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Converting Solid State to Tube Rectification on a Preamp

I am looking to convert my Preamp from a Bridge Rectifier to a Tube Rectifier.  Any members have done or knows how to do this. Your help are much appreciated!


128x128zipost
zipost's avatar
zipost OP
197 posts
 
Imhififan... the voltage on the secondary power transformer is around say 350v.   As an option on this preamp; Blue circle website do sell a separate power supply, pretty sure it will work with my preamp.  But i do not want to take that route.  

why would i change a solid state rect. to tube??? I am curious to see if a tube rect will outperform a solid states in my preamp.  All members feeback are much appreciated!  
czarivey
5,946 posts
 
2 triode approach is trivial and similar to semiconductor diode bridge only with vacuum tubes. Each triode is treated as 2 diodes to form that trivial rectifier bridge. 2x 300b or 2A3 is probably as pricey and unwise as having 4 conventional vacuum diodes.
zipost's avatar
zipost OP
197 posts
 
czarivey... so from your experiences, with triode rect., it sounds better than a solid state rectifier?  

I think Viva amps has two 211 or 845 as rectifier.   Talking about blowing crazy money, that is just be-on my league!  
czarivey
5,946 posts
 

To my experience upgrading current rectifier with better parts is quicker, smarter and cheaper approach with larger outcome. Just modifying for tube rectifier seems to be more like spiritual masturbation.

Tube rectifier maybe more safe for especially power tubes as it rises up operational voltage substantially slower than semiconductor.

 In preamp you may be better off with solid state sonically. There are upgrades to SS rectifiers you can research for more quiet designs with higher quality semiconductors and for a lot less money. I've done in the past replacements of separate diodes by integrated low-noise bridge on tube power amplifier. It's available in Newark.com and look for proper parameters of Semicron bridge models specifically designed for tube electronics with high operating voltages. Also another cheap trick is to throw over the AC terminals Jensen film in oil cap of few thousand pf -- these you can get at partsconnexion. 

imhififan's avatar
imhififan
2,204 posts
 
why would i change a solid state rect. to tube??? I am curious to see if a tube rect will outperform a solid states in my preamp.
Using four rectifier tubes like 6AX4 to create a full-wave bridge and a 6V 5A power supply for heaters should work, This is a schematic for your referance:

http://1.bp.blogspot.com/_ZXzBbxBRjUc/TVKRXcVOklI/AAAAAAAAAGc/i_zXDoVqTHw/s1600/6CB5A-PSU-Graetz-6AX...

maybe add some high DC voltage rating spdt relays control by a switch so you can select between tube or solid states rectifier.
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