• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Frank's Ultimate Tube Preamp

Frank's Ulitimate Tube Preamp.

This thread is for a new preamp by our fellow forum member Frank aka. Mr.Tube.

I hope there will be a good exchange of ideas and arrive with a design we could build.

The floor is all yours Frank. :king:

Jam

P.S. The preamp is going to be called Franken Tube for obvious reasons.:D
 
diyAudio Senior Member
Joined 2002
PREAMP.

Hi,

Let's just say that at this point we'll give it our best shot?

Shall we say that for now I see it as an open invitation to all to input their thoughts on active preamps...

Everyone is welcome I would think?

So, to get constructive...we are going to need some good volume control, a good low Zo PSU and the ability to drive any awkward load, balanced or not.

So far, we can manage that...

Cheers,;)
 
diyAudio Senior Member
Joined 2002
IN A JAM.

Hi,

Sounds good to me but what if someone wants a little bit of gain say 6db.

To burn it off somewhere else? Don't know about that but I figure that if you need gain from a line stage we could complicate things.

For the record, I don't need any preamp with gain other than my phono pre, if however, I can help anyone with a preamp we could make one with or without gain.
I feel that the idea about gain is wrong in that what you need is drive capability, not voltage gain as such.

Still, I'm listening to hear your needs,;)
 
Ok, now we are speaking spanish, that I can understand!!!

I'm late to this fest but ready and i guess on time too.

How come Frank, you are proposing a *series* regulator?

I'm Ok with a buffered or 6dB gain since Cd has been my plate since some time now.

We can concentrate ourself first to the line level and then if there interest on others in the phone section?

Of course, *Ladder* attenuator.

Tubes Frank?

How about EL34 or 6L6 as pass toobs (those i have, hehe) :clown:

IMO we should set a goal for output impedance. The lower the better? I'm driving a 10K load!!! So how about 1K?

Should we consider a 437A for this occasion?

---------------------If we can get one!!!---------------------------------
 
diyAudio Senior Member
Joined 2002
GF's

Hi,

I've got a feeling that somewhere...sometime...you had got a Spanish girlfriend!..

Having spent half of my life in Spain and Portugal that shouldn't come as no surprise.
Not to mention my days in South America an Bresil...:cool:

Lots of love going on...

You promise a cutting edge design ......to heck with the cost.

So, the banker said go for it.;)

Here is what I had in mind: dual mono construction,separate PSU and preamp chassis,star grounding throughout, regulated supply, rotary attenuator...only one R in series,constant Z, buffer with tremendous current and voltage swing/drive....this should be able to beat any commercial product.

How come Frank, you are proposing a *series* regulator?

As opposed to a shunt reg.? Well the series reg offers the advantage of isolating the PSU from the circuit better and I know it to work effectively this way.
Since I'm going to offer a shunt regulated buffer, a series reg
should do adequately.
I'm not going to propose something I'm not familiar with so I think it is wise to stick to this topology.

Cheers,;)
 
A traveler man!

Having spent half of my life in Spain and Portugal


Nice to know! ;)

Here is what I had in mind: dual mono construction,separate PSU and preamp chassis,star grounding throughout, regulated supply, rotary attenuator...only one R in series,constant Z, buffer with tremendous current and voltage swing/drive....this should be able to beat any commercial product

The comercial products that we have see in this last couple of days :bawling:

Congratulatins Frank is much curageous to design and post such a thing...because i belive, that are people here. that are always nit-picking and trying to defeat the others eforts!

But some one have to do it! :)

Good luck!

Sincearly!

Jorge
 
diyAudio Senior Member
Joined 2002
PREAMP.

Hi,

How about a buffer using a 6AS7G.

You could certainly do that, my only concern with this kind of tube is the high heater current and mayby microphony as well.

Other candidates are the noval range such as the 12B4A, 6S4, 6C19P and 12BH7A.

I had the latter in mind since it is still currently produced and a useful type of tube to have around.
Since we are going to need two triodes for the White CF, I think it is a good candidate.

In case you need a bit more power, to drive headphones the 6AS7G cicrcuit as shown on the Headwize site certainly is a good choice.

Basically, what we need is low output Z and good drive.

Ciao,;)
 
Re: PREAMP.

fdegrove said:
Hi,



Other candidates are the noval range such as the 12B4A, 6S4, 6C19P and 12BH7A.

I had the latter in mind since it is still currently produced and a useful type of tube to have around.
Since we are going to need two triodes for the White CF, I think it is a good candidate.

Ciao,;)


Certainly the 12BH7 looks good to me.

Are we having that schematic today Frank? Or it's still on be brewer?