[gjsmo]

I want to build a dual mic preamp, but I'm not really sure where to
start. I've got many 5963's (industrial 12AU7's) and 12AX7's lying
around that I'd like to use. It needs to have phantom power, and be
able to take balanced inputs and outputs. If possible I'd also like to
be able to flip a switch and turn it from a mic pre to a guitar pre
(with distortion), but if not that's just fine.

Are there any books or schematics on the net you'd recommend?

[Phil Allison[_3_]]

"gjsmo"

I want to build a dual mic preamp, but I'm not really sure where to
start. I've got many 5963's (industrial 12AU7's) and 12AX7's lying
around that I'd like to use. It needs to have phantom power, and be
able to take balanced inputs and outputs. If possible I'd also like to
be able to flip a switch and turn it from a mic pre to a guitar pre
(with distortion), but if not that's just fine.

Are there any books or schematics on the net you'd recommend?

** Do you own Google search - this was the very first hit.

http://www.tangible-technology.com/tubes/1566/1566.html


...... Phil

[gjsmo]

** Do you own Google search - *this was the very first hit.

http://www.tangible-technology.com/tubes/1566/1566.html

..... *Phil

What'd you search? I never got that... or really anything close. I got
stuff about either 1) really complicated stuff or 2) commercial stuff.
Neither one interests me. That's pretty simple though.

[Phil Allison[_3_]]

"gjsmo"

** Do you own Google search - this was the very first hit.

http://www.tangible-technology.com/tubes/1566/1566.html


What'd you search?

** Would you believe " tube mic preamp " ????

Google the through up several options, the third of which added the word "
schematic" and the forth added the term DIY.

I clicked on the third one.


I never got that... or really anything close. I got
stuff about either 1) really complicated stuff or 2) commercial stuff.
Neither one interests me. That's pretty simple though.


** All those transformers will cost you though.


...... Phil

[Bret L]

On Oct 21, 7:14*pm, gjsmo wrote:
** Do you own Google search - *this was the very first hit.

http://www.tangible-technology.com/tubes/1566/1566.html

..... *Phil

What'd you search? I never got that... or really anything close. I got
stuff about either 1) really complicated stuff or 2) commercial stuff.
Neither one interests me. That's pretty simple though.

Having one unit double as a mic and (electric) guitar pre is a dumb
idea.

Any of the xfmr vendors will give you schematics for several circuits
to use with their products, or you can copy a desireable vintage unit.
Or start from first principles on your own. It's up to you.

Copying a popular vintage unit is the fastest and direct path to
likely success, provided the transformers you can get are compatible.

For a guitar pre, copy the front end of a guitar amp you like up to
the drivers and have it drive a line output xfmr. Mesa MkIIB, Marshall
plexi and Fat Howard circuits are most popular.

[Ian Bell[_2_]]

Bret L wrote:
On Oct 21, 7:14 pm, gjsmo wrote:
** Do you own Google search - this was the very first hit.
http://www.tangible-technology.com/tubes/1566/1566.html
..... Phil
What'd you search? I never got that... or really anything close. I got
stuff about either 1) really complicated stuff or 2) commercial stuff.
Neither one interests me. That's pretty simple though.

Having one unit double as a mic and (electric) guitar pre is a dumb
idea.


I guess that means there are a lot of dumb manufacturers out there then
as pretty much every tube mic pre these days includes a high impedance
instrument input.

Cheers

Ian

[jh]

Ian Bell schrieb:
Bret L wrote:
On Oct 21, 7:14 pm, gjsmo wrote:
** Do you own Google search - this was the very first hit.
http://www.tangible-technology.com/tubes/1566/1566.html
..... Phil
What'd you search? I never got that... or really anything close. I got
stuff about either 1) really complicated stuff or 2) commercial stuff.
Neither one interests me. That's pretty simple though.

Having one unit double as a mic and (electric) guitar pre is a dumb
idea.


I guess that means there are a lot of dumb manufacturers out there then
as pretty much every tube mic pre these days includes a high impedance
instrument input.

Cheers

Ian

....Ian,

with all due respect, but those boxes are intended for the use as a DI.
More or less transparent with a tube touch, but NOT "distortion".

A guit preamp (think mesa, marshall, VHT) is intended to change the
signal completely in a certain way.

A mic-preamp with a Hi-Z input does NOT.

kindest regards


Jochen

[Bret L]

On Oct 22, 1:18*pm, Ian Bell wrote:
Bret L wrote:
On Oct 21, 7:14 pm, gjsmo wrote:
** Do you own Google search - *this was the very first hit.
http://www.tangible-technology.com/tubes/1566/1566.html
..... *Phil
What'd you search? I never got that... or really anything close. I got
stuff about either 1) really complicated stuff or 2) commercial stuff.
Neither one interests me. That's pretty simple though.

*Having one unit double as a mic and (electric) guitar pre is a dumb
idea.

I guess that means there are a lot of dumb manufacturers out there then
as pretty much every tube mic pre these days includes a high impedance
instrument input.

Yes, but it isn't really intended for lead guitar use. It works okay
for acoustic guitars and particularly bass though usually a DI box
works better in a lot of cases.

Recording a guitar direct to "tape" (it's usually PT) gives a sound
not too unlike Les Paul-not a regular Les Paul guitar through an amp,
but the sound Les Paul actually has on his records from the 40s and
50s. No one really wants that sound today, or really ever.(That, plus
their weight, made the only Les Pauls Gibson ever made resembling what
Les actually used unsaleable.) It sounds like a steel guitar without
the bends and glisses.

