Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: 1234-wanna-build-a-little on January 21, 2025, 12:40:14 pm

Title: Warbler Rev2
Post by: 1234-wanna-build-a-little on January 21, 2025, 12:40:14 pm

I ve got an old Selmer Treble and Bass, it has a FX Loop where I already place a tube driven echo unit.
I m missing a little wobble in my setup. So I found sluckeys shematic of the warbler.

Now I m sourcing parts (a Hammond AO-47 is already on the way)

- the shematic shows a PT with 69mA and 250 0 250 V secondary

I ve got a little PT 30mA and 230V secondary 1.4A heaters (both windings have no center tap so I have to use a bridge rectifier and other dropping resistors (lower value) between the filter caps)

first question: Does it fit? If I m right (but I m not sure) a DW7 draws about 12 mA and those two 5751 1mA each triode, the heaters in summary about 1A

next question: the shematic shows a balance 50K Pec locking pot, i ve got a cts 50K 1724 pot, can I use it at around 300V DC? Or do I need a wire wound one?

next question: should that 250K tone pot work linear?

Title: Re: Warbler Rev2
Post by: Latole on January 24, 2025, 01:02:43 pm

IMO 30 ma is the half power the circuits need. I will not use it.

Title: Re: Warbler Rev2
Post by: SEL49 on January 24, 2025, 01:27:02 pm

That circuit requires less than 20mA. Your PT is fine.