my own stereo preamp for copying high-quality LPs. I get too
much background hum from the phono preamp section of my solid-state
receiver, and I'd like something a bit better. I have plenty of experience
and lots of parts, the preferred preamp tube would probably be 6SN7 or 12AX7
/ 12AZ7 / etc, as I have plenty of these.
Anyone know some good links?
Thanks in advance.

I built this one some years ago, and like it a lot:
http://www.geocities.com/bobdanielak/phono.html

Best regards,

Mikkel C. Simonsen

I built that one too
could use a bit more gain to keep up with the CD player
Doug

"Mikkel C. Simonsen" wrote in message
...
Chris F. wrote:

Is there a good online source, for free schematics of phono preamps?
I'd
like to build my own stereo preamp for copying high-quality LPs. I get
too
much background hum from the phono preamp section of my solid-state
receiver, and I'd like something a bit better. I have plenty of
experience
and lots of parts, the preferred preamp tube would probably be 6SN7 or
12AX7
/ 12AZ7 / etc, as I have plenty of these.
Anyone know some good links?
Thanks in advance.

I built this one some years ago, and like it a lot:
http://www.geocities.com/bobdanielak/phono.html

Best regards,

Mikkel C. Simonsen

doug wrote:

I built that one too
could use a bit more gain to keep up with the CD player

You just need a preamp with programmable gain - I'm working on that

Best regards,

Mikkel C. Simonsen

Doug

"Mikkel C. Simonsen" wrote in message
...
Chris F. wrote:

Is there a good online source, for free schematics of phono preamps?
I'd
like to build my own stereo preamp for copying high-quality LPs. I get
too
much background hum from the phono preamp section of my solid-state
receiver, and I'd like something a bit better. I have plenty of
experience
and lots of parts, the preferred preamp tube would probably be 6SN7 or
12AX7
/ 12AZ7 / etc, as I have plenty of these.
Anyone know some good links?
Thanks in advance.

I built this one some years ago, and like it a lot:
http://www.geocities.com/bobdanielak/phono.html

Best regards,

Mikkel C. Simonsen