What is popular are several types of amp simulators and virtual amps.
These range from the old Tom Scholz Rockman to DSP implementations in
software through PC cards, to running guitar amps into complex speaker
emulators or sealed speaker boxes.

Acoustic guitars have several types of pickups or internal mics.
Internal mics are handled like any other mic. Piezo pickups are
generally buffered and treated as a line signal.

So yes, by all means put a Hi-Z input on your mic pre. But that's
nothing much to do with an electric guitar.

A guitar pre, by contrast,, is usually used in front of a power amp
in a rack setup. These underrated little beasts allow power amps
otherwise not of much use-old PA amps, as well as hi-fi amps, and pro
sound power amps to be used for guitar. If one is after clean jazz and
country sound, any fairly clean power amp works. A lot of dinky mono
alleged hi-fi amps as well as SET's borrowed from someone's slobber-fi
setup at home will give the recording guitarist a fantastic palette of
cool distorto sounds this way too. Recording with the guitar pre is
possible but not that much done.

[Ian Bell[_2_]]

jh wrote:
Ian Bell schrieb:
Bret L wrote:
On Oct 21, 7:14 pm, gjsmo wrote:
** Do you own Google search - this was the very first hit.
http://www.tangible-technology.com/tubes/1566/1566.html
..... Phil
What'd you search? I never got that... or really anything close. I got
stuff about either 1) really complicated stuff or 2) commercial stuff.
Neither one interests me. That's pretty simple though.

Having one unit double as a mic and (electric) guitar pre is a dumb
idea.


I guess that means there are a lot of dumb manufacturers out there
then as pretty much every tube mic pre these days includes a high
impedance instrument input.

Cheers

Ian

...Ian,

with all due respect, but those boxes are intended for the use as a DI.
More or less transparent with a tube touch, but NOT "distortion".

A guit preamp (think mesa, marshall, VHT) is intended to change the
signal completely in a certain way.

A mic-preamp with a Hi-Z input does NOT.

kindest regards


Jochen

[Ian Bell[_2_]]

jh wrote:
Ian Bell schrieb:
Bret L wrote:
On Oct 21, 7:14 pm, gjsmo wrote:
** Do you own Google search - this was the very first hit.
http://www.tangible-technology.com/tubes/1566/1566.html
..... Phil
What'd you search? I never got that... or really anything close. I got
stuff about either 1) really complicated stuff or 2) commercial stuff.
Neither one interests me. That's pretty simple though.

Having one unit double as a mic and (electric) guitar pre is a dumb
idea.


I guess that means there are a lot of dumb manufacturers out there
then as pretty much every tube mic pre these days includes a high
impedance instrument input.

Cheers

Ian

...Ian,

with all due respect, but those boxes are intended for the use as a DI.
More or less transparent with a tube touch, but NOT "distortion".

A guit preamp (think mesa, marshall, VHT) is intended to change the
signal completely in a certain way.

A mic-preamp with a Hi-Z input does NOT.

kindest regards


Jochen


Yes, what you say is true, however I do not recall the OP saying he
wanted distortion. Presumably he wants a mic pre to be able to record
and equally it is common to DI a guitar when tracking which allows the
'tone' to be determined later. A clean signal is required for
recording, not a distorted one.

Cheers

Ian

[Bret L]

Yes, what you say is true, however I do not recall the OP saying he
wanted distortion. Presumably he wants a mic pre to be able to record
and equally it is common to DI a guitar when tracking which allows the
'tone' to be determined later. *A clean signal is required for
recording, not a distorted one.

There are several issues in doing this, one being that the crest
factor of a live guitar feed can be very high indeed, and that
therefore a surprising dynamic range is needed even for a typical
track where the dynamic range seems small. This is also why guitar
drivers are very tough as opposed to normal modern hi fi speakers.

Yes, it can be done, but it doesn't work as well as you'd think. It's
generally better to record electric guitar "wet", in a form similar to
what is in the end required. You can EQ or compress after that but
the flexibility is indeed limited unless you do want a deliberately
processed sound.

Acoustic backing tracks, again, are a whole different proposition,
especially if "that demo sound" is what you indeed want. That sure
enough is how you get it: plug an Ovation straight in to a mic pre's
straight hi Z in. If you use silk and steel strings you've got it
nailed.

One refinement I don't see often enough, is recording an electric
guitar in stereo, with one clean and one raunchy signal through two
amps mic'd. You can then submix them or stereo pan them. To keep buzz
down the studio has to be really quiet unless you put the amp heads
together and bond them carefully, lifting the AC ground, and use long
speaker cables. I've advocated wiring guitars stereo with two
completely galvanically isolated channels but no one is going to
listen to little old ground loop hating me on this one. Keith Richards
diid this with the Stones a little bit but they never really took full
advantage of it, he's always out there on one side in thr finished
mix.

[jh[_2_]]

Ian Bell schrieb:
jh wrote:
Ian Bell schrieb:
Bret L wrote:
On Oct 21, 7:14 pm, gjsmo wrote:
** Do you own Google search - this was the very first hit.
http://www.tangible-technology.com/tubes/1566/1566.html
..... Phil
What'd you search? I never got that... or really anything close. I got
stuff about either 1) really complicated stuff or 2) commercial stuff.
Neither one interests me. That's pretty simple though.

Having one unit double as a mic and (electric) guitar pre is a dumb
idea.


I guess that means there are a lot of dumb manufacturers out there
then as pretty much every tube mic pre these days includes a high
impedance instrument input.

