[gurubhai]

Yup, looks like this is CV31 aka U18/20, a 4V version of U52 with 4 pin European B4 base. Doubt that any any pin was ever broken, more like someone trying to drill in another hole for some incomprehensible reason.

 

[punit]

Thanks for the clarification.

 

[2359glenn]

 

  ^Are you sure that it is a U52, because that looks like a B4 base to me?

Pics of the tube. It normally has 5 pins, but this one has one pin broken. That's why I wanted to check if it can still be used ?
 
 

 

It is a 4 pin tube that has a 4 volt heater Here is a adapter that will work with this tube with built in resistors to drop 5 volts to 4.
http://www.ebay.com/itm/U18-FW4-500-tube-adapter-to-instead-274B-5U4G-U52-socket-1pcs-/261772342579?hash=item3cf2d8f533m-LGaiGauDRfRt4v8ETsSyQ

 

[leftside]

I have a couple of fat bottle Cossor 53KU's. One has black base/black plates whilst the other has brown base/grey plates. The internals look very similar. Any idea when these tubes would have been made? At the same time, or one before the other? Is one "meant" to be better than the other? They are some of my favorite sounding rectifier tubes.
 
 
 

 

 

 

[gibosi]

The brown base was purported to provide better RF isolation and thus was more expensive. So one might conclude that the black base was standard and the brown base was an extra-cost option. I have two Cossor 53KU, both made in 1952, with dark-gray plates, but one has a brown base and the other a black base. I conclude that otherwise they are identical.
 
I also have a couple of these rectifiers with black plates. Unfortunately, there are no dates on these tubes and I can not say when they were manufactured. Apparently, Cossor ceased the manufacture of tubes sometime after 1956, so I am inclined to think that black plates indicate earlier production, sometime before 1952, but this is just a WAG.

 

[gibosi]

Has anyone tried a vintage Chinese 5Z3PA rectifier? It can provide 250 ma of rectified current and it is plug and play in a 5U4G socket, no adapter necessary. I find the construction very interesting, quite different than any other that I have seen (in my limited experience).
 
https://frank.pocnet.net/sheets/095/5/5Z3Pa.pdf
 
My tube was manufactured for the Chinese military in May, 1973, a year after President Nixon's trip to China.
 

 

 

 

 
First impression, it seems quite neutral, without emphasizing any part of the frequency spectrum. But of course, I will need to take more time before I can come to any conclusions about the sound.

 

[drumroaster]

Hi, I'm about to order a few Brimar 5Z4GY from langrex. Is that still considered one of the better options for the WA6 and HD800S? I have the GE 6SN7GTB drivers right now. Are there any drivers I should consider checking out at langrex? I have the 6SN7 and 7n7 adaptors for the WA6. Thanks!

 

[u2u2]

  Hi, I'm about to order a few Brimar 5Z4GY from langrex. Is that still considered one of the better options for the WA6 and HD800S? I have the GE 6SN7GTB drivers right now. Are there any drivers I should consider checking out at langrex? I have the 6SN7 and 7n7 adaptors for the WA6. Thanks!

The Brimar is a solid cost effective choice. I feed my WA6 with a couple of other Langrex sourced rectifiers as well: Mullard GZ 30 (CV2748) 1968, and RCA 5R4GY JAN, 1952. For 6SN7 drivers his GE Canada 6SN7GT and Raytheon 6SN7WGT (made for GE Canada) are both respectable choices. They aren't the usual favoured here but Langrex has superb true NOS examples. They are enjoyable in other amps such as the WA22 as well.

 

[drumroaster]

Thanks. I look forward to the Brimar 5Z4GY. The Sophia was a needed upgrade from the stock WA6 rectifier. If the Brimar holds its own compared to the sophia I'd be happy since it's cost way less. 

 

[abvolt]

  Thanks. I look forward to the Brimar 5Z4GY. The Sophia was a needed upgrade from the stock WA6 rectifier. If the Brimar holds its own compared to the sophia I'd be happy since it's cost way less. 

That's one of my favorites sure you'll really enjoy, another one I like is a Amperex 5r4gy well worth a try..

 

[3083joe]

Thanks. I look forward to the Brimar 5Z4GY. The Sophia was a needed upgrade from the stock WA6 rectifier. If the Brimar holds its own compared to the sophia I'd be happy since it's cost way less. 

Personally liked the 5r4 brimer over the 5z4 but it's a little more. Close to $100

 

[abvolt]

I'd also agree with joe, I've got an amperex & brimar 5r4gy both are much better then the brimar 5z4gy..enjoy

 

[Badas]

Can anyone tell me about these?
 
This was sold to me as a 5U4G Solid State rectifier. A drop in replacement.
Unlike other Solid State Rectifiers it looks like a tube and actually lights up and glows hot like a tube. GE markings with weird symbols on it.
 

 

 
The sound is incredible. I usually use the TAK274B. One very nice tube. This GE out does it and it is only $20. Snappier than the TAK274B. Not more bass but cleaner, more treble with no distortion and the speed is lightning fast. Very holographic and like I said snappier. I like it a lot.
 
I was warned to have a standby switch as the solid state rectifier can hurt the power and drive tubes. I timed the WA22. It has a 23 second warmup before engaging. Seemed to work fine.

 

[3083joe]

Can anyone tell me about these?

This was sold to me as a 5U4G Solid State rectifier. A drop in replacement.
Unlike other Solid State Rectifiers it looks like a tube and actually lights up and glows hot like a tube. GE markings with weird symbols on it.







The sound is incredible. I usually use the TAK274B. One very nice tube. This GE out does it and it is only $20. Snappier than the TAK274B. Not more bass but cleaner, more treble with no distortion and the speed is lightning fast. Very holographic and like I said snappier. I like it a lot.

I was warned to have a standby switch as the solid state rectifier can hurt the power and drive tubes. I timed the WA22. It has a 23 second warmup before engaging. Seemed to work fine.

Very interesting.

 

[Badas]

Very interesting.

The damn thing sounds amazing. I've always wanted a hybrid amp. Just drive and power tubes. Rectifiers only change AC power to DC and Solid State can do it better.
These drop in Solid State rectifiers essentially changes the amps into hybrids.