12B4 have a good sound ???

[aldovan]

Friends

I need a small gain tube for replace a 6N6P in a pre-amplifier...
I think in use the cheap and robust 12B4 or 12B4A...
This tube have a fine sound ?
Anyone have experience with this tube ?

Thanks,

Aldovan

[el156]

Originally Posted by aldovan

Friends

I need a small gain tube for replace a 6N6P in a pre-amplifier...
I think in use the cheap and robust 12B4 or 12B4A...
This tube have a fine sound ?
Anyone have experience with this tube ?

Thanks,

Aldovan

Hi !
I made some tests with 12B4A and was very positive! i like the sound very much. Go ahead with it ! And tell us the results.
Um abraco de Portugal
Silvino

[SGregory]

There is a lot of fans of the 12b4 in here, myself included. Do a search in this forum and you will find many "operating" points for optimum sound.

[aldovan]

Originally Posted by el156

Hi !
I made some tests with 12B4A and was very positive! i like the sound very much. Go ahead with it ! And tell us the results.
Um abraco de Portugal
Silvino

Silvino

Thanks, I will make some tests with this tubes !!!
Gosto muito de Portugal !!! ( I like Portugal !!!)

Um abraço, ( a hug)

Aldovan

[aldovan]

Originally Posted by SGregory

There is a lot of fans of the 12b4 in here, myself included. Do a search in this forum and you will find many "operating" points for optimum sound.

Thanks for the opinion, I will build a stage with this tube.

Aldovan

[SGregory]

the 12b4 or 12b4a is not without it issues either. It is a current hog, most people operate it around 17 - 25mA. If it is the input stage of the amp you will end up with a low impedance feedback loop if you use cathode feedback. Some of the tubes are microphonic, and all of mine tend to be more on the noisy side. I can hear a slight hiss, with 90dB speakers and 31dB gain on the amp.

I have not had stability issues but some claim that the tube is marginal with a CCS as the anode load. I presently use a resistive anode load and a bypassed CCS in the cahode circuit. I also run 21mA @ 150V. I do plan on experimenting with it next fall to find its true sweet spot.

The tube is imho worth the effort. I find it to be very neutral and also detailed. I dislike an overly warm sound that some tubes tend to give.

[aldovan]

Originally Posted by SGregory

the 12b4 or 12b4a is not without it issues either. It is a current hog, most people operate it around 17 - 25mA. If it is the input stage of the amp you will end up with a low impedance feedback loop if you use cathode feedback. Some of the tubes are microphonic, and all of mine tend to be more on the noisy side. I can hear a slight hiss, with 90dB speakers and 31dB gain on the amp.

I have not had stability issues but some claim that the tube is marginal with a CCS as the anode load. I presently use a resistive anode load and a bypassed CCS in the cahode circuit. I also run 21mA @ 150V. I do plan on experimenting with it next fall to find its true sweet spot.

The tube is imho worth the effort. I find it to be very neutral and also detailed. I dislike an overly warm sound that some tubes tend to give.

And what brands have best sound ?
RCA is fine ?
I will use with 20 to 25mA x 90 V( plate).


Aldovan

[SGregory]

RCA and GE JAN issued. Both sounded good.

[aldovan]

Originally Posted by SGregory

RCA and GE JAN issued. Both sounded good.

Fine.
I found some GE used that I removed of an old HP tester.
I will make some tests tomorrow and post the results here.
Thanks.

Aldovan

[FullRangeMan]

Alô Aldovan,
Você constroi valvulados?? Por acaso você já fez algum SET com a GM70??
Sempre é bom saber quem está construindo valvulados, pois gostaria de um SET GM70 no futuro.
Saudações, Gustavo