Solid Stete vs Tube Rectifier

[overdrive]

Solid State (sp)

Realize that this is a fundamental kind of query & I have read several articles to date on it. Most simply imply that it is dependent on the age/original design of the amplifier and/or the preference(s) of the builder.

My primary question(s)...which type is better from the standpoint of
(1) longevity & reliability (probably SS)
(2) overall sound
(3) feel

Reason for asking...a couple of smaller tube amplifiers (5W) that I am considering either have three tubes (one being the rectifier) or two tubes (pre-amp & power only) + the SS rectifier.

Is this a big deal or something worth taking into consideration?

[Chuck H]

My OPINION is that so many little amps have been built with tube rectos that it has become a standard feature. Probably because when amps of that size were useful, tube rectos were all that was available. Later designs moving up in watts and changing to a SS recto. But there is a mojo that follows the little amps because you can crank them without scaring everyone on the block. Tube rectos create "sag", a softening of the note attack and a bloom of the available power that creates a compression effect. Many players and builders consider this effect synonymous with the little amps. There are other ways to create sag so IMHO rectifier tubes are really just a novelty in a modern design. My one concession would be the little amps because with such a trim list of features anyway why not at least be novel. The three tube lineup is classic to many players and builders, sounds just fine and doesn't suffer any gross reliability problems. Now...

If you were to drop the tube recto, use a SS recto and induce sag another way the amp WOULD SOUND the same and never need a replacement rectifier tube. Though I doubt the SS recto model your considering has done this. And do you even want the sag? It's a brave new world since the predecessors of those amps were designed. How would such an amp sound if we didn't induce the sag at all? Seems perfectly reasonable that you may prefere it. So for me I will stick with the rectifier tube on this type of amp for nostalgic reasons. For YOU I would say that if you have similar inclinations to go with a rectifier tube. If not then you should listen to each model and pick the one that sounds best to you. Which you really should do anyway regardless of rectifier preference.

Chuck

[BiBi]

I thought with a single ended design you don't get "sag" from the tube rectifier so the only reason to put one in there is nostalgia and/or some voltage drop?

[Enzo]

That would be my thinking too. Sag occurs when current draw from the power supply changes. These little single tube amps are running class A which means the power draw is pretty much constant, so no sag to be had.

1. A solid state rectifier can last forever. But diodes can also fail and short out. Tube rectifiers in my experience tend to last a long time and are nowhere near as likely to be bad as a power tube. SO in my opinion, the reliability is a non-issue. However, the tube rectifier will need a transformer with the extra 5v winding in many cases, plus the extra tube socket and wiring to install. And that is one more tube heating the area. COmpared to 5 cents worth of silicon diodes.

2.3 - sound and feel. depends on the amp and what you want. In a little 5w amp, the power supply is not probably much of a factor. In a Deluxe type amp it may be just the thing. And if you play metal you may be far les interested in sag and expression than a blues player, just as the blues guy is less interested in an amp that can go chunk-chunk-chunk-chunk-CHAAAA all night.

[Chuck H]

True that class A amps don't sag... When they're running in class A. Push a Champ into OD and measure the plate voltage some time

[JoeM]

I would guess even with a SS rectifier, there would be sag depending on the PS.

[Chuck H]

Sure, but add series resistance to the power supply and there is more. Still, my only real reason (and the only reasonable one I can think of) to continue using rectifier tubes is nostalgia. And there's nothing wrong with that.

Chuck

[JoeM]

Sure, but add series resistance to the power supply and there is more.

That's obvious.

[Pedro Vecino]

The effect of a rectifier tube is different from a resistor installed in series in a typical class AB amplifier as a JTM45 or a Dual Rectifier for example. What sense would install tube rectifiers in a current Dual Rectifier (sockets, tubes, 5V winding, commutation wiring...) if the resistor does the same thing?
Feel is different in the instrument (compression, transition into overdrive, articulation...). The logical explanation is that the dynamic relation load/voltage drop must be different although there may be more factors. The resistor in series never had an interest for me. Tube rectifiers, yes

[Chuck H]

What sense would install tube rectifiers in a current Dual Rectifier (sockets, tubes, 5V winding, commutation wiring...) if the resistor does the same thing?

Because they coulnd't install a resistor and call it a Dual Rectifier Just kidding. But I do think the rectifier tube has held on strictly because it's always been. No one was adding series resistors to induce sag in the glory days of tube amps. Then it was discovered that solid state rectifiers had an effect on the sound of the amps that wasn't always a plus for all players. So a rectifier tube became the mystique mojo that was imbuing these amps with magic compression. At that point trying to sell an amp with a resistor following a diode rectifier and telling players "well, it's not a tube, but it'll sound the same." probably wouldn't have gotten you very far. We were all still pretty green and a lot of equipement was still using tube rectifiers anyway. So it became a feature. It's another tube, that has to be better, right? A "sag resistor" isn't a very impressive sounding feature. I doubt Mesa is going to introduce the Dual Sag Resistor any time soon. That's why they trouble with the extra expense and wiring.

I'm sure there are subtle differences in the envelope of a tube rectifier vs. a resistor but I'll bet they're so subtle you couldn't tell the difference in a blind test.

Chuck

[dai h.]

hope I'm not remembering wrong but I think there there were some other bits besides the resistor (which models the tube rectifier impedance) in those "tube rectifier emulator" devices (as far as I'm aware there are or were at least a couple of companies making them). I've never tried one, but if you can indeed emulate the tube rectifier response, then those would seem a better idea (tube rect. takes up space, uses more power, produces more heat--can have negative effect on longevity of parts).

[Chuck H]

One nice advantage to tube rectifiers is that they don't pass voltage before they heat up (indirectly heated anyway). So the other tubes have time to heat also. 90% of the "players" I've seen turn on a tube amp flip the power and standby on at the same time and start blanging away at the guitar until sound starts to come out. You can tell them to use the standby switch but they won't as quick as you leave. So... Hurray for rectifier tubes for these guys.

[guitarmike2107]

I would build it without a tube rectifier, make the plate supply stiff and then make the screen supply sag to add compression if that’s what you want.

Or build it with an 8 pin socket to use a valve rectifier and then use a valve base to build your own plug in solid state rectifier as back up for the gig bag.
8 PIN VALVE BASE - MAKE YOUR OWN REPLACEMENT RECTIFIER - MODULUS AMPLIFICATION

Mike

[dai h.]

seems like there are a set of general not-necessarily-true-beliefs and this could be one of them. Things like "tubes sound better than solid state". "Class A sounds better than Class AB". "No feedback sounds better than having feedback." "Uber functionality with triode/pentode switching, etc. will lead to a multitude of wondrous tones (rather can possibly leading to mediocrity and confusion)". "Carbon comps are warm." "Orange drops are harsh." "Metal films are cold." "Point-to-point wiring gives a fatter sound."

[dai h.]

One nice advantage to tube rectifiers is that they don't pass voltage before they heat up (indirectly heated anyway). So the other tubes have time to heat also.

True. Gradual ramping up of B+ does seem to be a desirable attribute. (Can be modeled?)

90% of the "players" I've seen turn on a tube amp flip the power and standby on at the same time and start blanging away at the guitar until sound starts to come out. You can tell them to use the standby switch but they won't as quick as you leave.

"Warm up?" "Why should I have to wait?" lol (That is also how I used to work the on/off and standy 'til I learned better though.)