Building rack preamps and transformer options

Chubbs

Chubbs

Well-known member
I'm looking to build a rack mount preamp, starting off simple with an 800 style design. Curious as to how you guys set up your rectification and what transformers you like. My plan is to set up the rectifier like a standard 800, with a 10uf filter to ground off the b+ line followed by a dropper and then a 50/50 with another dropper. Ive seen some guys use toroidal transformers but am not sure what exactly I should look like in terms of high voltage secondaries.
 
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Like PLX said the Anteks are good and if only using a couple tubes like a 800 pre could also use a hammond smaller

Heres a design guide for calculating your HT sec using a FWB capacitor input load rectifier.
Basically multiply your transformer secondary by 1.41 so 200V rectified will be approx 282V
https://www.hammfg.com/electronics/transformers/rectifier
Most of my builds power sections use (2) 47uF in parallel right off the secondary>10K(Node A)>22uF>10K(Node B)>22uF(Node C)
I suggest using the 50/50 at the first cap for filtering not 10uF
 
T Wilcox said:
Like PLX said the Anteks are good and if only using a couple tubes like a 800 pre could also use a hammond smaller

Heres a design guide for calculating your HT sec using a FWB capacitor input load rectifier.
Basically multiply your transformer secondary by 1.41 so 200V rectified will be approx 282V
https://www.hammfg.com/electronics/transformers/rectifier
Most of my builds power sections use (2) 47uF in parallel right off the secondary>10K(Node A)>22uF>10K(Node B)>22uF(Node C)
I suggest using the 50/50 at the first cap for filtering not 10uF
Click to expand...
Sweet, that's super helpful. I think that's how Soldano set his up which makes a lot more sense than just a 10uf.
 
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