"All Tube" - Not Always True

[Big John]

...It was for this reason I went with a custom shop amp based on Fender BF topology.

Most Fender BF amps used a tube rectifier, but not all of them. A rectifier does only one thing; it converts AC to DC. The "sag" characteristic that's usually associated with rect. tubes comes from voltage drop due to increased current demand. The amp loses it's capability to produce low notes; ie. spongy, no headroom. Solid state rectifiers were invented in the 50's, and they maintain a consistant voltage regardless of current. The amp has more power available to amplify the low notes; ie. headroom. Marshall started switching to solid state rectifiers in '67. Two of the most sought after tube amp brands in the world, Trainwreck & Dumble, use s.s. rectifiers.

FWIW, rectifiers aren't in the signal path, so in essense the actual tone of a s.s. rect. amp is still all-tube based. That is, unless the preamp is using diodes for generating distortion (Marshall Jubliee, etc.).

 

[coldsteal2]

Vintage Modern uses a tube rectifier

 

[siore]

djlogan,

Wonderful thing about MLP is the plethora of info you can find, mostly drawn from the wisdom of more experienced members. Check out this thread, for example, on using your controls. Using the tone controls was a revelation for me at that time. (the first post is actually the 2nd one, my post got bumped to 1st due to that 1982 glitch, you guys remember that?)

http://www.mylespaul.com/forums/ton...ike-jimmy-page-use-their-guitar-controls.html

Thank you splat! In summary, it depends on how your guitar is wired. But unlike a strat where a tone control cuts treble, the tone knob on a les paul helps thin out your sound when you don't want it thick and creamy, things like clean passages where you want some clean punch. It pays to explore the tone controls in conjunction with the volume controls. It was just what I needed when rolling off the volume still had some grit.

These days, I like to keep the gain on my amp pegged at a point where it will clean up when I go soft, and snarl when I turn up the attack. That way, I can go cleaner with my tone controls, or get good crunch when I floor them. Also, I can step on an overdrive pedal, and it will take me into heavy music territory or scorchy lead playing. It's all about getting the most dynamics out of the amp, not just a setting that will sound good at one point yet stay at that point no matter how you lessen or increase the attack you give it.

Bah, just read the thread. Lots of useful info there that doesn't deserve getting buried.

 

[LPV]

FWIW, rectifiers aren't in the signal path, so in essense the actual tone of a s.s. rect. amp is still all-tube based. That is, unless the preamp is using diodes for generating distortion (Marshall Jubliee, etc.).

+1. And the jcm900 (and 2000?).

But IMO, an important part of the rock guitar tone of the last 25+ years has been ss rectifiers. Tighter punch. Tube rectifiers aren't better, just different.

 

[hipofutura]

Don't get me wrong guys. I'm not trying to make the case that one is better than the other. They have different tones and each has its place in specific types of music. As I've perused MLP I've seen countless discussions on tone. I know many a guitar player is trying to capture the sound of Clapton (Bell Bottom Blues, "Layla", etc.), and Derek Truks, and Stevie Ray. I am always floored by Stevie Ray's version of Little Wing (There are few people who can do Hendrix better than Hendrix). Those musicians incorporate tube rectification sag into their music.

I started this thread because I was looking at Fender amps thinking they were like the ones I used in the early 70's (BF Bandmaster and Superreverb), only to realize on closer examination they were not. I realize the some of the new "vintage" amps still use tube rectifiers.

It really is a great time to be playing guitar. There have been so many advances in the past 30 years and I feel the equipment is much better for a variety of reasons. There are now so many choices in guitars and amps, not to mention effects pedals. It was pretty slim picking in 1972!

 

[ledfree]

Vintage Modern uses a tube rectifier

Don't forget the RI Bluesbreaker Combo and JTM45 and 1978X Combo and

.... I think you get the picture

 

[LPV]

It really is a great time to be playing guitar. There have been so many advances in the past 30 years and I feel the equipment is much better for a variety of reasons. There are now so many choices in guitars and amps, not to mention effects pedals. It was pretty slim picking in 1972!

