5AR4: Sovtek, Shuguang, or other?

[Maxxarcade]

Here's my documented rectifier failure/replacement timeline for my fully restored Scott LK-72A:

Unit was placed into service on July 28th, 2006.

JJ GZ34S - arc'd at 78 hours (38 days) after installation (Sep 5th 2006). Arcing noises became present intermittently well before that time. Tube was scrapped (then, I found out it was under warranty for 90 days.) DOH!

Installed on Sep 9th 2006 - JJ GZ34S - arc'd at 65 days after installation (Nov 12th 2006). Noises actually became present intermittently after about two to three weeks. Tube was kept after replacing.

Installed on Nov 14th 2006 - Sovtek GZ34 Cryoset - arc'd at startup!!! (same day) then appeared to be fine with some intermittent noises for 93 days (Feb 15th 2007). Noises increased and started about 25 minutes after startup until it eventually made those arcing noises almost all the time.

Installed on Feb 19th 2007 - JJ GZ34S - arc'd at 42 days after installation (Apr 2nd 2007). Noises were occasionally intermittent during that time. Tube was scrapped since it was happening nearly all the time after a month of use, and sometimes started making noises about 15 minutes after startup. Also seems to be happening a bit more frequently.

Installed on Apr 10th 2007 - Sino 5AR4 - Noises noticed 4 hours after installation!!! Never actually saw it arc, but I definitely heard it. Rushed into family room to turn off the amp. Tube was removed after cooling thrown into the metal waste bin at my local landfill the following morning. . .with extreme prejudice.

Reinstalled on Apr 11th 2007 - The Sovtek GZ34 Cryoset is currently back in the amp until replacement arrives. Noises are sometimes now starting only about 10 minutes after startup, and are more frequent.

April 27th 2007 - Sovtek GZ34 - Quiet for four days, but now noises are more frequent and can start happening as soon as 10 to 15 minutes after startup.

After putting a 1961 Mullard 5AR4 in there, the rectifier arcing stopped. It has been fine since I pulled all the new production tubes out and replaced them with vintage.

YMMV

. . Falcon

This makes me nervous, because I have a quad of JJ EL84's that I'm going to use on my Zenith amp. Though the 5U4G will be a vintage Sylvania or Philips.

 

[jaymanaa]

I've heard bad things about the Sovtek 5AR4, but have used them myself a couple times without failure yet.

 

[Radfordman]

My Quad II power amplifiers still have the original Mullard GZ32's in (yes GZ32 not 34) These amps were made in the 1960s. I purchased them about 1972. I don't know how many hours they have done, but it must be a lot. In the mid 70's I purchased Mullard GZ34 as spares, never needed to use them.

Recently I measured the HT voltages and they seemed very close to specification.

 

[magmod93]

This makes me nervous, because I have a quad of JJ EL84's that I'm going to use on my Zenith amp. Though the 5U4G will be a vintage Sylvania or Philips.

My Maggie 93 has been running the past 4 years with JJ EL84's, Slovac EU7's and an old GE 5U4GB... been fine, no problems.
Of course the amp is in proper working order, so I don't anticipate changing tubes for years.
In a proper working amp, tubes should last 20+ years. They always did before.

 

[Maxxarcade]

My Maggie 93 has been running the past 4 years with JJ EL84's, Slovac EU7's and an old GE 5U4GB... been fine, no problems.
Of course the amp is in proper working order, so I don't anticipate changing tubes for years.
In a proper working amp, tubes should last 20+ years. They always did before.

I agree. All but one of the original 1958 tubes on my Mag 175 amp are still working today. I'm afraid to "upgrade" to any new ones when they get weak.

Why do people always say that Solid State stuff lasts longer? I've seen plenty of tubes going all the way back to the 20's still in good working order.

 

[MoparMan]

I always try to find NOS or really good used tubes (that test new/almost new) in all my amps and equipment. Something as important as a rectifier or power tubes, you shouldn't comprimise on. That goes for preamp tubes as well. Older tubes (any of them) are just better built, better sounding and last MUCH longer than the junk that's being produced today. In order to build my stash of good old ones, I've learned to be patient and catch deals when they pop up. I don't get all excited then rush out buy at ridiculous prices or overbid. The best deals I've found are from the famous auction site. I may bid on 10 or 15 differen't auctions but maybe only win 1 so it's hit and miss. Patience is the key...

 

[Jim McShane]

I always try to find NOS or really good used tubes (that test new/almost new) in all my amps and equipment. Something as important as a rectifier or power tubes, you shouldn't comprimise on. That goes for preamp tubes as well. Older tubes (any of them) are just better built, better sounding and last MUCH longer than the junk that's being produced today. In order to build my stash of good old ones, I've learned to be patient and catch deals when they pop up. I don't get all excited then rush out buy at ridiculous prices or overbid. The best deals I've found are from the famous auction site. I may bid on 10 or 15 differen't auctions but maybe only win 1 so it's hit and miss. Patience is the key...

The current production power and small signal tubes are FAR better quality than the current rectifiers. The rectifier situation is not good - the JJ is horrible quality, the Sovtek struggles above 450 volts or so, the Chinese tube is probably the best of the bunch but becaue they were so bad for so long people are afraid of it. As well, the supply is drying up - whether Shuguang is going to put it back into production or not is unclear.

Actually the Russian 5Y3s are pretty decent, but it's hard to get to worked up about the rest.

You are wrong calling the new production tubes junk - there is some great new stuff out there. But none of them are rectifiers.

 

[magmod93]

I agree. All but one of the original 1958 tubes on my Mag 175 amp are still working today. I'm afraid to "upgrade" to any new ones when they get weak.

Why do people always say that Solid State stuff lasts longer? I've seen plenty of tubes going all the way back to the 20's still in good working order.

I agree, indeed!
Most of the antique radios I get in the shop for restoration rarely need tubes.
It's those ole wax-filled caps that I must rip out and replace.

 

[ldatlof]

My Quad II power amplifiers still have the original Mullard GZ32's in (yes GZ32 not 34) These amps were made in the 1960s. I purchased them about 1972. I don't know how many hours they have done, but it must be a lot. In the mid 70's I purchased Mullard GZ34 as spares, never needed to use them.

Recently I measured the HT voltages and they seemed very close to specification.

My Quad IIs, which I purchased last year, also have Mullard GZ32 installed in them. I assume, from the amount of dust on them, that they are original. Mullard rectifiers are high quality and long lasting. I can see why NOS ones demand high prices - you probably won't have to buy another.

 

[Glassweights]

Rectifiers and voltages

So,

If a rectifier of new vintage was allowing higher B+ though, that would mean it was not drawing as much voltage to run???

Too dang efficient I guess.

So far my expensive Fender branded Sovtek 5AR4 is working in the Scott 222C. (You remember the thread I think)

$26, man, it better be gold plated or I am going to lift the mullard from the amp I am working on. (For my bud who sold me the tube LoL - oh well he is my best friend, he forgave me for wiping the mullard logo off)

Ill let ya know if it fails.

About the arcing, was that rebuilt amp fixed up with like, lots of capacitance?

Inquiring minds want to know!

Dan

 

[GordonW]

You are wrong calling the new production tubes junk - there is some great new stuff out there. But none of them are rectifiers.

I'm afraid that this situation may not change much... most of the current hi-fi tube amp manufacturers have "given up" and gone to solid-state rectification. Even many of the makers of big, high-power tube-based guitar amps have gone to SS rectification, at least in some cases. So, there's not as much pressure on the manufacturers of tube rectifiers to clean up their acts... there's simply not much demand for high-quality tube rectifiers...

Regards,
Gordon.

 

[Radfordman]

My Quad IIs, which I purchased last year, also have Mullard GZ32 installed in them. I assume, from the amount of dust on them, that they are original. Mullard rectifiers are high quality and long lasting. I can see why NOS ones demand high prices - you probably won't have to buy another.

Nice sounding amps if in good condition, correction very nice sounding.

 

[ldatlof]

Nice sounding amps if in good condition, correction very nice sounding.

Electronically they are in great shape - refurbed by Terry Dewick. Cosmetically, I'd say about a seven. They also run on 220V like their native land.

I am very happy with them.

 

[oysterbar]

If you can afford the cost and your amp can handle these tubes, consider the Sophia Electric Princess 274b Mesh plate tubes as a replacement. I am running a Woo Audio WA6 SE headphone amp that came with 5U4G tubes. The 274b's were no problem with my amp design and the change in sound quality and soundstage was incredible.

 

[NOSValves]

NOS Valves...you make some valid points and I respect your opinion. But I must quote you on something..
"Most customer get 2 or 3 years of trouble free service out of the light load of these amps in properly working order. "
Me: If you use decient NOS tubes they will last much longer! I feel it is unacceptable to replace tubes every couple of years because this is what we have to settle for. Maybe we will see the day when better quality rectifiers will be available.

Marty,

Well the way I look at it you can buy about 8 - 12 Sovtek 5AR4's for the cost one NEW Mullard 5AR4 so its not like its breaking the bank.... Now if that supposed new Mullard that cost you $100 to $150 takes a crap in 2 or 3 years then that would upset me...

I'm not defending the quality of modern production tubes. I wish they all were allot better. I think they could be if the large tube dealers would put there foot down and demand better QC out of these factories.

Craig

 

[NOSValves]

This makes me nervous, because I have a quad of JJ EL84's that I'm going to use on my Zenith amp. Though the 5U4G will be a vintage Sylvania or Philips.

Don't be nervous JJ makes a great EL84.... just don't use it where a 7189 or 7189A is spec'd or the life spam will be on the low side. It's kind of strange how these manufacturers can make one tube that works great and another is a real POS... JJ 12AX7's and 12AU7's and 12DW7 are really good tubes also. Many here report problems with JJ 7591's but I've had very little problems with the burned in and matched quads I receive from Dougs Tubes. But he has told me he's sent many of them back that didn't pass his testing.

Craig

 

[RWFE]

I just won an auction for a Daystrom branded Mullard 5AR4. 53 bucks and good testing from a tube seller with 100 percent feedback. Code is f31 b1g1, which means it was made at Blackburn in the first week of July 1961. So while the conventional wisdom is that these tubes go for 100 plus dollars I have never paid more than 60 for one. You can find them fairly reasonably if you watch. I probably have enough now to last me the rest of my life. One in the amp and now two (soon to be three) in the drawer.

 

[NOSValves]

They do go for $100+ new which is what was mentioned here. Used is an entirely different game.....Buyng a used rectifier is a gamble. Tube testers tell you just about nothing of the health of the tube when it comes to rectifers. I've seen many a rectifier test just like new in my Hickok and arc over under load in a known good working amplifier. Most tube testers just do not place enough load on them to show full load flaws. Chances are you will do just fine with your purchase but some amount of gambleling is involved when buyng used tubes of any type or manufacturer. Thats why they are cheaper to purchase.

Craig

 

[FalconEddy]

I just won an auction for a Daystrom branded Mullard 5AR4. 53 bucks and good testing from a tube seller with 100 percent feedback. Code is f31 b1g1, which means it was made at Blackburn in the first week of July 1961. So while the conventional wisdom is that these tubes go for 100 plus dollars I have never paid more than 60 for one. You can find them fairly reasonably if you watch. I probably have enough now to last me the rest of my life. One in the amp and now two (soon to be three) in the drawer.

Yeah, I had my eye on that one also, but never bid on it.

Those fat-based Mullards produced from July 1958 through January 1962 are my favorites.

. . Falcon

 

[RWFE]

I have always bought used ones never had any problems so far. But I am sure you are right as anything used is a risk.

Falcon: I am glad you didn't!