Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Oddvar on October 31, 2018, 12:42:30 pm

Title: 3k vs 1.7k in OT's?
Post by: Oddvar on October 31, 2018, 12:42:30 pm

Hi.  Is there any significant difference between 1.7k and 3k ohms in an output transformer, or are they interchangeable?

Title: Re: 3k vs 1.7k in OT's?
Post by: sluckey on October 31, 2018, 12:53:20 pm

3K or 3.4K might be used with a pair of EL34s. 1.7K might be used with a quad of EL34s.

Title: Re: 3k vs 1.7k in OT's?
Post by: Oddvar on October 31, 2018, 01:10:29 pm

So it won't be usable with 4 6l6?

Title: Re: 3k vs 1.7k in OT's?
Post by: sluckey on October 31, 2018, 01:20:08 pm

Sure. Which one?

Title: Re: 3k vs 1.7k in OT's?
Post by: Oddvar on October 31, 2018, 01:52:39 pm

I am thinking of using it in a Dumble build...

Title: Re: 3k vs 1.7k in OT's?
Post by: sluckey on October 31, 2018, 03:34:35 pm

If I had one, I'd use this OT in a #183 build...

Title: Re: 3k vs 1.7k in OT's?
Post by: SoundmasterG on October 31, 2018, 09:29:58 pm

6L6's tend to like something closer to 2k for a quad and EL34's are very happy with 1.7k, but they will both work with either. The B+ used changes the optimum load as does the bias you set it to. There is a range of impedance that works with every tube type rather than a hard set value.

Greg

Title: Re: 3k vs 1.7k in OT's?
Post by: shooter on November 01, 2018, 08:48:24 am

Quote

happy with 1.7k,

fwiw I used a 1.2k with a Quad SE of EL 84's in a Fi build  ~20W clean