Rectifiers - Vacuum Tube or Solid State ???

[myles_rose]

On our website is a new paper on rectifiers in the area where the tube reviews are shown.

 

You will learn the differences between various rectifiers, and how you can make your rectifier equipped amp sound differently and play differently.

 

You will discover what happens when you plug a solid state rectfier into the socket normally designed for a vacuum tube rectifier.

 

You will discover the advantages of both types of rectifiers, and how the various tube types differ.

 

The aspects of caution are also covered in this topic.

 

The website link is below as usual.

[Seegs]

Thanks Myles good info.

 

I'll repost my question here, what is your take on substituting Freds for the normal diodes used in SS rectification?

 

Mark Baier from Victoria amps says it is the single best upgrade that you could make for a SS rectified amp, give it more tube like sag? I've had others over at HC dismiss this as nonsense.

 

Seegs

[Sylver]

Originally posted by myles111:

On our website is a new paper on rectifiers in the area where the tube reviews are shown.

 

You will learn the differences between various rectifiers, and how you can make your rectifier equipped amp sound differently and play differently.

 

You will discover what happens when you plug a solid state rectfier into the socket normally designed for a vacuum tube rectifier.

 

You will discover the advantages of both types of rectifiers, and how the various tube types differ.

 

The aspects of caution are also covered in this topic.

 

The website link is below as usual.

Myles ... Great article!

[Chipotle]

Some more great information. I have to weigh in on the tube rectifier for guitar amps. Most of the amps that really sound good (and feel/respond well) to me happen to have the tube. I think I've got NOS RCA 5U4G's in my dual rectifier and noticed a real nice improvement over the Mesa tubes, which, as you observed, are not as good as old stock. It certainly is interesting to be able to switch between the two on one amp. From listening, I wouldn't have guessed the time difference to full voltage between the solid state and tube rectifier was so great.

 

The question concerning the fast recovery diodes is interesting. I'm still confused as to what the benefit is in a tube amp. Myles, does the type of rectifier affect how quickly the voltage level drops back down or is that a function of the filter caps or something else? Your charts show the voltage ramp up, but I wonder if the corresponding way the voltage drops back down has any significant impact on an amp's response.

 

Thanks again for the information.

[myles_rose]

Originally posted by Seegs:

Thanks Myles good info.

 

I'll repost my question here, what is your take on substituting Freds for the normal diodes used in SS rectification?

 

Mark Baier from Victoria amps says it is the single best upgrade that you could make for a SS rectified amp, give it more tube like sag? I've had others over at HC dismiss this as nonsense.

 

Seegs

Seegs....

 

I answered this for you at Harmony Central where you also had this question posted.

 

Hope that's okay. I try to get to my responses and mail oldest first, so I guess you asked the question over there first.

 

Regards,

[myles_rose]

Originally posted by Sylver:

Originally posted by myles111:

On our website is a new paper on rectifiers in the area where the tube reviews are shown.

 

You will learn the differences between various rectifiers, and how you can make your rectifier equipped amp sound differently and play differently.

 

You will discover what happens when you plug a solid state rectfier into the socket normally designed for a vacuum tube rectifier.

 

You will discover the advantages of both types of rectifiers, and how the various tube types differ.

 

The aspects of caution are also covered in this topic.

 

The website link is below as usual.

Myles ... Great article!

Jack,

 

Thank you.

 

Myles

[Chip McDonald]

I posted this once a longgg time ago in Usenet....

 

Wouldn't it be possible to build a feedback circuit design for a tube rectifier that starved the rectifier based on frequency of the input, or rather on a ramped scale of the input?

 

In other word, to exaggerate the sag....

 

?

 

Just a thought...

[strat0124]

Myles, what do you think about those plug in rectifiers, the same ones you can swap out with a tube? Is there that much difference in tone? Or is this just perception? Haven't had my coffee yet....so I'll save tech questions for later.

[myles_rose]

Originally posted by Chipotle:

Some more great information. I have to weigh in on the tube rectifier for guitar amps. Most of the amps that really sound good (and feel/respond well) to me happen to have the tube. I think I've got NOS RCA 5U4G's in my dual rectifier and noticed a real nice improvement over the Mesa tubes, which, as you observed, are not as good as old stock. It certainly is interesting to be able to switch between the two on one amp. From listening, I wouldn't have guessed the time difference to full voltage between the solid state and tube rectifier was so great.

