Tube rectifiers VS solid state, ???

[miroslav]

I'm kinda lost as to what the real points are now being made here...?

I also think that when people are talking about "guitar tube amps"...there's a tendency to lump them all into a singular category, but IMO, there are HUGE differences between some cheap, assembly line amp builds...some "boutique" builds done by guys who have limited design knowledge, and are mostly just copying existing circuits with minor modifications...and most true *boutique* amps by builders who really know WTF they are doing, and are capable of implementing significant designs and fully understanding every aspect of those designs and what each and every component is doing and how it affects the total design, to include tube selection.

The last category are where you see many of the high-end builds, with substantial originality of design implementation, and proven quality over time, with a lot of support from top players.
I don't mean to say that there can't be an inexpensive assembly line amp of good quality, performance and sound...just that there are differences.

At this time, my 3-4 top-shelf amps all have SS rectifiers. They are not prone to any unusual, premature power tube failures, and the effect on the fell of the amp was reason for their choice.
I also very much disagree that power tubes have little to no real impact on your amp sound...??? I actually find that amps, that rely mostly on the preamp tubes for their sound, are usually amps that IMO, sounded like shit, and I've gone through a good number of them in the past, to where out of the 7-8 amps I currently have, they all get a good deal of their character from the power tube section.
I don't deny that the preamp tubes shape your initial tone, and if you just use the power tube section to sorta pass that one to the speakers...then yeah, your power tubes aren't adding much. However, every single amp I have comes to life, and exhibits a character transformation when you push the power tubes into their crunch zone, which is a way different sound, than when you're just driving the preamp tubes hard, and running the power tubes much cooler.
Often, it's a combination of both that provides most amps with a variety of character flavors, but I've always enjoyed amps more when the power tubes are being pushed hard, and the preamp tubes just provide some initial shaping of the character.
That's often not appealing to many folks who play mostly at bedroom levels, but IMO, unit you're moving some air, which requires the power tubes to be pushed, and they in-turn push the speakers and the cab...you rarely hit that tube amp magic.

AFA the vintage vs. reissue debate...I've got real black plate tubes, (a bunch of them), and I've used them side-by-side with non black-plate vintage or reissues, I never found that just the "black-plate" aspect was a major defining factor.

 

[weakenduser]

Maybe the pushing it to overdrive levels is why I cant hear very well any more, but I am an old fuck so having done that quite a bit in my 20s, it really has an impact after 50 years.... I dont build too much any more either, right eye is gone, makes any soldering, or pretty much anything else VERY hard to do.
That said..... Attenuation in those 50 years has only come into common use in the last 25-30, before that, just playing loud was how I got my best tones,... but until I really started inspecting why the tones changed at lower volumes, and really got into tube specs, and manuals,etc etc.... I moved from Oregon to NY and left ALL my music gear, amps, guitars, and all the gack that you accumulate ... down to a 12 string acoustic.... and work for a living that did not involve music...
then about '84 things changed and music was in my life again....
started building Champ clones and messing with circuitry and types of components, tweaks in speakers, size, type etc...
then tweed deluxe clones, and 18 watt clones, then the amp I use now is a Ceriatone Kit, 36 watt... with a nice cab I built.... you are right about pushing the tubes, most of the time I am playing now in a 12X12 room so high volume is not an option, cannot stand it beyond about three or four on the master volume....
S

 

[miroslav]

I always for headphones when recording...and I'm not limited to what levels I can use...there's no one I'm disturbing even at 3AM.
For awhile I played around with attenuators, and I have 3 on-hand...but I just stopped using them because I didn't like how they altered the sound/feel the minute you tried to push them amp and then crush the volume output. You need to move air, with a decent amount of output, so I just used headphones.
When I'm not recording and just jamming/practicing, I can live with a lower level, and if I want some more output, I have a few different types of ear plugs...from heavy to very light attenuation, and I'll mostly use the light version because it doesn't muck up the sound.

I was just recently looking at also getting some ClearSonic acrylic isolation shields...but for the studio and also for live use, so I can crank without blasting anyone in front of the speakers. You see a lot of pros using them on stage, so they can get push their amps buy control the blast.

