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

No commercial manufacturers using it that I know of. Best I have heard a 300B SET amp was with a solid state shunt regulator with CCS. More dynamic, better bass and lower noise than with the tube rectification.

 

Oh right, damper diodes are evil, nobody use them.

jeff

 

I don't think they are evil, they just aren't designed to do what we are talking about.

They MIGHT work, but as soon as someone builds a product using them they might find they don't.

 

I was just being sarcastic.

jeff

 

Yeah. I personally hope someone does find one that consistently works and builds a commercial product so I can sell the piles of them I've got for good money.

 

Stranger things have happened.

jeff

 

I'm not a listening expert but I have around 20 tubes amps. This week I sat down and noticed that SS rectification and Tube Rectification really have a different sound. The amps, even low powered single ended amps, with SS rectification had 'better' bass and sounded 'tighter' and I preferred them when playing on my Snell K speakers (8" woofer) but when I play SS or tube rectified amps on my Opera Consonance M-15's (15" woofer) it doesn't matter so much but I preferred the all tube versions.

But my brain tells me the more tubes in an amp the better


Let's talk regulator tubes. Anyone have an amp with them?

 

My amplifier is a home brew thing from the start of the 1960's, so I can't tell you the brand. I can, however, tell you that the rectifier is a GZ33 and it is branded Mullard. I have a couple of spares marked GEC, but they are Mullards as well. It's a nice indestructible tube. I've seen some interesting circuits made with GZ32 or GZ33 rectifiers as well.

 

Yes. The Lamm SETs have a indirectly heated 6C33C as the power triode and a second 6C33C as the voltage regulator - actually that was the role for which the tube was originally developed, if my understanding is correct. The Lamm also uses a small 5651A tube to provide a reference voltage (it's a gas regulator 80-90v) and a 6AK5 pentode to drive the plate grid of the regulator tube. I don't pretend to understand the circuit.

 

Thought I'd chime in on the guitar amp subject:

Ted Weber loudspeakers offers an alternative to a rectifier tube called a Copper Cap. I put one in my AC30 and like it. Probably less sag than a tube. Since the AC30 doesn't have a standby switch, it offers in-rush protection. Also probably reduces the heat buildup in the amp enclosure (always helpful with vintage VOX amps) since the power tranny is working less:

http://www.webervst.com/ccap.html

I wonder how it would sound in a Hi Fi amp?

Also here is an interesting article about substituting rectifier tubes in guitar amps:

http://www.premierguitar.com/articles/21380-ask-amp-man-restoring-a-deluxe-reverbs-magic

I have a number of amps that use rectifier tubes: Pro Reverb, Ampeg Reverberocket 2, Ampeg B-18N

 

My favorite tube amplifiers have been tube rectified - and that also goes for my DIY creations.

For those who don't want to splurge on a vintage Mullard GZ34, the Hitachi version is also verrrry good.

Some other tricks: 5X4 can be used in place of a 5U4G - provided you rewire the sockets. An even earlier version is the UX4 socket 5Z3 tube. I've used this in a DIY creation with great success.

And as already mentioned, lots of DIY builders are using TV dampers - http://vinylsavor.blogspot.com/2011/03/tube-of-month-6ax4.html Of course, with the exception of the 6BY5, they are single diodes so not exactly plug and play with commercial amplifiers.

 

I have a small collection of different 5AR4 / GZ34 I use in my DIY EL34 SET amp and they do make a difference in SET amps too.

I have Mullard fat base, regular base, and japanese version with the seam top. RCA copper plates and Sylvania big bottle too. They are all very good, just a little different. Mullard would have to get the nod overall but not by much. Prices are getting out of hand, hopefully new production can make one worth buying but it doesn't seem likely. The Gold Lion reissue line is pretty good but not as reliable as NOS... I've given up on even trying new production tubes anymore.

 

It's easy to build a solid state plug in replacement for most rectifier tubes. You mount diodes and series resistors on a small board or card and attach to an old tube base or AMP octal male plug. In this way a direct comparison can be made for sonics and also guitar players have a simple swap, since no commercial guitar amp makers want to challenge Randy Smith's probaby-bogus patent. Fender included one (with no series resistors) in with the old Bassman reissue as I recall.

The Weber VST copper cap is commercially made and works well in many audio products although the Collins crowd has had a few fail in the KWM-2 power supply. Weber disrecommends them in that app and has chosen not to build a stouter version.

There are several excellent rectifier tubes not pin compatible with the 5AR4 or other common types that are cheap NOS. I will leave finding them to others.

Damper diodes might work, then again, may not.

 

I agree completely, Steve. Whether it is a guitar amplifier or power amp for music listening, I always prefer tube rectification for the tube glow and magic they provide. Too many great amps have lost their magic after the designers changed to solid state rectifiers in the name of "reliability." My two favorite examples are my narrow panel Fender tweed Deluxe (using a single 5Y3 rectifier) and Air Tight ATM-1 (using twin GZ34/5AR4 Mullards).

 

I believe those copper-plate 5AR4s were made by GE. They're surprisingly small when compared to other 5AR4/GZ34s...

 

I've been using (in the system I have at my parents') a Valve Art 274B that I get cryo'd from cryoset.com. It's not like other 274B rectififers it seems, more like a big bottle 5U4G. . . and the sound is quite nice, the sound field is clear and big. The price is great and I've been using a pair for over a year without a single hiccup at all, quite reliable. I bought another pair and put it in my bedroom system, where they have been dishing out the goods flawlessly half a year. If you need one more for your collection. . .

 

My '67 Deluxe Reverb is still running strong on its original Mullard 5AR4/GZ34.

 

that's great - I was under the impression that Fender amps came with US tubes

 

Mine also came with Telefunken 12AT7s and Telefunken long-plate 12AX7s (plus RCA 7025s for the preamp and RCA gray plate 6V6s).

 

Modwright Oppo 105D.
The power supply uses a rectifier tube. I swapped the stock Sovtek out for a Philips 5R4GYS.

The Modwright Oppo makes CDs almost listenable at an affordable price.

 

so now I know - thanks

I would guess Leo put it the most cost effective reliable tubes he could buy