 

The question concerning the fast recovery diodes is interesting. I'm still confused as to what the benefit is in a tube amp. Myles, does the type of rectifier affect how quickly the voltage level drops back down or is that a function of the filter caps or something else? Your charts show the voltage ramp up, but I wonder if the corresponding way the voltage drops back down has any significant impact on an amp's response.

 

Thanks again for the information.

Chipotle,

 

There are a lot of factors in amp feel and response. The power supplies on some amps are barely adequate, and the supplies on others are very over engineered.

 

In the case of fast recovery devices, these might be great in some applications, but do we want them in a guitar amp? For some tastes, maybe, and for others, maybe not.

 

One of the main aspects of a tube rectified power supply is the longer rise time to be able to supply the voltage that is being demanded. This give a built in free compressor in a fashion. We hit the string full on, and the note is there, but the full voltage is still building. As the note is decaying, the voltage is building, and something of a more contant level is achieved.

 

Big capacitors in the power supplies, such as on Marshall amps, keep the voltages more constant too. I have a Marshall JTM-45, whose demands are not as high as the 50 watt Marshalls that came out later, yet its caps are the same value. If I turn the amp power off, and leave the standby switch in the play position, the amp can still be played for a few seconds. Yes, caps are a part of all this too.

 

Reserve capacity for transients in a power supply are also a part of the chain of events.

 

Hope this was of at least some help.

 

Regards

[myles_rose]

Originally posted by Chip McDonald:

I posted this once a longgg time ago in Usenet....

 

Wouldn't it be possible to build a feedback circuit design for a tube rectifier that starved the rectifier based on frequency of the input, or rather on a ramped scale of the input?

 

In other word, to exaggerate the sag....

 

?

 

Just a thought...

Chip McDonald,

 

Why not just use an envelope follower pedal?

 

Same effect, adjustable, cheaper.

 

Regards

[myles_rose]

Originally posted by strat0124:

Myles, what do you think about those plug in rectifiers, the same ones you can swap out with a tube? Is there that much difference in tone? Or is this just perception? Haven't had my coffee yet....so I'll save tech questions for later.

strat0124

 

They are great things. For an amp with a tube rectifier where you want to tighten things up and at times have more power and higher B+ voltages in some cases, this is a nice option.

 

The only issue here is, on older amps, its maybe a good idea to check them out first, as these ss recrifer replacements may put a bit more stress on other components that are not up to what they were when they were new.

 

I have a Marshall amp which is an older one, that came with a tube rectifier. I will plug a ss unit into the socket from time to time to get more of an edge. When I do that, my B+ voltage goes up about 30 volts.

 

Regards

[myles_rose]

bumping for the folks that missed this

[myles_rose]

Originally posted by Chip McDonald:

Originally posted by myles111:

Originally posted by Chip McDonald:

[qb]In other words, to exaggerate the sag....

Chip McDonald,

 

Why not just use an envelope follower pedal?

 

Same effect, adjustable, cheaper.

 

other things, but I'll stop here...

 

Oh well. What's the use.....

Not optimal, but "oh well", I'm going to have to try that soon....

Chip McDonald .....

 

The pickup thing has been done before with individual volume pots for each string, Ampeg made a sliding pickup, and Rick Turner has one that rotates.

 

I guess it hard for me to try to get down to your precise question in a way.

 

I'm still up though, to try to help if I can.

 

Regards

[myles_rose]

Bumping for those that may have missed this.

[Chip McDonald]

Originally posted by myles111:

The pickup thing has been done before with individual volume pots for each string,

I know - that's the reference to the Ripley system. The Ripley pickup was just 6 uniform discrete pickups; what I want is 6 custom-wound discrete pickups designed to complement each string's difference in sound in both volume and tone.

[myles_rose]

Originally posted by Chip McDonald:

Originally posted by myles111:

The pickup thing has been done before with individual volume pots for each string,

I know - that's the reference to the Ripley system. The Ripley pickup was just 6 uniform discrete pickups; what I want is 6 custom-wound discrete pickups designed to complement each string's difference in sound in both volume and tone.