 

[Guitargodgt]

I can only speak from my experience of owning a dual rectifier. I think the benefit of tube v silicon is merely just sound although it's not as crazy of a difference as people make it out to be. I mean there is a difference, but it's not like it changes the amp into something else. The response just changes. I would argue 6l6 vs el34 in the amp creates a larger difference in tone. Truthfully though speaker selection is like 90% of what makes an amp sound good so all these little things don't really matter that much overall in my opinion. Same goes for germanium v silicon, there is definitely a difference but it's not as crazy as people make it out to be (again in my opinion).

 

[ecc83]

I can only speak from my experience of owning a dual rectifier. I think the benefit of tube v silicon is merely just sound although it's not as crazy of a difference as people make it out to be. I mean there is a difference, but it's not like it changes the amp into something else. The response just changes. I would argue 6l6 vs el34 in the amp creates a larger difference in tone. Truthfully though speaker selection is like 90% of what makes an amp sound good so all these little things don't really matter that much overall in my opinion. Same goes for germanium v silicon, there is definitely a difference but it's not as crazy as people make it out to be (again in my opinion).

This ^ I think is the more realistic situation re vlave amp components. For example. I was charged to make a circuit that allowed two different brands of ECC83 to be A/B'ed in circuit instantly, a facility virtually no player has ever had. The results after two good guitarists and some other good "ears" tried it out with a couple of brands of triodes was...Yes, differences can be detected, just. The effect was more noticeable as the valves were driven harder but even so it was small. The conclusion drawn was that no customer is going to notice WHICH ECC83 was fitted in isolation.

IMHO this is the "standard condition". There are differences in the sound of components, you would expect that in an open loop system but they are small. Not least because valves are built with incredible precision. If you don't make an EL34 pretty much exactly per Mullard spec' it ceases to BE an EL34. Loudspeakers on the other hand can be seen to be radically different and sound it. It is in any case very tricky to keep pulp cones consistent (recordist know this and find one of their 4x12 cones to be favourite).

Those that have amps with Sstate rectifiers can get a resistor inserted in the HT path that virtually duplictates the loss of regulation and hence sound of a valve. For the GZ34 R is about 50 Ohms.

A GREAT deal of the gitamp retrofit parts industry is BS and just there to part you from your ill gottens.

I have a clip my lad sent me a day ago. Not the best recording or mic but it might be interesting to get some ideas from y'all!

Dave.

 

[ecc83]

There you go, just him arsing about with a wee Soundcraft mixer and a laptop. I think a little wine had been taken!

The guitar was a Rikky 330 and the mic a "Shure 100" he said, must look into that. But, anyone care to speculate on the amplifier?

Dave.

 

[miroslav]

Those that have amps with Sstate rectifiers can get a resistor inserted in the HT path that virtually duplictates the loss of regulation and hence sound of a valve. For the GZ34 R is about 50 Ohms.

And going in the opposite direction...I've got a few Weber Copper Caps, one for each three main rectifier tube types. I've tried them in a couple amps, switching between the tube rectifier and the Copper Cap...and there's little difference, though I'm not sure if a Copper Cap is identical internally to your typical SS rectifier.

All in all, the tube vs. ss rectifier is generally subtle, and you also have to have the amp driving harder somewhat to notice that "sag" vs. "tightness"
I think some people make way too much out of the rectifier choice. As I said, my top/favorite amps are all ss rectified, and I haven't noticed anything missing.
You have to take the whole amp as one unit that is the sum of all its parts, that is then combined with the right cab/speaker to give you the total package...and probably the speaker is the big single component that might have the most dramatic effect on the tone...not the tube brands/types.

 

[ecc83]

Ah! Rather gave away the make of amp there! Still that is all I am telling yous..For now.

Dave.

 

[snow lizard]

The influence of any tube depends on the circuit. Some of the more recent designs are less sensitive to what tubes you have. Something more like an old Fender or Marshall will let you hear what's going on. A Deluxe Reverb or Champ seems to be a good test bed for tube rolling.

