Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Lectroid on September 13, 2021, 02:27:10 pm

Title: 12DT8 vs. 12AT7: Are these two tubes as similar as they appear?
Post by: Lectroid on September 13, 2021, 02:27:10 pm

When I look at data sheets for these two tubes, they seem to be very similar.  Am I right in that?  If not, what major differences are there.

Has anyone ever used a 12DT8?  I plan to use it in a transformer-less reverb drive circuit.

Thanks!

Title: Re: 12DT8 vs. 12AT7: Are these two tubes as similar as they appear?
Post by: sluckey on September 13, 2021, 03:50:57 pm

One major difference... The 12DT8 can only use 12.6v heater voltage. Show stopper for me.

Title: Re: 12DT8 vs. 12AT7: Are these two tubes as similar as they appear?
Post by: HotBluePlates on September 13, 2021, 05:05:29 pm

Quote from: Lectroid on September 13, 2021, 02:27:10 pm

When I look at data sheets for these two tubes, they seem to be very similar.  Am I right in that?  ...

Same tube, except for the heater.

Quote from: sluckey on September 13, 2021, 03:50:57 pm

One major difference... The 12DT8 can only use 12.6v heater voltage. ...

Use the 6DT8.  Same tube except for heater voltage.  Just like a 12AT7 except for only using Pins 4 and 5 for the heater.

Title: Re: 12DT8 vs. 12AT7: Are these two tubes as similar as they appear?
Post by: Lectroid on September 14, 2021, 07:14:58 am

Thanks all.  I knew they had to be different, but I completely missed the heater specs.

 :worthy1: :BangHead: