Tube preamp with: 1V in and 15Vout???

[Tyimo]

Hi!

I am looking for a good, but simple tube "preamp" what could give 15V rms out from ca. 1V rms in.
It would drive a 330Kohm Zin Mosfet follower poweramp.
If it possible I would like to use ECC88 tubes.

Has somebody any idea?

Greets:

Tyimo

 

[ErikdeBest]

The first stage from this headphone amp!?
http://headwize.com/projects/showfile.php?file=cmoy5_prj.htm

B+ of 220V, plate resistor: 27k, cathode resistor: 750R, bypassed. Can't do the math right now, but should provide 15x gain, even more.

For a number closer to 15 you could try a SRPP stage with the ECC88. SRPP gives gain = 1/2 mu (mu is about 34 for the ECC88)

Erik

 

[Shoog]

The 5687 has gain of about 16. Loaded with a simple CCS you should get about that gain out of it. The 5687 sounds excellent, and certainly better than a simple ECC88 will achieve.

Shoog

 

[ErikdeBest]

I thought about a mu stage (or otherwise actively loaded) 12BH7A. Sounds great and has the right mu.

But probably Tyimo already has some ECC88, that's why he asks for something with this tube ?!?!

 

[dsavitsk]

The 5687 has gain of about 16. Loaded with a simple CCS you should get about that gain out of it. The 5687 sounds excellent, and certainly better than a simple ECC88 will achieve.

http://www.diyaudio.com/forums/showthread.php?postid=891244#post891244

 

[Tyimo]

Hi! Thanks for everybody!

For a number closer to 15 you could try a SRPP stage with the ECC88. SRPP gives gain = 1/2 mu (mu is about 34 for the ECC88)

The most important that the preamp could work with high input V, because mostly I use CDplayer which has more than 2V output.

But probably Tyimo already has some ECC88, that's why he asks for something with this tube ?!?!

Yes, but I have some ECC82 and ECC83 and ECL82 tubes too.

Greets:

Tyimo

 

[Tyimo]

Hi dsavitsk!

Could you tell me a bit more about your 2nd preamp with one triode? The values of the parts? How do you like the sound?

Greets:

Tyimo

 

[dsavitsk]

Hi dsavitsk!

Could you tell me a bit more about your 2nd preamp with one triode? The values of the parts? How do you like the sound?

It is still in the design stage, so I don't know how it sounds. I am hoping to get a board made soon. I haven't worked out all the parts to use yet, either, but the resistors in the CCS can be read from the Bottlehead manual, the input cap is dependent upon the resistor to ground right after it C = 1/(2*pi*F*R), the grid stopper is probably 1K, the plate stopper can probably be safely jumpered, but if not, something small, the bias resistor depends upon the operating point and the CCS current, which I haven't decided on, and the cathode bypass cap is probably 470uF as that seems to work usually, though smaller is probably fine too. Oh, and the ouput cap is probably going to be 4.7uF cause I have some 4.7uF caps I want to use.

 

[Tyimo]

Remus preamp

Thanks dsavitsk!


I found another interesting preamp the Remus.
Has somebody any info about it's specs??

Tyimo

 

[ErikdeBest]

the Remus

A traditional schematic - people around here (including myself) don't like the ECC82 that much - too much distortion. Gain is probably around 20, the output impedance is low. The output capacitor is pretty big - don't know if you need that. I would put a 1M resistor between the first grid and ground, otherwise the tube 'goes mad' if the contact from the pot fails. I would also install some grid stoppers.

But, a general advise... start to prototype a bit with the tubes and components you have. Everyone can post lots of schematics here, but that won't help if you don't start to test and compare them.

 

[Tyimo]

Thanks ErikdeBest!

But, a general advise... start to prototype a bit with the tubes and components you have. Everyone can post lots of schematics here, but that won't help if you don't start to test and compare them.

Yes, it is true. Now I am looking for the first step where to begin.

Should I ask some more?

What about this schematic?

Thanks

Tyimo