In a Deluxe Reverb you have a typical old school Fender layout. V1 is the first gain stage of the first channel. V2 is similar but for the second channel. These locations call out a 12AX7. The V1 (and V2 in this case) will let you hear the tube itself more readily than most of the other positions. Tone and gain factor as well as any problems like noise or microphonics. "Shuggies" (Chinese Shuguang factory 12AX7A) tend to be good as far as noise and microphonics, with a bright crispy sound and the most gain. Metal guys and shredders usually like these tubes. Probably in something other than a Deluxe Reverb. Most other 12AX7's should give more of a crunch/overdrive sound when you drive them hard rather than the harder square wave sound of the Shuggies. The Deluxe Reverb will let you hear what's going on if you have NOS tubes or something. Other amps (Blues Jr. for example) don't seem to care so much. If the amp cackles or squeals it might be a noisy or microphonic tube in the V1 position. You can also drop the gain factor by substituting a different type of tube. Easy enough to find a comparison chart for gain factor, but be careful. Other electrical factors to consider like current. The 12AX7 has a gain factor of 100 while the 12AT7 and 5751 both have a gain factor of 60 or 70. The 5751 is much closer electrically to what a 12AX7 is. If you're just rolling different 12AX7's to see what's up the differences can be very subtle shades of totally useable. Once in a while you might find something like an old RFT ECC83 or GE 12AX7A that really opens the amp up and sounds great. Again, the same swap in a Blues Jr. can be harder to notice, except the NOS tubes are much more expensive.

The V3 tube is the reverb driver. Spec calls for a 12AT7. NOS 12AT7's can be found for reasonable money. Noisy tubes are a problem in this circuit. Ive found stock modern tubes to work fine in terms of noise but can sound kind of "meh" in comparison to a good, quiet NOS tube. It's possible to find something that makes the reverb sound more lush and musical.

V4 12AX7 is the tone stack and reverb return. This position has less of a pure tone impact than V1 but certain tubes can die prematurely here if this is a cathode follower circuit. Sovtek 12AX7 LPS is an example which can work very well as a V1 or phase inverter tube, but isn't recommended for cathode follower circuits.

V5 is the tremolo circuit. Sometimes called vibrato. You gotta love Leo Fender. This is the perfect spot for noisy, microphonic or otherwise crappy 12AX7's. As long as the tube functions enough to oscillate, it doesn't matter. This circuit does not pass audio.

V6 12AT7 is the phase inverter. A noisy reverb tube can be fine here. A worn tube will show symptoms similar to if your power tubes are worn.

V7 & V8 are the 6V6 power tubes. A Deluxe Reverb can run these approaching 430 plate volts which is a lot to ask of a 6V6. Less robust designed tubes can be prone to early failure. Current production tubes are getting better than they were a few years ago, while NOS/old school tubes were more robust and less prone to failure. The current production J/J 6V6S can take a lot of punishment but sounds more like a 6L6.

V9 is the rectifier. A lot of the Deluxe Reverbs use a 5AR4/GZ34 tube. Some use a 5U4. The biggest differnce is filament current. Most rectifiers are 2 amp filament current while the 5U4 is 3 amp. Substituting one type for another can cause a lot of problems. (eg. blown transformer) If the amp uses a 5AR4 there are other rectifiers that can be used. A 5AR4 has the most power output, least sag and sounds closest to a solid state rectifier. Using a 5V4 or 5R4 here can be made to work. The amp will have more sag. It will also drop the plate voltage to the power tubes. Re-biasing the amp is absolutely necessary for fixed bias amps. If you're changing to a higher output rectifier there may be other modifications necessary. A Champ for example will use a 5Y3 rectifier. These are cathode bias amps, so there's no adjustment. The bias should be checked if running a higher output rectifier to make sure it's running within spec. You'd likely have to change the value of the bias resistor. Or just keep using the tubes the amp was designed to work with.

And yeah, using a Twin or JMP is a choice based on the sound and application you have. These are classic amps that don't suffer anything from not having tube rectifiers.

I have very little experience with things like the Mesa Triple Rectifier. Not my cup of tea, really. I don't have a lot of insight on how the rectifier can shape the tone, but going to a lower output rectifier as in the Deluxe Reverb can be useful if the plate voltage on the power tubes is high.

