Dubstep Girl's Massive 5AR4/5R4/5U4G Rectifier Review/Comparison! (Rectifer Tube Rolling thread)

Mar 1, 2018 at 4:08 AM Post #1,711 of 3,027
In general, Philip's Holland-made rectifiers (and double triodes) are not as warm as those manufactured by British Mullard, which I assume is the source of your fat base gz34. Since you seem to prefer the Mullard sound, I would encourage you to try the GZ32, GZ33 and GZ37. These were all manufactured in Mullard's Blackburn factory and have a similar warm tone. And you might also like the Cossor 53KU / CV378, sometimes called a "Fat GZ37", which is also a bit warmer.
I also purchased to gz32 and tried it for the first time yesterday and have to say it is a lot warmer than the Holland gz34 which is more to my liking I have also ordered the gz37 fat bottle
which I heard great things about , gz34 metal base already sold , man these metal base sells quick .
Great rectifier tho just not too my liking .
Thanks for your feedback guys much appreciated.
 
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May 8, 2018 at 9:28 AM Post #1,712 of 3,027
Not sure if anyone can help me, but I’m confused by the code on my Mullard GZ32 it doesn’t seem to conform with any of the references I’ve found anywhere...

1358 D 9

Anyone have any ideas?


EC80B91D-2D0C-46A1-984F-44883BA797F6.jpeg 81026139-0172-42DD-A396-C9E5E8A5B0E3.jpeg
 
May 8, 2018 at 10:34 AM Post #1,713 of 3,027
Not sure if anyone can help me, but I’m confused by the code on my Mullard GZ32 it doesn’t seem to conform with any of the references I’ve found anywhere...

1358 D 9

Anyone have any ideas?



My best guess... According to The National Valve Museum, the GZ32 was first introduced in 1946.

http://www.r-type.org/inx/inx1946.htm

However, Mullard did not adopt the Philips manufacturing code system until about 1955. So tubes manufactured prior to the switch over used an older Mullard production code. I have yet to find the key to this code, but it appears that "1358" = GZ32 and "D" = Blackburn. And just maybe, "9" = 1949?
 
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May 8, 2018 at 10:36 AM Post #1,714 of 3,027
Not sure if anyone can help me, but I’m confused by the code on my Mullard GZ32 it doesn’t seem to conform with any of the references I’ve found anywhere...

1358 D 9

Anyone have any ideas?
That's an earlier type Mullard code. It would seem to fit this system:
Those suggest to me that we are looking at an MY-format date code where A = Jan and L = Dec, and years range from 1948 to 1954. Thus A0 = Jan 1950.
1358 = GZ32. D = April. 9 = 1949. I'm not 100% sure about that but it kind of works…
 
May 8, 2018 at 11:22 AM Post #1,717 of 3,027
Yes, it does seem that the Mullard might have used more than one code over the years before adopting the Philips code. I have three old Mullard FW4/500. And the codes read "54 BZ", "54 BY" and "54 BH". Again, I can surmise that "54" = FW4/500, but I have no idea what the letters mean....

And since the FW4/500 is a rectifier, similar to the 5U4G, but with a 4-volt heater instead of 5, it isn't too far off topic to post a picture of one of these old beauties. :)

2018-05-08 11.15.26.jpg
 
May 8, 2018 at 12:02 PM Post #1,718 of 3,027
My best guess... According to The National Valve Museum, the GZ32 was first introduced in 1946.

http://www.r-type.org/inx/inx1946.htm

However, Mullard did not adopt the Philips manufacturing code system until about 1955. So tubes manufactured prior to the switch over used an older Mullard production code. I have yet to find the key to this code, but it appears that "1358" = GZ32 and "D" = Blackburn. And just maybe, "9" = 1949?

Thanks - that's really interesting. It's a real puzzle to work out these codes, innit?!!!
 
May 8, 2018 at 12:22 PM Post #1,720 of 3,027
Yes, it does seem that the Mullard might have used more than one code over the years before adopting the Philips code. I have three old Mullard FW4/500. And the codes read "54 BZ", "54 BY" and "54 BH". Again, I can surmise that "54" = FW4/500, but I have no idea what the letters mean....
Is that three older codes now? :thinking:
 
Nov 6, 2018 at 7:57 AM Post #1,723 of 3,027
Lampizator owners have been raving about the KR 5U4G made special for Lampizator, KR 5U4G Lampizator Anniversary. They sold out quickly and it is unobtanium for a while now. Anyone try this in other kit? Just found a source that has a few left. There are some tube rich Lampizator users who have compared it to some of the best rectifiers out there. But haven't heard much about how they sound in other equipment as tube was made for special for Lampizator and the owners quickly snapped them up.

http://www.lampizator.eu/Fikus/DHT_TUBES.html
======================================================

After chasing and reading many of the tube rolling reports bunch of "crazy" guys
upload_2018-11-6_13-56-52.gif
in form of @wisnon, @christoph, David and myself decided to do a quite big session of tube rolling of both rectifier and DHT tubes used in Lampi DACs.
As we had on hand three DACs (actually even 5) of top Lampi machines we also decided to find a best tube match per specific DAC model.
Of course some might say, you did not try this, you did not try that, but we tried tubes which are 'hot picks" at the moment and the tubes we managed to get.
In order for session to be as relevant as possible one by one DAC was at the main stage while other two were serving as tube heating stations (quite expensive ones).
upload_2018-11-6_13-56-52.gif

4 pair of ears were deployed at all time and results were consensus of all of us. In a nutshell these are the results and we hope those might serve to all Lampi users or hopefully future ones as kind of general instruction into which direction you might go to save you the time and money if you are not able to acquire tubes for home testing.
Of course everything, as always, is system and personal liking dependable.

