Tube rectifier ?s

[Tim Wyatt]

If I change my amp from diode to tube how much of a voltage drop can I expect? What would be a good tube to use(I would like one to fit an octal base, Have an extra on the chasis)?
Thanks

[mig-ru]

Voltage drop depends on the tube used. You could use an 83 mercury vapour tube since those have pretty much no drop, but I believe that it is a 4 pin tube. A 5U4 would have about a 15V drop, its also a common tube used and somewhat beefy; a close relative would be a 5AU4 which is just way beefier, its rarely used in mainstream amps so it would be a good choice, its also octal. A schem of the amp would help, also the current and voltages.

[Colt45]

normal tube rects - depends on the amount of current drawn.

merc'd rects.. (83, etc) is ~15v through the whole range of current.


5U4 @ ~200mA is something like a 45v drop.

[Sch3mat1c]

Mind that I've never seen a single merc toob rated for more than 5uF cap input. In other words, they require a choke input filter. You'll drop about 1.3 to 1.5 times the voltage as compared to a SS rectifier (with cap input) in doing so.

Tim

[Tim Wyatt]

Thanks, gives me a place to start. I will be going with a choke setup I think. Any thoughts on the 5ar4?

[316a]

Originally posted by Tim Wyatt
Thanks, gives me a place to start. I will be going with a choke setup I think. Any thoughts on the 5ar4?

Unless you're going to use new production , 5AR4/GZ34 will be expensive . Dampers such as the 6D22 and PY500a/42EC4 are excellent , rugged and fairly inexpensive . I have been using PY500A for the past two years and they can take anything I can throw at them . Dampers offer a slow start , high current , low volt drop and can withstand cap input topology . Try using the 6D22 model on PSUD2 and you'll see what I mean

316a

[Alastair E]

If you need some PY 500A or PY88 valves, I have a pile of the things, all NOS and nout to do with them!!

Make us an offer!!

[Majestic]

Hi all,

I was thinking of starting a thread on some of the better damper diodes to use, but since it's been brought up here, I might as well piggy-back my question on it now:


Given the current price of good sounding GZ34's ; What are fellow DIYer's opinions of which types are the nicer sounding "TV Damper diodes" around to start playing with?


I guess it would convienient if they didn't use top-caps; but ultimately, I'm not really fussed about that. I'll do what it takes to get good quality.

(Addendum: At the moment, my anticipated application for them is for a balanced preamp curcuit.)

[Colt45]

good sounding diodes eh?

ah.. i'll be nice this time.

[Majestic]

Originally posted by Colt45
good sounding diodes eh?

ah.. i'll be nice this time.

Thanks for not shooting me over my first post Colt45

I am aware that not everyone thinks that individual component types (let alone brand...) have sonic signiatures of their own. So rather than re-start a controversy that I'm sure has been had on these forums already in many guises; my 'plea' for assistance goes out to who have already had a play around with some of these already, and might be able to offer some reccomendations.

I've only used GZ34's in the past myself (and the odd GZ37), and unfortunately I ain't rich enough to afford buying handfuls of each type of available damper diode to try myself, so I thought I'd ask those who might have gone through this already.

cheers again.