5ar4 / gz34 rectifier replacement favorites

Yomaha · « **on:** 9 Oct 2016, 01:18 am »

I recently had to replace the 274B sophia princess rectifier in my Dennis Had kt150 power amp. I now have the Tube Amp Doctor (TAD) gz34 as a placeholder. Maybe the TAD needs more burn in time, but as of now I've noticed less low-end and diminished roundness. The stereo image seems to also be lacking in depth as well as instrument separation. The mids and highs do not sound as engaging as they did with the princess.

I haven't really rolled other rectifiers thru this amp so I am curious of the board members favorites.

I see that the nos metal base MUllard's have quite a good reputation but a hefty price tag to match -$450ish. Id prefer to stay sub $300. I also keep running across the upscale audio Holland made Phillips 5r4gy for $120. I've run across a nos mullard gz34 fat base for around $200.

This rectifier "shoot out" seemed to have a lot of good info all in one place. http://www.head-fi.org/t/694525/dubstep-girls-massive-5ar4-5r4-5u4g-rectifier-review-comparison-rectifer-tube-rolling-thread

The Brett Jesse site had good info as well. I would love to hear more experienced members thoughts before I plunk down $200 to try a tube. I guess that is part of the thrill of the hunt though!

JackD · « **Reply #1 on:** 9 Oct 2016, 02:16 am »

Yomaha

A good safe replacement is the Japanese manufactured 5AR4 built in the Mullard tooled factory. It is sold under many different brand names like Westinghouse, IEC, etc. Brett and Andy Bowman both have them NIB for around $60. I have one as well as two Blackburn Mullards and you would be hard pressed to tell me the difference if you didn't see which one I put in. As to the genuine Blackburn Mullards they were also purchased and re-labled by many other companies. Mine two are labeled Hammond and Phillips, but there are also ones out there labeled Westinghouse, GE and others. Safest bet is to just call Andy Bowman and get a NOS tube that he has tested and guaranties. Should be just over $100. As to the 5R4G's they are fairly plentiful and can be bought from other reputable dealers even on E-Bay for a lost less. I bought a NOS NIB Raytheon for less than $20 including shipping. Look for Raytheon, Tung Sol and RCA.

Syrah · « **Reply #2 on:** 9 Oct 2016, 02:38 am »

I've had two different components that used GZ34s - a Supratek preamp and a Modwright modded CD player. They taught me that it is very circuit dependent. The Supratek loves the Bendix 6101, the Modwright hated it. I mean really hated it! The Modwright loved the EML 5U4G.

So you might want to give particular attention to anyone who has rolled tubes in your amp before you blow $200 on a super NOS tube. The "best" GZ34 might not be the best in your amp.

JackD · « **Reply #3 on:** 9 Oct 2016, 03:30 am »

You don't need to buy a "super NOS" in any case, but you do need to stay away from the crap Chinese and Russian rectifiers regardless of the fancy graphics and packaging as they are all made in one of a few factories and packaged differently to sell at different price points. Buy a good tried and tested tube once and be done. And buy from a dealer like Andy, Brett or Kevin who is available and stands by there products unlike a lot of others. I also have two pieces that allow choices of 6 volt rectifiers and the cheap rectifiers were removed before they were powered up the first time.

Yomaha · « **Reply #4 on:** 9 Oct 2016, 04:58 pm »

Thanks for the thoughtful replys. I'm going to call Andy Monday. I think it makes a lot of sense that certain tubes might not jive with certain circuits. Hopefully his extensive knowledge can guide me in the right direction based on what equipment I have and my specific sonic tastes.

Dennis Had recommended the reissue gold lion gz34s. I'm curious to try a reissue versus a nice nos.

paul79 · « **Reply #5 on:** 9 Oct 2016, 05:05 pm »

The Gold Lion, Mullard, Tung Sol, etc reissue tubes are the same exact tube as the Sovtek 5AR4. Don't spend more money for a name, as the tube won't sound any different. Just get a Sovtek from a reputable dealer that actually burns in the tubes and tests them well, and you will get a good tube. Doug's Tubes does the best job of eliminating junk that I have found, so would be my recommendation for a new production 5AR4.

cheech · « **Reply #6 on:** 9 Oct 2016, 07:34 pm »

I use NOS Mullard 4 notch plate GZ34s in both Line Magnetic 518IA (integrated) and Modwright Elysee (DAC) , it is sonically pleasing in both. I use a Philips GZ34 in Modwright LS100 and am similarly satisfied. Would have used Philips again if it had been available. Likewise, I wouldn't hesitate using NOS Mullard again

Tubeburner · « **Reply #7 on:** 9 Oct 2016, 07:43 pm »

Do you have a tube tester?

I have used the Shagung 274b in a Melody preamp and had no issues with the one I had. Cheap if you want to try one:

http://www.thetubestore.com/Tubes/5U4-Tube-Types/Preferred-Series-274B-5U4G

I prefer the Mullard 5AR4/GZ34 in some circuits, but as Syrah said in his post, tube rolling is very circuit dependent. Don't shy away from a used Mullard GZ34 as they have a life of 10,000 hours.

I have been told the WE 422A is an excellent rectifier, but they are pricey.

The 274b is a more lively tube in my experience and the Mullard GZ34 has a better mid range. My experience, but like all audio, it is a matter of opinion.

Good luck with your search.

