Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: mikhett on January 17, 2022, 09:01:58 am

Title: Champ 5F1 with 7591
Post by: mikhett on January 17, 2022, 09:01:58 am

I'm building a 5F1 with  7591 output tube instead of a 6V6 because I have some spares from a gutted Ampeg .Anyone ever tried it? Thanks

Title: Re: Champ 5F1 with 7591
Post by: Latole on January 17, 2022, 09:56:39 am

Heater need almost twice heater current

Title: Re: Champ 5F1 with 7591
Post by: Stuff4bikes on January 17, 2022, 11:48:21 am

I have a 5f2a clone with a 7868 that sounds very nice..

Title: Re: Champ 5F1 with 7591
Post by: sluckey on January 17, 2022, 12:53:54 pm

I like 7591s. You may need to use a different cathode resistor.

Title: Re: Champ 5F1 with 7591
Post by: mikhett on January 18, 2022, 06:23:50 pm

I do I increase heater current without changing the transformer?

Title: Re: Champ 5F1 with 7591
Post by: mresistor on January 18, 2022, 07:00:16 pm

What power transformer are you using and what is the rating of the 6.3VAc winding?

Title: Re: Champ 5F1 with 7591
Post by: sluckey on January 18, 2022, 07:06:35 pm

Quote from: mikhett on January 18, 2022, 06:23:50 pm

I do I increase heater current without changing the transformer?

I don't understand your question.

The 12AX7 and 7591 will want 1.1A current. Is that a problem? How much filament current can your PT supply?

Title: Re: Champ 5F1 with 7591
Post by: mikhett on January 18, 2022, 08:52:15 pm

Typo SORRY.HOW do I increase heater current without changing the transformer?I'm using a stock Champ transformer.THANKS

Title: Re: Champ 5F1 with 7591
Post by: sluckey on January 18, 2022, 09:15:22 pm

Don't worry about it. The Hammond 290AX Champ replacement is rated for 6.3V @ 2.25A. More than enough for a 7591. I suspect other champ replacements are rated similarly.

Title: Re: Champ 5F1 with 7591
Post by: mikhett on January 18, 2022, 10:57:21 pm

Thanks MR.SLUCKEY!