Rectifier tubes, the hidden "sweetness" of electronic gear, vintage and new, guitar amps and stereo.

I've had 275s, 240s, 75s and now the 60s. Like the 60s so much I almost purchased a single one off Ebay just in case. Every now and then get the urge to go SET but then go back and listen and recognize my audio disease has affected my judgement. Haven't heard the 30s and they would power my speakers w/o any issues. Sold a pair of 275s to Max Guzikowski in DC many years ago. Long deceased but I made him a happy man.

 

The only ones I haven't heard are the MC30s and 40s. The MC60s are my favorite Mac tube amps.

 

Hi,

Im new to this forum. I have an icon audio ls4 preamp which came fitted with three 6sn7gb and one 274b rectifier, all of chinese origin.

The 6sn7's were noisy so i replaced them with nos toshibas which not only got rid of the noise but also improved the sound in general.

Then I tried replacing the 274b with a (supposedly) nos sovtek gz34. Not a good idea. The chinese 274b is back.

My question is: what would really work in that rectifier hole?

Rest of the line is: radford sta 25 (with mullard and brimar valves), tannoy mg 15", a garrard 301, and a zoo of lencos.

Jesper

 

It is common in many tube-type jukeboxes to use a 5U4 rectifier tube.

 

I totally get it with tube guitar amps. In that application, you can use that "sag" in a creative sense the same way you use preamp tube distortion.

My Fisher 800C has solid-state rectification, but it must do a good job with it. That said, I WOULD like to pick up an old 800, the early one with tube rectification. That's supposed to be a nice receiver. The 800C sounds sweet though, SS-rectified or not. Plus, it has that killer headphone output that the earlier Fishers don't have.

 

The rectifier tube along with a choke is what I feel contributes to the sag, in my opinion. And, not to get off topic, I liked how the old radios used the electro-magnet on the speaker as the choke for the DC supply.

 

I have several Fender "tweed circuits" amps that use rectifier tubes. The tubes I am familiar with are the 5AR4, 5U4 and 5Y3. Mostly, I use NOS tubes. The 5AR4 are Mullard (Blackburn factory), the others are USA made RCA, Sylvania, GE mostly.

When you ask for brand I think that is a bit inaccurate as most "tube o philes" don't concern with brand as much as "what factory and what year" for tube manufacture. Many tube plants manufactured tubes that were then sold with various brand names. The audio perception (tone etc) of the tube is most commonly ascribed to the factory and production run, not the bran on the tube.

Hope this helps. Not sure what you are seeking exactly. Most Fenders had tubes branded with RCA and Tung Sol tubes up until the early 1960's, then Tung Sol is less frequently occurring and we see RCA and Sylvania as the "brand" found originally in Fenders from the early to mid 1960's. But other USA brands were used as well. Especially Blackburn made "RCA" 5AR4 rectifiers. Today people refer to these as "Mullards".

 

I'm interested in trying a 5AR4/GZ34 for my pre-amp power supply. Can I get a recommendation as to where to buy online?

Seems that the new production Mullard is made in Russia and perhaps doesn't live up to the NOS standard. Thoughts? Recommendations?

 

Buy one and find out...?

 

The new production Mullard has nothing to do with original Mullards. Different company, totally different products. Only the spelling is the same.

You don't want the new production, you want the original. I would ask Brent Jessee what he has in stock: http://www.audiotubes.com

 

I've rolled a number of these in the power supply to my phono stage- every one makes it sound a little different, sometimes a lot. The older Mullards, fat base, are highly regarded, but not a good as the metal base. Those are expensive. Some folks with the same brand of phono stage found a pre-WWII RCA to be the bomb- I can get you the exact type/designation if that interests you- they aren't cheap, but aren't quite to Mullard money. I'm currently using a GEC U-52, which is equivalent and prefer it to the sound of the Mullard. I think the sound of these things is obviously circuit dependent.
My usual go-to for reliable info and tube selection is Brendan at Tube World. His site is easier to navigate than some. The Tubemonger is a new source for me, and it may be worth checking what he has- I found NIB GEC EF86 tubes from him.

PS: this makes for great reading, perhaps I already posted it in this thread, if so, here it is again:
Dubstep Girl's Massive 5AR4/5R4/5U4G Rectifier Review/Comparison! (Rectifer Tube Rolling thread)

 

If budget prevents you from going NOS, then I can recommend the current production Genalex/Gold Lion GZ34. It is not in the same league as a NOS Mullard, but it has different strengths, and costs about 10% of what a metal base Mullard is going to cost.

 

Yeah, I'll have to think about it. If I find a reliable source, perhaps Brent, then I can always start with a decent new production and save up for an ideal NOS.

 

Brent can help you with the NOS tubes. He doesn't deal in many current production tubes. I think the fat base Mullards usually run about $250, with the metal base closer to $500. However, I found my metal base on Audiogon and offered $300 and it was accepted. So if you are patient you can find some better deals. I wouldn't recommend any new production rectifiers other than Genalex. I bought 3 of them myself because they have a different presentation from the Mullards and like Bill Hart said above, just because a tube is excellent, does not mean that it is a perfect match in every circuit or in partnership with all other tubes. Balance is the name of the game. Original Mullards are SMOOTH! They really are wonderful, but it is possible that they will not be a perfect match for the rest of your system.

 

PM me - I have some NOS Mullard made GZ34s in stock. Mullard UK made a GZ34 with a 40,000 hour rated lifespan - they run a loooooong time.

 

Whew! I'm not sure if the fat base would be accommodated, but it seems the metal are same size as the Chinese tube that it came with. Hard for me to believe I'd find value in dropping $350+.

I'm getting the following upgrade now:

- “maxing out” the filtering capabilities along the entire power supply chain, all the way into and including the preamplifier; not just adding an extra 1200uf of UCC electrolytic capacitance into the main B+ (high voltage) supply but also an additional total of 125uf of Polypropylene capacitors throughout the B+ line. This includes a huge 100uf Polypropylene capacitor right at the line stage PC board. The rest of the additional capacitors are used as bypass capacitors across each UCC electrolytic filter capacitor

- In the line stage circuit, change the resistors to high quality 1% Vishay metal film plate load and cathode resistors; removing all of the coupling capacitors and installing (10) Mundorf MCap coupling capacitors throughout the entire line section


Hoping for blacker background.

So, anyhow, that was my motivation to look into upgrading the rectifier tube.

 

Again - shoot me a PM - I can set you up with a nice Mullard GZ34 for a lot less than $250+...

 

You should definitely take Indy Mike up on his offer!

 

My Line Magnetic 508ia came with a Sovtek 6SL7 rectifier tube. The amp had a very slight buzz which went away when I changed that tube to a Northern Electric 6SL7 tube. Don't know why that was and didn't really care after the amp quieted down.
I haven't started down the road of NOS tubes yet, but that day is coming soon.
I would actually love some opinions of what is the best 6SL7 tube out there. New or NOS.

 

My HH Scott 208 has a 5AR4 recitifier tube. All I know is it sounds good.

Unfortunately right now it's out of commission and needs a little TLC.

 

Count me in for liking tube rectification sound. I have an old Quicksilver preamp with 6x4s and 8417 mono amps with 5AR4s and the sound is fantastic, great soundstage.

 

Can that be used as a rectifier tube? Isn't the 6SL7 a pre-amp tube?

 

I think so. Would one of you mind recommending the appropriate thread to discuss pre-amp tubes? I have some questions on mine as well.

 

Start your own thread.

jeff