Custom Power Transformer for Dumble 102.

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desertmouth90
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Joined: Tue Jan 23, 2024 9:35 am

Custom Power Transformer for Dumble 102.

Post by desertmouth90 »

So... Hear me out, I think this is a good question for us noobs getting into Amp building.
I got my Power and Output custom made. I asked for exactly the same spec as the Dumble Transformers from TT but I got something slightly different... And I just need to run through a few things.
I asked the questions and it seems he based it off the ODS #0124 Model contained within this forum. he replied with this:
Hi Clive,
I followed the colours on the attached layout. As this is what I will be using in my kits.
But standardized colours are as follows.
B
  • lue-Brown 240v Primary
    Red - Black* - Red - HV Power Supply
    Black* - Blue - Bias Supply
    *black shared on the windings
    Green - G/Y - Green - 6.3v heaters with centre tap (Don't fit 100r heater resistors)
    Yellow - White - Yellow 12v Heater supply (for 6v use yellow -white only) This is from memory as I am not at the office so please check it!
Thanks
Michael
On the AA Electronics layout the Heaters were 3.5v, How come I have two sets of Heaters?

in the end I decided to use 6.3v (The Green G/Y Green), is there any advantage to using 6.3v or 12v?

Thanks all you have been great in assisting me on this build and it 100% wont be my last.

I included the layout which is also on here somewhere too.

Clive
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martin manning
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Re: Custom Power Transformer for Dumble 102.

Post by martin manning »

You don't specify current capability for the 6V and 12V windings. My assumption would be that the 6.3V winding is for the heaters. If you ground the center tap you will see 3.15V on the heater pins. The current rating must be consistent with the tubes you are using, 4x 6L6 @ 0.9A + 3x 12AX7 at 0.3A = 4.5A (minimum). The 12V-0-12V winding can very conveniently be used for the relay supply. It only needs to provide a couple of hundred mA.
desertmouth90
Posts: 24
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Re: Custom Power Transformer for Dumble 102.

Post by desertmouth90 »

martin manning wrote: Tue Jul 09, 2024 10:28 pm You don't specify current capability for the 6V and 12V windings. My assumption would be that the 6.3V winding is for the heaters. If you ground the center tap you will see 3.15V on the heater pins. The current rating must be consistent with the tubes you are using, 4x 6L6 @ 0.9A + 3x 12AX7 at 0.3A = 4.5A (minimum). The 12V-0-12V winding can very conveniently be used for the relay supply. It only needs to provide a couple of hundred mA.
Thanks for that answer. Makes perfect sense.

I have two relay chips on my PCB would it be 12v if I had extra relays?
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martin manning
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Re: Custom Power Transformer for Dumble 102.

Post by martin manning »

I am not familiar with the PCB you are using. Maybe there is some documentation on this? However, I see three large caps and two rectifiers near the regulator, which suggests that you have a voltage doubler supply for the relays, same as in the 124 layout. That would only need 6V, half of the 12V winding. What is a relay chip? I see one regulator and two electromechanical relays, and no open spaces for more.
desertmouth90
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Re: Custom Power Transformer for Dumble 102.

Post by desertmouth90 »

I’m
martin manning wrote: Wed Jul 10, 2024 12:09 am I am not familiar with the PCB you are using. Maybe there is some documentation on this? However, I see three large caps and two rectifiers near the regulator, which suggests that you have a voltage doubler supply for the relays, same as in the 124 layout. That would only need 6V, half of the 12V winding. What is a relay chip? I see one regulator and two electromechanical relays, and no open spaces for more.
Okay think you answered it, so just tape off the 12v wires and all is good?

Thanks
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martin manning
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Re: Custom Power Transformer for Dumble 102.

Post by martin manning »

No, you need to use half of the 12V winding (white and either of the yellow leads) for the relay power. The AAE 102 layout shows the relay power supply connections clearly. The only difference is your PT has a 12V CT winding instead of a 6V for the relay power.
pdf64
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Location: Staffordshire, UK

Re: Custom Power Transformer for Dumble 102.

Post by pdf64 »

desertmouth90 wrote: Tue Jul 09, 2024 9:54 pm ... On the AA Electronics layout the Heaters were 3.5v, How come I have two sets of Heaters?

in the end I decided to use 6.3v (The Green G/Y Green) ...
A 6.3V winding with a centre tap = a 3.15V - 0 - 3.15V winding.
It's just different ways of describing the same thing.
desertmouth90
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Re: Custom Power Transformer for Dumble 102.

Post by desertmouth90 »

pdf64 wrote: Wed Jul 10, 2024 10:29 am
desertmouth90 wrote: Tue Jul 09, 2024 9:54 pm ... On the AA Electronics layout the Heaters were 3.5v, How come I have two sets of Heaters?

in the end I decided to use 6.3v (The Green G/Y Green) ...
A 6.3V winding with a centre tap = a 3.15V - 0 - 3.15V winding.
It's just different ways of describing the same thing.
Thanks, Honestly didnt know this. I have wired it all up now, just trying to figure out how to test the amp!
pdf64
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Joined: Sat Mar 12, 2011 9:23 pm
Location: Staffordshire, UK

Re: Custom Power Transformer for Dumble 102.

Post by pdf64 »

No-one's born knowing this stuff, there's a heap of arcane info that newbs need to get up to speed with, and we can never know everything anyway, no matter how long we've been involved.
So don't be afraid of asking anything, the only stupid questions are those that don't get asked for fear of looking stupid :)

Regarding testing, if you haven't got yourself sorted out with a light bulb limiter (and a variety of bulb wattages), now is the time!
See the sticky thread on the topic https://ampgarage.com/forum/viewtopic.php?f=6&t=20341
desertmouth90
Posts: 24
Joined: Tue Jan 23, 2024 9:35 am

Re: Custom Power Transformer for Dumble 102.

Post by desertmouth90 »

pdf64 wrote: Wed Jul 10, 2024 12:49 pm No-one's born knowing this stuff, there's a heap of arcane info that newbs need to get up to speed with, and we can never know everything anyway, no matter how long we've been involved.
So don't be afraid of asking anything, the only stupid questions are those that don't get asked for fear of looking stupid :)

Regarding testing, if you haven't got yourself sorted out with a light bulb limiter (and a variety of bulb wattages), now is the time!
See the sticky thread on the topic https://ampgarage.com/forum/viewtopic.php?f=6&t=20341

Thanks for this, I’m ordering parts. I was looking at Variacs too but they are mighty expensive. I need to upgrade my DMM too.
jabguit
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Re: Custom Power Transformer for Dumble 102.

Post by jabguit »

pdf64 wrote: Wed Jul 10, 2024 12:49 pm No-one's born knowing this stuff, there's a heap of arcane info that newbs need to get up to speed with, and we can never know everything anyway, no matter how long we've been involved.
So don't be afraid of asking anything, the only stupid questions are those that don't get asked for fear of looking stupid :)

This!

cheers,
Jack Briggs
Briggs Guitars
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