Tube Preamp philips Mullard

[trean27]

I been looking around for a while and cant seem to find out the right scematics for my tubes I inherit.

I want to build a preamp, and is there any tubes here that would do ?
and then is there a type of scematics. ?
best regards Niklas.

I have
EF39
EBF32
EL33
ECH35

 

[JonSnell Electronic]

Not suitable for a pre amp. EBF32 is a double diode pentode for frequency changing in radio sets. EF39 is an RF amplifier, ECH35 is a triode hexode frequency changer and EL33 is the little brother to the EL37. Two can produce up to 8Watts at no more than 15% harmonic distortion.

 

[trean27]

so not any good these then.

thanks so much for the help

 

[trean27]

by the way, what tube should I buy to get the best sound specially for Rock music.
I will connect this to a transistor amp just for gain. .
I seen a scematics on a 12au7

 

[Eli Duttman]

The 12AU7 makes a wretched, non-linear, voltage amplifier. As long as the doubled heater current is present, linear 12BH7s drop right right into 12AU7 circuits.

If all of your signal sources are line level, like CDPs, you may not need linestage gain.

 

[trean27]

Thanks for input Eli. I guess that I dont need so much gain, I would like to benefit from the sound from the tube.. so a 12BH7 would then be a good alternative ?

 

[Eli Duttman]

Gain from a 12AU7 and a 12BH7 are approx. equal.

Do you want an effects machine or a HIFI setup? Search the archives for 12B4 designs. The 12B4 is both linear and low μ (amplification factor).

BTW, what is the I/P impedance of your SS power amp? As low as 10 Kohms is within the IHF "standard". The 12B4 is one of a very small number of tubes that can drive such a low downstream load successfully, when wired as a common cathode gain stage.

 

[TonyTecson]

EL33 is the little brother to the EL37

you might get away with it in triode mode though....http://www.r-type.org/pdfs/el33.pdf

g1-g2 mu of about 20 is like that of the 6sn7, but that is all...

please have a look at the diyaudio thread where the 6V6 is used as a line amp...http://www.diyaudio.com/forums/tubes-valves/102352-6v6-line-preamp.html

so there you go, go build a line amp.....

btw, since the pinouts are the same, you can even roll between the two....

 

[DF96]

by the way, what tube should I buy to get the best sound specially for Rock music.

What is "best"?

I would like to benefit from the sound from the tube..

Drop it on the floor. If it just bounces then drop it again. Eventually you will hear the sound from the tube. Onlookers may hear the sound from the tube owner too.

 

[trean27]

df96... funny... but seriously, i got hold of a few more today.
is any of these duable for line preamp. ??
6GK6, or Ecc85 , ech 81 , ebf89, ecl86??
best regards Niklas

 

[DF96]

More radio valves. None of them are suitable for a line stage - but then most systems don't need a line stage. Sell them to someone maintaining old radio sets (or, better still, leave them in the old radio set they came from).

 

[lordearl]

12B4 is great.
I just built this - easy project and a nice clean sound.
diytube.com • View topic - Budgie Preamplifier w/ Arduino - 6/23/14

 

[TonyTecson]

6gk6 is more like a 6bq5, have tried and sounds nce too...
ecc85 is also a nice double triode..

 

[Eli Duttman]

The ECC85/6AQ8 closely resembles the 12AT7/ECC81. Given the reasonably high transconductance (gm), a stereo buffered (cathode follower) volume control could be made from a single specimen. Well executed, the setup would be highly transparent. However, the OP has yet to answer my question about wanting linearity or an effects box.

 

[DF96]

As the ECC85 is not being made, better to sell it to someone who needs one and use an ECC81 instead.