Some of the truest words I have read here

 

[KSG_Standard]

Some food for thought...

GuitarNuts.com - Debunking Amplifier Myths

 

[Big John]

...Those musicians incorporate tube rectification sag into their music.

I started this thread because I was looking at Fender amps thinking they were like the ones I used in the early 70's (BF Bandmaster and Superreverb)...

Hendrix's main amp was a Marshall Super 100 (s.s. rectifier).

As for SRV using tube rectifiers with his Fenders, that depends on who you ask. Cesar Diaz, SRV's amp & guitar tech through most of his career, was known to have switched out the tube rectifiers in Vaughn's old Vibroverbs (Twins, too), as well as swapping the output trannys out of the Vibes for Twin Reverb trannys; all in an effort to maintain the low end and boost headroom. In fact on the Fender Custom Shop Vibroverb designed by Diaz, this is why there's a s.s. option. SRV's Marshalls and Dumbles were all s.s. rectified.

You mentioned Bandmasters. The BF Bandmaster used a s.s. rectifier, as well as the blonde and brown Bandmasters. The tweed 3x10 Bandmaster was the only Bandmaster to use a tube rectifier.

OK, I'm done.

 

[Darkburst]

Tube vs SS rectifiers comes down to feel and tone desired. If you want tighter bass response, than SS rectification is the way to go. One isn't better than the other IMO.

 

[Standard 64]

Solid state amps like the spider series sounds good and you can really get into the tones,and say to yourself these are some really good tones,but then you plug into a tube amp and play and you realize those spider tones are not so good any more,or not as good.I can really dig into a line 6 and have fun,but when I plug into a tube amp,forget about it,no comparison.Some people like my neighbor who I jam with cant tell to much of a difference between tube and solid state but he also admits he doesnt have much of a musical ear.

 

[overdriver]

It's true that most amps today use solid state rectifiers but they still have an all tube signal path. The signal never passes through the rectifier. The rectifier converts AC voltages to the DC voltages that tubes use. It's true that they do affect sound due to the fact that they are less efficient than the solid state counterparts.....

Most of the newer guys with SS rect.s also have ss rev. driver. And a bunch of tone sucking junk in a second dirt channel and boost etc..

 

[overdriver]

I've noticed many members and manufacturers referring to amps as "all tube". This is a bit of a misnomer as most of these "all tube" amps are not, as they use solid state rectification. There aren't a whole lot of amps being made that still use tube rectifiers. I fell this distinction is important as the tube rectifier is responsible for the sag that is the distinctive tone from the 60's - 70's amplifiers.

Deciding a few months ago to pick up the guitar after a thirty year break, I began researching what amp to buy. It wasn't until I looked really close at the amp specification (sometimes the schematics) that I realized even many of the "all tube" Fenders used solid state rectifiers. I was quite surprised as tube rectifiers were a huge part of the old Fender sound. It was for this reason I went with a custom shop amp based on Fender BF topology.

Yes you are correct , but all the Fender RI are pretty much All tube,and many clones , custom make etc. Any exceptions are ones like the 63 vibroverbRI. Some of the Brown faced Fender had SS rectifiers. Alot of 70s Fender had SS rect.s Ya you could say that a SS rectifier makes a amp not ALL tube, but, IDK where do ya draw the line.

And the purpose of the 50s dual tube rectifier was to decrease sag.

 

[Belzeebub]

most fender bf amps used a tube rectifier, but not all of them. A rectifier does only one thing; it converts ac to dc. The "sag" characteristic that's usually associated with rect. Tubes comes from voltage drop due to increased current demand. The amp loses it's capability to produce low notes; ie. Spongy, no headroom. Solid state rectifiers were invented in the 50's, and they maintain a consistant voltage regardless of current. The amp has more power available to amplify the low notes; ie. Headroom. Marshall started switching to solid state rectifiers in '67. Two of the most sought after tube amp brands in the world, trainwreck & dumble, use s.s. Rectifiers.

