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Which is the best tube preamp for me?

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C

ctechdx

Member
Joined 2016
Hello folks,

I´m looking for a stereo tube preamp to build. I know theres a lot of projects in the internet and here on this forum, but I´m newbie on this and need some help to decide which one will be the best choice for me.

I gonna use this for audio recording. Will feed it with line signal, and go back to an AD converter to record the audio with the tube color.

What I need:

*Balanced inputs and outputs (it´s not a must, but would be great to have it)
*stereo preamp
*I need something with a full range response... 20hz to 20k
*I want a tube warmth but I need it to be as clean as possible. (Lowest possible noise)
*I´m looking for fat low end and smooth highs sound
*I like the sound of ECC88s. A project with these would be great, but also open for suggestions.
*I´m and experienced audio engineer but newbie on electronics. Better if there´s a kit avaible or some instructions to build.

Hope you guys can help me

Thank u so much!
 
Last edited:
petertub

petertub

Member
Joined 2015
tubular-well.se
Paid Member
ctechdx said:
Hello folks,

I´m looking for a stereo tube preamp to build. I know theres a lot of projects in the internet and here on this forum, but I´m newbie on this and need some help to decide which one will be the best choice for me.

I gonna use this for audio recording. Will feed it with line signal, and go back to an AD converter to record the audio with the tube color.

What I need:

*Balanced inputs and outputs (it´s not a must, but would be great to have it)
*stereo preamp
*I need something with a full range response... 20hz to 20k
*I want a tube warmth but I need it to be as clean as possible. (Lowest possible noise)
*I´m looking for fat low end and smooth highs sound
*I´m and experienced audio engineer but newbie on electronics. Better if there´s a kit avaible or some instructions to build.

Hope you guys can help me

Thank u so much!
Click to expand...
Tubes has no color or "warmth".

Any hifi amp will have full response in audio range and will only have

as much low end (and high end) as the program material has.
 
C

ctechdx

Member
Joined 2016
petertub said:
Tubes has no color or "warmth".

Any hifi amp will have full response in audio range and will only have

as much low end (and high end) as the program material has.
Click to expand...


Ok, but look tubes are not exactly precise components, it changes the sound and add harmonic distortion. Those changes and distortion are what I call "color" or "warmth". Tubes are definitely not a fully transparent piece that the signal goes out exactly the way it comes in. And that´s what i´m looking for.

I mentioned about the full range response because there´s some tube preamps made for instruments and those can have some filtered low end.
 
Last edited:
petertub

petertub

Member
Joined 2015
tubular-well.se
Paid Member
ctechdx said:
Ok, but look tubes are not exactly precise components, it changes the sound and add harmonic distortion. Those changes and distortion are what I call "color" or "warmth". Tubes are definitely not a fully transparent piece that the signal goes out exactly the way it comes in. And that´s what i´m looking for.

I mentioned about the full range response because there´s some tube preamps made for instruments and those can have some filtered low end.
Click to expand...
Tubes _may_ change the sound and add distortion, but then we are not
talking about hifi ( or neutral ) amps.

There is nothing wrong with coloring or changing the sound that emanates
from a source, but it is not neutral or transparent, it's according to one's taste.


Well built tube amps will not add sweetness or any other type of distortion,
instead they will replicate the source. Any amp that are used at it's limits will
change the sound, here tubeamps is usually behaving differently then sandamps.
 
C

ctechdx

Member
Joined 2016
petertub said:
Tubes _may_ change the sound and add distortion, but then we are not
talking about hifi ( or neutral ) amps.

There is nothing wrong with coloring or changing the sound that emanates
from a source, but it is not neutral or transparent, it's according to one's taste.


Well built tube amps will not add sweetness or any other type of distortion,
instead they will replicate the source. Any amp that are used at it's limits will
change the sound, here tubeamps is usually behaving differently then sandamps.
Click to expand...

Ok right, i understand. But what im looking for is some tube preamp that actually color the sound. Specialy something that help the signal sounds Fuller, and with a smooth top end. Can u suggest me something?

Thanks
 
J

jakruby

Member
Joined 2007
You want a single-ended circuit with transformers for input and output. Single-ended gives you the tube 'distortion signature' or sound (no harmonic cancellation as would occur in a balanced circuit) and the transformers will give you balanced (or single ended) input and outputs.
 
C

ctechdx

Member
Joined 2016
jakruby said:
You want a single-ended circuit with transformers for input and output. Single-ended gives you the tube 'distortion signature' or sound (no harmonic cancellation as would occur in a balanced circuit) and the transformers will give you balanced (or single ended) input and outputs.
Click to expand...

Thanks for the reply!

Do you know where can i start? Is there some diy kits or pcb for a project such u have described?

Thank you!
 
A

audiowize

Member
Joined 2005
I would put input and output transformers around the preamp section of an old Fisher tube receiver. That would likely meet your needs reasonably well. I go out of my way to avoid 12AX7s in anything I build, and I don't really see a lot of new published preamp designs using them.
 
6

6A3sUMMER

Member
Joined 2016
Anything that adds phase changes (and group delay changes), frequency response changes, and distortion will add some color.
The questions are:
How much color?
Can you hear it?

For distortion that is generated by a small signal transformer, some causes are:
Magnetized core
DC offset from the prior circuit
Large signal levels
 
Last edited:
C

ctechdx

Member
Joined 2016
6A3sUMMER said:
Anything that adds phase changes (and group delay changes), frequency response changes, and distortion will add some color.
The question is, how much color?
Click to expand...

I gonna use this to add color to Full songs, stereo recording, then It has to be something subtle. The good tube processing i have tried makes music sound Fuller, and adds some body to the low end, makes the high end smoother. But of course in a subtle way... Nothing extreme.

Can u suggest me something for this purpose?

Thanks!
 
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