 

[cmbaziira]

Great stuff. Amplifiers, tubes all will work but you may need to hire a professional music mixer for much better advice. Wish you luck my friend

 

[Guitargodgt]

As I said, my top/favorite amps are all ss rectified, and I haven't noticed anything missing.

I think if I ever get another amp that uses a tube recto over a SSR I will yank the tube and plug in an SSR instead.

The exception being if it was some kind of designated one trick pony clean amp.

 

[rob aylestone]

I suspect there's a good degree of snake oil poured here. The ramp up of heater voltage IS beneficial, and ever since we started using vacuum tube for higher power purposes, it was normal to use a thermistor - a very simple temperature control resistor, to do exactly this. A solid state rectifier feeding the heaters via a thermistor is a bog standard part of the design going back VERY long time. It was almost standard in things like RF amps and higher power audio amps because it did exactly what was needed. Let's not reinforce the attitude that solid state means bad and vacuum tube rectification is good. Selective use of facts really annoys me. Temperature stress is fact. Gradual warm up is sensible for longer life. The actual power source just needs to supply smoothed power - solid state or tube based is irrelevant.

 

[ecc83]

Snake oil for sure Rob but thermistors in heater circuits? Can't say I have seen that except in series wired "AC/DC" TVs?

The "burning" resistance of an EL34 is 4.2 Ohms, likely at least two and some triodes. It would be a fat thermistor that surge protected that lot and they were THE most unreliable of components (in tellys at least) mainly I suppose because they ran bloody hot!

In fact the heater is about the most rugged part of a valve! In the aforementioned TVs, despite the surge limiter, they lit up like a Christmas tree and then dimmed but an O/C heater was a very rare event. I have never had one fail in an amp. I did have an ECC83 fail in a pedal, just one half! One in a million mnfctring fault.

"We" actually run power valve heaters in series so they "surge limit" each other. At 12 or 24 volts transformer regulation is better. Pre amp valves are DC heated. Socking great cap slows volts build up a bit but regulation is perfect, no mains V wobble.

As for Silicon V vacuum? Like you I don't think anyone could tell the difference between a valve rect and sstate plus the equivalent resistance. But then nobody with the resources will ever do the test except the amp makers and it suits their adpuff "machine" to keep things mysterious.

Dave.

 

[miroslav]

I think if I ever get another amp that uses a tube recto over a SSR I will yank the tube and plug in an SSR instead.

The exception being if it was some kind of designated one trick pony clean amp.

At this point...having gone through my share of amps, and finally settling the keepers and my favorite few top-shelf amps...I've accepted the designs of these amps at face-value. Meaning...this crop of amps I now have are keepers for good reason, and I don't ever question or think about the choice of tube vs. SS rectifier or which tubes are used in the preamp or power sections, and any other aspect of the builds.
IOW, the builders knew what they were doing...and I'm good with it.

I've got three "American" flavored 6V6 amps, all are tube rectified...and I've got three + a fourth build coming, that are "English" flavored amps, and all are SS rectified.

I have experimented with a couple of the tube rectified amps, by trying out different rectifier types, because their designs allow it...but TBH, I might fall in love with something different for a short bit, but eventually I put back the original tube spec, and always find that the amp sounds best with it...so again, I'm confident that the builders knew what they were doing.

 

[ecc83]

"IOW, the builders knew what they were doing...and I'm good with it." Well said Miroslav. I have spent some time watching and listening to the MD and technical director "sweating" over the voicing of an amp design...Play, listen, solder, tea,play,listen,***k! MORE soldering,tea, until the sound is as the MD and a couple of other critical "ears" (never mine!) were satisied. Then comes the intricate task of testing the response and gains of the resultant rat's nest so that production specification can be kept within a +or- 2dB window.

I remember well the MD calling the staff together to annonce that a new, radical design would NOT hit its release date because the sound was not, IHO "quite there yet" He said it was 90% there but he wanted to be dead bang sure.

Very often I read such bollocks about amp tone and the snake oil surrounding it. The masses of unsupported "night and day" claims and the impression is given that amps are "thrown in a box" and then the marketing dept' pushes them out to the gullible public? Not MY experience.

Dave.