PACIFIC DAC:

1) Ayon 5u4g, Eml Mesh 45 - Could have a bit more punch, rest OK, airy
2) Ayon 5u4g, RK 300b - more upper bass, full bodied, slightly colored in a positive way, more focus, bigger stage, dryer
3) Ayon 5u4g, KR PX25 - Air, weight, ideal tubey sound, lots of air, bloom, decay
4) Ayon 5u4g, KR 242 - more FW sounding, less tubey, less layered depth, very transparent, faster
5) Ayon 5u4g, EML Mesh 45 Ann Globe - Soft, tubey, less substance, laid back on the other hand very airy, not enough meat. Norm preferred it to 242 in vocals.
6) RK 5u4g, EML Mesh 45 Ann Globe - Crispier, cleaner, bigger stage, livelier, more body but still lacking substance and body
7) RK 5u4g, 101d - small stage, not the same league as the other ones
8) RK 5u4g, KR 242 - No major objection, fast, transparent, layering, great staging, more dynamic with this recti...noticeably better than Ayon recti
9) RK 5u4g, KR PX25 - Spaciousness, great overall performer, perfect match with RK recti, huge stage. Top combo in Pacific!
10) KR 5u4g white ceramic base, KR PX25 - very close as above, just maybe a bit less dynamic but all very close. Upon going back to RK recti it is better combo for sure!
11) RK 5u4g, RK 300b - A lot better than with Ayon, we find this combo close to PX25 combo, seems like more meat to PX25, combines virtues of 242 and PX25.

Top pic for PACIFIC was KR PX25 with RK 5u4g.

Golden Gate 1:

1) KR 5u4g white ceramic base, KR242 - Chris favourite combination in his GG. Vs. PAC different presentation type, more tubey sound, less detailed than PAC, less stage high, more treble with PAC.
2) RK 5u4g, KR242 - again massive difference with RK recti - very detailed, open sound. Big in all directions.
3) RK 5u4g, RK300b - excellent combination but 242 is doing things in this DAC just better in all terms - more punch, more resolution, staging...
4) RK 5u4g, KR PX25 - again great combo, more tubey sounding but still great details, punch, warm, very 3D and palpable
5) RK 5u4g, Elrog 300b - we like it, punch, detail, great vocals, overall great performer
6) RK 5u4g, EML Mesh 45 Globe Ann - not a great match for PAC but in GG a nice match. Good weight, spaciousness. Not enough weight with classical.

Consensus is that RK recti and KR PX25 works best.

Golden Gate 2.5:

1) RK 5u4g, KR242 - Fantastic speed, decay, bloom, tonality. Mellowness is just right, more treble extension.
2) RK 5u4g, KR PX25 - keeping the main character from 242 but adding additional tube sweetness in positive sense. Very natural sounding. Awesome instrument color of cello, brass,...
3) RK 5u4g, RK 300b - Very transparent, huge stage, detailed, punchy without losing control.

Could not draw a conclusion which tube was the favourite as they all performed exceptional but depending on the music 242 and PX25 stand out. With complex music 242 creates less congestion and PX25 creates more magic with 'easier music'.

DAC comparison:
Pacific is the most transparent & dynamic making several more tube choices play on exceptional level.
GG1 warmer sounding or tubey sounding doing everything right where 242 is the right choice giving additional kick and dynamic. GG2.5 is a perfect/great blend of both directions being dynamic and transparent but not lacking any tube magic.

Equipment used:
Speakers - hOrns Universum III
Amp - KR Kronzilla
Preamp - Aries Cerat Incito
Server - LampizatOr Superkomputer
DAC: LampizatOr Pacific SE, Golden Gate 2.5 SE, Golden Gate 1 SE

I would like to thank Chris for his always great hospitality!!!!
 
Jan 8, 2019 at 8:52 PM Post #1,724 of 3,027
Here's a very nice sounding rectifier I found on ebay (35.) it's a large bottle mullard gz 30 I have 2 of the small bottle gz 30's, this is an excellent sounding rectifier much different then the small bottle if you've not heard one it's well worth a try. It's also the first large bottle I've seen didn't know mullard made them even..

gz30.jpg
 
Jan 8, 2019 at 9:30 PM Post #1,725 of 3,027
I'd love to be able to try a GZ30. However, my Glenn OTL requires a rectifier that can provide at least 250ma. Since the GZ30 can provide at most 125ma, it would likely die a quick death if I tried to use it... :frowning2:

I would suggest that you make sure it is compatible with your amp before purchasing one...
 

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