Check it out - new 5AR4s

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Hi,
Looking at the construction of these three (3) new rectifier tubes...you have to wonder if these are
all the same tubes with just different branding and base variations?

Maybe Jim McShane can shed some light on this?

Kevin @ Dynakit

I use the inexpensive Sovtek im my ST 70 since march without any problems.

Michael

Zimmer64 wrote:I use the inexpensive Sovtek im my ST 70 since march without any problems.

Michael

Same here  

They certainly do look like the same tube with different branding, higher prices (than the Sovtek), and a shorter plastic base on the "Mullard". But looks don't always tell the whole story. Maybe they've actually improved things. That'd be nice. But I'll let others prove or disprove that.

Alright gang, I decided to go ahead and bite the bullet and get the Mullard GZ34 Reissue. And I have gone ahead and purchased the Mullard EL34 Reissue. Might as well see what they all sound like together. No fear. I will let you guys know. Because I have saved and stored my vintage Mullards GZ34, EL34 and such. I know how they sound with the original PC3 and I'll see how they sound with the 'reissues'.

There is some feedback on the Genalex-branded tube towards the end of the following Audiogon thread:
http://forum.audiogon.com/cgi-bin/fr.pl?fcabl&1341498195&&&/5AR4-GZ34-Rectifier-Tubes

I have a pr of Eico hf60s.......setup to run 6550s......for year i have been told that it was the better output tranfourmers......that gave the Eico better, sweeter, diff sound than my Dynaco MK3s... all stock .....new caps ........
But i got to looking at the hf60s an saw thay use No choke off there GZ34 for the b+..............
 
So all i did is move the MK3s Red output trans B+ feed from in front of my choke...to the back..to right on pin 8 on the GZ34.
 
WOW...funny thing all $50-100 ONS GZ34s an 5u4s...still sound great but even my $12 Rudy an sovtek 5ar4 that i would not even use befor..  also sound much better ....an i think the new tube sound better.......the so called better,older GZ34s can sound a littel dark..
.Has any one done this??.....an what do you think of the sound??
You well lose some output....but the MK3s never sounded better...well to me...
 
 
All i am saying.......is we all put some much $$ into caps an tube..an tranfourmers.........you may give this set a try...an hear what these rectifier tubes..........Can sound like!
An as for a $13-5. Choke that were sending all the GZ34 B+ in to....we may wount to get better chokes.......
I am NOT puting down the chokes that are sold in these Kits.....i know that there much better than the 60 year old stock chokes in my MK3s.........
how about a 5H 300ma..........to big?what other down sides
 
It just may be money well spent on the geting better B+ to our output an front end tubes............
 
Thanks..........an thanks for this site Bob.....

So maybe I DID make an improvement when I went with the larger C17x chokes in my ST120 ...



Truth be told, only reason I did the substitution was I had the room with a custom case. They wouldn't fit in the standard dynaco type chassis.



One thing I just realized ... The chokes are mounted to the wood sides, and I never did get around to running ground straps to the chassis plate. Guess I didn't have to after all ... next time in though, I might add them just ... well ... uh ... because ...

skriefal wrote:There is some feedback on the Genalex-branded tube towards the end of the following Audiogon thread:
http://forum.audiogon.com/cgi-bin/fr.pl?fcabl&1341498195&&&/5AR4-GZ34-Rectifier-Tubes

Thanks sir. I am actually going to check those out too. And Bob gave me the idea of trying that with KT66 Gold Lion's. I'm so excited about all of this.

FG.

sKIZo.......yes i saw your upgread choke...Vary cool.....But what about two chokes in you Amp....why just one for bouth ch??
As if you dont know....you amps looks killer...thanks for all the info you have posted...an pic..

.....till i move the output tran  B+ to pin 8...i also thought that my MK3 sounded better with EH KT88- EI KT90s............but now the 50 years old GE6550  an my new EH6550 sound so much better than any other tube i have ever tryed in the MK3s....the choke seems to add a dealy to the sound that just is not there...........but that what it dose is ....choke..the sound!
I also used this setup with ea. 1N4007 having 1A / 1,000 ....an no GZ34....as dose other tube amp  Quicksilver ....No choke on the output....just the frount end.......
 
Even if you dont keep this setup in............an move back to the choke....you well have a much better insite on how these tube rely sound............
i have found that  haveing 60mf an a .1mf pp caps right at pin 8 of the 5ar4....is all thats needed to keep the noise down.....
All this is just one mans o-pine..........have fun...
 
Thanks for the site Bob....

Derail! Derail I say!!  

But what about two chokes in you Amp....why just one for bouth ch??

Keeping in mind the ST120 is a stereo amp ... The original chokes were good for around 400mA current flow total - ONE C17a tops out at 300mA. Multiple chokes prevent coupling and improve isolation ... Besides that, I wasn't looking to redesign an effective circuit. My main goal was to improve heat dissipation by adding iron - not necessarily a problem with the original chokes, but as long as I had the room ...

