Check this massive rectifier I just got

[thehoj]

http://i.imgur.com/0sEbN0P.jpg?1

Can't believe the size of this military-grade 5R4 rectifier.. Just had to post a picture of it. works great in place of a 5Y3, similar specs.

It's beside a few other common tubes for comparison.
From left to right: 12ax7, 5y3gt, 5v4g, 5r4wga

 

[damian1]

Wow! That thing is sweet!

 

[pima1234]

It's called "the potato smasher" and is great!

 

[55hz]

Plates n plates n plates!

 

[Chrome Dinette]

I have some of those, just never seem to think of anything to use them in.

Be careful, the max capacitor value recommended for those is 4uf.

I have seen diy HiFi schematics that use bigger values, though still not as high as you might like without then following it with a massive(expensive) choke.

They probably work fine in small guitar amps that aren't otherwise going near the other design maximums.

 

[Blue Strat]

I have some of those, just never seem to think of anything to use them in.

Be careful, the max capacitor value recommended for those is 4uf.

I thought the spec said 8uf, which is STILL wrong.

100s of these sold (5R4s in general) and used in amps with 20-40uf. Either they didn't think anyone would ever care, someone dropped a zero, or it was just a bad day. If you've ever worked for a company, with people, you know what I mean.

 

[pdf64]

I've seen it explained that these were intended for military / aerospace applications in which the ac power frequency to be rectified would be several hundred Hz, rather than 60.
In which case a few uF would be more than adequate as reservoir and minimise stress on the tube.
Also seen people advising that later info had much higher reservoir cap max values, though no scans to prove it.
Pete

 

[thehoj]

I have some of those, just never seem to think of anything to use them in.

Be careful, the max capacitor value recommended for those is 4uf.

I have seen diy HiFi schematics that use bigger values, though still not as high as you might like without then following it with a massive(expensive) choke.

They probably work fine in small guitar amps that aren't otherwise going near the other design maximums.

As others have mentioned I think the datasheets list 4uF as a typical capacitor rating, not necessarily max.

I read through a number of threads talking about people running 40uF with no problems. I've got a 22uf cap, and I'm not overly worried about it. I've got two of these and they were cheap. I'll see how it goes.

Here's a pic in the amp.. The thing barely fits in there.
http://i.imgur.com/QZLX8QV.jpg

 

[drbob1]

I've been using one as an alternative in an Emery Superbaby for a while, off and on, with no trouble. I'm sure I've got more than 8uF in there...

 

[teefus]

If you've ever worked for a company, with people, you know what I mean.

ha!

 

[Baxtercat]

Wonder why they designed such a big base on those.

 

[Chrome Dinette]

I thought the spec said 8uf, which is STILL wrong.

100s of these sold (5R4s in general) and used in amps with 20-40uf. Either they didn't think anyone would ever care, someone dropped a zero, or it was just a bad day. If you've ever worked for a company, with people, you know what I mean.

Good to know.

I have been apprehensive about using them, because of what the data sheet says.

The few I have are pretty much the only nos old rectifiers I have. I should probably build something to take advantage of them.

 

[Chrome Dinette]

I've seen it explained that these were intended for military / aerospace applications in which the ac power frequency to be rectified would be several hundred Hz, rather than 60.
In which case a few uF would be more than adequate as reservoir and minimise stress on the tube.
Also seen people advising that later info had much higher reservoir cap max values, though no scans to prove it.
Pete

Aha, makes sense.

I know I have seen diy hi fi schematics using these with 20-40uf. I wasn't sure if it was sensible or people being daredevils.

 

[trobbins]

The point to note I think is that the valve has such a high voltage rating. As such, for the stated effective source impedance (125 ohm) the peak hot-switching transient current stays within a certain limit. And so with that stated effective source impedance, there is a relatively low capacitance of 4uF for which the maximum repetitive peak current level is reached for the stated load resistance or current.

The RCA datasheet shows a graph representing the max loading with heater and plate voltages applied at same time, or delayed. That indicates the influence of supply voltage on the peak current stress. I'd be thinking that most applications nowadays would use a relatively low supply voltage, and hence a larger filter capacitance may not end up causing short term problems depending on the effective source resistance.

 

[bluesky636]

I've seen it explained that these were intended for military / aerospace applications in which the ac power frequency to be rectified would be several hundred Hz, rather than 60.

Aircraft AC is typically 400 Hz. If you've never heard a 400 Hz cooling fan, you haven't lived.

 

[sector9]

I use them in my deluxe reverb, they are awesome.

 

['58Bassman]

I thought the spec said 8uf, which is STILL wrong.

100s of these sold (5R4s in general) and used in amps with 20-40uf. Either they didn't think anyone would ever care, someone dropped a zero, or it was just a bad day. If you've ever worked for a company, with people, you know what I mean.

How can you say that? People don't make mistakes, it's all computer errors, right? People are perfect- just ask them.