Bottlehead Forum

Bottlehead Kits => Crack => Topic started by: teleamp on November 10, 2020, 06:45:13 AM

Title: will the Lundahl 1683 PT work as a transformer upgrade? OOPS, I should have said
Post by: teleamp on November 10, 2020, 06:45:13 AM

Inquiring minds need to know. Thanks.

Edit to add: See reply #5...

Title: Re: will the Lundahl 1683 PT work as a transformer upgrade?
Post by: Deke609 on November 10, 2020, 06:58:15 AM

Why would you want to change the power transformer? All it does is take the AC wall voltage and steps it up for the high voltage supply that feeds the tube plates and steps it down for the tube heaters.  There's only a few things that can go wrong: mechanical vibration, electromagnetic interference/coupling with adjacent wiring/coils, and not having the proper current/voltage rating for the amp. I have a crack, two Stereomours, a BeePre and a Kaiju -- all with stock PTs. Never had an issue with vibration or EMF intereference/coupling with any of them -- and the stock PT is obviously suited to the voltage/current requirements of the amp.

cheers, Derek

Title: Re: will the Lundahl 1683 PT work as a transformer upgrade?
Post by: Paul Birkeland on November 10, 2020, 07:04:12 AM

You would need to redesign the Crack with a very different power supply in order to get the voltage that you need without overloading the high voltage windings on that Lundahl.

I would not say that it would be an upgrade.

Title: Re: will the Lundahl 1683 PT work as a transformer upgrade?
Post by: teleamp on November 10, 2020, 07:17:37 AM

Thanks PB, basically I want to build a Crack and replace the PT on my Darkvoice. The Lundahl # was a shot in the dark and I am clueless in my search.

Title: Re: will the Lundahl 1683 PT work as a transformer upgrade?
Post by: oguinn on November 10, 2020, 07:40:54 AM

From all accounts the Bottlehead PTs are about as good as you’re going to get. I’d spend the money on caps or tubes or a Crack-A-Two-A if you want to go crazy on upgrades

Title: Re: will the Lundahl 1683 PT work as a transformer upgrade?
Post by: teleamp on November 11, 2020, 02:30:27 AM

Thanks. I plan to leave the Crack stock and enjoy it for what it is...

My usage is a bit different though.

I play electric guitar and my current living situation requires no loud noises. So, I listen with headphones.

My current setup is a home assembled telecaster into a Strymon Iridium then into a headphone amp (currently a Darkvoice).

The Darkvoice power transformer has 110V primaries. My house has 120 VAC (nominal) at the outlets. I would like to find a suitable replacement for the DV iron and buildin a Crack will be a good learning experience.

Title: Re: will the Lundahl 1683 PT work as a transformer upgrade? OOPS, I should have said
Post by: Paul Birkeland on November 11, 2020, 06:20:53 AM

You can make a 10V bucking transformer for the DV or use an appropriate dropping resistor between line and power transformer to knock 10V off the incoming AC.