# 5V4 rectifier tubes



## bcmatt (Aug 25, 2007)

I have heard that most people prefer the difference that 2x 5V4s make in comparison to the 1x GZ34 in their DC30s. I think I would like to give it a try as well.
However, I am wondering what an acceptable (but not outrageously priced) brand might be to try. 

I only see 2 types at tubesandmore.com and they are both used:
the 5V4GA and the 5V4G. Anyone know anything about these? The prices seem reasonable at about $8 each.

thetubestore.com has some NOS 5V4s at $20 each

Anyone have any advice?


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## Jeff Flowerday (Jan 23, 2006)

I hate to say it but give Evil Bay a try. There are a few good sellers on there. You probably can find some old RCAs that will last you a lifetime.


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## nitehawk55 (Sep 19, 2007)

The 5V4G is the old coke bottle type and the 5V4GA is the modern version which are shorter , less prone to vibration and a better choice of the 2 . 

EL84's like the 5V4 type rectifier , it doesn't drive them quite as hard so you get slightly less output and a bit more sag plus an earlier breakup....excellent for getting creamy OD for blues . sdsre

Spend the $20 at the tube store , it's a good investment .


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## bcmatt (Aug 25, 2007)

Thanks guys!
Both comment were very helpful.
The tubestore one would be a $40 spend plus taxes and shipping, because I need 2.
Any other thoughts anyone?


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## Adicted to Tubes (Mar 5, 2006)

Or you could order a Weber Copper cap with the right voltage drop and no need to drill another hole for the extra rectifier tube.Just a thought.Or just use a 120 ohm 25 watt sag resistor after the rectifier,before the first filter cap.

www.claramps.com


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## nitehawk55 (Sep 19, 2007)

bcmatt said:


> Thanks guys!
> Both comment were very helpful.
> The tubestore one would be a $40 spend plus taxes and shipping, because I need 2.
> Any other thoughts anyone?


Try and find a seller on ebay with good feedback , you shouldn't have much trouble unless they have a stupid high shipping rate . If the send regular 1st class post it shouldn't cost more that $10 tops from the USA . Try the CDN ebay too , you might get lucky .


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## bcmatt (Aug 25, 2007)

Adicted to Tubes said:


> Or you could order a Weber Copper cap with the right voltage drop and no need to drill another hole for the extra rectifier tube.Just a thought.Or just use a 120 ohm 25 watt sag resistor after the rectifier,before the first filter cap.
> 
> www.claramps.com


I don't need another hole. It is already set up wired with 2 tube sockets for the rectifier tubes. You can put in either one GZ34 or 2 5V4s. So, right now it has an empty socket.


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## Wild Bill (May 3, 2006)

Adicted to Tubes said:


> Or you could order a Weber Copper cap with the right voltage drop and no need to drill another hole for the extra rectifier tube.Just a thought.Or just use a 120 ohm 25 watt sag resistor after the rectifier,before the first filter cap.
> 
> www.claramps.com


I never use such a high wattage resistor for sag. Consider, if watts = I^2 x R then even if we had a steady 200 ma draw (which is nuts I know but I'm overestimating here) then .2 x .2 x 120 = 4.8 watts!

A 5 watt unit should be fine. Since I'm still a bit of a chicken I use a 10 watt unit.

:food-smiley-004:


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## bcmatt (Aug 25, 2007)

So I am wondering what the opinions(especially the professional ones) on this issue actually are.

Is there any advantage to going with 5V4 tubes, or is it just that they will produce less sag? Then if that is the case, should I just go to SS rectification with a couple choices of sag resistors to switch between?
I will have to do more reading on rectifiers I guess to see all that they do.
(Perhaps this is a good time for me to use the forum search function)


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## Adicted to Tubes (Mar 5, 2006)

The simgle GZ34 has a voltage drop of about 1.3 x your power tap.
The dual 5V4's would have more of a voltage drop but it is likely they will sag more.
So lets say 300v x 1.3 = 390v,then the dual 5V4's would be about 300v x 1.2 = 360v or somewhere near that.( I don't know what the B+ of a DC30 is off the top)I am pretty sure that two 5V4's would be necessary because the draw would be too much for a single 5V4 in this amp.The only way you can find out how it works and what the real voltage drop is is to test them in your amp.
I'm thinking they may sag more than the GZ34 does,as the DC30 has less current draw than a typical Super Reverb with a GZ34.
So less voltage and MORE sag is what you can expect.You can't use two GZ34's because the PT would likely not support the heater current draw.

www.claramps.com


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