Cheers

Ian

...Ian,

with all due respect, but those boxes are intended for the use as a
DI. More or less transparent with a tube touch, but NOT "distortion".

A guit preamp (think mesa, marshall, VHT) is intended to change the
signal completely in a certain way.

A mic-preamp with a Hi-Z input does NOT.

kindest regards


Jochen


Yes, what you say is true, however I do not recall the OP saying he
wanted distortion. Presumably he wants a mic pre to be able to record
and equally it is common to DI a guitar when tracking which allows the
'tone' to be determined later. A clean signal is required for
recording, not a distorted one.

Cheers

Ian

:-O

I thought he explicitely mentioned it, didn't he?


Jochen

[Ian Bell[_2_]]

Bret L wrote:
Yes, what you say is true, however I do not recall the OP saying he
wanted distortion. Presumably he wants a mic pre to be able to record
and equally it is common to DI a guitar when tracking which allows the
'tone' to be determined later. A clean signal is required for
recording, not a distorted one.

There are several issues in doing this, one being that the crest
factor of a live guitar feed can be very high indeed, and that
therefore a surprising dynamic range is needed even for a typical
track where the dynamic range seems small. This is also why guitar
drivers are very tough as opposed to normal modern hi fi speakers.

Yes, it can be done, but it doesn't work as well as you'd think. It's
generally better to record electric guitar "wet", in a form similar to
what is in the end required. You can EQ or compress after that but
the flexibility is indeed limited unless you do want a deliberately
processed sound.


Actually, it does work rather well. I do it all the time and so do many
pro studios. As I mentioned before, the point of doing it is to get a
clean recorded sound which leaves your options wide open for processing.
One option, which I am sure you have heard of, is re-amping where the
recorded clean signal is played back through a guitar amp and miced up
in the usual fashion.


Cheers

Ian

[Ian Bell[_2_]]

jh wrote:
Ian Bell schrieb:
jh wrote:
Ian Bell schrieb:
Bret L wrote:
On Oct 21, 7:14 pm, gjsmo wrote:
** Do you own Google search - this was the very first hit.
http://www.tangible-technology.com/tubes/1566/1566.html
..... Phil
What'd you search? I never got that... or really anything close. I
got
stuff about either 1) really complicated stuff or 2) commercial
stuff.
Neither one interests me. That's pretty simple though.

Having one unit double as a mic and (electric) guitar pre is a dumb
idea.


I guess that means there are a lot of dumb manufacturers out there
then as pretty much every tube mic pre these days includes a high
impedance instrument input.

Cheers

Ian

...Ian,

with all due respect, but those boxes are intended for the use as a
DI. More or less transparent with a tube touch, but NOT "distortion".

A guit preamp (think mesa, marshall, VHT) is intended to change the
signal completely in a certain way.

A mic-preamp with a Hi-Z input does NOT.

kindest regards


Jochen


Yes, what you say is true, however I do not recall the OP saying he
wanted distortion. Presumably he wants a mic pre to be able to record
and equally it is common to DI a guitar when tracking which allows the
'tone' to be determined later. A clean signal is required for
recording, not a distorted one.

Cheers

Ian

:-O

I thought he explicitely mentioned it, didn't he?


Jochen


Yes, you are right, I just checked back to his original post. I agree,
if he want guitar amp like distortion he won't get it that way.

Cheers

Ian

[Ian Bell[_2_]]

Bret L wrote:
On Oct 22, 1:18 pm, Ian Bell wrote:
Bret L wrote:
On Oct 21, 7:14 pm, gjsmo wrote:
** Do you own Google search - this was the very first hit.
http://www.tangible-technology.com/tubes/1566/1566.html
..... Phil
What'd you search? I never got that... or really anything close. I got
stuff about either 1) really complicated stuff or 2) commercial stuff.
Neither one interests me. That's pretty simple though.
Having one unit double as a mic and (electric) guitar pre is a dumb
idea.
I guess that means there are a lot of dumb manufacturers out there then
as pretty much every tube mic pre these days includes a high impedance
instrument input.

Yes, but it isn't really intended for lead guitar use. It works okay
for acoustic guitars and particularly bass though usually a DI box
works better in a lot of cases.

Recording a guitar direct to "tape" (it's usually PT) gives a sound
not too unlike Les Paul-not a regular Les Paul guitar through an amp,
but the sound Les Paul actually has on his records from the 40s and
50s. No one really wants that sound today, or really ever.(That, plus
their weight, made the only Les Pauls Gibson ever made resembling what
Les actually used unsaleable.) It sounds like a steel guitar without
the bends and glisses.


Yes, but see my other post as to why you want to do this.

Cheers

Ian

[Bret L]

On Oct 23, 3:48*am, Ian Bell wrote:
Bret L wrote:
Yes, what you say is true, however I do not recall the OP saying he
wanted distortion. Presumably he wants a mic pre to be able to record
and equally it is common to DI a guitar when tracking which allows the
'tone' to be determined later. *A clean signal is required for
recording, not a distorted one.

*There are several issues in doing this, one being that the crest
factor of a live guitar feed can be very high indeed, and that
therefore a surprising dynamic range is needed even for a typical
track where the dynamic range seems small. This is also why guitar
drivers are very tough as opposed to normal modern hi fi speakers.

*Yes, it can be done, but it doesn't work as well as you'd think. It's
generally better to record electric guitar "wet", in a form similar to
what is in the end required. You can EQ or compress after that *but
the flexibility is indeed limited unless you do want a deliberately
processed sound.

