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November 26, 2021, 03:10:26 PM

Author Topic: Powering additional devices from Crack's transformer, e.g Raspberry  (Read 379 times)

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Offline ipetruk

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  • Igor Petruk
Hi everyone,

I was exploring what could be embedded into Crack - DACs or even Raspberry with DAC hats. This has a potential of making a Wifi Roon Endpoint out of Crack that requires only a single power cable and no other input wires.

I've found a "DIY KIT LT1083 High-Power Linear Variable Regulated DC Power Supply Board Kit" on Ebay. It has the following specs.

  • Input voltage range: 2.5-38V
  • Output voltage range: 1.25-36V (current up to 7A)
  • Suitable for tube filament circuit, digital turntable, DAC and other portable devices
  • The minimum differential input and output: 2.5 V

Raspberry needs up to 600mA at 5.1V via micro USB.

If this is connected to the transformer AC output for filaments, do you think this could work? In particularly for Crack+Speedball?
Roon -> Raspberry 4 -> Khadas Tone in Bottlehead Crack+Speedball -> detachable cable modded DT880

Offline Thermioniclife

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Re: Powering additional devices from Crack's transformer, e.g Raspberry
« Reply #1 on: March 19, 2021, 08:56:35 AM »
I think you are out of luck. The min differential voltage is 2.5v using the 6.3v filament winding leaves you at a 1.3v diff.
Plus you will have to rectify and filter the 6.3 ac to dc.
« Last Edit: March 19, 2021, 09:12:19 AM by Thermioniclife »
Lee R.

Offline ipetruk

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Re: Powering additional devices from Crack's transformer, e.g Raspberry
« Reply #2 on: March 19, 2021, 09:36:00 AM »
Isn't the purpose of the circuit to rectify and filter? I think it accepts raw AC. Drawing on the board says "AC IN"
Roon -> Raspberry 4 -> Khadas Tone in Bottlehead Crack+Speedball -> detachable cable modded DT880

Offline Paul Birkeland

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Re: Powering additional devices from Crack's transformer, e.g Raspberry
« Reply #3 on: March 19, 2021, 09:56:18 AM »
The board I see on eBay looks like it has a rectifier bridge and some caps that go with the regulator.  You could hook that up to the 6V winding on the Crack to power a Raspberry PI, as the current draw looks pretty low, but I would recommend measuring the AC voltage on the 6.3V winding and posting it here with everything running to be absolutely certain.

Under no circumstances should you use that board to also feed the heaters of the tubes.  That would be a bad idea and failure would be pretty rapid.
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man