Chip McDonald ...

 

Got it.

 

Would you want to make all the stings sound more the same, or make the differences sound more different?

 

It seems pretty much to me like added complexity. I tend not to even adjust pole pieces after setting the basic pickup height, but that's just me.

 

I tend to try to keep things more simple I guess. I have heard a lot of players whose tone I love, and they use all sorts of things, some of them have pickups that I would not put on any guitar by choice, but when they play, its magic.

 

In any case, good luck on your quest. There are a lot of folks that like your thinking, and that is why the folks at place like Roland make devices where you can simulate doing just what you are after, and why folks in the past have tried doing that for real without the simulation.

 

I'd maybe drop an email to Rick Turner at Turner Guitars. He is probably the sharpest fellow I have ever met in this area, and would probably know this subject from every angle to the "enth" degree. He has also probably done this a lot of times. Maybe that is why he has his rotating pickup, which he has had for decades by now, which really does work too.

 

Regards,

 

Myles

[Chip McDonald]

Originally posted by myles111:

Would you want to make all the stings sound more the same, or make the differences sound more different?

The way I see it is that adjustable pole pieces/pickup height are a primitive way of doing things.

 

There's two aspects as I see it: string volume and string timbre. Complicating that is the overall character one desires, as far as single vs. double coil type sound, but I'm ignoring that for now:

 

So the first aspect would be balancing the output of each string's discrete coil winding-wise. I think that alone would add a great clarity to chordal playing as opposed to just tilting the pickup or adjusting the polepieces.

 

String timbre: here I would say that this can have two philosophical approaches. One would be that of desiring a more "balanced" sound from the wound strings to the high E. The purpose being to make it overall more natural responding across the strings, which would serve the purpose of evening out timbrally what one plays. The downside being "less guitarist". The flipside approach being to exaggerate the differences in order to provide a wider palette.

 

Or a combination between. Optimizing the individual coils by selecting certain magnet material for each string, varying the size, varying the "window" of the bobbin, etc. I'm trying to learn to gear my brain down so I don't spend "unneccessary clock cycles" pursuing what usually amounts to nothing at all, so I suppose this much info alone points towards a different concept.

 

I don't know why no one has pursued this sort of thing before. I mean, I could think of a hypothetical hybrid pickup I might want:

 

High E string: resonant low mid peak to thicken, wide window for a humbuckerish sound. More specifically: BB King/hollow body sound high E - but on a solid body. Probably a big-faced alnico.

 

B string: a little bitier, standard vintage single coil.

 

G string: thinner with a peak in the treble, more Texas-Special but output balanced to be not hotter than the rest...

 

D string: JB-ish humbucker sound.

 

A string: PAF sound, maybe like a Fred in the high end.

 

E string: vintage single coil.

 

.... all output balanced.

 

In other words, I want a thicker sounding high E (no, without changing to a stupid gauge); if I change the tone controls to do that, then I lose bite on the B and G strings. A humbucker sounds nicer on the high E to me, but I like a single coil G's snap. I don't like the way a D string sounds on a single coil, it's never right because of the high/low string eq compromise you have to make tone control wise. The A I like with a humbucking sound, but fairly bright; I like the way the Dimarzio Fred sounds (as well as the pickup in the Wolfgang) for the A because you can get a pseudo-single coil attack out of them, which gives definition on the low side of the guitar..

 

Then you HAVE to have the single coil low E string for Jimi comping, which is a big part of my playing style.

 

SO.....

 

I'm insane.

 

... and at this point I think of an old Python episode: "it's a good thing he didn't ask him about the guitar" (or amp that I want....).

 

But I think the pickup would be doable.

 

I could easily see Duncan or Dimarzio do a "dual string coil" configuration - maybe not 6 discrete coils, but maybe two seperate ones for the wound strings and the unwound, that could still be height adjustable and maybe have optimized magnet material (as well as magnet sizes).

 

Of course, that would also let one do cool combination pickup position wiring tricks: neck pickup treble/unwound strings combined with bridge pickup/wound strings.... etc.

 

Seems simple enough to me.

 

Signed,

Sirius Loon

[myles_rose]

Bumping for new forum folks