Actually, it does work rather well. I do it *all the time and so do many
pro studios. As I mentioned before, the point of doing it is to get a
clean recorded sound which leaves your options wide open for processing.
One option, which I am sure you have heard of, is re-amping where the
recorded clean signal is played back through a guitar amp and miced up
in the usual fashion.

Yes, they even sell a box called ReAmp. it works but IMO not all that
well. It's OK for jingles and demos but a good player needs to have
something like the final live sound to work with, plus the original
guitar feed ALWAYS has a lot of spikes you are going to lop off that
are what make the speaker really crank. Tape or any real world digital
system can't do it.

I heard a dry line out recording of Brian May once that had all these
"clickump" noises I had never heard before. Turns out May uses old,
predecimal Brit coins for picks and that's the string against the
pick. When he's through an amp you don't hear that, you just hear the
string respond and the thump comes out in a whole different way.

Reamp is GREAT for Halloween sound tracks though. ESPECIALLY if you
have a Leslie and the old triangular Combo Pre that looks like
something for a kirby vacuum.

[gjsmo]

Alright, guys, I'll do my best to respond to this flood (not really
used to this kind of response time).

@Bret L
I agree with everyone else, it isn't a bad idea. It's just a new one
to you (I think).
Maybe having the distortion is a bad idea, but Hi-Z and Lo-Z isn't bad
- what if I wanted to use a Hi-Z dynamic mic? Why is this a bad idea,
to have one, instead of two seperate pre's, that I have to build,
debug and maintain seperately?

@Ian
I've seen them, and from (supposedly) good manufacturers.

@jh
really? I made distortion once with a pretty good-sounding tube radio
by using the phono output. Didn't sound too bad either, but it was
very soft so needed to be mic'd. Of course, there was a pre-amp
_before_ that, but nevertheless it's doing distortion with hi-fi
equipment.

@Bret L
Fine then. But why can't I just turn the volume up on the pre and down
on the mixer? If I give it enough gain, won't it distort? Isn't that
what distortion is, pushing the tubes past their limits so they create
a different sound?

@Ian
Yeah, I could do that... too bad I'm limited on recording channels.

@Bret L
Fine. And just how would you like me to record with the effects
already in place? Oooh, I know! Why don't we let the preamp distort?
(don't really want to be a jerk, but it's a solution)

@jh
Yeah, I did. But I also said it isn't required.

@Ian
No, I haven't heard of that. But that's a nice idea! Too bad I don't
even have a good tube amp :-((((( Not much money, so the preamp's good
enough.
Fine. I won't do it.

So should it have distortion or not? I'm torn between the ways.
Or should I just go ahead and build separate pre's? Use one for mics
and the other for guitars?

My personal opinion is this: I need a mic pre, with preferably Lo-Z
and Hi-Z inputs, and that's what I'm going to build. If I want to try
distortion, I'm just going to crank up the volume until I hear
something resembling what I want.

Could I create a negative feedback loop for mics, and then put a
switch somewhere to disconnect it (and allow distortion to occur)?
Just a thought.

[Ian Iveson]

I want to build a dual mic preamp, but I'm not really sure
where to
start. I've got many 5963's (industrial 12AU7's) and
12AX7's lying
around that I'd like to use. It needs to have phantom
power, and be
able to take balanced inputs and outputs. If possible I'd
also like to
be able to flip a switch and turn it from a mic pre to a
guitar pre
(with distortion), but if not that's just fine.

Are there any books or schematics on the net you'd
recommend?

Balanced input and output means transformers, if you want
simplicity. Phil's Altec link looks like a good bet. There's
still a lot of work there for a beginner. Don't
underestimate the work involved in metalwork and layout.

A proper guitar preamp does proper guitar distortion, and a
fair amount of filtering. Have a look at a Fender or
Marshall for an idea of how the standard palette of sounds
is achieved. You would need at least one extra 12AX7 and a
lot of experiment and playing to produce the right sound,
AFAICS.

Something rarely discussed here. Exactly what does a guitar
need to sound right, apart from a good guitarist?

The common conception, flawed in my view, that fidelity can
be reduced to the minimisation of distortion, is a license
for musical and tonal illiteracy amongst audio engineers. As
with all aspects of music and musical instruments, tradition
is the best guide to development. It's a social thing: you
can't just make it up on your own.

No-one's mentioned books, and I can't think of anything
suitable either. Depends what you already know, and whether
you want to get into a hobby or just build one amp.

Ian

[Ian Bell[_2_]]

Bret L wrote:
On Oct 23, 3:48 am, Ian Bell wrote:
Bret L wrote:
Yes, what you say is true, however I do not recall the OP saying he
wanted distortion. Presumably he wants a mic pre to be able to record
and equally it is common to DI a guitar when tracking which allows the
'tone' to be determined later. A clean signal is required for
recording, not a distorted one.
There are several issues in doing this, one being that the crest
factor of a live guitar feed can be very high indeed, and that
therefore a surprising dynamic range is needed even for a typical
track where the dynamic range seems small. This is also why guitar
drivers are very tough as opposed to normal modern hi fi speakers.
Yes, it can be done, but it doesn't work as well as you'd think. It's
generally better to record electric guitar "wet", in a form similar to
what is in the end required. You can EQ or compress after that but
the flexibility is indeed limited unless you do want a deliberately
processed sound.
Actually, it does work rather well. I do it all the time and so do many
pro studios. As I mentioned before, the point of doing it is to get a
clean recorded sound which leaves your options wide open for processing.
One option, which I am sure you have heard of, is re-amping where the
recorded clean signal is played back through a guitar amp and miced up
in the usual fashion.

