Octal Preamp Triode Thoughts (IDHT's)

[rcollege]

I'm building a preamp using a very basic SE design to drive a Dynakit ST35.
It has an input impedance of 500K. My main source has a 200mV RMS output...so I will need some gain to bring it to 1V RMS.

Any thoughts about using a 6K5gt for a preamp or phono stage? Mu of 70.
I also have a 7F7 (double triode) and access to more- Mu of 70.

Also any thoughts of 6C5g's vs. 6J5gt's? Are they too close to warrant changing from one to another?

Any thoughts on other IDHT octal triodes would be awesome- especially single triodes.

Thanks

 

[kevinkr]

Both 6C5 and 6J5 would be an excellent choice for a simple line stage. See which you like best.

 

[Eli Duttman]

You mentioned the Loctal 7F7, which is electrically equivalent to the Octal 6SL7. An interesting Loctal medium mu twin triode is the 7AF7. The advantage of this type is its 300 mA. heater draw. The 7AF7 makes a fine common cathode voltage amplifier. However, its relatively low gm is a warning against cathode follower service.

 

[Vinylsavor]

Hi!

Is this for a line stage or phono or both?

In terms of high mu octals I like the 6SF5:

VinylSavor: Tube of the Month : The 6SF5


and the 6SC7 (both sections paralleled):

VinylSavor: Tube of the Month: The 6SC7


I used both of these in phono stages with success.

For line stages I like the 6AH4:

VinylSavor: Tube of the Month: The 6AH4


Bets regards

Thomas

 

[rcollege]

Thanks for your responses.

Just picked up a pair of 6J5GT's for $6.50ea.

Has anyone tried the 6K5G in a phono stage...or any audio?
It has a high Mu...low heater current draw (0.3amps). It's curves look good- if I'm looking at them correctly.
I tried it in a line stage with a clean response...more in the highs...but I'm interested in others' comments and or experiences.

 

[alexkhar]

Hello.
I use 6K5GT as driver in SE Amp. Ua=230V, Ia=1,17 mA. Sound is very clear so I like it.