6sn7: GT GTA GTB sono differences for HIFI

[Achi70]

Hi

On ampli we have sonic difference among these different kinds of preamp/drivers tubes?...apart different brands of course.

For example the 5w dissipation for GTA/b produce a louder sound compared to gt (2.5w)???

Is safe to use GTB to subistitute a 6sn7 in ampli?

Thanks in advance

 

[Hilmar53]

Yes it is safe.
The difference between GTA and GTB is the warmup time of the Heater.
The difference between GT and GTA is that the A has a higher anode voltage.
GT = 300V max.
GTA = 500V max.
If your powersupply is below 300V nothing bad can be happen.
I hope i answered your question.
Happy new year
Hilmar

 

[ruffrecords]

You might like to read these:

http://www.ianbell.ukfsn.org/data/mufollowerdistortion.pdf

http://www.ianbell.ukfsn.org/data/6CG7mufollowerdistortion.pdf

Cheers

Ian

 

[Achi70]

Thanks

A bit difficult for me the distortion papers..

In a few words:
1) I've understand that with a power supply like 230W is safe to use GTA/GTB instead of GT.

2) I don't understand if the different plate dissipation between GT and GTA/B (2.5W vs 5W) produces a different sonic effect like more loud in the ampli or other sonic audible effect,

In a few words:
1) I've understand that with a power supply like 230W is safe to use GTA/GTB instead of GT.

2) I don't understand if the different plate dissipation between GT and GTA/B (2.5W vs 5W) produces a different sonic effect like more loud in the ampli or other audible sonic effect apart the brand of the tube.

Thus, I must take of care about GT and GTA/GTB for 6SN7 or I must take of care about brand, getter, chrome dome and so on, but indifferent about GT and GTA/GTB.

Thanks again

 

[DF96]

In a few words:
1) I've understand that with a power supply like 230W is safe to use GTA/GTB instead of GT.

2) I don't understand if the different plate dissipation between GT and GTA/B (2.5W vs 5W) produces a different sonic effect like more loud in the ampli or other sonic audible effect,

1) No. The power rating of the PSU is irrelevant.
2) No. Higher power rating in a small signal valve and 'sonic effects' are not well correlated - you can deduce nothing except that the valve can cope with dissipating more power.

In most good circuits you need not take care of any characteristics except ensuring your 6SN7 actually are 6SN7 and not something else.

 

[Achi70]

Thanks DF96

Finally is clear.
No sound effect due to different plate dissipitation on 6SN7 GT/GTA/GTB
Thanks a lot