Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: oldhippy on April 16, 2012, 07:14:44 pm

Title: output impedance mis-match on a TOS
Post by: oldhippy on April 16, 2012, 07:14:44 pm

greetings...
I'm thinking about building a TOS board to put in a 5F6a chassis, using the existing iron. I've ran the 5f6a with only 1 ea. 8 ohm spkr to reduce the volume despite the 2 ohm OT, with no problems. Can I do the same with the TOS innards without causing a problem or will the mis-match be more of an issue? Thanks in advance.

Title: Re: output impedance mis-match on a TOS
Post by: sluckey on April 16, 2012, 07:46:55 pm

If you use the same output tubes, the results should be the same.

Title: Re: output impedance mis-match on a TOS
Post by: oldhippy on April 18, 2012, 07:30:48 pm

sluckey, thnx for the reply. I mis-posted, I've been running a 4 ohm spkr rather than the 8 ohm I stated earlier. My 5f6a is fixed bias and the TOS I'm looking at is cathode biased. Not an issue? thanks

Title: Re: output impedance mis-match on a TOS
Post by: HotBluePlates on April 18, 2012, 08:00:12 pm

Nope. The tubes, OT and speaker see all this as the same situation as you had in your original 5F6A circuit.