Yomaha · « **Reply #8 on:** 10 Oct 2016, 04:26 am »

Hi tubeburner - I do not have a tube tester. Interestingly I've been seeing tube testers at some socal vintage shops and antique malls recently. Not sure on the pricing though.

Hugh · « **Reply #9 on:** 10 Oct 2016, 05:30 am »

I second this.

Quote from: Tubeburner on 9 Oct 2016, 07:43 pm

Do you have a tube tester?

I have used the Shagung 274b in a Melody preamp and had no issues with the one I had. Cheap if you want to try one:

http://www.thetubestore.com/Tubes/5U4-Tube-Types/Preferred-Series-274B-5U4G

I prefer the Mullard 5AR4/GZ34 in some circuits, but as Syrah said in his post, tube rolling is very circuit dependent. Don't shy away from a used Mullard GZ34 as they have a life of 10,000 hours.

I have been told the WE 422A is an excellent rectifier, but they are pricey.

The 274b is a more lively tube in my experience and the Mullard GZ34 has a better mid range. My experience, but like all audio, it is a matter of opinion.

Good luck with your search.

FullRangeMan · « **Reply #10 on:** 10 Oct 2016, 11:16 am »

Decware suggestions seems usefull:
http://www.decware.com/newsite/tubes.html
The rectifier location is compatible with 5U4G, 5AR4, 5Y3GT, and some 274B. Many owners of this amp like using the 274B however not all 274B tubes are completely compatible, so we ship the amp with one that we know IS. Each rectifier change will also make audible differences in the sound and performance of the amplifier.

mick wolfe · « **Reply #11 on:** 10 Oct 2016, 03:57 pm »

Quote from: Yomaha on 9 Oct 2016, 04:58 pm

Thanks for the thoughtful replys. I'm going to call Andy Monday. I think it makes a lot of sense that certain tubes might not jive with certain circuits. Hopefully his extensive knowledge can guide me in the right direction based on what equipment I have and my specific sonic tastes.

Dennis Had recommended the reissue gold lion gz34s. I'm curious to try a reissue versus a nice nos.

I currently use the Gold Lion re-issue. Nice tube.... be it a Sovtek as mentioned or whatever. Bought new and fully tested from Jim McShane.

Yomaha · « **Reply #12 on:** 13 Oct 2016, 01:53 pm »

Ok - so I called Andy Bouwman and had a nice, informative talk. It was great because I told him what I liked about my previous 274b Princess, what I did not like about the TubeAmp Doctor gz34, and the equipment that I have, so he could help me make a more informed decision. After going back and forth for a while with Andy, I settled on the Mullard GZ34 fat base. I'm due to get it this weekend, so pretty excited about that. As time goes on, I hope to get around to trying some of the other tubes suggested here on the board.

Thanks!

FullRangeMan · « **Reply #13 on:** 13 Oct 2016, 02:25 pm »

Andy reputation is untarnished, since 1990s I see good talk from him.

rbbert · « **Reply #14 on:** 13 Oct 2016, 06:10 pm »

The Mullard fat base, and probably even the non-fat base Mullards iof the next few years, are pretty nice sounding tubes

S Clark · « **Reply #15 on:** 13 Oct 2016, 06:34 pm »

Are the Mullard fat base and the Sylvania fat base different tubes? I've used the Sylvania for several years and found them superior to JJ and Sovtek- but they aren't in the same price level either.

avahifi · « **Reply #16 on:** 13 Oct 2016, 06:44 pm »

Just wondering if anyone actually tests their rectifier tubes properly?

There will be a reasonally random DC voltage output of your rectifier tube depending upon age, manufacturer, and circuit demands.

In a tube circuit if the DC high voltage to the audio tubes is lower than normal, this will reduce the tube gain, change the feedback, and change the sound of the unit. In general a low output rectifier tube will cause things to get golden and euphonic at a bit too low and warm and muddy as the output gets lower yet. A very high output rectifier will turn the circuits on harder, increase feedback, lower THD but increase transient overload distortion. A little of a good thing will give you a clear and engaging unit, too high will provide hard and bright sound.

So, check the output voltage of your rectifier, see what the manufacturer of the unit wanted, and pick a rectifier tube with that ballpark of output voltage.

No magic, no good sounding or bad sounding rectifier tubes, just one with the right output voltage for your circuit needs.

Frank Van Alstine

FullRangeMan · « **Reply #17 on:** 13 Oct 2016, 06:49 pm »

Thanks for post Frank, great piece of info

Syrah · « **Reply #18 on:** 13 Oct 2016, 08:20 pm »

Yes, thanks Frank. That sounds familiar. My 6106 makes my Supratek preamp sound more euphonic (in a good way) its creator told me the same thing. Which led to my conclusion that these things are very circuit dependent. It must be too low for my Modwright unit, which is why it sounds like crap in that.

Wind Chaser · « **Reply #19 on:** 13 Oct 2016, 09:27 pm »

Quote from: FullRangeMan on 10 Oct 2016, 11:16 am

Decware suggestions seems usefull:
http://www.decware.com/newsite/tubes.html
The rectifier location is compatible with 5U4G, 5AR4, 5Y3GT, and some 274B. Many owners of this amp like using the 274B however not all 274B tubes are completely compatible, so we ship the amp with one that we know IS.

That's very important. Failing that may lead to unnecessary regrets.

Quote

Each rectifier change will also make audible differences in the sound and performance of the amplifier.[/b]

I had a Decware amp and I found swapping input tubes make a much bigger difference than swapping rectifiers.