End derail!

Bob, I recently noticed that there is a build up of waxy stuff that is as you described to the bottom of my cover. in fact I'm looking at it right now and it is at the bottom of the choke. Does the choke indeed need to be replaced or can I run it like this?

Jon

I ordered a new one. I figure that the choke was being killed by the bad quad cap. So I'll just go ahead and replace both and be good.

Jon

Someone earlier mentioned my name...

I have the new brown base Tung-Sol 5AR4 in stock, so far so good, but there are just a few out there. I can't get the Genalex until mid-month or a bit later, they are on back order all the way to Russia. But I will carry them, no doubt.

The Tung-Sol reissue stuff has been excellent, I suspect the 5AR4 will be as well. And I agree with Bob, the JJ 5AR4 is not a very reliable tube.

I've had much better luck with Ruby 5AR4's than with Sovtek or JJ.

http://www.amplifiedparts.com/products/T-5AR4-C

corndog71 wrote:I've had much better luck with Ruby 5AR4's than with Sovtek or JJ.

http://www.amplifiedparts.com/products/T-5AR4-C

Ruby is not a tube maker, they are a relabeler. You've likely been using Sovtek or Chinese tubes, the 5AR4C is Chinese. Ruby does do a nice job of screening though, that helps.

Yup ... same could be said of Psvane, TAD, or any one of a number of tube suppliers. I remember seeing some ridiculous number on rejects quoted by Grant. Best I can say is their KT88's work real fine here ...

Not to go completely off track here on a rectifier thread, but the same seems to be happening with KT120's ... makes me wonder if the relabels aren't really the way to go if they're getting additional screening before relabeling?

Well the JJ tube vary unrelabel............an thay dont sound any better than any of the Chinese tubes....EL34 ...5AR4...
So the Rudy must be the sovtek 5AR4........ i can see that.......with the choke bypass...the sovtek-Rudy...sound vary close....But the Rudy  5AR4s wins... sweeter,fuller sounding.....Vary good
 
An can anyone say if any other tube makers.... that make the KT120-KT150..... Are Tung-Sol the only one??
So any other brand.......relabeler..........an thay well be better??

I think Jim McShane is the only one on this site... that dose a lot of tube testing an matching...i know the jim thinks highy of the Tung-Sol 6550s....so i well get some of there 5AR4s...
Thanks jim for your input an info on All tubes......
 
Thanks for the site Bob.........

Gents,

So far, I have obtained the JJ GZ34 and the Mullard Reissue GZ34. I also in my kit have two GE 5AR4 NoS tubes. I wanted to do an experiment as you know to see if these different rectifiers would make a difference in my ST70 sound-wise. Now after the reading that I have done, I know that these are rectifier tubes (From Quad Cap 2 to pin 8 on the Rectifier) and shouldn't affect sound. Pardon me being new, but I figure if the rectifier is in line with the power tubes (My EH EL34s) that they play an integral part in the grid voltage of the power tubes. And of course, there is the 7199s/6GH8A (depending on what I'm using...) that DO affect sound due to how they are all being driven. I have done some listening on the JJ, Mullard and vintage GE. Hands down, what drives this system better is the vintage GE 5AR4, but the Mullard and the JJ both have their uses. I personally found the Mullard GZ34 reissue (Russian made, not British Blackburn) to have a great affect on the tone of the tubes. The mids were clear, the bass was light for my tastes, but the highs were great. The JJ was the flattest sounding of them all. I find it to be utilitarian and somewhat weak. I'll be doing more studying with my meters to see if there is an actual difference when it comes down to the numbers of all three. But, nothing beats these NoS GE 5AR4s out of what I have tested.

For Christmas, my brother in law is going to be getting me the GL GZ34 as I hear that it is the closest to the Blackburn Mullards as possible. I'm curious what the thoughts are of you folks. I just thought that I would share what I have observed. And of course, what is good to my ear would be totally different from yours. Therefore I submit this as my .02 cents with the understanding that all things are subjective.

-Jon

Here's an interesting one ... Peavey Euro GZ34/5AR4.
Unusual structure, unless it's just a bad pic ... I expect the "euro" part means it's Russian?

Looks like a 5U4GB.

All the Nos GZ34  GE, RCA, Mullard... i have with the choke in the power supplie sound best......An the new 5AR4 Sovtek , Rudy, JJ............ an others sound brite...with less bass.........
Choke out...........just on the output tubes.....the sovtek,Rudys sound just right,highs mids an lows
All Nos have fat bottem ends,rolled off top, mids ok............but the new 5AR4s win........
An in the No choke setup the 6550......sound much better than the KT88s....any brand Nos are new..
go fig...........have fun
 
Thanks for the site Bob.......happy Hoho.
zx