Fwiw, rectifiers aren't in the signal path, so in essense the actual tone of a s.s. Rect. Amp is still all-tube based. That is, unless the preamp is using diodes for generating distortion (marshall jubliee, etc.).

+1

 

[overdriver]

+1

Although thought not to have much effect on tone , they do, but more importantly feel and overall way an amp performs. Much better playing with a tube rect.

 

[BillB1960]

My Dual Rectifier has the option of tube or diode rectification (hence the name)

While your Dual Rec does have the option of using SS or tube rectification it also sports 2 5U4 rectifier tubes which is I'm pretty sure where the name comes from. The Triple Rec has 3 5U4s as well as SS. I don't know what the advantage of having multiple rectifier tubes is but who cares as long as it sounds good

 

[Splattle101]

The rectifier is not actually in the audio path. It’s in the power supply, and it affects tone by the effectiveness with which it delivers power. More precisely, it’s the lack of effectiveness. The sag comes from the time it takes the rectifier to produce the voltage demanded. Valve rectifiers can take around a hundredth of a second (i.e., 10 ms) to produce full voltage. That’s an audible time lag.

Solid state has much smaller sag time. However, the effect can be a harsh. The effect of a diode rectifier is a bit like slamming off the water tap (faucet for those of the American persuasion). It’s the contrast between this harshness and the saggy valve tone that players notice.

The HiFi heads have developed a new kind of rectifier that is SS but it smooths out the harsh edges of a diode rectified supply, without producing the sag of a valve. Who knows, if this technology makes it across to guitar amps it might be just what the speed and metal heads have been waiting for.

But as far as ‘vintage’ tone is concerned, no, I’m afraid this valve recto business is mostly bullshit. Marshall moved to SS rectifiers in the 1960s. Fender did likewise in the 70s. Most of the Brit manufacturers did, too. And in a Class A amp, it doesn’t really matter if you’ve got valve or SS rectification because the bloody thing is already sagged!

I like my two Fender amps, both of which have valve rectifiers (GZ34 in my Bassman, 5U4GB in my Super Reverb). Nice noise. I also liked the sound of my old Marshall JMP, which had SS recto. Is a Plexi not vintage?

 

[BillB1960]

Some food for thought...

GuitarNuts.com - Debunking Amplifier Myths

Excellent info in that article. Thanks!

 

[BillB1960]

My Fender Prosonic has 3 modes: Class A (no recto), Class A/B Tube rec (GZ34) and Class A/B SS rec. I have yet to be able to discern the difference between Tube rec and SS rec but then I very rarely open the amp up to it's full 60 watt+ potential even with an attenuator. Certainly at low volume it makes no difference whether it's on clean or gain channel.

 

[Splattle101]

My Fender Prosonic has 3 modes: Class A (no recto), Class A/B Tube rec (GZ34) and Class A/B SS rec. I have yet to be able to discern the difference between Tube rec and SS rec but then I very rarely open the amp up to it's full 60 watt+ potential even with an attenuator. Certainly at low volume it makes no difference whether it's on clean or gain channel.

That's exactly what you would expect! The valve rectifier will only 'sag' when it is asked to produce so much voltage that the rise time becomes significant and audible. That condition is only met if you push the amp.

This is yet another example of why a lot of the talk about valve amps is just bullshit. If you never get the amp to 50% power, you will never hear:

* rectifier sag;
* power supply distoriton (other than the rectifier: transformer, hash, etc);
* power valve distortion;
* output transformer distortion; or
* speaker distortion.

Each of these forms an important part of the tone of the overdriven amp. You will hear precisely NONE of them until you get the amp close to producing maximum clean power.