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12B4 have a good sound ???

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el156

el156

Member
Joined 2010
aldovan said:
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
Click to expand...
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

SGregory

Member
Joined 2003
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.
 
A

aldovan

Member
Joined 2005
SGregory said:
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.
Click to expand...


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


Aldovan
 
A

aldovan

Member
Joined 2005
12b4

FullRangeMan said:
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
Click to expand...

Gustavo

Sim, eu construo, mas não comercialmente, por enquanto.
Pretendo construir um SET with a GM70 no futuro, mas por enquanto tenho construído SET com potências mais baixas, na faixa de 5W a 10W.

Um abraço,

Aldovan
 
A

aldovan

Member
Joined 2005
12B4...excellent !!!

el156 said:
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
Click to expand...

Silvino

Today I make some tests with a GE 12B4A.
This tube sound very fine, with big bass extension and is very detailed and clear...
A good choice, I will to buy some RCA, Sylvania and Tungsol for a tube taste...


Abraços,( hug´s)

AldovanI
 
el156

el156

Member
Joined 2010
aldovan said:
Silvino

Today I make some tests with a GE 12B4A.
This tube sound very fine, with big bass extension and is very detailed and clear...
A good choice, I will to buy some RCA, Sylvania and Tungsol for a tube taste...


Abraços,( hug´s)

AldovanI
Click to expand...
Oi Aldovan!
The 12b4a has indeed a very fine sound ,and i like it very much as cathodine phase splitter,it works just perfect! Can you buy new ones in Brazil? Here is not a common tube ,the TVs here never used this tube for vertical deflection, we used most PCL805.
Um abraco de Portugal e boa sorte
Silvino
 
A

aldovan

Member
Joined 2005
el156 said:
Oi Aldovan!
The 12b4a has indeed a very fine sound ,and i like it very much as cathodine phase splitter,it works just perfect! Can you buy new ones in Brazil? Here is not a common tube ,the TVs here never used this tube for vertical deflection, we used most PCL805.
Um abraco de Portugal e boa sorte
Silvino
Click to expand...

Silvino

Yes, I find some units ,here.
But I will to buy a lot from USA.
My e-mail is aldovanr@yahoo.com.br.
Write me and we will talk in portuguese...

Aldovan
 
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