Yes, they even sell a box called ReAmp. it works but IMO not all that
well. It's OK for jingles and demos but a good player needs to have
something like the final live sound to work with, plus the original
guitar feed ALWAYS has a lot of spikes you are going to lop off that
are what make the speaker really crank. Tape or any real world digital
system can't do it.


Agreed. The point is they are different techniques with different pros
and cons. Neither is the 'correct' way to do it, they are both equally
valid.

Cheers

Ian

[Phil Allison[_3_]]

"Ian Iveson"


Something rarely discussed here. Exactly what does a guitar need to sound
right, apart from a good guitarist?


** Ah - a guitar amp is just like a successful politician.

In order to be liked, he must play to the prejudice of the voters.

He must speak like the great politicians that have gone before him.

Any pretence to novelty equates to political suicide.

Tubes rule.

SS is about as popular as communism.



..... Phil

[jh[_2_]]

gjsmo schrieb:
Alright, guys, I'll do my best to respond to this flood (not really
used to this kind of response time).

@Bret L
I agree with everyone else, it isn't a bad idea. It's just a new one
to you (I think).
Maybe having the distortion is a bad idea, but Hi-Z and Lo-Z isn't bad
- what if I wanted to use a Hi-Z dynamic mic? Why is this a bad idea,
to have one, instead of two seperate pre's, that I have to build,
debug and maintain seperately?

@Ian
I've seen them, and from (supposedly) good manufacturers.

@jh
really? I made distortion once with a pretty good-sounding tube radio
by using the phono output. Didn't sound too bad either, but it was
very soft so needed to be mic'd. Of course, there was a pre-amp
_before_ that, but nevertheless it's doing distortion with hi-fi
equipment.

@Bret L
Fine then. But why can't I just turn the volume up on the pre and down
on the mixer? If I give it enough gain, won't it distort? Isn't that
what distortion is, pushing the tubes past their limits so they create
a different sound?

@Ian
Yeah, I could do that... too bad I'm limited on recording channels.

@Bret L
Fine. And just how would you like me to record with the effects
already in place? Oooh, I know! Why don't we let the preamp distort?
(don't really want to be a jerk, but it's a solution)

@jh
Yeah, I did. But I also said it isn't required.


There is not so much of a difference between an old tube radio and a
generic guitar amplifier (think basic tweed fenders). I bet you did not
get it to sound like a higain marshall or a rectifier without any
external help - booster, overdrive or distortion. But a radio IS an
amplifier and it has a speaker. Additionally the old speakers found in a
radio have almost the same high end cut as the ones found in guitar
amps. You're not talking about a preamp there anymore, it's more or less
like a combo.

Hi-Z inputs in tube preamps are a very nice thing to have, to go direct.
I still bet you don't want to overdrive them and use them as a
distortion unit. IMHO this sounds like crap, unless you begin to shape
the tone and add a decent speaker simulator - be it hardware or software.

A decent quality microphone preamp and a serious guitar preamp are IMHO
to completely different things. The first one normally tries to amplify
the signal with the the most possible transparency, maybe add a tiny bit
of distortion, whereas the other one shapes the signal, and creates lot
of things, the initial signal did not have.
As an special FX it's sometimes nice to feed a vocal through a
distorting guitar amp, but I bet this gets very annoying if sustained.
S/N ratio is the next thing to consider.

just my opinion, YMMV

regards

Jochen







@Ian
No, I haven't heard of that. But that's a nice idea! Too bad I don't
even have a good tube amp :-((((( Not much money, so the preamp's good
enough.
Fine. I won't do it.

So should it have distortion or not? I'm torn between the ways.
Or should I just go ahead and build separate pre's? Use one for mics
and the other for guitars?

My personal opinion is this: I need a mic pre, with preferably Lo-Z
and Hi-Z inputs, and that's what I'm going to build. If I want to try
distortion, I'm just going to crank up the volume until I hear
something resembling what I want.

Could I create a negative feedback loop for mics, and then put a
switch somewhere to disconnect it (and allow distortion to occur)?
Just a thought.

[gjsmo]

How to build my pre? Let me count the ways... :-)

SS is about as popular as communism.
I beg to differ... unfortunately, most music these days is digital. On
CDs, or (ugh!) MP3s. I confess to using an iPod touch for my music.
Not that I like it, but then again, I can't fit 20+ LPs plus a player
and small headphone amp in my pocket. Solid-state is about as popular
as white bread (and just as bad).

I still bet you don't want to overdrive them and use them as a distortion unit. IMHO this sounds like crap
Ok, then I won't.

So I guess the altec "electric crayon" is just fine, then? Or should I
keep looking (I'm a bit new to audio equipment, but that really
doesn't prevent me from knowing good sound when I hear it...)

If this helps, I have a 600V 500mA max tube power supply. It needs a
new pot for the bias, but it'll provide A voltage, B voltage (up to
600V) and C if I fix the pot (I think it's 0 to -150V). It's really
big though, and weighs about 50 pounds, and needs a 6336 tube which
costs 50 bucks. I think that would work for a power supply though,
don't you think?

[jh[_2_]]

gjsmo schrieb:
How to build my pre? Let me count the ways... :-)

SS is about as popular as communism.

this was not from my posting...

I beg to differ... unfortunately, most music these days is digital. On
CDs, or (ugh!) MP3s. I confess to using an iPod touch for my music.
Not that I like it, but then again, I can't fit 20+ LPs plus a player
and small headphone amp in my pocket. Solid-state is about as popular
as white bread (and just as bad).

