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Dual rectifiers?


xoundmind
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In the hope of learning more about tube HiFi, what is the rationale for having two rectifier tubes in a circuit? Is this more prevalent in SET amps?

 

(I know that some - particularly Mesa Boogie - guitar amps have two rectifiers, but it is not at all common.) 

 

Thanks for any wisdom on the matter. 

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20 hours ago, xoundmind said:

In the hope of learning more about tube HiFi, what is the rationale for having two rectifier tubes in a circuit? Is this more prevalent in SET amps?

 

(I know that some - particularly Mesa Boogie - guitar amps have two rectifiers, but it is not at all common.) 

 

Thanks for any wisdom on the matter. 


Tube rectifiers drop a certain amount of voltage which, generally, is proportional to the dc current drawn.  Two tubes are sometimes used in parallel to limit the voltage drop in amps in which the current draw varies quite a bit.  In amps like SETs, in which the dc current draw Is quite constant, it is unnecessary.  Manufactures sometimes used 2 rectifier tubes for marketing purposes.
 

In guitar amps voltage sag is sometimes preferred as it can result in a distortion characteristic which some like. You can’t compare that with high fidelity applications.
 

This topic can get involved and can be discussed in more detail if needed.

 

Tubes like the 5U4 are full wave, not dual, rectifiers and were made for use with a center tapped transformer secondary.

 

 

Maynard

 

 

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  • 3 weeks later...

Since rectifier was brought.... I have Cary 805C monoblocks that have one rectifier in each amp. Cary states as 1629/6U5. Researched and find that the 1629 and 6U5 is the same “if I am understanding it correctly”. One of the amps has the rectifier going out. Should I replace both ?  They are both the same age. 

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7 hours ago, Jim Gregory said:

Since rectifier was brought.... I have Cary 805C monoblocks that have one rectifier in each amp. Cary states as 1629/6U5. Researched and find that the 1629 and 6U5 is the same “if I am understanding it correctly”. One of the amps has the rectifier going out. Should I replace both ?  They are both the same age. 


The 1629 and 6U5 are not rectifiers.  They are “tuning eyes.”  Their filament voltages are not the same, and require different sockets.
 

 

Maynard

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5 hours ago, tube fanatic said:


The 1629 and 6U5 are not rectifiers.  They are “tuning eyes.”  Their filament voltages are not the same, and require different sockets.
 

 

Maynard

Thanks Maynard

Read some more and find that the tube is used as a visual voltage indicator. 

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