I still bet you don't want to overdrive them and use them as a distortion unit. IMHO this sounds like crap
Ok, then I won't.

So I guess the altec "electric crayon" is just fine, then? Or should I
keep looking (I'm a bit new to audio equipment, but that really
doesn't prevent me from knowing good sound when I hear it...)

If this helps, I have a 600V 500mA max tube power supply. It needs a
new pot for the bias, but it'll provide A voltage, B voltage (up to
600V) and C if I fix the pot (I think it's 0 to -150V). It's really
big though, and weighs about 50 pounds, and needs a 6336 tube which
costs 50 bucks. I think that would work for a power supply though,
don't you think?

shooting sparrows with cannons. A decent 1/2 lbs power supply with
enough beef can be built for less money. IMHO 600V is much too much.
350V is plenty there.

regards

Jochen

[gjsmo]

On Oct 24, 3:21*pm, jh wrote:
gjsmo schrieb:

How to build my pre? Let me count the ways... :-)

SS is about as popular as communism.

this was not from my posting...





I beg to differ... unfortunately, most music these days is digital. On
CDs, or (ugh!) MP3s. I confess to using an iPod touch for my music.
Not that I like it, but then again, I can't fit 20+ LPs plus a player
and small headphone amp in my pocket. Solid-state is about as popular
as white bread (and just as bad).

I still bet you don't want to overdrive them and use them as a distortion unit. IMHO this sounds like crap
Ok, then I won't.

So I guess the altec "electric crayon" is just fine, then? Or should I
keep looking (I'm a bit new to audio equipment, but that really
doesn't prevent me from knowing good sound when I hear it...)

If this helps, I have a 600V 500mA max tube power supply. It needs a
new pot for the bias, but it'll provide A voltage, B voltage (up to
600V) and C if I fix the pot (I think it's 0 to -150V). It's really
big though, and weighs about 50 pounds, and needs a 6336 tube which
costs 50 bucks. I think that would work for a power supply though,
don't you think?

shooting sparrows with cannons. A decent 1/2 lbs power supply with
enough beef can be built for less money. IMHO 600V is much too much.
350V is plenty there.

regards

Jochen

it's adjustable, up to 600V... you're right about that, but it seems
to operate ok, although I'm not sure if it's good to do that (there's
a total of 3 power tubes). But you really think I could build a good
HV power supply for less than 50 bucks? and half a pound? that's new
to me.
I look for "HV power supply" and "350V power supply on google. no
luck.
Is 50 mA @ 320V enough? I did find http://www.elecfree.com/electronic/p...-10-350v-50ma/
..

[jh[_2_]]

gjsmo schrieb:
On Oct 24, 3:21 pm, jh wrote:
gjsmo schrieb:

How to build my pre? Let me count the ways... :-)
SS is about as popular as communism.
this was not from my posting...





I beg to differ... unfortunately, most music these days is digital. On
CDs, or (ugh!) MP3s. I confess to using an iPod touch for my music.
Not that I like it, but then again, I can't fit 20+ LPs plus a player
and small headphone amp in my pocket. Solid-state is about as popular
as white bread (and just as bad).
I still bet you don't want to overdrive them and use them as a distortion unit. IMHO this sounds like crap
Ok, then I won't.
So I guess the altec "electric crayon" is just fine, then? Or should I
keep looking (I'm a bit new to audio equipment, but that really
doesn't prevent me from knowing good sound when I hear it...)
If this helps, I have a 600V 500mA max tube power supply. It needs a
new pot for the bias, but it'll provide A voltage, B voltage (up to
600V) and C if I fix the pot (I think it's 0 to -150V). It's really
big though, and weighs about 50 pounds, and needs a 6336 tube which
costs 50 bucks. I think that would work for a power supply though,
don't you think?
shooting sparrows with cannons. A decent 1/2 lbs power supply with
enough beef can be built for less money. IMHO 600V is much too much.
350V is plenty there.

regards

Jochen

it's adjustable, up to 600V... you're right about that, but it seems
to operate ok, although I'm not sure if it's good to do that (there's
a total of 3 power tubes). But you really think I could build a good
HV power supply for less than 50 bucks? and half a pound? that's new
to me.
I look for "HV power supply" and "350V power supply on google. no
luck.
Is 50 mA @ 320V enough? I did find http://www.elecfree.com/electronic/p...-10-350v-50ma/
.

Although this on would fit your purpose perfectly in regards of voltage
and power, i'd still regard it a bit of overkill, (current limiting,
metering why'd you need that in a preamp...).
320-350V @50mA is the range i'd expect for a single channel. For the
first crapshot i'd take a small transformer with heater and HV winding -
tube radio or replacement comes into mind, a few diodes resistors and
caps and you're finished. I don't think the "original" power supply of
the altec contained anything else. If you really want a regulated HV,
there are some other suggestions in the book where the scheme you posted
is coming from.

this transformer might fit although the vendor is in germany..
http://www.tube-town.net/ttstore/pro...VA-Preamp.html

ok i have to correct my statement, the TX already has 530 grams, so it
would be 1 1/2 lbs.

regards

Jochen

[gjsmo]

On Oct 25, 4:55*am, jh wrote:
gjsmo schrieb:





On Oct 24, 3:21 pm, jh wrote:
gjsmo schrieb:

How to build my pre? Let me count the ways... :-)
SS is about as popular as communism.
this was not from my posting...

I beg to differ... unfortunately, most music these days is digital. On
CDs, or (ugh!) MP3s. I confess to using an iPod touch for my music.
Not that I like it, but then again, I can't fit 20+ LPs plus a player
and small headphone amp in my pocket. Solid-state is about as popular
as white bread (and just as bad).
I still bet you don't want to overdrive them and use them as a distortion unit. IMHO this sounds like crap
Ok, then I won't.
So I guess the altec "electric crayon" is just fine, then? Or should I
keep looking (I'm a bit new to audio equipment, but that really
doesn't prevent me from knowing good sound when I hear it...)
If this helps, I have a 600V 500mA max tube power supply. It needs a
new pot for the bias, but it'll provide A voltage, B voltage (up to
600V) and C if I fix the pot (I think it's 0 to -150V). It's really
big though, and weighs about 50 pounds, and needs a 6336 tube which
costs 50 bucks. I think that would work for a power supply though,
don't you think?
shooting sparrows with cannons. A decent 1/2 lbs power supply with
enough beef can be built for less money. IMHO 600V is much too much.
350V is plenty there.

regards

Jochen

it's adjustable, up to 600V... you're right about that, but it seems
to operate ok, although I'm not sure if it's good to do that (there's
a total of 3 power tubes). But you really think I could build a good
HV power supply for less than 50 bucks? and half a pound? that's new
to me.
I look for "HV power supply" and "350V power supply on google. no
luck.
Is 50 mA @ 320V enough? I did findhttp://www.elecfree.com/electronic/power-supply-regulator-10-350v-50ma/
.

Although this on would fit your purpose perfectly in regards of voltage
and power, i'd still regard it a bit of overkill, (current limiting,
metering why'd you need that in a preamp...).
320-350V @50mA is the range i'd expect for a single channel. For the
first crapshot i'd take a small transformer with heater and HV winding -
tube radio or replacement comes into mind, a few diodes resistors and
caps and you're finished. I don't think the "original" power supply of
the altec contained anything else. If you really want a regulated HV,
there are some other suggestions in the book where the scheme you posted
is coming from.

this transformer might fit although the vendor is in germany..http://www.tube-town.net/ttstore/pro...p2192_Ringkern...

ok i have to correct my statement, the TX already has 530 grams, so it
would be 1 1/2 lbs.

regards

Jochen

sorry 'bout this... but for me that fails on so many levels.
One: I'm in the USA, which means I need a step-up, not step-down
transformer (shoulda told you that)
Two: I ain't in Germany, and I ain't paying for shipping
Three: I have no euros.

Anyways, if something like that is what I need (but USA version), then
what about http://www.tubesandmore.com/scripts/...?item=P-T269AX
I'd need two (or is it four? I think you can get away with two using
the center tap) big diodes. 1.6 lbs, $42.20.
I'd probably want a minimally regulated output... maybe. Or not.
Whatever. If I don't really notice a difference in volume, the forget
it.

I'm still not really sure about which preamp design to use, so I'll
wait on the power supply.

[Eeyore[_4_]]

gjsmo wrote:
I want to build a dual mic preamp, but I'm not really sure where to
start. I've got many 5963's (industrial 12AU7's) and 12AX7's lying
around that I'd like to use.

So you don't want a particularly quiet mic pre then ?

There are some sites online that have mic pre circuits from Telefunken,
Siemens et al that were made for the German broadcaster WDR in the 50s
and 60s to fit standardised equpment racks. These are probably some of
the best tube designs around to date.

US mic amps tended to be somewhat simpler.

Check out ......
http://www.google.co.uk/search?hl=en...meta=&aq=f&oq=

That will give you some model numbers to search for. The V72 seems to be
quite popular with today's tube sluts.

Here you go ......
http://audio.kubarth.com/rundfunk/index.cgi


Graham

[jh[_2_]]

gjsmo schrieb:
On Oct 25, 4:55 am, jh wrote:
gjsmo schrieb:





On Oct 24, 3:21 pm, jh wrote:
gjsmo schrieb:
How to build my pre? Let me count the ways... :-)
SS is about as popular as communism.
this was not from my posting...
I beg to differ... unfortunately, most music these days is digital. On
CDs, or (ugh!) MP3s. I confess to using an iPod touch for my music.
Not that I like it, but then again, I can't fit 20+ LPs plus a player
and small headphone amp in my pocket. Solid-state is about as popular
as white bread (and just as bad).
I still bet you don't want to overdrive them and use them as a distortion unit. IMHO this sounds like crap
Ok, then I won't.
So I guess the altec "electric crayon" is just fine, then? Or should I
keep looking (I'm a bit new to audio equipment, but that really
doesn't prevent me from knowing good sound when I hear it...)
If this helps, I have a 600V 500mA max tube power supply. It needs a
new pot for the bias, but it'll provide A voltage, B voltage (up to
600V) and C if I fix the pot (I think it's 0 to -150V). It's really
big though, and weighs about 50 pounds, and needs a 6336 tube which
costs 50 bucks. I think that would work for a power supply though,
don't you think?
shooting sparrows with cannons. A decent 1/2 lbs power supply with
enough beef can be built for less money. IMHO 600V is much too much.
350V is plenty there.
regards
Jochen
it's adjustable, up to 600V... you're right about that, but it seems
to operate ok, although I'm not sure if it's good to do that (there's
a total of 3 power tubes). But you really think I could build a good
HV power supply for less than 50 bucks? and half a pound? that's new
to me.
I look for "HV power supply" and "350V power supply on google. no
luck.
Is 50 mA @ 320V enough? I did findhttp://www.elecfree.com/electronic/power-supply-regulator-10-350v-50ma/
.
Although this on would fit your purpose perfectly in regards of voltage
and power, i'd still regard it a bit of overkill, (current limiting,
metering why'd you need that in a preamp...).
320-350V @50mA is the range i'd expect for a single channel. For the
first crapshot i'd take a small transformer with heater and HV winding -
tube radio or replacement comes into mind, a few diodes resistors and
caps and you're finished. I don't think the "original" power supply of
the altec contained anything else. If you really want a regulated HV,
there are some other suggestions in the book where the scheme you posted
is coming from.

this transformer might fit although the vendor is in germany..http://www.tube-town.net/ttstore/pro...p2192_Ringkern...

ok i have to correct my statement, the TX already has 530 grams, so it
would be 1 1/2 lbs.

regards

Jochen

sorry 'bout this... but for me that fails on so many levels.
One: I'm in the USA, which means I need a step-up, not step-down
transformer (shoulda told you that)
Two: I ain't in Germany, and I ain't paying for shipping
Three: I have no euros.

Anyways, if something like that is what I need (but USA version), then
what about http://www.tubesandmore.com/scripts/...?item=P-T269AX
I'd need two (or is it four? I think you can get away with two using
the center tap) big diodes. 1.6 lbs, $42.20.
I'd probably want a minimally regulated output... maybe. Or not.
Whatever. If I don't really notice a difference in volume, the forget
it.

I'm still not really sure about which preamp design to use, so I'll
wait on the power supply.


...i thought it'd b a nice example of a small leightweight transformer.
Of course i did not thonk you'd order one in europe.

your example is quite nice and could power two channels easily. I can't
see th dimensions, but one of the nice things about thos toroid donuts
is, that they fit in a 1U case.

regards

Jochen

[Ian Bell[_2_]]

Eeyore wrote:
gjsmo wrote:
I want to build a dual mic preamp, but I'm not really sure where to
start. I've got many 5963's (industrial 12AU7's) and 12AX7's lying
around that I'd like to use.

So you don't want a particularly quiet mic pre then ?


Why does his statement preclude the ability to make a quiet mic pre?

Cheers

Ian

[Ian Bell[_2_]]

gjsmo wrote:

mega snip

I'm still not really sure about which preamp design to use, so I'll
wait on the power supply.


Instead of all these worries about what power supply to use and where to
get the transformer, why not start in a more straightforward fashion and
build a kit? Look he

http://www.paia.com/

and search for their 9407K kit - its less than a hundred bucks.

Cheers

Ian

[gjsmo]

Why does his statement preclude the ability to make a quiet mic pre?
It doesn't. In fact, I'd like a very noise-free preamp. I suppose I'm
getting ahead of myself, since I don't care so much about regulated
power - which will give me hum.
I still have that regulated beast.

With regards to the Aikido pre, could you PLEASE tell me why we are
going through the trouble to regulate HEATER voltage? In a 12A[TUX]7,
the heater is not part of the audio path (not directly, at least).
It's just there to heat the plate.

And the PAiA preamp seems like more than I would spend just ordering
parts. Am I nuts? Because I really have no knowledge of good prices
for tube stuff, but I sure know I like it (look up the Line 6 HD100
guitar amp head - it's beautiful, and the distortion is SWEET). If I
wanted to do that, I think I might just get a Behringer preamp/DI box
(http://www.behringer.com/EN/Products/MIC2200.aspx). It's guaranteed
to work, too... although there would be no distortion, for sure.

[Ian Iveson]

gjsmo wrote:

Why does his statement preclude the ability to make a
quiet mic pre?
It doesn't. In fact, I'd like a very noise-free preamp. I
suppose I'm
getting ahead of myself, since I don't care so much about
regulated
power - which will give me hum.
I still have that regulated beast.

With regards to the Aikido pre, could you PLEASE tell me
why we are
going through the trouble to regulate HEATER voltage? In a
12A[TUX]7,
the heater is not part of the audio path (not directly, at
least).
It's just there to heat the plate.

To remove hum and noise from the heater circuit, probably,
so they don't get transmitted by various means to other
parts of the circuit. Regulators are cheap and easy.

Ian

And the PAiA preamp seems like more than I would spend
just ordering
parts. Am I nuts? Because I really have no knowledge of
good prices
for tube stuff, but I sure know I like it (look up the
Line 6 HD100
guitar amp head - it's beautiful, and the distortion is
SWEET). If I
wanted to do that, I think I might just get a Behringer
preamp/DI box
(http://www.behringer.com/EN/Products/MIC2200.aspx). It's
guaranteed
to work, too... although there would be no distortion, for
sure.

[Eeyore[_4_]]

Ian Bell wrote:
Eeyore wrote:
gjsmo wrote:
I want to build a dual mic preamp, but I'm not really sure where to
start. I've got many 5963's (industrial 12AU7's) and 12AX7's lying
around that I'd like to use.

So you don't want a particularly quiet mic pre then ?


Why does his statement preclude the ability to make a quiet mic pre?

State of the art semiconducors ( not necessarily even exensive ones )
can be stunningly quiet ( sub 1nV / sqrt Hz ) and can be direct coupled
to the mic avoiding the cost and 'distortions' of an input transformer.

For a really good input transformer look at Lundahl or Jensen. I know
Lundahl have one designed to match to tubes with a high turns ratio and
they know how to layer their windings for optimum performance.

Graham